40 CFR Part 192, Subpart D EPA 402-D-93-001
Standards for Management of Uranium
Byproduct Materials
TECHNICAL SUPPORT FOR
AMENDING STANDARDS FOR
MANAGEMENT OF URANIUM
BYPRODUCT MATERIALS
DRAFT
BACKGROUND INFORMATION DOCUMENT
Prepared for
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Radiation and Indoor Air
401 M Street, S.W.
Washington, D.C. 20460
May 1993
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DISCLAIMER
Mention of any specific product or trade name in this report
does not imply an endorsement or guarantee on the part of the
Environmental Protection Agency.
LIST OF PREPARERS
Various staff members from EPA's Office of Radiation and
Indoor Air contributed to the development and preparation of the
Background Information Document (BID).
Albert Colli Chief, Air Standards and Reviewer
Economics Branch
Byron Hunger Economist Writer/Reviewer
Fran Jonesi Chief, NESHAPs Section Reviewer
Gale Bonanno Attorney Advisor Reviewer
An EPA contractor, S. Cohen & Associates, Inc. in McLean,
Va, provided significant technical support in preparation of the
BID.
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PREFACE
The Environmental Protection Agency (EPA) is proposing to
amend 40 CFR 192, Subpart D, dealing with disposal of uranium
mill tailings at nonoperational sites licensed by the Nuclear
Regulatory Commission (NRC) or an Agreement State pursuant to the
Uranium Mill Tailings Radiation Control Act (UMTRCA) of 1978 (42
U.S.C. 2022, 7901-7942).
This Background Information Document (BID) has been prepared
in support of the rulemaking proceedings for EPA's action. This
BID only considers long-term disposal of tailings at facilities
licensed by the NRC or an Agreement State, and designated as
Title II facilities in the UMTRCA. Currently, the tailings at
these facilities are subject to the disposal and long-term
stabilization regulations developed under the UMTRCA by the EPA
and the NRC and set forth in 40 CFR 192, Subpart D. In addition,
the standards at 40 CFR Part 61, Subpart T (National Emission
Standard for Hazardous Air Pollutants) which would otherwise
apply to these sites, are currently stayed until EPA takes final
action on its proposal to rescind Subpart T or until June 30,
1994, whichever occurs first.
Copies of this BID, in whole or in part, are available to
all interested persons. An announcement of the availability
appears in the Federal Register. For additional information,
contact Eleanor Thornton at (202) 233-9773 or write to:
Director, Criteria & Standards Division
Office of Radiation and Indoor Air (6602J)
Environmental Protection Agency
401 M Street, SW
Washington, DC 20460
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TABLE OF CONTENTS
Disclaimer ii
List of Preparers ii
Preface iii
List of Figures , viii
List of Tables ......... v
CHAPTER 1 BACKGROUND INFORMATION 1-1
1.1 STATEMENT OF PURPOSE 1-1
1.2 REGULATION OF URANIUM MILL TAILINGS 1-3
1.3 THE 1989 CAA NESHAP STANDARDS AND THE
CLEAN AIR ACT AMENDMENTS OF 1990 1-8
CHAPTER 2 INDUSTRY PROFILE .......... 2-1
2.1 DEMAND AND USES 2-1
2.2 SUPPLY 2-7
2.3 INDUSTRY STRUCTURE AND PERFORMANCE 2-12
2.4 ECONOMIC AND FINANCIAL CHARACTERISTICS .... 2-14
2.5 INDUSTRY FORECAST AND OUTLOOK 2-15
2.6 EVALUATION OF FORECASTS AND URANIUM
MARKET DEMAND ..... 2-17
CHAPTER 3 BACKGROUND INFORMATION FOR LICENSED NON-
OPERATING URANIUM MILL TAILINGS IMPOUNDMENTS. . 3-1
3.1 OVERVIEW 3-1
3.2 FACILITY-SPECIFIC CHARACTERISTICS 3-3
CHAPTER 4 RADON-222 SOURCES, ENVIRONMENTAL TRANSPORT,
and RISK COEFFICIENTS ............. 4-1
4.1 MILL TAILINGS: ENVIRONMENTAL SOURCE TERMS
FOR RADON-222 4-1
4.2 RADON-222 EXPOSURE PATHWAYS AND RISK TO
HUMAN HEALTH 4-10
CHAPTER 5 70-YEAR RADON EMISSION FROM NON-OPERATIONAL
TAILINGS IMPOUNDMENTS AND HEALTH RISKS TO
NEARBY POPULATIONS ..... 5-1
5.1 THE 70-YEAR ASSESSMENT PERIOD 5-1
5.2 PROTOCOL FOR ESTIMATING RADON EMISSIONS .... 5-4
5.3 RADON EMISSIONS FROM NON-OPERATIONAL
TAILINGS IMPOUNDMENTS 5-10
5.4 POPULATION EXPOSURES AND HEALTH RISKS 5-14
5.5 MEASURED RADON EMISSION LEVELS 5-17
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TABLE OF CONTENTS (Continued)
CHAPTER 6 RADON-222 CONTROL TECHNIQUES 6-1
6.1 INTERIM RADON CONTROL TECHNIQUES 6-1
6.2 DEWATERING OF TAILINGS PILES IN PREPARATION
FOR PERMANENT COVER 6-2
6.3 LONG-TERM RADON CONTROL TECHNIQUES 6-3
6.4 COMPARISON OF EARTH COVERS TO OTHER
CONTROL TECHNIQUES , 6-6
CHAPTER 7 COSTS AND BENEFITS 7-1
7.1 THE COSTS AND BENEFITS OF RADON COVER IN
PERSPECTIVE 7-1
7.2 COSTS OF COVERING THE PILES . 7-2
7.3 COST OF VERIFYING RADON EMISSIONS . 7-4
7.4 COST SAVINGS DUE TO POSTPONING THE TIME
OF COVER 7-6
7.5 COST SAVINGS AND RISK INCREASES COMPARED. ... 7-6
7.6 FINANCIAL BURDEN ON INDUSTRY 7-7
7.7 REGULATORY FLEXIBILITY ANALYSIS . 7-8
APPENDIX A. CAP88-PC INFORMATION SHEETS .... A-l
APPENDIX B. SYNOPSIS REPORT FOR LUCKY McMILL ....... B-l
REFERENCES R-l
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LIST OF TABLES
CHAPTER 2;
2-1 STATUS OF U.S. NUCLEAR PLANTS AS OF
DECEMBER 31, 1990 2-3
2-2 COMMITMENTS FOR DELIVERY OF URANIUM FROM
DOMESTIC SUPPLIERS . 2-4
2-3 ORIGIN OF URANIUM COMMITTED FOR DELIVERY ... 2-5
2-4 EXPORTS OF URANIUM BY UTILITIES AND
DOMESTIC SUPPLIERS . 2-6
2-5 PRODUCTION OF URANIUM CONCENTRATE BY
CONVENTIONAL MILLS AND OTHER SOURCES 2-8
2-6 URANIUM MILL CAPACITY 2-9
2-7 IMPORTS OF URANIUM FOR COMMERCIAL USES .... 2-10
2-8 U.S. COMMERCIALLY-OWNED URANIUM INVENTORIES . . 2-12
2-9 CAPITAL EXPENDITURES, EMPLOYMENT, AND
ACTIVE MILLS 2-13
2-10 COMPARISON OF URANIUM PROJECTIONS 2-17
2-11 EMPLOYMENT IN THE U.S. URANIUM INDUSTRY
UNDER CURRENT MARKET CONDITIONS ... 2-18
2-12 PROJECTED U.S. NUCLEAR POWER CAPACITY AND
URANIUM REQUIREMENTS ........ 2-20
2-13 U.S. REASONABLY ASSURED RESOURCES . 2-22
CHAPTER 3;
3-1 1992 STATUS OF NON-OPERATIONAL TAILINGS
IMPOUNDMENTS 3-2
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LIST OF TABLES (Continued)
CHAPTER 4;
4-1 RADON-222 DECAY PRODUCT EQUILIBRIUM
FRACTION 4-9
4-2 FAST RISK ESTIMATES FOR EXPOSURE TO
RADON PROGENY 4-15
4-3 BEIR IV RISK MODEL - LIFETIME EXPOSURE AND
LIFETIME RISK .......... 4-20
4-4 ESTIMATED LUNG CANCER RISK FROM RADON
PROGENY EXPOSURE FOR THREE MINER COHORTS . . . 4-20
4-5 LIFETIME RISKS FROM RADON DAUGHTER EXPOSURE
OF LUNG CANCER DEATH 4-24
4-6 LIFETIME RISK FROM EXCESS RADON DAUGHTER
EXPOSURE 4-26
4-7 SUMMARY OF K FACTORS FOR BRONCHIAL DOSE .... 4-28
CHAPTER 5;
5-1 ASSESSMENT PERIOD FOR NON-OPERATIONAL
TAILINGS IMPOUNDMENTS , 5-3
5-2 1992 STATUS OF NON-OPERATIONAL TAILINGS
IMPOUNDMENTS 5-5
5-3 COEFFICIENT b VALUES FOR SELECT SOIL TYPES
AND MOISTURE CONTENT 5-6
5-4 SUMMARY OF EMISSIONS FOR THE PATHFINDER-
LUCKY MC FACILITY 5-10
5-5 RADON EMISSIONS FOR NON-OPERATIONAL
IMPOUNDMENTS 5-11
5-6 RADON-222 EXPOSURES AND ASSOCIATED RISKS
FOR MOU DISPOSAL SCHEDULE 5-16
5-7 RADON-222 EXPOSURES AND ASSOCIATED RISKS
FOR BASELINE EMISSIONS 5-18
Vll
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LIST OF TABLES (Continued)
CHAPTER 7:
7-1 FACILITY-SPECIFIC RELEASE RATES, COVER DEPTHS,
AND AREAS 7-3
7-2 COSTS OF ACHIEVING THE REGULATORY EMISSION
STANDARDS 7-5
7-3 PRESENT VALUE COSTS TO COVER BY MOU TARGET
DATES 7-6
va.ii
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LIST OF FIGURES
CHAPTER 4:
4-1 URANIUM-238 DECAY CHAIN AND HALF-LIVES OF
PRINCIPAL RADIONUCLIDES . 4-2
4-2 RADON EMANATION PROCESS ............ 4-3
4-3 EFFECT OF PILE DEPTH ON HYPERBOLIC TANGENT
TERM IN RADON-222 FLUX EQUATION 4-5
CHAPTER 5:
5-1 CHANGES IN RADON-222 PENETRATION WITH EARTH
COVER THICKNESS . . 5-7
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Page Intentionally Blank
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CHAPTER 1
BACKGROUND INFORMATION
1.1 STATEMENT OF PURPOSE
Uranium mill tailings refer to the wastes that result from the
processing of ores to recover uranium. Since commercially-
processed uranium ores in the United States typically contain 0.05
to 0.2 percent uranium, virtually the entire ore throughput of
milling becomes tailings waste. Historically, uranium mill tail-
ings have been stored in large surface impoundments, or piles, in
quantities ranging from less than one million tons to over 30
million tons. These impoundments cover areas from seven to over
three hundred acres.
Tailings emit radon gas, a radioactive decay product of
uranium. Since tailings impoundments often have large unprotected
surface areas, the exposure to radon-222 is a health concern.
Under the authority of the Uranium Mill Tailings Radiation Control
Act (UMTRCA) and the Clean Air Act (CAA), the U.S. Environmental
Protection Agency (EPA), the Department of Energy (DOE), and the
Nuclear Regulatory Commission (NRC) have devised and implemented
controls to limit risks from the milling of uranium ores during
both the active period of operations and the closure/disposal
phase, when active milling of ore has ceased.
This Background Information Document (BID) only considers
long-term disposal of tailings at facilities licensed by the NRC or
an Agreement State, and designated as Title II facilities in the
UMTRCA. Currently, the tailings at these facilities are subject to
the disposal and long-term stabilization regulations developed
under the UMTRCA by the EPA and the NRC and set forth in 40 CFR
192, Subpart D.
As discussed in the sections that follow, the EPA initially
promulgated regulations in 1983 under the UMTRCA that established
generally applicable environmental standards for both radiological
and non-radiological contaminants. The NRC subsequently developed
specific licensing and design criteria to implement the EPA's
standards for Title II sites. In 1989, under the authority of the
CAA, the EPA promulgated National Emission Standards for Hazardous
Air Pollutants (NESHAPs), 40 CFR 61, Subpart T, which address only
the emission of radon-222 from the disposal of tailings. Subpart T
requires that a radon barrier capable of limiting emissions to an
average of 20 pCi/m2-s be installed within two years of the promul-
gation date of the NESHAPs or two years from cessation of opera-
tions, which ever is later. Subpart T also requires that a one-
time emission test be performed to assure that the design objective
of 20 pci/m2-s for the radon barrier has been achieved. In promul-
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gating Subpart T, the EPA found that the regulations established
under UMTRCA did not set specific deadlines for disposal; therefore
a NESHAPs was required to achieve radon-222 emissions at levels
consistent with protection of the public's health with an ample
margin of safety.
In its review of the EPA's Subpart T NESHAPs, the NRG ex-
pressed concerns regarding the duplication of the UMTRCA require-
ments. In response to the concerns regarding duplication, Congress
amended the CAA prior to its reauthorization in 1990. This amend-
ment gives the EPA the authority to amend the CAA to avoid duplica-
tive regulation while still protecting public health with an ample
margin of safety. Under the authority of this amendment, and after
consultations with the NRC and affected Agreement States, the
Administrator has undertaken the following actions:
» Stayed the NESHAPs (40 CFR 61, Subpart T) as it applies
to the Title II uranium mill tailings (NRC- or Agreement
State-licensed) until the date on which the rulemakings
discussed below have been completed (or June 30, 1994,
whichever occurs first)
• Proposed to rescind 40 CFR 61 Subpart T as it applies
to Title II facilities
• Published an Advanced Notice of Proposed Rulemaking to
amend its UMTRCA regulations (40 CFR 192, Subpart D) to
require emplacement of radon control barriers at cur-
rently non-operational impoundments by specified dates
and at operational impoundment within seven years of
cessation of operations, and to require one-time test-
ing of the radon barriers to assure that the design
flux has been attained.
This Background Information Document provides information in
support of these rulemakings. This chapter provides a historical
summary of mill tailings regulations under the UMTRCA and CAA,
details of the possible rescission of 40 CFR 61, Subpart Tf and
the amendment of 40 CFR 192, Subpart D. Chapter 2 of this BID
provides a profile of the uranium milling industry and an assess-
ment of its economic status. Past operational information and
the current status of the non-operational impoundments are
presented in Chapter 3. Radon sources, environmental transport,
and risk coefficients are developed in Chapter 4. Chapter 5
summarizes the exposures and health risks to nearby populations
from non-operational tailings impoundments. Chapters 6 and 7
discuss radon control techniques and provide cost estimates for
the emplacement of an earthen cover that will reduce radon emis-
sions to regulatory standards.
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1.2 REGULATION OF URANIUH MILL TAILINGS
1.2,1 UMTRCA Authorities
The Atomic Energy Act of 1954 gave the Atomic Energy Commis-
sion (AEC) authority to license and regulate source material
(uranium and thorium) processed at uranium mills. However, once
a mill stopped operating, the AEC had no authority to regulate
the tailings piles that remained. One result was that some
tailings were used in the 1960s as fill around foundations of
houses, causing high indoor radon concentrations. The 1976
Resource Conservation and Recovery Act (RCRA) gave EPA the
authority to place controls on mill tailings, if EPA considered
them hazardous. However, in 1978 Congress passed UMTRCA (P.L.
95-604, 42 USC 2022, 7901-7942), which gave the EPA the authority
to regulate mill tailings for the purpose of protecting the
public from radon and other exposure pathways.
UMTRCA set up two programs to protect public health and the
environment from mill tailings hazards. Both programs required
EPA to set standards for disposal of tailings; the other agencies
involved were required to implement those standards. The "Title
I" program directed the Department of Energy (DOE) to remediate
the tailings at inactive (generally abandoned) uranium mill sites
that did not have an effective AEC or NRC license as of January
1, 1978. The "Title II" program was for "active" sites licensed
by the NRC or an Agreement State. EPA standards for these sites
were to cover final disposal of the tailings, including radon
control after the mill closed, and to be consistent with stan-
dards for wastes promulgated under the RCRA. UMTRCA directed EPA
to set standards for Title I sites within one year and standards
for Title II sites within 18 months of enactment.
1.2.2 EPA's UMTRCA Rulemakings
On April 22, 1980, EPA proposed cleanup standards for Title
I sites, covering open lands and buildings contaminated with
residual radioactive materials from uranium processing (to be
codified in 40 CFR 192, Subpart A). These were made immediately
effective as interim standards pending public review and promul-
gation of final standards (45 FR 27370 and 27366). On January 9,
1981, EPA proposed disposal standards for Title I sites (46 FR
2556), and on January 5, 1983, EPA promulgated final rules for
the disposal and cleanup of the Title I sites (48 FR 605).
About this time Congress amended UMTRCA. PL 97-415, passed
in January 1983, included a provision that would strip EPA of its
standard-setting authority if EPA did not set standards for Title
II sites by September 30 of that year. In response, EPA proposed
general environmental standards for Title II uranium and thorium
mill tailings sites on April 29, 1983 (48 FR 19584) and promul-
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gated final rules on September 30 (48 FR 45926, codified in 40
CFR 192, Subparts D and E).
Both the UMTRCA Title I and Title II standards were chal-
lenged in the Tenth Circuit Court of Appeals by several parties
in thirteen separate suits filed in 1983 and 1984 (56 FR 67570
lists the case numbers of these suits). In September of 1985,
the court upheld all provisions of the standards, as promulgated,
except those dealing with groundwater protection at Title I
sites. The court directed EPA to promulgate groundwater stan-
dards for Title I sites similar to those for Title II sites. EPA
proposed new ground water regulations to replace those set aside
on September 24, 1987 (52 FR 36000). Promulgation of the final
standards is awaiting the Office of Management and Budget's
review. Groundwater protection standards are not the focus of
these proposed rulemakings.
For Title II sites, the EPA's UMTRCA standards require, in
part, that management of byproduct materials (tailings) during
operations and prior to the end of the closure period be consis-
tent with the standards set forth in 40 CFR 190. However, 40 CFR
190 does not address the doses caused by radon and its decay
products, nor does it establish a numerical limit for radon
emissions from the tailings piles. Instead, it requires that
radon emissions be kept as far below Federal Radiation Protection
Guides as is practicable.
EPA's UMTRCA standards established a limit on radon emis-
sions from the tailings piles that have been closed, requiring
that they not exceed an average of 20 pCi/m2-s, and that the
radon barrier be effective for 1000 years.
1.2.3 NRC * s UMTRCA Rulemakings
UMTRCA placed requirements on NRC as well as on EPA. To
prevent existing uranium milling operations licensed by NRC as
well as by Agreement States from violating the Atomic Energy Act
as amended by UMTRCA, NRC proposed rules relating to uranium mill
tailings and construction of major plants on August 24, 1979 (44
FR 50015). On the same date, NRC also promulgated final regula-
tions (with request for public comments) for uranium mill tail-
ings licensing (44 FR 50012). On October 3, 1980, NRC promulgat-
ed final rules that specified licensing requirements for uranium
and thorium milling (45 FR 65521).
The January 1983 Congressional amendments to UMTRCA that
required EPA to issue regulations for Title II sites, in turn,
caused the NRC to suspend, on May 26, 1983, portions of their ru-
les (48 FR 23649). NRC licensees could have incurred significant
costs to implement the NRC standards, had the NRC not modified
its standards to conform with those issued by EPA, as UMTRCA
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required. On November 26, 1984, NRG proposed rules that would
conform its requirements to EPA's standards (49 FR 46418}. Since
these proposed rules excluded EPA groundwater protection stan-
dards, the NRC also issued, on the same date, a notice of pro-
posed rulemaking to incorporate the groundwater and other provi-
sions of EPA's 40 CFR 192, Subpart D standards into NRC standards
(49 FR 46425). In various other actions in 1985, 1986, and 1987,
NRC proposed and promulgated rules that incorporated all EPA
standards for UMTRCA Title II mill tailings sites (50 FR 41852,
51 FR 24679, and 52 FR 43562). Thus, by November of 1987, the
NRC's standards under UMTRCA were fully compatible with those
promulgated by the EPA.
1.2.4 CleanAir Act Rulemakinqs
When Congress amended the Clean Air Act in 1977, it specifi-
cally addressed emissions of radioactive materials. Before that
time, emissions of radionuclides either were regulated under the
Atomic Energy Act or were not regulated at all. Section 112 of
the Clean Air Act required the EPA Administrator to determine,
after public notice and opportunity for public hearings (44 FR
21704, April 11, 1979), whether emissions of radionuclides cause
or contribute to air pollution that may reasonably be expected to
endanger public health. In December of 1979, the EPA published a
notice in the Federal Register listing radionuclides as hazardous
air pollutants under Section 112 of the Clean Air Act (44 FR
76738, December 27, 1979). This determination was supported by a
technical report issued by the EPA detailing emission levels,
applicable effluent controls, and the radiological impacts caused
by airborne radioactive effluents released by various source
categories of facilities (1PA79).
In June of 1981, the Sierra Club filed a suit alleging that
the Clean Air Act required the EPA to propose standards for
radionuclides within 180 days of listing them as hazardous
pollutants under Section 112. The court agreed with the Sierra
Club and in September of 1982 ordered the EPA to publish proposed
emissions standards for radionuclides, with notice of public
hearing within 180 days of that order.
In April of 1983, the EPA proposed radionuclides emission
standards for four source categories: DOE facilities; NRC-
licensed and non-DOE Federal facilities; underground uranium
mines; and elemental phosphorus plants. The Agency also deter-
mined that emissions from several other source categories did not
require regulations: coal-fired boilers; the phosphate industry;
other mineral extraction industries; uranium fuel cycle facili-
ties; uranium mill tailings; high-level radioactive waste facili-
ties; and low energy accelerators (48 FR 15077, April 6, 1983).
The Agency prepared a draft background information document in
support of these decisions (EPA83).
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After several extended comment periods and two public
hearings, the Sierra Club again filed suit in February of 1984 to
compel the EPA either to make the standards final or to determine
that radionuclides are not hazardous air pollutants and "delist"
them. In August of that year, the court ordered the Agency to
take final action by October 23, 1984. In response to that
order, the EPA withdrew the proposed standards for elemental
phosphorus plants, DOE facilities, and NRG licensees, finding the
control practices used for these source categories already
protective of public health. The proposed standard for under-
ground uranium mines was also withdrawn, but with the intent to
set a different standard. The Agency also announced its inten-
tion to regulate radon-222 emissions from licensed uranium mills
and reaffirmed its decision not to regulate emissions from
coal-fired boilers, the phosphate industry, other extraction
industries, uranium fuel cycle facilities, and high-level radio-
active waste. Phosphogypsum stacks would be studied to determine
whether a standard was needed.
In December 1984, the court ordered the EPA either to issue
final standards for the original four source categories or delist
radionuclides. The Agency then promulgated NESHAPs for elemental
phosphorus plants, DOE facilities, and NRC-licensed facilities
(50 FR 7280, February 6, 1985). Two other NESHAPs established
work practice standards to control radon emissions from under-
ground uranium mines (50 FR 15385, April 17, 1985) and licensed
uranium mill tailings (51 FR 34056, September 24, 1986). These
standards were again cliallenged in court.
While these suits were being adjudicated, the U.S. Court of
Appeals for the D.C. Circuit found that the EPA's NESHAPs for
vinyl chloride was defective because the Agency had considered
costs and technological feasibility without first making a
determination based only on health risk. The court proposed a
two-step process as one means for the Administrator to establish
NESHAPs that met the Congressional intent of safe with an ample
margin of safety. As a first step, a level that would be deemed
acceptable is established based solely on consideration of the
health risks imposed by that level. Once an acceptable level of
emissions is determined, the ample margin of safety is addressed
by evaluating all relevant factors including technical feasibili-
ty of controls, cost of controls, etc.
The court also ordered the EPA to examine the effect of the
vinyl chloride decision on other standards. Concluding that
costs had been considered in many of the radionuclide rule-
makings, the Agency asked the court to let those NESHAPs remain
in place while it reconsidered them and all other issues raised
in the lawsuits.
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In early December 1987, the court accepted the EPA's propos-
al to reconsider all the NESHAPs using this two-step approach and
established a time schedule requiring the Agency to propose
decisions for all radionuclide source categories within 180 days
and make final decisions within 360 days. This schedule was
later modified to require proposed regulatory decisions by
February 28, 1989, and final action by August 31, 1989.
On March 7, 1989, the EPA published proposed NESHAPs that
described four possible policy approaches for regulating emis-
sions of radionuclides (54 FR 9612). Public hearings were held
in April. On July 14, 1989, the court extended the deadline for
final action until October 31, 1989. The NESHAPs were made final
on that date and most, including Subpart T, became effective on
December 15, 1989, when they were published in the Federal
Register (54 FR 51654).
In establishing the final radionuclide NESHAPs for each
source category, the EPA adopted three risk criteria as central
to the determination of acceptable levels of emissions and in its
determination of the ample margin of safety:
• Maximum Individual Risk (MIR) - the maximum additional
risk of any individual member of the public contracting
fatal cancer from exposure to radioactive materials
released to the air from any facility that is part of
the source category. In evaluating the MIR, the EPA
calculates a 70-year lifetime risk to an individual
assuming that the level of emissions is constant
throughout the persons entire life. The EPA considers
that a risk to the maximum exposed individual of ap-
proximately one in ten thousand (1E-4) is presumptively
acceptable.
• Risk Distribution - an estimate of how many persons
exposed to the airborne effluents from the facilities
that comprise a given source category are at a given
level of individual risk. In evaluating the risk
distribution, the EPA assesses the doses to all indi-
viduals within 80 kilometers of any facility in the
source category. The Agency's goal is to assure that
as many persons as possible are at a lifetime risk of
less than one in one million (1E-6).
• Incidence - an estimate of the health impact on the
entire population within a given area from exposure to
a facility's emissions. The EPA considers no more than
approximately 1 fatal cancer per year caused by all
facilities in the source category to be acceptable.
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These criteria are not absolute, but serve as guidelines
that the EPA considers along with other factors which may be
unique to each source category.
In establishing the NESHAPs for disposal of uranium mill
tailings (40 CFR 61, Subpart T), the Administrator found that
emissions of radon-222 which meet the UMTRCA design criteria of
20 pCi/m2-s averaged over the entire disposal area represent a
level that is safe with an ample margin of safety. By promulgat-
ing the NESHAPs, the Administrator assured that final disposal
would be achieved as expeditiously as possible and the monitoring
of emissions would be made prior to final stabilization to assure
that the design objective of 20 pCi/m2-s was indeed achieved by
the radon barrier.
1.3 THE 1989 CAA NESHAP STANDARDS AND THE CLEAN AIR ACT
AMENDMENTS OF 1990
On December 15, 1989, the Environmental Protection Agency
(EPA) promulgated National Emission Standards for Hazardous Air
Pollutants (NESHAPs) under Section 112 of the Clean Air Act
(CAA). These standards regulated radionuclide emissions to the
ambient air from several source categories, inclusive of non-
operational uranium mill tailings sites. These sites are also
regulated under the Uranium Mill Tailings Radiation Control Act
(UMTRCA). The UMTRCA separated these sites into (1) inactive and
abandoned sites controlled by the DOE (Title I sites) and (2)
tailings sites licensed and regulated by the Nuclear Regulatory
Commission (NRC) or an Agreement State (Title II sites).
The NESHAPs for licensed, but non-operational uranium mill
tailings sites, Subpart T of 40 CFR 61, specifies that once a
uranium mill tailings pile or impoundment ceases to be operation-
al, it must be disposed of and brought into compliance with the
radon emission standard (not greater than 20 pCi/m2-s) within two
years. For impoundments that were non-operational at the time of
rulemaking, this meant emplacement of an earthen cover had to be
completed by December 15, 1991 to meet the standard. In addition
to specifying a time for closure and emission limits, Subpart T
also requires specific monitoring and record keeping.
The UMTRCA regulations, as implemented by the NRC, specify a
design flux that must be met for 1000 years. This flux is
identical to the emission standard in Subpart T, but UMTRCA cur-
rently establishes no time limits for disposal of the piles. The
UMTRCA standards also do not require monitoring to confirm that
the design flux limits have been achieved.
Although the NESHAPs and UMTRCA complement each other, they
create dual regulatory oversight, including independent procedur-
al requirements seeking to ensure compliance with the common 20
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pCi/m2-s flux standard. Concern over the duplication and compli-
cation created by the two regulations resulted in petitions by
the NRC and the American Mining Congress, which urged the EPA to
reconsider its position.
Congress, in response to its own concerns over the dual
authority established by the UMTRCA and CAA regulations, substan-
tially amended the CAA in 1990. As part of that enactment,
section 112(d)(9) was added to the statute. It states the
following:
"No standard for radionuclide emissions from any cate-
gory or subcategory of facilities licensed by the
Nuclear Regulatory Commission (or an Agreement State)
is required to be promulgated under this section if the
Administrator determines, by rule, and after consulta-
tion with the Nuclear Regulatory Commission, that the
regulatory program established by the Nuclear Regulato-
ry Commission pursuant to the Atomic Energy Act for
such category or subcategory provides an ample margin
of safety to protect the public health."
This provision strives to eliminate duplicative regulations
by the EPA and the NRC and preserve governmental resources.
Moreover, Congress expressed sensitivity to the special
compliance problems of uranium mill tailings sites through new
section 112(i)(3). This section provides an additional three-
year extension to mining waste operations (e.g., uranium mill
tailings) if the four years allowed (including a one-year exten-
sion) for compliance with standards promulgated under the amended
section 112 is insufficient to dry and cover the mining waste.
The result is that the EPA, NRC, and affected Agreement
States have consulted and drafted a Memorandum of Understanding
(MOU). The primary purpose of the MOU is to ensure that the
nineteen non-operational uranium mill tailings piles licensed by
the NRC or the affected Agreement States achieve compliance
through an effective installation of an earthen cover that limits
radon emissions to the 20 pci/m2-s flux standard as defined in 40
CFR 192.32(b)(1). A second objective of the MOU was to ensure
that compliance proceeds as expeditiously as practicable consid-
ering technological feasibility. Target dates for the nineteen
non-operational uranium mill tailings piles were established for
meeting the radon emission standard; the target dates are based
on a guiding objective that disposal occur by the end of 1997 or
within seven years of when the existing operating and standby
sites enter disposal status.
1-9
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Page Intentionally Blank
-------
CHAPTER 2
INDUSTRY PROFILE
The U.S. uranium milling industry is an integral part of a
domestic uranium production industry that includes companies
engaged in uranium exploration, mining, milling, and downstream
activities leading to the production of fuel for nuclear power
plants. The product of uranium milling is uranium concentrate,
also referred to as uranium oxide, yellowcake, or U3O8.
2.1 DEMAND AND USES
Domestic producers of uranium concentrate have two markets:
the U.S. nuclear power industry and exports. The nuclear power
industry is by far the more important of the two. Military uses,
once the only source of demand for uranium, have been supplied
solely by government stockpiles since 1970 (DOE87a).
Demand for domestically produced uranium reached its highest
level in 1979 when utilities delivered 30.9 million pounds of U3O8
to DOE for enrichment, but has fallen since then. By 1990 less
than 15 million pounds of domestic U3O8 were sent to DOE for enrich-
ment. Domestic production reached its highest level in 1980 and
has steadily declined since then. Exports also have declined
substantially. Exports of uranium by domestic suppliers in 1990
totaled 2.0 million pounds, slightly less than the 2.1 million
pounds in 1989 and less than one-third of total exports in 1978,
the year of highest exports (DOE91b).
A number of negative forces have combined to cause the current
depressed state of the industry. The boom of the 1970's along with
high expectations for the 1980's, encouraged large scale domestic
and foreign exploration. The discovery of low cost foreign re-
serves, coupled with relaxed restrictions on imports effectively
priced the domestic sources out of the market. Expectations are
that a growing portion of utility requirements will be supplied by
foreign-origin uranium during the second half of this decade.
Further exacerbating the downturn in domestic production is the
slow growth in overall demand for electrical power and the slower
than anticipated expansion of nuclear energy as power source for
generating electricity. Growth also has been hindered by delays in
completing construction of new plants and by the cancellation of
projected construction (DOE91a).
Also contributing to the depressed state in the domestic
uranium industry are the large inventories of yellowcake, enriched
uranium and fabricated fuel being held by both producers and
utilities. These inventories accumulated because utilities,
anticipating a growing need for uranium a decade or more ago,
entered into long-term contracts to purchase large amounts of
2-1
-------
domestically produced uranium. As actual needs fell short of
expected needs due to nuclear power plant construction delays and
cancellations, large inventories accumulated. These inventory
supplies were once estimated to cover four to five years of utility
requirements, and they adversely affected suppliers in two ways:
Primarily, they served to extend the downturn in uranium demand for
a number of years by decreasing the need for utilities to enter
into new contracts. In addition, high interest rates increased
inventory holding costs, leading some utilities to contribute to
current excess supply by offering inventory stocks for sale on the
spot market (EPA86). By 1990, utilities had reduced their inven-
tories to three years of forward coverage (DOE91a).
Provided below is a brief description of the historical uses
and demand for uranium in the United States.
2.1.1 Military Applications
In the early 1950's, the U.S. government's need for uranium
for defense uses far exceeded the world's production capability. A
Federally funded production incentives program was then instituted.
The incentives program was so effective that the government phased
it out in the 1960's and terminated its purchase program in 1970.
The government still has sufficient stockpiles to meet military
requirements well into the future.
2.1.2 Nuclear Power Plants
Since 1971, utilities, which use uranium as fuel for nuclear
power plants, have been virtually the only source of demand for
current uranium production. Commercial generation of nuclear
powered electricity began in 1957 with the operation of the first
central station reactor at Shippingport, Pennsylvania. By the end
of 1990, 111 nuclear reactors were licensed to operate in the
United States, with 99.6 gigawatts of net generating capacity
(DOE91c).
Demand for uranium by utilities may be directly linked to the
fuel requirements of currently operating or planned nuclear power
plants. The status of U.S. nuclear power plants as of December 31,
1990 is shown in Table 2-1. Because of the long lead times associ-
ated with the ordering, construction and permitting of nuclear
power plants, it is extremely unlikely that any additional orders
for new nuclear plants will result in operable capacity before 1998
(DOE87c). Historical consumption data for utilities are not
available. However, information on contract commitments between
suppliers and utilities, which constitutes a share of total utility
uranium consumption, is available. Commitments for deliveries from
1990 to 2000 are listed in Table 2-2. In 1990, utilities signed 49
uranium procurement contracts with domestic suppliers equal to 27
million pounds of uranium. Thirty-eight contracts were based on
spot-market purchases and 11 were long-term contracts. Although
2-2
-------
these contracts are with domestic suppliers, not all of the uranium
delivered will be domestic in origin. Domestic suppliers import a
significant share of uranium which they deliver to utilities. The
origin of committed uranium for the years 1990 through 2000 are
given in Table 2-3. In 1990, domestic suppliers delivered a total
of 20.5 million pounds of uranium to utilities, 30 percent of these
deliveries were foreign in origin. Utilities and suppliers ac-
counted for roughly equal shares of 1990 imports. The quantity of
deliveries from domestic suppliers is projected to decline markedly
between now and 2000. By the end of 1990, market commitments for
delivery in 1991 and beyond from domestic suppliers totaled 87.9
million pounds. Just more than 50 percent of that uranium has been
specified as being of domestic origin (DOE91b). Over the same
period, commitments from foreign suppliers for the same period
totaled 137.3 million pounds. For years beyond 1990, the data show
that utility commitments account for 84% of the total quantity
under contract as of December 31, 1990.
Table 2-1. Status of U.S. Nuclear Power Plants as of December 31, 1990
Net Summer
Status Number of Reactors Capability (GWe)
Operable*
In Commercial Operation**
In Power Ascension
Total
In Construction
In Low-Power Testing
Under Construction
Indefinitely Deferred***
Total
Total
111
0
111
0
3
5
8
119
99.6
0
99.6
0
3.4
6.1
9.6
109.2
Notes:
* Operable units or reactors are those that have been issued a full power
license by the Nuclear Regulatory Commission. Retired units are not
included. Shoreham received a possession-only license in June, 1991.
Since the unit is not currently scheduled to operate, it is not included
in the total for units in the construction pipeline or operable units.
** Three Mile Island 2, Hanford-N, Fort St. Vrain, and Rancho Seco are not
included.
*** Includes Bellafonte 1 and 2, Perry 2, WNP1 and WNP3.
Source: (DOE91c)
2-3
-------
Table 2-2. Commitments for Delivery of Uranium from Domestic Suppliers to U.S. Utilities:
1990 to 2000 and Later, (Million Pounds Up,)
Delivery
1990*
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000 and Later
TOTAL
As of December 31, 1989
Firm
13.1
11.2
9.5
8.3
6.1
6.3
4.5
2.5
2.0
1.6
1.4
66.5
Optional
1.1
3.1
3.2
4.5
3.7
4.3
3.9
2.8
2.3
1.8
3.5
34.1
Total
14.2
14.3
12.7
12.8
9.8
10.6
8.4
5.3
4.3
3.4
4.8
100.7
Cumulative
14.2
28.5
41.2
54.0
63.8
74.4
82.8
88.2
92.5
95.9
100.7
—
As of December 31, 1990
Firm
20.5
18.9
9.7
10.3
6.6
6.5
3.6
2.6
0.9
0.6
0.2
80.3
Optional
0.0
1.0
3.4
3.5
3.5
4.4
3.9
2.4
2.3
1.7
2.0
28.1
* Total
20.5
19.9
13.0
13.8
10.1
10.9
7.5
4.9
3.2
2.3
2.2
108.4
Cumulative
20.5
40.4
53.4
67.2
77.3
88.2
95.7
100.7
103.9
106.2
108.4
—
Change in Total From
December 31, 1990
Total
6.3
5.6
0.3
1.0
0.3
0.3
-0.9
-0.4
-1.1
-1.1
-2.6
—
Cumulative
6.3
11.9
12.2
13.2
13.5
13.8
12.9
12.5
11.4
10.3
7.7
—
to
Notes:
* Actual deliveries
— Not applicable
Source: (DOE91b)
-------
Table 2-3. Origin of Uranium Committed for Delivery to U.S. Utilities from
Domestic Suppliers: 1990 to 2000 and Later,
as of December 31, 1990 {Million Pounds U3O8)
Year of Delivery
1990*
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000 & Later
TOTAL
Origin
Domestic
14.3
6.7
6.4
6.4
6.4
6.3
i.3
3.5
2.4
1.7
1.8
61.3
of Committed
Unspecified
0.0
12.4
6.0
6.8
3.1
4.0
2.2
1.4
0.8
0.6
0.4
37.7
Uranium
Foreign
6.2
0.8
0.6
0.6
0.6
0.6
0.0
0.0
0.0
0.0
0.0
9.4
Total
20.5
19.9
13.0
13.8
10.1
10.9
7.5
4.9
3.2
2.3
2.2
108.4
Notes:
* Actual deliveries
Source: (DOE91b)
2.1.3 Exports
Exports of uranium by producers have generally declined
since 1979. In 1987, they were at their lowest level since 1975,
but have grown slightly since 1987. For 1990, exports of uranium
concentrate totaled 2 million pounds. As of December 31, 1990,
contracts were in place for exports of an additional 17.5 million
pounds for 1991-2000 (DOE91b). Exports of uranium by utilities
and domestic suppliers for 1977-1990, as well as commitments for
1991 through 2000 are shown in Table 2-4. Since 1967, U.S.
companies have exported a total of 69.4 million pounds of uranium
concentrate equivalent.
2-5
-------
Table 2-4, Exports of Uranium toy Utilities and Domestic Suppliers
1967 to 2000 and Later, as of December 31, 1990
(Million Pounds UaO8)
Year of Delivery Annual Cumulative
Actual Deliveries:
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
Subtotal
Commitments :
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
Subtotal
TOTAL
Notes :
Figures for 1967-1981
Sources (DOE91b)
1.4
1.6
1.0
4.2
0.4
0.2
1.2
3.O
1.0
1.2
4.0
6.8
6.2
5.8
4.4
6.2
3.3
2.2
5.3
1.6
1.0
3.3
2.1
2.0
69.4
2.0
2.5
2.6
2.6
2.3
2.0
1.3
1.1
1.1
0.0
17. i
86,9
represent exports by uranium producers
1.4
3.0
4.0
8.2
8.6
8.8
10.0
13. 0
14.0
15.2
19.2
26.0
32.2
38.0
42.4
48.6
51.9
54.1
59.4
61.0
62.0
65.3
67.4
69.4
—
71.4
73.9
76.5
79.1
81.4
83.4
84.7
85.8
86.9
86.9
—
—
only.
2-6
-------
2.2 SUPPLY
2.2.1 Sources of Supply
The uranium used to fuel nuclear reactors is supplied by
domestic and foreign producers and inventories held by utilities.
The role of each is described in the following sections.
Domestic Production
Table 2-5 shows trends in domestic production of uranium
concentrate from 1953 to 1990, by state. Total production was
relatively constant at 10,500 to 12,500 tons per year until 1977,
when it began an increase that peaked in 1980 at 21,852 tons.
Production has declined almost every year since, reaching only
5,657 tons in 1985 and falling to 4,443 tons in 1990 (DOE91b).
Coinciding with the overall decline in the domestic produc-
tion industry is a decline in the share of production represented
by conventional mills. Historically, conventional milling
accounted for approximately 70 percent of U.S. production.
However, by 1985, the conventional share of production had fallen
to 54 percent. It rose to 66 percent in 1986, but then declined
again (DOE87b). By 1990 conventional milling accounted for 52
percent of total production (DOE91b).
Although non-conventional methods of production are limited
in the quantity of uranium concentrate they can produce, they
produce it cheaply. DOE has estimated that by the middle of
1991, nearly two-thirds of domestic uranium was produced from two
non-conventional methods, in-situ leaching and by-product recov-
ery. This shift has occurred because these non-conventional
methods can produce low quantities of uranium cheaply. The trend
towards non-conventional methods is expected to continue in the
near term, and is expected to account for nearly all production
by 1993.
The decline in domestic production by conventional methods
has resulted in severe over capacity and mill shutdowns. Milling
capacity, which almost doubled between 1975 and 1980 when the
price of uranium was high and optimistic demand forecasts stimu-
lated investment in milling facilities, once enjoyed a utiliza-
tion rate of 94 percent (EPA86). In December 1986, capacity
utilization was about 32 percent at operating mills, and only 9
percent of the total industry potential. By December of 1990
conventional mills were operating at a mere 7 percent of total
available industry capacity. The number of operating mills has
also declined dramatically, from 20 in 1981 to a low Of two in
June 1985. NUEXCO indicates that six mills operated in 1987, but
the number was only two by the end of December 1990 (DOE91b). In
terms of nonconventional milling, at the end of 1990 there
2-7
-------
TAKLE 2-5. Production of Uranium Concentrate by Conventional Mills and Other
Sources: 1953 through 1990 (Tons U3O8)
Year New Mexico Wyoming Texas Utah Colorado Others Total
19S3
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
Mf-0
847
2,891
2,534
3,604
6,772
7,760
7,750
7,293
5,512
4,747
4,591
5,076
5,933
6,192
5,993
5,771
5,305
5,464
4,634
4,951
5,191
6,059
6,779
8,539
7,423
7,751
6,206
3,906
2,550
1,458
692
926
1,166
1,130
1,152
306
_—
—
—
—
1,247
1,675
2,770
2,823
3,055
2,566
2,216
2,097
2,248
2,667
2,873
3,063
3,654
3,487
4,216
5,159
3,767
3,447
4,046
4,990
5,329
5,452
6,036
4,355
2,521
2,630
1,560
1,214
317
284
1,004
804
684
*«.*
—
—
__
__
__
—
—
—
—
__
—
—
—
—
—
—
—
—
—
—
*
*
*
*
2,651
3,408
3,141
2,131
1,650
1,310
1,084
1,293
1,358
1,403
1,470
916
214
180
454
1,222
3,291
3,822
3,535
3,034
2,954
3,188
3,080
2,063
1,510
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
940
1,239
1,483
1,726
1,966
2,917
3,278
3,117
2,951
2,652
2,134
1,800
1,290
1,423
1,340
1,614
1,678
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
—
9
181
—
119
691
847
979
956
870
820
925
1,020
954
1,842
1,313
1,689
925
3,480
3,481
3,220
3,442
2,810
2,962
2,642
3,170
4,618
3,210
4,657
5,535
4,876
3,750
3,113
2,667
4,768
4,504
4,159
3,343
2,537
1,163
1,600
2,784
5,958
8,482
12,437
16,239
17,637
17,348
17,008
14,217
11,846
10,442
10,589
11,253
12,368
11,659
12,905
12,273
12,900
13,235
11,528
11,600
12,747
14,939
18,486
18,736
21,852
19,237
13,434
10,580
7,441
5,657
7,304
7,312
7,696
6,769
4,443
Notes:
—• No production
* Individual state production aggregated with "others".
Source: Personal Communication, Mining and Mineral Division, HeH Mexico Energy, Mineral and Natural Resources
Department.
U.S. and comparative New Mexico data from U.S. Department of Energy, 1979-1982;
Hew Mexico data from Mining and Minerals Division, New Mexico Energy, Minerals
and Natural Resource Department for 1983-1990;
Mon-New Mexico data from Energy Information Administration for 1983-1990;
Texas recovery for 1986-1987 included unspecified quantity of U3Q8 milled from
Hew Mexico ore.
2-8
-------
were 3 phosphate and 2 in-situ mills in operation. They produced
4.2 million pounds of uranium concentrate, 1.4 million pounds
less than in 1989. Uranium mill capacities and utilization
levels are listed in Table 2-6.
TABLE 2-6. Uranium Mill Capacity
(Tons of Ore per Day)
Year
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
Total
Capacity
54,050
55,050
51,650
48,450
47,250
42,650
34,650
30,600
30,600
30,600
Operating
Capacity
49,800
33,650
29,250
19,250
6,550
11,650
13,250
7,900
7,900
4,300
Operating
Capacity
Utilization
Rate
83%
74%
58%
64%
78%
32%
31%
44%
45%
48%
Total
Capacity
Utilization
Rate
77%
45%
33%
25%
11%
9%
12%
11%
12%
7%
Source: (DO191a)
Imports
A second source of uranium is the import market. Until
1975, foreign uranium was effectively banned from U.S. markets by
a Federal law prohibiting the enrichment of imports for domestic
use. This restriction was lifted gradually after 1975, and was
eliminated completely in 1984. From 1975 through 1977, imports
amounted to a small portion of total domestic requirements, and
U.S. exports actually exceeded imports in each year from 1978
through 1980. By 1986, however, imports supplied 44 percent of
U.S. requirements. Total imports in 1990 have grown 54 percent
since 1986 to a total of 23.7 million pounds of uranium concen-
trate, surpassing domestic supply. This is a marked increase
from the 13.1 million in imports reported in 1989. Table 2-7
lists U.S. imports from 1975 through 1990, as well as import
commitments through the year 2000 (DO187a, DOE91b).
2-9
-------
TABLE 2-7. Imports of Uranium for Commercial Uses, 1975 - 1990
(Million Pounds, U3O8>
Year of Delivery
Actual Deliveries:
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
Subtotal
Commitments :
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
Subtotal
TOTAL
Annual
1.4
3.6
5.6
5.2
3.0
3.6
6.6
17.1
8.2
12.5
11.7
13.5
15.1
15.8
13.1
23.7
159.7
20.2
16.2
18.7
15.6
15.6
14.1
13.2
7.5
8.3
14.7
144.1
303.8
Cumulative
1.4
5.0
10.6
15.8
18.8
22.4
29.0
46.1
54.3
66.8
78.5
92.0
107.1
122.9
136.0
159.7
—
179.9
196.1
214.8
230.4
246.0
260.1
273.3
280.8
289.1
303.8
—
—
Source: (DOE91b)
2-10
-------
Utilities and suppliers purchased roughly equal shares of
1990 imports. For delivery commitments beyond 1990, utilities
account for 84% of the total quantity of imports under contract
as of December 31, 1990 (DGE91b).
The primary sources of U.S. uranium imports have been
Canada, South Africa and Australia. In 1990, 43 percent of U.S.
uranium imports were from Canada, 32 percent were from Australia,
and 25 percent were from various other countries. The United
States has not imported uranium from South Africa since the 1986
ban which was called for in the Comprehensive Anti-Apartheid Act.
However, on July 11, 1991 the U.S. eliminated restrictions
against South Africa, and uranium imports have been permitted to
resume.
Forecasts of import penetration call for the import share to
grow through the 1990's. The Department of Energy projects that
without government intervention, imports will rise from 52
percent in 1991 to 83 percent by the year 2003. Many factors
will affect the amount of uranium imported in the near future,
including; the extent to which the U.S. resumes trade with
Namibia and South Africa, whether Germany sells its unwanted
inventories, whether Australia lifts regulations restricting
certain drilling and whether the former Soviet Republics are able
to produce and sell uranium on a large scale (DOE91a).
Inventories
Utilities hold uranium inventories in order to meet changes
in the scheduling of various stages of the fuel cycle, such as
minor delays in deliveries of uranium feed. Uranium inventories
also protect the utilities against disruption of nuclear fuel
supplies.
Table 2-8 lists inventories of commercially owned natural
and enriched uranium held in the United States as of December 31,
1988, 1989, and 1990. DOE-owned inventories are not included in
this table. The uranium inventory owned by utilities alone at
the end of 1984 represented almost four years of forward cover-
age. Forward coverage dropped to 3 years by the end of 1990. In
1990 total commercial inventories decreased by 5.9 million pounds
from 138.1 million pounds in December of 1989 to 132.2 million
pounds in December of 1990. Utility inventories decreased from
115.8 million pounds in 1989 to 102 million pounds in 1990 - a
reduction of 13.8 million pounds. Government held inventories of
uranium concentrate decreased from 77.5 million pounds in 1989 to
59.8 million pounds in 1990. Finally, in 1990, the amount of
enriched uranium held in inventory by the Government increased
from 24.7 million pounds to 32.8 million pounds (DOE91b).
2-11
-------
SABLE 2-8.
U.S. Commercially—Owned Uranium Inventories as of
December 31, 1988, 1989 and 1990
(Million Pounds, W308 Equivalent)
Owner Category
Utilities
Suppliers
TOTAL
1988
Natural
80.2
18.2
98.4
Enriched
45.3*
1.1
46.4
1989
Natural
R67.3
R21.2
R88.6
Inriched
R48.S*
1.0
R49.S
1990
Natural
61.4
25.8
87.2
Enriche
40.6*
4.4
45.0
Notes:
* Includes fabricated fuels {23.7 million pounds U3O$ in 1988,
22.8 million pounds in 1989 and 19.5 million pounds in 1990),
R = Revised from data published DOS90a
Sourcei (DOB91a)
2.3 INDUSTRY STRUCTURE AND PERFORMANCE
The number of tirms participating in the domestic uranium
milling industry declined between 1977 and 1983, and again after
1987. In 1977, 26 companies owned active uranium mills. By June
1985, there were only two (DO187b). In 1987, six companies
operated six mills (industry sources). However, by 1990 only two
mills were operational and by the middle of 1992 the remaining
two mills plan to shut down and begin reclamation (industry
sources). The contraction of the industry can also be seen in
trends in employment and capital expenditures (Table 2-9).
Capital expenditures in 1986 were only $1 million, compared to
$72 million in 1981 (1986 dollars) (DO187a, DOE87b). By 1990
capitol expenditures for conventional milling were so small that
the DO1 no longer published the figure independently of other
processing methods. Employment in 1984 was 513 person-years,
compared to 2,367 person-years in 1981. In 1990, employment had
dropped to 304 person years (DOE87a, DOE91a, DOE91b). The
overall level of employment in the raw materials industry report-
ed in 1990, 1,335 person-years, was approximately 6% of the level
of 21,251 person-years reported in the peak year 1979 (DOE91b).
A wide variety of companies have been represented within the
uranium industry. In the industry's early years, holdings were
dominated by independent mining and exploration companies. Since
then, mergers, acquisitions, and the entry of conglomerates have
considerably altered industry structure. During the 1970's, the
oil embargo and optimistic forecasts of future nuclear power
capacity made entry into the uranium market attractive to oil
2-12
-------
companies and utilities. However, by 1990 depressed market
conditions prompted multinational domestic oil companies to leave
the uranium industry.
TABLE 2-9. Capital Expenditures, Employment, and Active Mills:
Conventional Uranium Milling Industry
Capital Expenditures* Employment Number of Active
Year (Million Constant 1990 S) (Person-Years) Mills At Year-End
1987
1988
1989
1990
1991**
1992***
0.3
7.3
4.6
0.6
0.5
NA
432
572
367
304
—
NA
6
6
3
2
—
0
Notes:
* Capital Expenditures figures include processing activities/unconventional
mines. Expenditures for conventional mines fall every year. They
constitute a negligible percentage of the figures given above.
** Capital Expenditures for 1991 are projected. Other data for the
same year are not available.
*** The two remaining active mills are expected to decommission be the end of
1992.
Sources (DOE91a, DOE91b)
Currently, uranium milling and mining has experienced an
increased level of industry concentration. Nine firms account
for almost all domestic uranium output, both conventional and
non-conventional. Four firms account for almost 80 percent of
all domestic production. The DOE projects that the industry will
become even more concentrated in the near term. The sale and
production of uranium is only a small segment of the firms'
principal activities for nearly all of the firms remaining in the
industry. Among the four largest uranium firms in 1990; two were
foreign-based energy firms, one was controlled by a foreign-based
uranium firm, and one was a wholly owned subsidiary of a domestic
utility (DOE91a),
These ownership characteristics influence the financial
viability of the industry. The desire of the parent companies to
weather a downturn in the uranium market and to retain an inter-
est in producing properties is a function of how necessary their
involvement is to their main business activity. Most firms are
continuing to withdraw from an extremely soft market. Foreign
2-13
-------
owned firms appear to have adopted a longer term viewpoint than
have some of their domestic counterparts. It is certain that the
industry will continue to undergo structural change. This change
will depend on the regulatory environment, domestic and foreign
demand, costs of production, and the industry's ability to
compete with lower-priced imports (DOE87a, DOE91a).
2.4 ECONOMIC AND FINANCIAL CHARACTERISTICS
In March 1992, the departments of mining or natural resourc-
es in the states with uranium mills were contacted to provide
their assessments of the status of the uranium industry. This
assessment disclosed that due to protracted low prices no li-
censed mill will be active beyond the spring of this year. Only
two mills are currently operational, and both plan to shut down,
one will begin decommissioning.
In New Mexico, the two milling facilities together employ 61
people, although neither facility is operational. The laborers
at those mills are engaged in reclamation work and the leaching
of small quantities of uranium. The State estimates that a total
of 87 workers are employed in both the milling and mining indus-
try, down from 318 the year before. Grants, New Mexico, the
location of the two remaining licensed facilities in the state,
has been in steady economic decline. The Rio Algom Mill in
Grants, which once employed between 1,300 and 1,600 people, now
employs only 37. Most of their former employees have left the
state, some work for a new prison facility and a few others now
are employed by a local coal mine (NM92).
Wyoming still has one mill in operation, the Pathfinder Mill,
in Shirley Basin. The Pathfinder Mill is operating significantly
below capacity, and plans to close in spring 1992. However, it
will remain on standby status. State figures on employment in
the industry remain unchanged since 1984, at 454 people. Employ-
ment is expected to drop after the mill closes (WY92).
The uranium industry in the state of Washington has been
inactive since 1985, and no indication has been shown that this
will change. No new industries have entered the regions where
mining took place. The workers who were not part of the Indian
community have left the area (WA92).
Texas, like Wyoming, has one mill which is still operating.
This mill is scheduled to shut down and will begin decommission-
ing in April of 1992. The mill, recently bought from Chevron by
General Atoms, currently employs 60 people. Most of the workers
are currently engaged in dismantling the mill. The area around
the mill is economically depressed, however most of the labor
hopes to find work in the larger economy of San Antonio. All
other mills in Texas have been permanently closed, although the
2-14
-------
former Conquista Project, once owned by Conoco, now by DuPont,
still employs several people (TX92).
Colorado and Utah experienced some activity in the late
1980's, but more recently have had no milling production. Both
states have a skeletal labor force in the uranium industry. The
Cotter Mill in Canon City, Colorado is in danger of decommission-
ing, causing a permanent loss of between 100 and 150 jobs. These
jobs translate into a $5 to $7.5 million per year pay-roll loss
to the local economy. The situation in Utah is similar. The
Umetco Minerals Mill in Blanding has been opened recently, and is
currently on stand-by status (CO92, UT92).
2.5 INDUSTRY FORECAST AND OUTLOOK
This section presents projections of total U.S. utility
market requirements, domestic uranium production and net imports.
Developed for a fifteen year period (1991-2005), these projec-
tions are considered "near term." A basic assumption of the near
term projections is that current conditions, as defined by the
Department of Energy's Energy Information Administration (DOE,
EIA), will continue unchanged through the end of this century.
This section is based on the reference case projections in EIA's
Domestic Uranium Mining and Milling Industry: 1990 Viability
Assessment (DOE91a).
2.5.1 Projections of Domestic Production
The EIA's Reference case1 forecasts for 1991-2005 in five
year intervals are based on the output of two EIA economic
models; the Uranium Market Model (UMM) which projects demand, and
the Uranium Supply Analysis System which projects supply. The
methodology of these models is beyond the scope of this study; it
is fully described in Appendix D of the 1990 Viability Assess-
ment. The EIA examines future developments in the domestic
uranium industry and in the domestic and international uranium
markets under current market conditions and under certain hypo-
thetical supply disruption scenarios.2 The current market condi-
tions are generally the same as those presented in Sections 2.1-
1 The EIA publishes three projection cases, an upper, lower and
no new order case. However, in the near term no significant
difference exists among any of these cases.
2 These scenarios, the "current disruption status" scenario
and the "projected disruption status" scenario, are used to test
the viability of the U.S. uranium industry, to examine the ability
of this industry to respond to an abrogation of various fractions
of contracts for uranium imports intended for domestic end use.
Both of these bear only tangentially to this study and will not be
discussed further here.
2-15
-------
2.4 of this study and are based on historical trends in the
domestic uranium industry as outlined by the Viability Assessment
and the EIA's Uranium Industry Annual 1990. In addition to the
uranium prices, production and imports, exploration expenditures,
capital expenditures, and employment data developed for inclusion
as "current market conditions," the EIA identifies several
international political uncertainties which could affect the
uranium industry. Also taken into account by DOE are assumptions
on future electricity generation, fuel burnup levels, enrichment
in tails assay, and inventory drawdowns.
2.5.2 Near-Term Projections
The reference case projections for uranium concentrate re-
quirements, domestic production and net imports through the year
2005 is shown in tabular form in Table 2-10, along with compari-
sons to previous DOE and independent projections. Aggregate
domestic production from 1991 though the year 2000 is projected
to be 82.8 million pounds, about the same as total domestic
production in the years 1980 and 1981. Production is expected to
remain low through 2005 (DOE91a) .
Using the same models, the Department of Energy has forecast
industry-wide employment through the year 2005. The DOE projects
that employment will remain steady at approximately 1,200 person-
years per year in mining, milling, and processing past the turn
of the century. However, the DOE does not predict how that labor
will be dispersed throughout the industry (DOE91a). Both histor-
ical and projected employment are presented in tabular form in
Table 2-11.
In the immediate future, very little of the domestic produc-
tion of uranium can be expected to come from conventional milling
methods. As of the winter of 1992 many mills have filed for
decommissioning status. The remaining mills will remain on
standby status for a short period to evaluate changing market
conditions. If conditions remain unchanged, the last facilities
will likely shut down as well.
Whereas low prices have forced conventional domestic milling
out of the market, they have less of an affect on processing
methods such as by-product recovery and in-situ leaching.
Thesenon-conventional methods of production have a lower marginal
cost of production than do conventional producers, and therefore
are less affected by the fluctuations in uranium market prices.
However, the non-conventional methods have a relatively low
capacity and will not be able to respond to large increases in
demand (DOE92).
2-16
-------
TABLE 2-10. Comparison of Uranium Projections: U.S. Uranium Requirements
Domestic Production, and Net Imports (Million Pounds U3Og)
Projection Period
Source
1991-1995
1996-2000 2001-2005
Total,
1991-2000
Total,
1991-20
Uranium Requirements
1990 Viability
1989 Viability
1988 Viability
1987 Viability
Assessment
Assessment
Assessment
Assessment
Nuexco, Reference Case
Energy Resources International,
Inc. , Low Case
209
195
189
168
218
196
.2
.1
.6
.8
.3
.1
213
198
181
173
208
188
.1
.2
.8
.2
.5
.4
203
193
176
—
205
182
.3
.8
.0
.0
.6
422
393
371
342
426
384
.3
.5
.4
.0
.8
.5
625
587
547
-
631
569
.6
.3
.4
-
.8
.1
Domestic Production
1990 Viability
1989 Viability
1988 Viability
1987 Viability
Assessment
Assessment
Assessment
Assessment
Nuexco, Reference Case
44.
45.
47.
41.
35.
3
8
1
3
8
38.
46.
49.
69.
65.
5
4
9
3
3
31.
68.
74.
—
72.
6
5
7
3
82.
92.
97.
110
88.
8
2
0
.6
4
114
160
171
-
127
.4
.7
.7
-
.0
Net Imports
1990 Viability
1989 Viability
1988 Viability
1987 Viability
Assessment
Assessment
Assessment
Assessment
129
117
113
106
.7
.8
.2
.1
156
128
112
92.
.7
.6
.8
1
161
110
92.
—
.4
.5
6
-
286
246
226
198
.4
.4
.0
.2
447
356
318
-
.8
.9
.6
-
Source: (DOE91a)
The Reference case EIA projections of domestic U3O8 produc-
tion through the year 2000 are based on a unit by unit review of
nuclear power plants that are new, operating, under construction,
or units for which orders have been placed and for which licenses
are currently being processed. Under EIA's Reference case,
nuclear generating capacity is expected to increase from 99.6 GWe
in 1991 to 106.5 GWe in 2005 (Table 2-12).
2.6 EVALUATION OF FORECASTS AND URANIUM MARKET DEMAND
This section compares our scenario, as developed from DOE
forecasts, for total domestic production of U3O8 to total domestic
uranium resources.
2-17
-------
TABLE 2-11.
Year
Employment in the U.S. Uranium Industry Under Current
Market Conditions: 1975 TO 2005 (Person-Years)
Exploration
Mining, Milling
and Processing**
Total
Historical :
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
Projected:
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2,049
2,793
4,140
4,449
4,066
3,370
2,300
769
374
235
163
162
183
144
86
73
60
60
60
60
60
60
60
60
70
70
70
70
60
60
60
Notes ;
* Includes 140 contract truckers
** Includes employment in byproduct
7,623
10,330
13,901
16,391
17,455 R
16,549
11,376
8,338 *
5,241
3,362
2,283
1,957
1,819
1,997
1,497
1,262
1,200
1,300
1,300
1,300
1,300
1,200
1,200
1,200
1,100
1,000
800
800
800
1,000
1,100
9,672
13,123
18,041
20,840
21,521 R
19,919
13,676
9,107
5,615
3,597
2,446
2,119
2,002
2,141
1,583
1,335
1,260
1,360
1,360
1,360
1,360
1,260
1,260
1,260
1,170
1,070
870
870
860
1,060
1,160
and in-situ processing.
R Revised from data published in the 1989 viability
report (DOE89a) .
Source: (DOE91a)
assessment
2-18
-------
2.6.1 Domestic Uranium Resources
The most recent projections of domestic U3Og production shown
in Table 2-10 indicate that slightly over 114 million pounds of
U3O8 will be produced domestically between the years 1991 and
2005. By-product recovery and in-situ leaching are expected to
account for much of this production. Historically, these methods
have processed between 3.7 and 6.5 million pounds of uranium per
year. Moreover, non-conventional production at this level is not
greatly impacted by market forces. The marginal cost of process-
ing small quantities of uranium from by-product recovery of
minerals such as copper and phosphate is negligible. In-situ
leaching also can produce small quantities of uranium at low
costs. However, the capacity for production from these two
methods at costs below current market prices is limited.
If these methods produce at their historical maximum capaci-
ty and process 6.5 million pounds of uranium each year between
the years 1991 and 2005, 97.5 million pounds of U3Og will be
generated by non-conventional methods. On the other hand, if the
non-conventional methods operate at a minimal capacity and
process only 3.7 million pounds, then over the fifteen years only
55.5 million pounds will be generated. Therefore, non-conven-
tional methods can be expected to produce somewhere between 55.5
million pounds and 97.5 million pounds accounting for between 48
and 85 percent of total projected domestic production. Since
domestic production is expected to decline over the projected
years, while domestic non-conventional production could remain
steady, non-conventional production could easily account for all
of the 31.6 million pounds projected between the year 2000 and
2005. Thus, conventional milling should account for the remain-
ing 16.9 million pounds to 58.9 million pounds of the 114.4
million forecast for this period. Most of this production should
be expected in the earlier projection years.
2.6.2 Conventional Milling Domestic Resources
DOE also estimates the total "endowment" of domestic U3O8 re-
sources. The "endowment" is defined as all U3O8 in deposits
containing at least 0.01 percent (100 ppm) of U3O8. Resources are
grouped according to resource categories, as defined below. The
three resource categories used by DOS are also those used by the
International Atomic Energy Commission and the OECD Nuclear Power
Agency:
• Reasonably Assured Resources (RAR) refers to uranium in
known mineral deposits which could be recovered within
given cost ranges, and using currently proven technol-
ogy. This corresponds to DOE's Reserves Category;
2-19
-------
TABLE 2-12.
Projected U.S. Nuclear Power Capacity and Uranium
Requirements
(Million Pounds, U3Og)
Year
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
Net
Design
Capaci-
ty*
(GWe)
99.6
100.8
101.9
101.9
103.1
103.1
103.1
104.3
104.3
105.4
105.4
105.4
106.6
106.6
106.5
Uranium
Require-
ments**
(Million
Pounds, U3O8)
41.8
41.8
40.8
42.4
42.4
43.5
43.5
42.4
42.4
41.3
41.3
42.7
39.9
39.9
39.5
Opti-
mal
Vari-
able
Tails
Assay-
s***
0.30
0.30
0.30
0.30
0.30
0.30
0.30
0.30
0.30
0.30
0.29
0.28
0.27
0.26
0.25
Utility Con-
tract
Commitments
(Million
Pounds, U3O8)
33.5
26.5
28.8
23.8
24.6
19.9
16.2
9,3
9.2
6.2
3.6
NA
NA
NA
NA
Utility Un-
filled
Requirements
and Inventory
Drawdowns * * * *
(Million
Pounds, U3Og)
8.2
15.3
12.1
18.6
17.9
23.6
27.3
33.1
33.2
35.1
37.7
NA
NA
NA
NA
Notes:
* Capacity in operation at the end of the year
** These projections have been smoothed to reduce the magnitude
of yearly variations due to reactor fueling schedules? smoothing,
however, does not affect the overall trend of the projections.
*** Percent U-235 transaction enrichment tails assay.
**** Uranium requirements minus contact commitments equals
unfilled requirements and inventory drawdowns.
Source; (DOE91a) '
2-20
-------
• Estimated Additional Resources (EAR) refers to uranium
in addition to RAR that is expected to occur, mostly on
the basis of direct geological evidence in extension of
well explored deposits, little explored deposits, and
undiscovered deposits believed to exist along well
defined geological trends with known deposits, such
that the uranium can be recovered within the given cost
estimates. This corresponds to DOl's Provable Poten-
tial Category;
« Speculative Resources (SR) refers to uranium in addi-
tion to EAR and RAR which is thought to exist, mostly
on the basis of indirect evidence and geological ex-
trapolations. This corresponds to DOE's Possible
Potential Resource Category.
The "forward cost of recovery" of uranium resources repre-
sents estimates of most future costs of mining, processing, and
marketing U3O8, exclusive of return to capital. These estimates
include the costs of transportation, environment and waste
management, construction of new operating units and maintenance
of all operating units, and future exploration and development
costs. Also, appropriate indirect costs such as those for office
overhead, taxes and royalties are included. Table 2-15 presents
estimates of all reasonably assured U3O8 resources having a
"forward cost of recovery" of no more than $50/lb (DOE91a). In
addition to the reasonably assured resources, the DOE expects
2,200 million pounds of estimated available resources as well as
1,300 million pounds of speculative resources, both at a forward
cost of recovery of less than $30 per pound. At a forward cost
of recovery of up to $50 per pound, expectations rise to 3,400
million pounds and 2,200 million pounds, respectively.
Using only Reasonably Assured Resources, Table 2-13 suggests
that the United States currently has about 265 million pounds of
U3O8 with a forward cost of recovery of no more than $30 per pound
(DOESla). Assuming an average U3O8 recovery rate of about 90
percent, domestic mills have enough resources in this category to
cover all of the projected domestic production through 2005 even
without the expected contribution of non-conventional methods.
The determination of conventional milling output over the
fifteen year period is not only dependent on the accuracy of the
DOE forecasts, but also on the assumption that no technology is
introduced to expand the capabilities of non-conventional pro-
cessing. Although the introduction of such technology is not
anticipated under current market conditions, some possibilities
remain open. These possibilities include: increased by-product
recovery in the processing of bauxite and beryllium ores, and by
extraction of uranium from copper waste dumps (DOE80). Studies
are also being conducted to remove uranium from seawater. Scien-
2-21
-------
tists are capable of accessing the large quantities of uranium
found in seawater but the economical viability of such technology
is questionable (Ca79, Ro79).
TABLE 2-13. U.S. Reasonably Assured Resources (RAR) by State
by Mining Method, as of December 31, 1990
(Million Pounds U3O8)
Forward-Cost Category (Nominal $)
$30 Per $50 Per
Origin
State
New Mexico
Wyoming
Texas
Arizona, Colorado, & Utah
Other*
Total**
Pound U3O8
85
71
23
43
43
265
Pound U3Og
351
330
47
125
73
926
Mining Method
Underground 141 468
Open Pit 39 277
In Situ 84 163
Other*** 1 18
Total** 265 926
Notes:
* Includes California, Idaho, Nebraska, Nevada, North
Dakota, Oregon, South Dakota and Washington
** Uranium resources that could be recovered as a byproduct
of phosphate and copper mining are not included, but may
amount to 37 million pounds U3O8.
*** Includes heap leaching, mine water and low grade stockpile.
Reasonably Assured Resources (RAR) in forward-cost categories
are cumulative; i.e. the quantity listed at $50/lb U3O8 includes
all RAR at $30/lb.
Source: (DOE9la)
2-22
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CHAPTER 3
BACKGROUND INFORMATION FOR LICENSED NON-OPERATING
URANIUM MILL TAILINGS IMPOUNDMENTS
3.1 OVERVIEW
Uranium mills process ore for the purpose of recovering and
concentrating uranium to an intermediate, semi-refined product
called yellowcake. There are two basic conventional processes for
extracting uranium from the ore: the acid-leach process and the
alkaline-leach process. The leaching process removes the uranium
from the crushed ore, with sulfuric acid as the leaching agent in
the acid-leach process; a mixed sodium carbonate sodium bicarbonate
solution is the leaching agent in the alkaline-leach process
(NRC80).
Both milling processes involve a series of operations, includ-
ing ore handling and preparation (crushing and grinding), extrac-
tion, concentration and precipitation, product preparation, and
tailings disposal (EPA86). Although each of these milling activi-
ties has the potential to release radon, essentially all the radon-
222 emissions associated with the uranium mill process come from
the tailings disposal area. Previous evaluations have shown that
radon releases from other milling operations are insignificant
(NRC80; EPA83b; EPA85). Therefore, the reduction of radon-222
emissions at licensed uranium mill sites is accomplished most
effectively by reducing the emission from the tailings disposal
area.
The tailings represent the bulk of the wastes originating from
the uranium mill and contain (1) all the contaminants present in
the original ore, (2) about 10 percent of the uranium not recovered
in the milling process, and (3) a variety of chemicals and addi-
tives, inclusive of water, used in the extraction processes. Both
the acid-leach and alkaline-leach extraction processes create waste
with concentrated levels of thorium and radium. In the acid-leach
process, approximately 95 percent of the thorium in the original
ore remains in the solid tailings waste. Less than one percent of
the radium is dissolved in the liquids. Even greater amounts of-
thorium and radium remain in the solid waste from the alkaline-
leach process (EPA83b). These concentrated levels of thorium and
radium in the tailings waste are the source of radon-222 emissions.
This Section provides a historical overview of the licensed
non-operating uranium mills identified in the Memorandum of Under-
standing (MOU) between the EPA and the NRG and the current status
of the associated tailings impoundments. Impoundment characteris-
tics and surface area status are summarized in Table 3-1. It
should be noted that seven of the twenty tailings impoundments
listed in Table 3-1 contain evaporation ponds within the tailings
3-1
-------
disposal area. Evaporation ponds are used for dewatering of the
piles and for long-term maintenance of ground water. Since the use
of the evaporation ponds is an integral part of the remediation
process, it is not the EPA's intent to require the final radon
cover to include these ponds, even when located on the tailings
pile, by the target dates specified in the MOU. Therefore, the
acreage associated with the evaporation ponds has not been included
in the total surface areas of the tailings impoundments.
Data were compiled using NRG dockets and EPA documents written
in support of previous rulemakings associated with the UMTRCA and
the CAA. An updated status of the tailings surface configuration,
obtained from mill facility licensees, was provided by the NRC's
Uranium Recovery Field Office and cognizant individuals from
affected Agreement states.
Table 3-1.
1992 STATUS OF NON-OPERATIONAL TAILING IMPOUNDMENTS
IDENTIFIED IN THE MEMORANDUM OF UNDERSTANDING
TAILINGS SURFACE
FACILITY
ANC, Gas Hill, WY
ARCO Coal, Bluewater, NM
Atlas, Moab, UT
Conoco, Conquista, TX
Ford— Dawn Mining, Ford, WA
Hecla Mining, Durita, CO
Homestake, NM (large impoundment:}
Homestake, NM (small impoundment)
Pathfinder-Lucky Me, GH, WY
Petrotoraics, Shirley Basin, WY
Quivera, Ambrosia take, NM
Rio Algom, Lisbon, UT
Sohio-L-Bar, NM
UMETCO, Gas Hills, WY
UMETCO, Maybell, CO
UMETCO, Uravan, CO
UNO, Church Rock, NM
Union Pacific, Bear Creek, WY
WNI, Sherwood, WA
WNI, Split Rock, WY
Total
110
300
128
250
123
35
170
13
203
114
368
100
80
192
SO
70
103
178
94
223
Ponded
0
0
0
0
0
0
0
0
9
0
0
0
0
0
0
0
0
0
0
0
Wet
0
0
10
100
28
0
18
0
6
0
0
0
0
0
0
0
0
0
44
0
AREA (Acres)
Dry
0
150
118
0
0
0
152
7
0
0
36
0
0
0
15
0
0
0
50
0
Interim
Cover
110
150
0
150
95
35
0
6
188
114
332
100
80
192
35
70
103
178
0
223
MOU
Target
Date
1995
1995
1996
1996
2010
1997
1996
1997
1998
1995
1997
1996
1992
1995
1997
1997
1997
1996
1996
1995
3-2
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3.2 FACILITY-SPECIFIC CHARACTERISTICS
3.2.1 ANC, G^a Hillj (also known as FAP)
In 1959, Federal-American Partners (FAP) began operation of a
uranium mill located in the Gas Hills Mining District of Wyoming.
FAP was originally a partnership consisting of two corporations,
Federal Resources Corporation and American Nuclear Corporation
(ANC). Tennessee Valley Authority (TVA) was the leaseholder.
The ANC Gas Hills mill was licensed to process 860 metric tons
per day. The mill used acid leach-solvent extraction process to
recover uranium oxide from the ore. Waste tailings were deposited
in a dam impoundment (Tailings Pond No. 2) as a slurry and the
liquid was decanted into Tailings Pond No.l, which served as a
solar evaporation pond. The total tailings area encompasses
approximately 110 acres.
During the operation period of 1959 through 1981, approxi-
mately 5.4 million metric tons of tailings waste was generated. In
February 1981, TVA instructed FAP to suspend their mining opera-
tion. Milling of stockpiled ores continued until October 1981,
when the mill was shutdown.
Currently, reclamation activities at the site include decom-
missioning of the mill and reshaping and regrading of both tailings
impoundments. A six-inch interim soil cover has been placed over
the 110-acre tailings area. The MOU target date for completion of
a final earthen cover over the tailings impoundments to reduce
radon levels to the UMTRCA standard is 1995.
3.2.2 ARCO, Coa1,; _Bluewater Mil 1
The Bluewater Uranium Mill is owned by the Anaconda Minerals
Company, a unit of ARCO Coal Company, a Division of Atlantic
Richfield Company. The mill is located about ten miles northwest
of Grants, New Mexico. The mill operated between 1953 and February
1982.
Originally, Bluewater Mill was designed to process 300 tons of
ore per day using a carbonate leaching operation to extract urani-
um. In 1959, the mill was upgraded to handle 6000 to 7000 tons of
sandstone ore, and the carbonate process was replaced by an acid
leach method.
The mill site has three tailings impoundments. Tailings from
the carbonate leach process were initially stored in an above-
ground area covering about 47 acres (Impoundment No. 2) north of
the mill. After the process changed to acid leach, slurring of the
materials began, and the tailings were deposited in the main
tailings impoundment (No. l), which is a natural basin enhanced and
enlarged through earthen dikes and embankment to encompass roughly
3-3
-------
230 acres. A third tailings impoundment, the north area acid pile,
is situated immediately northwest of the main pile and covers 23
acres.
From 1982 until 1985, ARCO dewatered the main tailings im-
poundment and removed the dissolved uranium from the liquid by
solvent extraction. The waste from this recycling process, or
barren raffinate, was pumped to the tailings pile until the end of
1983. Thereafter, the barren raffinate was pumped directly to the
evaporation ponds. Approximately 25 million tons of tailings
materials, generated during operating and recycling activities,
have been deposited in the main tailings impoundment.
Reclamation activities are currently underway at the site.
These activities include removal of tailings material in four
evaporation ponds to the tailings slime area, regrading of tailings
embankments, and pickup of windblown tailings and placement into
impoundment. Approximately 150 acres of the 300-acre tailings area
has been covered with an average of 2.5 feet of native soil.
According to the Memorandum of Understanding, it is projected that
the radon cover will be in place by 1995.
3.2.3 Atlas. Moab Mill
The Moab uranium recovery facility, located in Moab, Utah, is
owned by Atlas Minerals Corporation. Milling operations began in
October 1956. The ore processing circuits underwent several design
changes over the years. The mill's initial design consisted of two
alkaline leach circuits. A copper circuit was added in 1965 and
operated until December 1970. In 1965, one of the alkaline leach
circuits was converted to an acid leach and a uranium and vanadium
solvent extraction unit was installed. A fire in 1968 temporarily
suspended operations. The alkaline leach circuit was restarted in
1969 and ran until January 1982. The acid leach and solvent extrac-
tion circuits operated until the mill was put on a standby status
in March 1984.
Waste tailings were disposed in a single tailings impoundment
consisting of five embankments formed by sand tailings dikes.
Approximately 10.6 million tons of waste were deposited as a slurry
in the tailings impoundment. The tailings disposal area covers
approximately 128 acres.
Presently, site reclamation activities are proceeding. The
tailings pile is currently being dewatered, with 118 acres dry and
the remaining 10 acres wet. The MOU target date for completion of
an earthen cover, which meets the UMTRCA emission standards, is
1996.
3-4
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3.2.4 Conocof Concruista Mill
The Conquista Mill is located in Falls City, Texas, an Agree-
ment State. The owner, Conoco, Inc., operated the mill between
1972 through the early 1980's. The mill was licensed to process a
maximum of 3100 metric tons of ore per day.
Approximately 8 million metric tons of tailings waste was pro-
duced during the mill's operating life. The tailings were deposit-
ed in an above-grade tailings impoundment constructed of natural
clay. This single impoundment encompasses approximately 250 acres.
Currently, reclamation of the Conquista site is underway.
Mill decommissioning has been completed. A permanent radon cover,
which meets the UMTRCA emission standard of 20 pCi/m2-s, has been
placed over approximately 150 acres of the tailings impoundment.
The remaining tailings area (100 acres) is wet. In accordance with
the MOU, the entire tailings disposal area will have a final radon
cover by 1996.
3.2.5 Ford-Dawn Mill
The Dawn Mill is located in Ford, Washington, an Agreement
State. Dawn Mining Company operated the mill from 1957 until 1964
under government contract. The mill was shut down and rehabilitat-
ed between 1965 to 1969. The mill resumed operations in 1969
processing uranium ore under commercial contracts until 1982, when
it was placed in a standby mode for economic reasons.
During operations, production capacity of the mill was 600
tons of ore per day resulting in the generation of approximately
2.9 million tons of tailings waste. These tailings were deposited
in three unlined, above-grade impoundments, constructed behind
earthen dams, and one lined, below-grade disposal area. The three
above-grade impoundments encompass an area of 95 acres. The below-
grade disposal area covers 28 acres.
Presently, the three above-grade impoundments have been
blanketed with a five-foot interim earthen cover. There have been
no reclamation activities performed on the lined, below-grade
disposal area. A target date of 1996 has been established for
completion of a final radon cover over the entire impoundment
areas, as stated in the Memorandum of Understanding.
3.2.6 Hecla Mining. DuritaProject
The Durita site was constructed and operated as a secondary-
extraction heap leach facility that recovered uranium and vanadium
from mill tailings originally processed through the Naturita Mill.
The Durita Site occupies 160 acres in Montrose County, Colorado/
(an Agreement State), about three miles southwest of the town of
Naturita. The operation is managed by Hecla Mining Company.
• 3-5
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The site contains an ore preparation facility, a plant for
leachate recovery, three leach tanks (piles), and six evaporation
ponds. The three small heap leach piles encompass approximately 35
acres and contain 600,000 tons of tailings. The leach areas were
constructed of earthen dikes, underlain by a clay liner.
The Durita site is in the process of reclamation. An interim
soil cover of approximately 2 feet of compacted sandy clay soil has
been placed over the three heap leach piles. Based on the MOU, a
final radon cover, which satisfies the emissions standard of 20
pCi/m2-s, will be in place by 1997.
3.2.7 Homestake Mill
The Homestake Uranium Mill is located in Grants, New Mexico.
Homestake's milling facilities were constructed and originally
operated as two distinct partnerships, with Homestake Mining
Company acting as the managing partner for both.
The smaller of the two mills was organized as Homestake-New
Mexico Partners. The mill operated between February 1958 and
January 1962 at a nominal capacity of 750 tons per day. An alka-
line leach-caustic precipitation extraction process was used to
recover uranium.
The larger mill, organized under Homestake-Sapin Partners,
began operations in May 1958 at a capacity of 1750 tons of ore per
day. The mill was designed as an alkaline leach extraction facili-
ty. In April 1968, through a change in the distribution of owner-
ship, Homestake-Sapin Partners became United Nuclear-
Homestake Partners. In March 1981, Homestake purchased United
Nuclear Corporation's interest and operated the mill as Homestake
Mining Company-Grants until February 1990.
A separate tailings impoundment area was constructed for each
of the two mills. The first and smaller tailings impoundment
(associated with the Homestake-New Mexico Partners facility) was
constructed of earthen embankments. Approximately 1.22 million
tons of tailings were deposited in the approximately 13-acre
impoundment area. This impoundment is designated as
Homestake's "small impoundment" in Table 3-1.
The second tailings disposal area, associated with
Homestake-Sapin Partners, was constructed of compacted coarse
tailings embankments and is divided into two cells. The impound-
ment encompasses approximately 170 acres and contains over 22
million tons of tailings. This impoundment area is designated as
Homestake's "large impoundment" in Table 3-1.
Reclamation activities have commenced at the sites which
include mill decommissioning and tailings impoundment dewatering.
3-6
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A lined evaporation pond has been constructed to aid in the
dewatering process. Currently, the configuration of the large
tailings pile consists of 152 acres that are dry, with no soil
cover, and 18 acres wet. Seven acres of the total 13-acre small
tailings pile currently exists in a dry, uncovered state. The
remaining 7 acres have been blanketed with an interim soil cover.
The EPA and NRC have decided to treat the reclamation of the
two Homestake tailings disposal areas separately. Therefore, in
accordance with the Memorandum of Understanding, a 1997 target date
for completion of a final earthen cover has been set for the large
tailings impoundment; and a date of 2001 has been established for
the small impoundment.
3.2.8 Pathfinder-Luckv Me Mill
The Lucky Me Mill, located in Gas Hills, Wyoming, is owned by
Pathfinder Mines Corporation. The mill commenced operations in
1958 with an ore-processing capacity of 935 tons per day. Subse-
quently, the capacity was expanded to about 2800 tons of ore per
day. An acid leach process is used to recover uranium from the
ore.
The tailings retention system consists of four unlined,
earthen dam impoundments having a surface area of roughly 87, 63,
38, and 15 acres. Approximately 10.7 million tons of tailings have
been disposed of in the 203-acre impoundment areas.
Currently, an interim soil cover has been placed over 188
acres of the tailings disposal areas. The remaining impoundment
areas consist of 9 acres which are covered with free standing water
(ponded) and 6 acres that are wet. As specified by the MOUf an
earthen cover reducing radon emanation to 20 pCi/nr-s will be in
place by 1998.
3.2.9 Petrotomics. Shirley Basin Mill
The Shirley Basin Mill is owned by Petrotomics Company, a
subsidiary of Texaco. The mill is located in Shirley Basin,
Wyoming. Petrotomics operated the mill from 1962 until 1985. An
acid leach-solvent extraction process was used to extract uranium
oxide from ore. The mill operated at a maximum ore processing
capacity of 1400 tons per day.
During operations, about 6.4 million tons of tailings waste
was generated and deposited in a single above-grade, earthen dam
constructed impoundment. The tailings impoundment area encompasses
approximately 114 acres.
Petrotomics is proceeding with reclamation activities at the
site. To date, these activities include completion of the mill
' 3-7
-------
decommission, drying of the tailings area, and placement of an
interim stabilization soil cover over the entire tailings pile.
Based on the MOU, a target date of 1995 has been set for completion
of a final radon attenuation cover over the impoundment area.
3.2.10 Quivera. Ambrosia Lake
The Ambrosia Lake Mill, located in Ambrosia Lake, New Mexico,
is owned by Quivera Mining Company. Milling operations began in
1958 under the ownership of Kerr-McGee at a design capacity of 3630
tons of sandstone ore per day. The capacity was subsequently
expanded to 7000 tons per day. In 1985, the mines and mill were
placed in standby status. The mill utilized a conventional sulfu-
ric acid leach and solvent extraction recovery process. Ion
exchange units were also used to extract uranium from mine water
discharged during dewatering of the Quivera mines.
Approximately 33 million tons of process solids were deposited
on-site in two main tailings impoundments (Nos. 1 and 2a) and two
ancillary impoundments (No. 2b and 2c). The disposal areas are
enclosed by dams (embankments) constructed with sand tailings.
Impoundment No. 1 encompasses approximately 229 acres and was used
almost exclusively during operations; Impoundment No. 2a, 2b, and
2c covers approximately 139 acres. Liquid tails were decanted as
clear solutions and pumped to lined ponds for evaporation. Solids
from the evaporation ponds will be returned to the tailings pile.
Interim site reclamation activities are currently underway.
Tailings pile No. 1 has been regraded and recontoured to convey
precipitation off the top and covered with an interim cover con-
sisting of one-foot of alluvium material. Approximately 85 acres
of Impoundment No. 2a, 2b, and 2c have also been dried and blanket-
ed with a one-foot interim soil cover. In accordance with the
Memorandum of Understanding between the EPA and NRG, the target
date for completing emplacement of a final earthen cover to limit
radon emissions to a flux of 20 pci/m2/s or less is 1997.
3.2.11 Rio Alaom Mill
The Rio Algom Mill owned by Rio Algom Mining Corporation is
located in Lisbon, Utah. Rio Algom operated the mill from May 1972
until October 1988, when it was shut down due to declining ore
reserves.
The mill's designed throughput was 750 tons of ore per day.
The ore was processed by alkaline leaching and ion exchange.
During operations, tailings were deposited in two above-grade,
earthen dam constructed impoundments. The impoundments are unlined
but dug into natural clay. The total tailings disposal area
encompasses an estimated 100 acres with approximately 3.3 million
tons of tailings.
3-8
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Reclamation activities, to date, include completion of a
three-foot interim radon attenuating cover of clay and clay silt
over both tailings impoundments. Based on the MOU, a final radon
cover will be in place over the entire impoundment area by 1996.
3-2.12 Sohio-L-Bar Mill
The L-Bar Uranium Mill is located in Seboyeta, New Mexico.
Mining and milling operations were managed by Kennecott Corpora-
tion, a subsidiary of BP America, from 1977 until cessation of
operations in May 1981. The source materials license was trans-
ferred to Sohio Western Mining Company in 1990.
The L-Bar mill utilized an acid leach process for extracting
uranium from the ore. An estimated 1.6 million tons of tailings
waste, consisting of about 38 percent solids mixed with water,
acid, and a variety of spent process chemicals, was generated
during the operating period. These tailings were pumped into an
above-grade tailings impoundment. The impoundment dam was con-
structed from a starter dam of weathered Mancos Shale, with a
bottom lining of salt-treated shale (to promote clay swelling).
The tailings disposal area encompasses approximately 80 acres.
Reclamation activities at the site are nearing completion. A
final earthen cover, which meets the radon emission limit of 20
pci/m2-s, has been placed over the entire impoundment area. Rock
erosion protection is in place over the embankment slopes and
spillways, and vegetation is beginning to grow on the pile top.
The MOU target date for the L-Bar site has been set for 1992.
3.2.13 UMETCO. Gas Hills Mill
Umetco Minerals Corporation, a wholly owned subsidiary of
Union Carbide Corporation, began operations of the Gas Hill Mill,
located in East Gas Hills, Wyoming, in 1960. The mill's initial
throughput capacity of 1100 tons of ore per day was increased to
1400 tons per day in 1980. An acid leach process was used to
extract the uranium from the start of operations in 1960 until late
1984. Heap leach operations at the mill were introduced in March
1980. The heap was extended in November 1982 and leaching opera-
tions continued until shut down in December 1984. The facility
remained in a standby status from 1985 until 1987 awaiting improved
market conditions. Operations resumed in May 1987 and shut down
permanently on January 1, 1988.
The mill site encompasses a total of 235 acres which includes
the uranium mill, two tailings impoundments (one above-grade
tailings area and the A-9 below-grade tailings pit), heap leach
operations, and evaporation ponds. The 147-acre above-grade tail-
ings disposal area was used between 1960 and 1980 and contains
3-9
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approximately 5.8 million tons of tailings. The 24-acre A-9 pit (a
clay-lined, depleted open pit mine) received approximately 1.4
million tons of tailings between 1980 and 1984. In addition, the
A-9 pit has received 2.3 million tons of tailings from the Riverton
site (Title I), The total tailings area (two impoundments and the
heap leach pile) encompasses approximately 192 acres.
Reclamation activities have begun at the Umetco Gas Hill site.
Currently, a four-foot interim soil cover has been placed over the
192-acre tailings impoundment area. According to the MOU, all
tailings areas will have a final cover, which meets the UMTRCA
emission standards, by 1995.
3.2.14 UMSTCO. Mavbe11 Site
The Maybell, located northeast of Maybell Colorado (an Agree-
ment State) is a heap leach facility. Umetco Minerals Corporation
operated the facility between 1975 and 1982.
At the Maybell site, low grade uranium ore was placed on a
clay liner in piles (heaps) from 35 to 50 foot high. The heap
leach process consisted of ponding a dilute solution of sulfuric
acid in cells on top of heaps of low grade uranium ore. The acid
percolated through the ore producing uranium-laden fluids (leach-
ate) . The leachate was collected by a drain system, constructed
above the clay liner, and piped to an adjacent plant for concen-
tration.
The heaps cover an area of approximately 50 acres. A thick
containment berm constructed of mine overburden surrounds the
perimeter of the leach piles.
Reclamation activities, to date, include dewatering of the
heaps and placement of a six-inch interim soil cover over approx-
imately 35 acres. The remaining 15 acres are currently dry and
uncovered. In accordance with the MOU, a target date of 1997 has
been set for completion of an earthen cover, which meets the radon
emanation limit of 20 pCi/m2-s.
3.2.15 UMETCO. Uravan Mill
The Uravan Mill is located in Uravan, Colorado (an Agreement
State). Umetco Mineral Corporation, a subsidiary of Union Carbide
Corporation, owns the mill. The mill began processing uranium,
vanadium, and radium in 1915 using a two-stage acid leach operation
to recover uranium and vanadium. The mill operated at a maximum
licensed capacity of 1400 tons of ore per day. In November 1984,
the mill was placed on standby. In 1987, the license was amended
to maintain the mill on standby and to permit reclamation of the
existing tailings.
3-10
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An estimated 12 million tons of tailings was produced during
operations. This waste was disposed of in three tailings impound-
ments situated on mesas. Impoundments 1 and 2 are adjacent and
overlapping and actually constitute one impoundment, which combined
cover approximately 39 acres. The outward face of the impoundment
is constructed behind dikes of coarse tailings and the inward side
is contained by the native terrain. Impoundment 3 is also con-
structed behind embankments of course tailings and encompasses
about 19 acres. In addition, the site contains a 12-acre sludge
pile.
Reclamation activities, to date, include placement of a ten-
foot soil cover over approximately 90% of the impoundment area.
The remaining 10% (about 7 acres) contains a one-foot interim soil
cover. The MOU specifies a target date of 2002. However, a CERCLA
Consent Decree requires final cover over the tailings by 1997 with
the exception of a small portion of the impoundment (roughly 1%),
which may remain open to receive residues from groundwater restora-
tion activities. For the purposes of this analysis, 1997 will be
used as the target date.
3.2.16 UNC. Church Rock Mill
United Nuclear Corporation's (UNC) Church Rock Uranium Mill
facility is located about 17 miles northeast of Gallup, New Mexico.
The mill operated from 1977 until May 1982, when activities were
stopped due to the poor uranium market.
The mill normally processed approximately 3500 tons of ore per
day using an acid leaching process to extract the uranium. The
resulting acid solution and tailings were stored in a series of
three unlined tailings impoundments, each of earthen dam construc-
tion. In July 1979, there was a breach in the earthen retaining dam
of one of the ponds spilling approximately 94 million gallons of
acidified effluent and about 1100 tons of tailings slurry. Follow-
ing the dam failure, UNC dug two pits (Borrow Pits 1 and 2) for
disposal of mill solutions and tailings. The total tailings
disposal area covers about 103 acres.
Currently, the Church Rock Mill is in the process of being
decommissioned. Other reclamation activities are in progress at
the site including the completion of a one-foot interim soil cover
over the entire tailings impoundment. A final earthen cover, which
meets the UMTRCA emission standards, will be in place by 1997.
3-11
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3.2.17 UnionPacific. Bear CreekMill
Bear Creek Uranium Company, owned by Rocky Mountain Energy (a
subsidiary of Union Pacific Corporation) operated the Bear Creek
Mill located in Powder River Basin, Wyoming. The mill was operated
from September 1977 through January 1986, when it was shut down due
to unfavorable uranium market conditions.
The mill utilized a conventional sulfuric acid leach-solvent
extraction process for extracting uranium oxide. The original mill
throughput capacity of 1000 tons per day was expanded to 2000 tons
per day in 1979. Tailings were disposed in an earth-filled dam
constructed from mine overburden. With the increased mill through-
put, it was recognized that the original design capacity of the
tailings area would be inadequate. Therefore, the mined out B-3
pit was used as a second tailings disposal impoundment. The
coarse, dewatered solids (sands) were deposited in the B-3 pit and
the fine tailings solids (slimes) and solution were disposed in the
originally designed tailings impoundment area. The total tailings
disposal surface area occupies approximately 178 acres.
Bear Creek Uranium Company has begun reclamation activities at
the site. Mill decommissioning has been completed. Currently, the
tailings surface is protected with an average one-foot thick
interim cover of clay soil. The projected target date for comple-
tion of the final earthen cover is 1996 in accordance with the
Memorandum of Understanding.
3•2.18 WNI. Sherwood Mill
The Sherwood Mill is located on the Spokane Indian Reservation
in Washington, an agreement state. Western Nuclear, Inc. (WNI)
operated the mill from 1978 through 1984. In 1984 the mill was
maintained in a "hot" standby mode between 1984 and 1988. In 1988,
the boilers were shut down and the mill was considered to be in
"cold" standby.
A conventional acid leach-solvent extraction circuit was used
for the recovery of uranium oxide from ore. The mill was designed
to process 2000 tons of ore per day. Resultant tailings waste
(approximately 2.3 million tons) was disposed in a single above-
grade tailings impoundment constructed with earthen embankments.
This tailings area encompasses about 94 acres and at the cessation
of operations was filled to approximately 70% of full capacity.
Decommissioning of the mill commenced in January i990.
Western Nuclear, Inc. is currently in the process of dewatering the
tailings impoundment area. To date, approximately 50 acres are
dry and 44 acres are wet. In accordance with the MOU, the
target date of 1996 has been set for completion of a radon attenua-
tion cover over the tailings area.
3-12
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3-2.19 WNI. Split Rock Mill
Between the years of 1957 and 1981, Western Nuclear Inc. (WNI)
operated the Split Rock Uranium Mill and adjacent tailings disposal
areas, located in Jeffery City, Wyoming. The mill was placed on
standby status during the period of 1981 through 1986. In 1986,
the license was amended to terminate use of the tailings pond for
tailings disposal. During operations, the mill was licensed to
process 1700 tons of ore per day using an acid leach-solvent
extraction method.
The original tailings disposal area, constructed with an
earthen starter dike and a tailings sand embankment, was utilized
from 1958 to 1977. In 1977, the tailings liquid breached the
extreme northern section of the embankment. Following the breach,
the embankment was repaired and the impoundment area was enlarged
by constructing a new compacted tailings dam upstream of the
existing embankment. The entire 223 acre disposal area contains
approximately 7.7 million tons of tailings waste.
To date, WNI has completed decommissioning activities at the
site. Reclamation operations, inclusive of an interim cover over
the entire impoundment area, are underway. As specified in the
MOU, a target date of 1995 has been set for completion of an
earthen cover which reduces radon levels to 20 pCi/m2-s or less.
3-13
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Page Intentionally Blank
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CHAPTER 4
RADON-222 SOURCES, ENVIRONMENTAL TRANSPORT, AND RISK COEFFICIENTS
This chapter presents the physical and chemical properties of
radon-222, where and how it is emitted from the uranium tailings,
and the mechanism by which it is transported through the environ-
ment. Also presented are the methods used to model the atmospheric
dispersion of the radon-222 and a description of how the health
risks associated with these emissions are estimated.
Uranium ore contains both uranium and its decay products,
including significant concentrations of radium-226. Radon-222 is a
naturally occurring radioactive gaseous element that is formed by
the radioactive decay of radium-226. Radium-226 is a long-lived
(1620 year half-life) decay product of the uranium-238 series. In
nature, uranium is about 99.3 percent uranium-238; thus, it is the
decay products of uranium-238 (Figure 4-1) that govern the radioac-
tive content of the ore.
4.1 MILL TAILINGS: ENVIRONMENTAL SOURCE TERMS FOR RADON-222
Uranium ore that is processed in mills to concentrate uranium
to an intermediate semi-refined product called yellowcake, yields a
waste material with significant concentrations of radium. About
ten percent of the starting concentrations of the uranium-238 and
virtually all of the decay products in the ore inclusive of radium-
226 are contained in the tailings. Radium-226 undergoes further
radioactive decay to produce radon-222 gas. The half-life of
radon-222 is 3.8 days. Therefore, when radon is released to the
atmosphere, the released atoms can travel large distances before
they decay. Tailings represent the largest and longest lasting
source of radon-222 emissions from licensed uranium mills because
of the large exposed area and the residual concentrations of
radium.
Radon-220, a decay product of thorium-232, is also contained
in tailings. Because of its short half-life of only 55 seconds, it
has a limited time to be released into the atmosphere and reach a
potential target population. Radon-220 is regarded to have an
insignificant impact on human health when released from uranium
mill tailings piles and will, therefore, not be considered in this
report.
Radon, as an inert gas, is chemically unreactive with most
materials and is free to travel through the small spaces between
particles which constitute a tailings pile. The fine slime fraction
contains the majority of radium-226 in the tailings (NRC80). The
sand fraction contains radium-226 in concentrations ranging from 26
to 100 pCi per gram (NRC80), and the tailings liquid (raffinate)
contains 1.7 to 35,000 pCi per liter of radium-226 (EPA83b).
4-1
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U-238
a,7
4.5 x 109 y
Th-234
18,7
24.1 d
Pa-234
18,7
1.17 m
Ra-226
01,7
7.7 x 104 y
Th-230
a,7
2.44 x 105 y
U-234
1.6 x 103 y
Rn-222
a,7
3.82 d
Po-218
a
3.05 m
Pb-214
0,7
26.8 m
Pb-210
a,7
1.64 x 1Q-4
Po-214
0,7
Bi-214
19.8 x m
0/7
22.3 y
Bi-210
Po-210
5.01 d
a/7
138.4 d
Pb-206
Y
d
m
s
years
days
minutes
seconds
Figure 4-1.
Uranium-238 Decay Chain and Half-Lives of Principal
Radionuclides
4-2
-------
Not all the radon produced within the pile will be released to
the pore spaces between particles. Some of radon produced will
remain trapped within the physical structure of the particles or
through recoil become "impacted" in adjoining particles and will,
therefore, be unable to enter the pore spaces (Figure 4-2}. Because
radon is moderately soluble in water, the single most important
variable is moisture content of the piles. However, a limited
amount of water is thought to enhance the apparent emission of
radon because it reduces the radon atom's recoil range and may
prevent radon atoms from lodging in adjacent grains. The radon
atom can then diffuse into the pore air space where it is available
to migrate through the pile. If the pore spaces are totally
saturated, as is the case when piles are wetted or in ponded areas,
the radon atom has a low probability of emanating from the pile.
This is due to the fact that water hinders radon's,migration by
lowering the diffusion coefficient and by absorbing radon atoms
(Ta86). Radon solubility depends on the water temperature; the
colder the water, the greater the radon's solubility. A measure of
gas solubility is given by the solubility coefficient. The radon
solubility coefficient is defined as the ratio of the radon concen-
tration in water to that in air (Co86). The warmer the water
temperature, the more radon is released,* and, therefore, the lower
the solubility coefficient. The maximum solubility coefficient of
radon is about 0.5 at water temperatures approaching 0°C. Solubil-
ity decreases exponentially with a rise in temperature and is
reduced to about 0.25 at 20°C and 0.1 at 90°C.
* Rodium-226
A- Rodon-222
Of Alpha Panicle
R Recoil Range — The distance *not o
radon—222 atoms troveis -«nen :ne
rodium-226 otom
Figure 4-2. Radon Emanation Process
4-3
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4.1.1 BsjtiroatingRadon Emissions from Tailings Impoundments
In addition to moisture content, the amount of radon-222
emitted from tailings impoundments depends on a number of highly
variable factors, such as ore grade, grain size, porosity, tempera-
ture, and barometric pressure. These factors, in turn, vary
between sites, between locations on the same site, and with time
(PEI85). For these reasons, mathematical models typically have
been used to estimate average radon-222 emissions on a theoretical
basis. Considerable research has been conducted to develop and
refine ways of calculating average radon-222 flux from infinitely
thick or deep sources (i.e., at least 1 meter deep). This work has
largely been carried out in support of the Uranium Mill Tailings
Remedial Action Program (OMTRAP) and pertains to inactive mill
tailings piles. Empirical measurements have been made of radon-222
emissions from licensed uranium mills and tailings piles, and
studies have demonstrated good agreement between actual measure-
ments and estimates based on mathematical models (EPA83b).
A one-dimensional, steady-state, radon-222 diffusion equation
has been developed for sources (e.g., ore piles and tailings) that
are more than several meters thick (Ni84, Fr84). Equation 4-1
defines the radon flux at the surface as follows:
j; = 104 RpE (jD)m (Eq. 4-1)
where Jt is the radon-222 flux at the surface of the source
CpCi/m2-s) ; R is the specific activity of radium-226 in ore or
tailings equal to 2812 x (uranium ore grade in percent), pCi/g; p
is the bulk dry density of the source (g/cm3) ; E is the radon-222
emanating fraction of source, dimensionless; j is the radon-222
decay constant (2.1 x 10'Vs) ; D is the effective diffusion coeffi-
cient for radon-222, equal to bulk radon diffusion coefficient/
porosity De/p (cm2/s) ; and p is the porosity, equal to 1- (bulk
density/ specific gravity).
For piles that are less than a few meters thick, Equation 4-1
should be multiplied by a hyperbolic tangent function that varies
with depth or thickness (T), as shown in Figure 4-3. With the
exception of the radon-222 decay constant, these parameters can
vary significantly from location to location within the source,
both horizontally and with depth, in a given ore pile or tailings
impoundment. Except for the decay constant and bulk density, these
parameters are difficult to measure. They are based on the physi-
cal characteristics of the source materials, which vary (1) over
time (e.g., radium-226 content may decrease over the life of the
mill as ore grade declines), (2) seasonally, and (3) with changing
mill operation. Given the complexity and variability of parameters
affecting radon emission and the scarcity of site-specific measure-
ments, the EPA has adopted the following generic correlation
between radon emissions and radium concentration (EPA83b):
4-4
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Radon emanation estimates in this report are based on the
average radium concentration of a pile using the simplified
relationship of 1 pCi Ra-222/m2-s per pCi Ra-226 per gram of
tailings. This emanation rate is applied to all areas of a
pile that are free of significant moisture. Wetted or ponded
areas of a pile are assumed to emit no significant levels of
radon.
Dfi= BULK DIFFUSION COEFFICIENT
0,0
40 120 200 280 360
DEPTH,cm
440
520
600
Figure 4-3. Effect of Pile Depth on Hyperbolic Tangent Term in
Radon-222 Flux Equation (Ha85).
4-5
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4.1.2 Ingrowth of Radon -.2 2 2 ..... Decay Products
At the point where radon-222 diffuses out of the tailings pile
surface, the concentrations of associated radon- 222 decay products
are zero, because those decay products generated prior to diffusion
from the surface are retained in the tailings. As soon as radon -
222 is airborne, ingrowth of decay products commences. The quanti-
tative relationship between radon and radon decay products depends
on the extent to which radioactive equilibrium is reached. If the
rate of formation and disintegration of the decay products suspend-
ed in air is exactly equal, a condition of secular equilibrium is
reached. .Although secular equilibrium is a theoretical upper
limit, in reality it is not achievable due to plume depletion of
radon daughters by dry and wet deposition and precipitation scav-
enging .
Human exposure to radon- 222 progeny from tailings piles is
based on an indoor/outdoor exposure model . The model, assumes that
the average individual spends about 75 percent of the time indoors
and 25 percent outdoors (Mo76; Oa72) . Radon- 222 and its decay
products may enter a structure that is downwind and enhance the
normal indoor air concentration.
The specific activity of radon or individual decay product
isotopes is commonly quantified in picocuries per liter {pCi/1} .
However, the specific activity of short-lived radon decay products
collectively is also measured in units called working levels (WL) .
One working level is any concentration of short-life radon-222
progeny having 1.3 x 10 MeV per liter of potential alpha energy
(PRC67) . The relationship between the working level concentration
of decay products and the picocurie per liter concentration of
radon, depends on the degree of equilibrium between radon and radon
daughters. At secular equilibrium, one WL is equal to 100 pCi/1 of
radon-222.
Equation 4-2 defines the relationship between WL and pCi/1 in
terms of the equilibrium fraction:
Equilibrium Fraction - f j-°° (Eq. 4-2}
UP / •*
The exposure to radon-222 progeny at a site of interest is
based on the calculated radon-222 concentration and the calculated
radon-222 progeny equilibrium fraction:
(Eq. 4-3)
Radon progeny Radon Radon progeny
concentration = concentration x equil. fraction x 1.0 x 10"2
(WL) (pCi/1) (£*) (WL/pCi/1)
4-6
-------
Calculations of radon-222 progeny equilibrium fractions are
based on distance from a source and the time required to reach the
exposure site. By using the ingrowth model of Evans (Ev69) and the
potential alpha energy data of United Nations Scientific Committee
on the Effects of Atomic Radiation (UNSCEAR77) , the outdoor
equilibrium fraction can be calculated by the expression:
feout = 1.0 - 0.0479e-t/4J9 - 2,1963e-'BS'6 + 1.2442e-tf28'4 (Eq. 4-4}
where t is the travel time in minutes (distance/transport
velocity),
The indoor equilibrium fraction presumes that those decay
products associated with the radon-222 release also enter the
building and that a ventilation rate of 1 hour"1 (one air change per
hour) in combination with indoor removal processes (e.g., deposi-
tion onto room surfaces) produces an indoor equilibrium fraction
of 0.35 when there are no decay products in the ventilation air and
0.70 when the decay products are in equilibrium with the radon-222
in the ventilation air (EPA83b). A simple linear interpolation is
used to obtain the indoor equilibrium fraction:
f/ = 0.35 (1 + f,.0"1) (Eq. 4-5}
If one further assumes that a person spends 75 percent of his
or her time indoors and the remaining 25 percent outdoors at the
same location, the effective equilibrium fraction is given by:
feeff = 0.75 fsm + 0.25 feout = 0.2625 4- 0.5125 feout (Eq. 4-5)
To calculate air exposure concentrations for specific members
of the public and regional populations, EPA uses the computer model
CAP-88 EPA 1991 (SPA 520/6-91/022, December 1991, "User's Guide for
CAP88-PC"). CAP-88, which stands for Clean Air Act Assessment
Package - 1988, is a set of computer programs, databases, and
associated utility programs for estimating dose and risk from a
variety of radionuclide emissions to air inclusive of radon from
large area sources. Large area sources are modeled in CAP88-PC
using a method described by Mills and Reeves, as modified by
Christopher Nelson, EPA, and implemented by Culkowski and Patterson
(Mo79). The method transforms the original area source into an
annular segment with the same area. The transformation is depen-
dent on the distance between the centroid of the area source and
the receptor. At large distances {where the distance/diameter
ratio is 2.5), the area source is modeled as a point source; at
close distances it becomes a circular source centered at the
receptor. A point source model is also used if the area source is
10 meters in diameter or less.
4-7
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CAP-88 uses a modified Gaussian plume equation along with
proximal meteorological data. Annual average meteorological data
sets include frequencies for several windspeed categories for each
wind direction and Pasquill atmospheric stability category. CAP-88
uses reciprocal-averaged wind speeds in the atmospheric dispersion
equations, which permit a single calculation for each wind speed
category.
The principle of reciprocity is used to calculate the effec-
tive chi/Q. The problem is equivalent to interchanging source and
receptor and calculating the mean chi/Q from a point source to one
or more sector segments according to the angular width of the
transformed source. The mean value of chi/Q for each sector
segment is estimated by determining chi/Q at the distance which
would provide the exact __value of the mean if the variation in chi/Q
were proportional to r"La for distances from the point source to
location within the sector segment. The chi/Q for the entire
transformed source is the sum of the chi/Q values for each sector
weighted by the portion of the total annular source contained in
that sector,
Table 4-1 provides a sample set of values for a 3.5 m/s
windspeed and various distances from an 80 hectare source. Removal
processes outdoors were assumed to limit the equilibrium fraction
to 0.85, which corresponds to an indoor equilibrium fraction of
0.65 and an effective fraction of 0.70. Table 4-1 shows that this
limit is reached at a distance of 19,550 meters.
4-8
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Table 4-1. Radon-222 Decay Product Equilibrium Fraction at
Selected Distances from the Center of a 80 Hectare
Tailings Impoundment1
Distance
(m)
150
200
250
300
400
500
600
800
1,000
1,500
2,000
2,500
3,000
4,000
5,000
6,000
8,000
10,000
15,000
19,551
f OUt
-*-e
0.013
0.020
0.026
0.031
0.041
0.051
0.060
0.078
0.094
0.133
0.168
0.201
0.234
0.295
0.353
0.407
0.507
0.593
0.755
0.850
fe™
0.355
0.357
0.359
0.361
0.364
0.368
0.371
0.377
0.383
0.397
0.409
0.421
0.435
0.453
0.473
0.493
0.527
0.558
0.614
0.648
fecff
0.267
0.273
0.276
0.278
0.284
0.289
0.293
0.302
0.311
0.331
0.349
0.366
0.382
0.414
0.443
0.471
0.522
0.566
0.650
0.698
Calculations (tabulated to 3 decimal places to
facilitate comparisons) presume: a 3.5 m/s
windspeed for the outdoor equilibrium fraction;
an indoor equilibrium fraction of 0.35 for no
radon-222 decay products in the ventilation air
and 0.70 for ventilation air with 100 percent
equilibrium between radon-222 and its decay
products; and an effective equilibrium fraction
based on 75 percent of time indoors and 25
percent of time outdoors.
4-9
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4.2 RADON-222 EXPOSURE PATHWAYS AND RISKS TO HUMAN HEALTH
Radon-222 has a half-life of 3,8 days and follows a decay
process that involves seven principal decay products* before ending
as stable non-radioactive lead (see Figure 4-1). The dominant
decay products are those with very short half-lives and include
polonium-218, lead-214, bismuth-214, and polonium-214. It is
generally believed that it is radon decay products, rather than
radon itself, that may induce lung cancer among exposed individu-
als. The quantitative relationship between radon and radon decay
products depends on the extent to which radioactive equilibrium is
reached. Polonium-218, the first decay product, has a half-life of
just over three minutes. This, however, is long enough for most of
these electrically charged and chemically reactive atoms to attach
themselves to microscopic airborne dust particles. The total radon
daughter products (attached and unattached) that remain suspended
in air is reduced by several processes so that secular equilibrium
is never reached. Removal processes are affected by the concentra-
tion of airborne dust particles, the size of dust particles,
surface to volume ratio, surface texture, air flow, etc. Based on
simultaneous measurements of radon and radon decay products, it has
been found that the indoor equilibrium fraction ranges from 0.3 to
0.7 with an average of about 0.5 (Ge85).
When inhaled, attached radon decay products with particle
sizes in the micron range are deposited on the moist epithelial
lining of the larger bronchi of the lung. Unattached radon decay
products when inhaled penetrate smaller regions of the lung where
they may be deposited. Although most particles are eventually
removed from the larger bronchi and upper respiratory tract by
natural mechanisms, radioactive decay occurs in time to expose lung
cells to ionizing radiation. Two of the short-lived decay prod-
ucts, polonium-218 and polonium-214, emit alpha particles during
the decay process, which exposes proximal cells to radiation with
high linear energy transfer (high-LET).
High-LET radiations have a larger biological effect per unit
dose (rad) than low-LET radiations. How much greater depends on
the particular biological endpoint under consideration. For cell
killing and other readily discernable endpoints, the relative
biological effectiveness (RBE) of high-LET alpha radiation may be
10 or even 20 times greater than low-LET radiation. The RBE value
is also influenced by the dose level; for example, if linear and
linear-quadratic dose response functions are demonstrated for high-
and low-LET irradiations, respectively, the RBS must be assumed to
decrease with increasing dose for the high-LET radiation.
For purposes of calculating dose equivalent, each type of
radiation emission is assigned a quality factor (Q) to account for
* Radon decay products are also referred to as radon daughters.
4-10
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its relative efficiency in producing biological damage. The dose
equivalent (in rems) is the absorbed dose (in rad) times the
appropriate quality factor (Q) for a specified kind of radiation.
Unlike an RBE value, which is usually defined in terms of a specif-
ic target cell, biological endpoint, and dose-level, a quality
factor represents a generic assessment by radiation experts of the
potential harm of a given radiation relative to X- or gamma-rays.
In 1977, the International Commission on Radiological Protection
(ICRP) assigned a quality factor of 20 to alpha particle irradia-
tion from internal emitters (ICRP77). The ICRP also found evidence
that for very low dose rates such as in occupational settings, the
biological risks were lower by a factor of 2.5 than the same
exposure received over a short period of time. Implicit in ICRP's
risk estimates for low dose/low dose rate is a dose reduction
factor (DREF) of about 2.5. The EPA risk model does not employ
DREF; therefore, in order to avoid an artificial inflation in high-
LET risk estimates, EPA has assumed a RBE of 8 (i.e., 20/2.5 = 8)
for calculating the risks from internal alpha particles.
In the case of alpha irradiation of the lung by radon decay
products, an assessment of risk is not only limited by uncertain-
ties regarding RBE values but also by the non-uniformity of radio-
nuclide distribution and dose distribution among and within indi-
vidual target cells. Adequate characterization cannot be made of
the exact doses delivered to cells that eventually become cancer-
ous. In uranium miners, and the general population, the majority
of lung cancers arise from the epithelium of bronchial airways. In
this tissue, both secretory and basal cells are considered to be
targets for lung cancer development (NRC91). Knowledge of the
deposition pattern of the radioactive particles and non-attached
decay products and the geometric spacing of decay progeny to cells
that are susceptible can only be ascertained by theoretical models.
(Ha82, Ja80, Ja81, Mc78, Mc83). Fortunately, there are human
epidemiological data that allow direct estimates of risks per unit
of exposure that do not use a dosimetric approach. The Agency's
estimates of risk of lung cancer due to inhaled radon progeny is
based on the epidemiological approach adopted by the National
Academy of Science, in which risk estimates are based on observed
excess lung cancers among groups exposed to varying time-integrated
air concentrations of radon progeny. In effect, EPA's estimates of
lung cancer risks are based on the amount of inhaled radon-222
decay products to which people are exposed rather than on the dose
absorbed by specific target cells of the lung.
4.2.1 Characterizing Exposures and Risks to the General Population
Vis-a-Vis Underground Miners
Epidemiological investigations of uranium and other under-
ground miners have provided valuable data on the quantitative risks
of lung cancer associated with exposure to radon progeny in under-
ground mines. The principal occupational groups that constitute
4-11
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the epidemiological database for the risk estimates include: (1)
U.S. uranium miners, (2) Czechoslovakian uranium miners, (3)
Ontario uranium miners, (4) Malmberget iron miners, and (5)
Eldorado uranium miners.
As discussed above, exposure to radon-222 decay products under
working conditions is commonly reported in the unit of working
level (WL). The WL unit was developed because the concentration of
specific radon progeny depends on ventilation rates and other
factors. A working level month (WLM) is the unit used to charac-
terize a miner's exposure to one working level of radon progeny for
a working month of about 170 hours. Because the results of epide-
miological studies are expressed in units of WL and WLM, the
following outlines how they can be interpreted for members of the
general population exposed to radon progeny.
The EPA assumes that a mine worker inhales 30 liters per
minute (averaged over a work day). This average corresponds to
about 4 hours of light activity and 4 hours of moderately heavy
work per day (ICRP75). The new ICRP radon-222 model, however,
assumes an inhalation rate of 20 liters per minute for mine work-
ers, which corresponds to 8 hours of light activity per day
(ICRP81). This may be appropriate for nuclear workers; however,
studies of the metabolic rate of mine workers clearly show that
they are not engaged in light activity only (Sp56; ICRP75; NASA73).
Therefore, 30 liters appears to be a more realistic estimate of the
average per minute volume for this group. Based on this per minute
volume, a mine worker inhales 3.6 x 103 cubic meters in a working
year of 2000 hours (ICRP79). One working level of radon-222
progeny is equivalent to 2.08 x 10~5 joules per cubic meter (1.3 x
10s MeV per liter); therefore, in a working year, the potential
alpha energy inhaled by a mine worker exposed to one working level
is 7.5 x 10^ joules.
There are age- and sex-specific respiratory rate and volume
differences, as well as differences in duration of exposure, in a
general population as compared to a mining population. According
to the ICRP Task Group Report on Reference Man (ICRP75), an inhaled
air volume of 2.3 x 104 liters per day is assumed for adult males,
2.1 x 104 liters per day for adult females of the general popula-
tion. Reduced volumes of air are respired by children. However,
the smaller bronchial area of children, as compared with that of
adults, more than offsets their lower per minute volume.
For a given concentration of radon-222 progeny, the amount of
potential alpha energy a member of the general population inhales
in a month is more than the amount a mine worker receives in a
working month. Although members of the general population are
exposed longer (up to 24 hours per day, 7 days a week), the average
amount of air inhaled per minute (minute volume) is less in this
group than that for a mine worker when periods of sleeping and
4-12
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resting are taken into account (EPA79; Th82). The radon-222
progeny exposure of a mine worker can be compared with that of a
member of the general population by considering the amount of
potential alpha energy each inhales per year (Ev69). That radon
daughter deposition {and dose) in the conducting airways of the
lung is proportional to ventilation rate (quantity inhaled) has
also been recommended by other investigators (Ra 85; Ho 82).
In earlier reports, EPA used an "exposure equivalent," a
modified WLM in which adjustments were made for age-specific
differences in airway dimensions and surface area, respiratory
frequency, and minute volume. These factors were expected to
influence aerosol deposition and, therefore, radiation dose from
radon daughters. This approach to quantifying exposure, correcting
for differences in these factors, was recommended by Evans (Ev69)
and is consistent with the original derivation of the working level
(Ho57).
The BSIR IV Committee, however, concluded that the tracheo-
bronchial "dose per WLM in homes, as compared to that in mines,
differs by less than a factor of 2," and, at the time the BEIR IV
Report was issued, advised that the dose and risk per WLM exposure
in residences and in mines should be considered to be identical
until better dosimetric estimates are developed (NAS88). The BEIR
IV Report, however, also stated the need for further research and
analysis on uncertainties in applying lung cancer risks character-
ized for underground miners to people in their homes. Because of
the importance to the public of the risks of radon exposure in
homes and schools, the EPA asked the National Research Council to
initiate a study of the dosimetric considerations affecting the
applications of risk estimates, based on studies of miners to the
general population. The EPA asked that a panel be assembled to
investigate the differences between underground miners and members
of the general public in the doses they receive per unit exposure
due to inhaled radon progeny. In 1991, the NRC published a compan-
ion report to the BEIR IV Report entitled "Comparative Dosimetry of
Radon in Mines and Homes," (NRC91).
On the basis of this publication and review of other current
information, the EPA, in 1992, with approval of its Science
Advisory Board, adopted a risk coefficient of 2,24 x 10"4 lung
cancer deaths per person-WLM.
This risk coefficient applies to residential radon exposure
received by the general public and is based on a modified BEIR IV
model using a standard life table calculation with 1980 U.S. vital
statistics. Modifications to the BEIR IV model include the K
factor value of 0.7 and an adjustment to account for background
radon exposure. The K factor is defined and discussed in Section
4.2.4 below.
4-13
-------
The following provides a historical account of the EPA risk
model and derives the current risk coefficient of 2.24 x 10"4 lung
cancer deaths per person-WLM.
4.2.2 TheHistory and Derivation of EPA's Radon Risk Coefficients
The Early EPJl Model. The initial EPA method for calculating
radon risks has been described in detail (EPA79, E179). As new
data were reported, the EPA revised its model to reflect changes,
as contained in consecutive reports (EPA79, EPA82, EPA83a, EPA83b,
EPA84, EPA85, and EPA86). The Agency initially projected radon lung
cancer deaths for both absolute and relative risk models, but since
1978, EPA has based risk estimates due to inhaled radon-222 progeny
on a linear dose response function, a relative risk projection
model, and a minimum cancer induction period of 10 years. A life
table analysis has been used to project this risk over a full life
span,. Lifetime risks were initially projected on the assumption
that an effective exposure of 1 WLM increased the age-specific risk
of lung cancer by 3 percent over the age-specific rate in the U.S.
population as a whole (EPA79). In the most recent documents,
lifetime risks were calculated for a range of risk coefficients
from 1 percent to 4 percent per WLM (EPA86).
Comparison of Earlier Risk Estimates. Several estimates of
the risk due to radon progeny have been published since the origi-
nal EPA model was developed. These risk estimates were reviewed in
a number of EPA reports (EPA84, EPA85, and EPA86).
Previous EPA risk estimates for lifetime exposure to a general
population, along with Atomic Energy Control Board (AECB), National
Academy of Sciences (NAS), UNSCEAR, ICRP, and National Council on
Radiation Protection and Measurements (NCRP) estimates of the risk
of lung cancer resulting from inhaled radon progeny, are listed in
Table 4-2. The AECB estimate for lifetime exposure to Canadian
males is 830 fatalities per million person-WLM (Th82). In Table 4-
2, this estimate has been adjusted for the U.S. 1970 male and
female population.
4-14
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Table 4-2, Past Risk Estimate for Exposures to Radon Progeny
Fatalities per
Organization Model 106 person-WLM
EPA
NAS*
AECBb
ICRP
UNSCEAR
NCRP°
Rel.
A-S Abs.
Rel.
Dec.
760 (460)a
730 (440}a
600 (300)a
150-450
200-450
130
Exposure
Period
Lifetime
Lifetime
Lifetime
Working
Lifetime
Lifetime
Lifetime
Expression
Period
Lifetime
Lifetime
Lifetime
30 years
40 years
Lifetime
Abs.
TBEIR in
a EPA and AECB based their estimates of risk for the general
population on an exposure equivalent, corrected for breathing
rate (and other factors). For comparison purposes, the values in
parentheses express the risk in more customary units, in which a
continuous annual exposure to 1 WL corresponds to 51.6 WLM.
b Adjusted for U.S. General Population: see text.
0 NCRP84: Table 10.2; assumes risk diminishes exponentially with a
20-year halftime, and no lung cancer risk is expressed before age
40.
Sources: EPA83b; NAS80; Th82; ICRP81; EPA86; IMSCEAR77; NCRP84;
USRPC80.
Models: Rel. - Relative Risk Projection
A-S Abs. - Age-Specific Absolute Risk Projection
Dec. Abs. - Decaying Absolute Risk Projection
4-15
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The National Institute for Occupational Safety and Health
reviewed published data on miner studies used as a basis for
estimated risk coefficients and pointed out some of the strengths
and limitations of selected studies (NIOSH87).
The occupational exposure groups that constitute the epide-
miological database for the risk estimates are as follows:
1. U.S. Uranium Miners (NIOSH87)
(a) Strengths: A large, clearly defined, well-traced
cohort with some smoking histories and exposure records
on the same persons. Standard sampling techniques were
used to make measurements.
(b) Limitations: There were few measurements in small
mines, work histories were self-reported, exposures
were high, and potential error due to excursions in
exposure levels is high.
(c) Follow-up: 19 years in 1977.
2. Chechoslovakian Uranium Miners (NIOSH87)
(a) Strengths: Extensive exposure data with a large number
of low level exposures and limited exposure to other
underground mining. Many possible confounding factors
have been investigated and eliminated.
(b) Limitations: Exposure estimates prior to 1960 based on
radon gas measurements. Person years at risk not
determined in standard manner. Smoking effect neglect-
ed. Elevated levels of arsenic in ore.
{c) Follow-up: 26 years in 1975.
3. Ontario Uranium Miners (NIOSH87)
(a) Strengths: Miners received low mean cumulative expo-
sures. Prior mining experience was carefully traced.
Exposures prior to 1967 may be disputed.
(b) Limitations: Median age of the cohort was 39 years in
1977. Thoron and gamma exposures may have been high
but not accounted for. Smoking history is limited.
(c) Follow-up: 18 years in 1977.
4. Malmberget Iron Miners (NIOSH87)
(a) Strengths: Low exposure levels, long follow-up and
stability of work force. Complete ascertainment of
4-16
-------
vital status and. confirmation of diagnosis. Risk from
confounders was examined and ruled out.
{b) Limitations: Relatively small cohort with limited
exposure data and an unclear cohort definition.
(c) Follow-up: 44 years in 1976
5. Eldorado - Uranium Miners (NAS88)
(a) Strengths: Very low exposure rates, miners screened
for prior mining experience, roughly equal groups
of surface only and underground only miners, Silica
and diesel exhaust exposures low. Potential
confounders investigated.
{b) Limitations: Exposure estimates are disputed. Sixteen
percent of the miners excluded for incorrect or missing
data. Average age in 1980 was 43 years.
(c) Follow-up: 14 years in 1980.
BBIR_...IV Risk Estimates. In early 1988, the National Academy
of Sciences released the BEIR IV Committee report, which compre-
hensively examined information on the risks from radon and other
alpha-emitting radionuclides (NAS88). With the cooperation of
the principal investigators, BEIR IV reviewed in detail the
mortality experience of four cohorts of underground miners (the
U.S., Ontario, and Eldorado uranium miners and the Malmberget
iron miners) and how the mortality related to radon daughter
exposure. The Committee calculated the relationship of age-
specific relative risk to exposure level and time-since-exposure
(TSE) in two analyses. The first used internal cohort compari-
sons and was a grouped-data analog of a Cox relative-risk regres-
sion (NAS88). The second analysis compared the cohorts with
external rates and was a generalization of common standard
mortality ratio (SMR) methods. Separate parallel analyses were
carried out to establish a single combined value for each parame-
ter.
The mathematical form of the Committee's preferred TSE model
for the radon related age-specific mortality rate at age (a) is
r(a) = r0(a) [1 + 0.025 j (a) (Wt + 0.5W2)] (4-7)
where:
r(a) is the lung cancer mortality at attained age (a) due to
all causes,
4-17
-------
r0(a) is the age-specific baseline rate of lung cancer death
in the absence of any excess radon exposure over low back-
ground levels,
7(a) is the age-specific adjustment to the relative risk
coefficient for radon with
7(a) - 1.2 when a < 55 years
= 1.0 when a is 55-64 years
= 0.4 when a a 65 years
The -y (a) adjustment decreases the radon-induced lung cancer
risk with age. This incorporates the Committee's finding
that excess relative risk in the miners decreased with age
at risk.
(Wj + 0.5W2) represents cumulative lifetime exposure up to
age (a) modified as follows:
W, « cumulative exposure occurring from 5-15 years
before age (a), and
W2 - cumulative exposure up to age a-15 years.
Since W2 is reduced by 50 percent, the model gives less
weight to exposures more distant in time since exposure. This
reflects the Committee's conclusion that risk decreases with time
since exposure as modeled for the four cohort studies of miners.
Hence, the relative risk coefficient (S = 0.025) effectively
varies from 0.5 percent per WLM to 3.0 percent per WLM, depending
upon age at risk and time since exposure (Pu89). Therefore,
r0(a) (0.025) (ya) (VJt + 0.5W2) represents the rate of excess lung
cancer due to radon.
The Committee model is, therefore, an age-specific, rela-
tive-risk projection model with a 5-year latent period prior to
expression of risk.
In its analysis, the BEIR IV Committee identified two major
areas of uncertainty affecting its conclusions: (1) uncertainty
related to the Committee's analysis of cohort data and (2) uncer-
tainty related to projection of the risk to other groups. The
Committee's TSE model uses risk coefficients derived from analy-
sis of data from four miner cohorts. Random or systematic
errors, particularly systematic errors, could bias the conclu-
sions. Sources of error in addition to basic sampling variation
include: (1) errors in exposure estimates, particularly since the
magnitude of error may differ among the studies; (2) errors of
misclassification of cause of death; (3) errors in smoking status
4-18
-------
of individual miners, and (4) modeling uncertainty--i.e., does
the model properly address all parameters that are determinants
of risk?
Having developed the TSE model for miners, the Committee
anticipated the following sources of uncertainty in projecting
the model across other groups: (1) effect of gender (miner data
are for males); (2) effect of age (miner data contain no informa-
tion on exposures before about age 20); (3) effect of smoking
(miner data contain poor information on smoking status); (4)
temporal expression of risk (not enough miners have died to
establish accurately the pattern of lifetime risk from radon
exposure), and (5) extrapolation from mining to indoor environ-
ments (what are significant differences in the air in mines
compared to air indoors?). After reviewing the various sources
of uncertainty, the BEIR IV Committee concluded [p42], " ...The
imprecision that results from sampling variation can be readily
quantified, but other sources of variation cannot be estimated in
a quantitative fashion." Therefore, the Committee chose not to
combine the various uncertainties into a single numerical value"
(NAS88).
The question of errors in exposure estimates is particularly
interesting since the modeling is strongly influenced by the U.S.
uranium miner data. In fact, the model risk estimates would be
33 percent higher if the U.S. cohort was removed. Exposure in
the U.S. cohort is poorly known: cumulative WLM (CWLM) are
calculated from measured radon levels for only 10.3 percent of
the miners, estimates are used for about 36.1 percent of the
miners, and "guesstimates" are employed for about 53.6 percent of
the miners (NAS88, Lu71). Only 26.1 percent of the U.S. uranium
miner exposure data are based on measured values (Lu71).
The Ontario cohort exposure estimates also are not well
founded. Upper and lower estimates were developed: the lower
from measured values, the upper based on engineering judgment
(NAS88). Eldorado cohort estimates of CWLM were based almost
entirely on measured values, while Malmberget cohort estimates
were based on a reconstruction of past ventilation conditions
(NAS88). Of the four cohorts, the United States has one of the
poorest bases for CWLM estimates. One serious problem is the
potential error due to large excursions in radon daughter concen-
trations (NIOSH87). The uncertainties in exposure estimates are
particularly significant in view of the rather large impact the
U.S. cohort has on the form of the model.
When the BEIR IV model is run with the 1980 lifetable and
vital statistics at an exposure level of 0.001 WLM per year, the
reference risk can be calculated (Table 4-3).
4-19
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Table 4-3. BEIR IV Risk Model - Lifetime Exposure and Lifetime
Risk.
Group Risk (10'VWLM)
Male 530
Female 185
Combined 350
ICRP 50. The International Commission on Radiological
Protection, in its Publication 50, addressed the question of lung
cancer risk from indoor radon daughter exposures. The ICRP Task
Group took a direction quite different from the BEIR Committee.
The Task Group reviewed published data on three miner cohorts:
U.S., Ontario, and Czech uranium miners. The estimated risk
coefficients by cohort are presented in Table 4-4.
Table 4-4. Estimated Lung Cancer Risk Coefficients from Radon
Progeny Exposure for Three Miner Cohorts.
Cohort Follow-up Relative model Absolute model
U.S.
Czech
Ontario
Average
Source: ICRP87
1950
1948
1958
•
-1977
-1975
-1981
0
1
0
.3%-
.0%-
.5%-
1%
1.
2.
1.
0%
0%
3%
2-8
10-25
3-7
10
cases/10
cases/10
cases/10
cases/10
6
6
6
6
PWLMY
PWLMY
PWLMY
PWLMY
The relative risk model then developed for a constant exposure
rate is:
t-T
X(t) = X0(t) [1 + j r(te) E(te) dte] (4-8)
0
= the mortality rate at age t
where:
X0(t) = the age-specific lung cancer rate at age t
r(te) = risk coefficient at age of exposure te
•
E(t0) = age - dependent exposure rate
4-20
-------
T = time lag (minimal latency) =10 years
In the case of a constant exposure rate or constant annual
exposure, the equation collapses to:
X(t) = X0{t) [1 + r E(t - T}] (4-9)
where:
r = age-averaged relative risk coefficient
E(t - T) - E [t - T]
= cumulative exposure to radon daughters to age t-r
Since ICRP recommends the use of the relative risk model,
the ICRP 50 absolute risk model will not be addressed further in
this document.
To adapt the relative risk model derived from studies of
underground miners for the general population, the ICRP Task
Group introduced several adjustments. The first was to correct
for co-carcinogenic influences in mines. To account for unidenti-
fied, unproven carcinogens that might be present in mine environ-
ments but not elsewhere, only 80 percent of the risk was attrib-
uted to radon. The second adjustment was for dosimetric correc-
tions. The dose to bronchial epithelium used by the Task Group
for persons indoors was estimated to be only 80 percent as large
as that for persons in minesj therefore, the risk to the public
from radon was considered to be 80 percent of the risk of miners,
Adjusting the average relative risk coefficient of 1 percent
per WLM by these two factors gives a risk coefficient of 0.64
percent per WLM:
1.0% x 0.8 x 0.8 = 0.64%. (4-10)
The third adjustment made by the Task Group is related to
age. Since reports of Japanese A-bomb survivors and other
radiation-exposed groups support an elevated estimate of risk in
children compared to adults, the Task Group increased the risk
coefficient of persons between birth and age 20 by a factor of 3.
The final relative risk coefficients in the ICRP 50 model
are: 1.9 percent per WLM if the age at time of exposure is
between birth and 20 years, and 0.64 percent per WLM if age at
time of exposure exceeds 20 years.
4-21
-------
When the ICRP 50 relative risk model is run with 1980 U.S.
lif stable and vital statistics at an exposure level of 0.001 WLM
per year, the reference risk calculated is:
Group Risk (lO
Male 610
Female 205
Combined 420
BJEBJ s Selection of Risk Coefficients in Earlier Documents.
To estimate the range of reasonable risks from exposure to radon-
222 progeny for use in the Background Information Document for
Underground Uranium Mines (EPA85) , EPA averaged the estimates of
BEIR III, the EPA model, and the AECB to establish an upper bound
of the range. The lower bound of the range was established by
averaging the UNSCEAR and ICRP estimates. The Agency chose not
to include the NCRP estimate in its determination of the lower
bound because this estimate was believed to be outside the lower
bound. With this procedure, the EPA arrived at relative risk
coefficients of 1.2 percent to 2.8 percent per WLM exposure
equivalent (300 to 700 fatalities per million person-WLM exposure
equivalent) as estimates of the possible range of effects from
inhaling radon- 222 progeny for a full lifetime. Although these
risk estimates did not encompass the full range of uncertainty,
they seemed to illustrate the breadth of much of scientific
opinion at that time.
The lower limit of the range of 1985 EPA relative risk
coefficients, 1.2 percent per effective WLM, was similar to that
derived by the Ad Hoc Working Group to Develop Radioepidemio-
logical Tables, which also used 1.2 percent per WLM (NIH85) .
However, some other estimates based only on U.S. and Czech miner •
data averaged 1 percent per WLM (Ja85) or l.l percent per WLM
(St8S) , On the other hand, three studies - two on miners (Ra84,,
Ho87) and one on residential exposure {Ed83; Ed84) - indicated a
relative risk coefficient greater than 3 percent per WLM, perhaps
as large as 3 . 6 percent .
The EPAf therefore, increased the upper limit of its esti-
mated range of relative risk coefficients. To estimate the risk
due to radon- 222 progeny, the EPA used the range of relative risk
coefficients of 1 to 4 percent per WLM. (See EPA86 for a more
detailed discussion.) Based on 1980 vital statistics, this
yielded, for members of the general public, a range of lifetime
risks from 380 to 1,520 fatal cases per 106 WLM (expressed in
exposure equivalents) . In standard exposure units, uncorrected
for breathing rate and age, this corresponds to 230 to 920 cases
per 106 WLM. Co incident ally, the geometric mean estimate ob-
tained in this way with 1980 vital statistics, 4.6xlO"4/WLM in
standard units of exposure, is numerically the same as that
4-22
-------
obtained using a. 3 percent relative risk coefficient and 1970
vital statistics.
In response to the consensus-based reports, BEIR IV and ICRP
50, and a recent report on the Czech miner groups (Se88), the
Agency subsequently reviewed its basis for radon risk estimation.
Comparable relative risk coefficients for miners (age-constant
relative risk) yielded a coefficient of around 1 percent in ICRP
50, 1.34 percent in BEIR IV, and 1.5 percent in the Czechs. This
suggested that the range, 1 percent to 4 percent, previously used
by EPA, may have been too wide.
The BEIR IV Committee noted and modeled a drop in relative
risk with increasing time of exposure and a decreasing relative
risk with increasing age after exposure (NAS88). The Czech
miners show a similar response pattern (Se88). Though the
Committee did note a dose rate effect in the U.S. uranium miner
cohort, i.e., a decrease in risk per unit exposure at high dose
rates, it was not included in the model (NAS88). The possibility
of a similar dose-rate effect was found recently in a study on
Port Radium uranium miners (Ho87).
The ICRP 50 Task Group worked from a different database and
developed a simpler model with fewer age- and time-dependent
parameters. The Task Group provided a 3 times higher risk for
exposure between birth and 20 years of age than after 20 years of
age (ICRP87). The finding in the recent Czech report that risk
prior to age 30 is 2 to 2.5 times greater than after age 30 lends
some support to the ICRP conclusions (Se88).
Both BEIR IV and ICRP 50 models treat radon and smoking
risks as multiplicative. This conclusion is based primarily on
data from the U.S. uranium miner cohort. Although apparently
based on weaker evidence, the report on Malmberget miners and the
recent report on Czech miners both concluded that the interaction
of smoking and radon exposure is small (Ra84, Se83). The attrib-
utable risk per unit exposure in smokers and non-smokers was
essentially the same (Se88). The true interaction of radon and
cigarette smoking is controversial. Both antagonistic (Lu79) and
multiplicative (Lu69, Wh83) interactions have been reported in
man, and animal studies can be found to justify either position
(Ch81, Ch85). In prior calculations, EPA has always treated the
interaction between radon daughters and cigarette smoke as
multiplicative. EPA continues to treat the radon daughter-smoke
interaction as multiplicative at this time.
At the advice of the Radiation Advisory Committee of EPA's
Science Advisory Board, EPA continued to use relative risk models
but included both BEIR IV and ICRP 50 model calculations to
illustrate the difference in results from the two models. The
ICRP 50 model was slightly modified. To compensate for differ-
ences in dosimetry, the risk reduction factor of 0.8 was elimi-
4-23
-------
nated to place the ICRP 50 model and BEIR IV model on a compara-
tive basis. Calculations in the ICRP 50 model were made using
risk coefficients of 2,4 percent per WLM from birth to age 20 and
0.8 percent per WIM for ages greater than 20 years, yielding
estimates listed in Table 4-5.
Table 4-5 also summarizes previous risk estimates based on
the BEIR IV and the ICRP 50 model, modified as described above.
Both models were adjusted for the effect of background radon
exposure (see section below).
Table 4-5. Lifetime Risks from Radon. Daughter Exposure of Lung
Cancer Death (per 106 WLM) .
Model
Group BEIR IV ICRP 50
Men 530 760
Women 185 255
Combined Population 350 500
(Range) - (170-840)
The ICRP Task Group concluded that, all things considered,
the range of variation of the mean relative risk coefficient is
from about 0.3 up to 2 times the value stated (ICRP87). The
range of risk cited in Table 4-5 for the ICRP model reflects this
uncertainty in the risk coefficient. Since the BEIR IV Committee
did not provide a numerical range of uncertainty, no range is
given for that model.
4.2.3 Correctionof Radon Risk Estimates for the Effect of
Background Exposure
A relative risk model for radon-induced lung cancer general-
ly assumes the excess risk, Xr, from a given exposure, is propor-
tional to the observed baseline risk of lung cancer in the
population, X0. Thus, for a constant exposure rate, w, the
excess risk at age, a, attributable to previous exposure can be
written:
Xr(w,a) = X0(a) |8(a)f (w,a) (4-11)
4-24
-------
For example, in the case of an age-constant relative risk
model with a 10-yr minimum latency:
]8(a) = |8 = constant
f(w,a) = (a-10}w
(4-12)
(4-13)
Although Xr is commonly assumed to be proportional to X0, a
more consistent (and biologically plausible) way to formulate a
relative risk model is to assume that the radon risk, Xr, is
proportional to X0', the lung cancer rate that would prevail in
the absence of any radon exposure (Pu88):
Xr(w,a) = X0 (a)|8(a)f (w,a)
(4-14)
Presuming that the risk model can be used to relate X0(a) to
X0'(a) , then
X0(a) = X0' (a) [1 + /3(a)f(w,a)3 (4-15)
where w is the average exposure rate in the population. It
follows from the previous equation that
Xo (a) = X0(a)/[l + 0(a)f(w,a)] (4-16)
The inferred baseline rate without radon exposure depends,
of course, on both the risk model and the presumed average
background exposure rate. The excess risk associated with an
arbitrary exposure situation can be calculated using standard
life-table methodology.
The ICRP 50 committee did correct the baseline rate in this
way in.calculating lifetime population risks, assuming an average
exposure rate of 0.2 WLM/yr. The BEIR IV Committee did not
incorporate the correction, noting that it would be small (see
NAS88, p. 53). In arriving at a final estimate based on the ICRP
50 and BEIR IV models (Table 4-6), EPA has incorporated a model-
specific baseline correction, calculated on the assumption of a
0.25 WLM/yr average radon exposure rate (Pu88). As seen from
Table 4-5, this correction results in roughly a 15 percent
reduction in each of the estimates of lifetime risk for the
general population.
4-25
-------
Table 4-6. Lifetime Risk from Excess Radon Daughter Exposure
(Adjusted for a Background Exposure of 0.25 WLM/yr).
Risk of Excess Lung Cancer Deaths per 106 WLM
Group BEIR IV ICRP 50 Average
Men 460 640 550
Women 160 215 190
Population 305 420 360
Combined
(Range) (140-720) (140-720)
Consistent with the recommendations of the Agency's Radia-
tion Advisory Committee, EPA averaged the risk estimates derived
from the BEIR IV and ICRP 50 models. These estimates are based
on 1980 U.S. vital statistics and are adjusted for an assumed
background exposure of 0.25 WLM/yr. Thus, as shown in Table 4-6,
the excess lifetime risk in the general population due to a
constant, low-level, lifetime exposure was estimated by the EPA
to be 360 excess lung cancer deaths per 106 WLM, with a range of
140 to 720 excess lung cancer deaths per 106 WLM. The EPA used
the risk coefficient of 3.6 x 10"4 fatal lung cancer per WLM in
its risk assessment involving NESHAPs radionuclides (EPA89).
4.2.4 EPA's Current Risk Projection Approach - Adjusted BEIR IV
Model
In 1991, the Office of Radiation Programs requested that
the SAB review proposed revisions to EPA's radon risk assessment
methodology. The SAB recommended that the Agency use only the
BEIR IV model for assessment of risk from residential exposure to
radon. The recommendation to use only the BEIR IV model and
discontinue use of the ICRP 50 model was based on several new
pieces of information. The first was evidence from epidemiologi-
cal studies of a decrease in lung cancer risk with time since
exposure, which had been incorporated into the BEIR IV model, but
not the ICRP 50 model. The second was the publication of the
BEIR V report (NAS90) and a study of Chinese miners exposed to
radon gas (Lu90). These publications found no evidence of
dependence on age at exposure for lung cancer. This was not
consistent with the increased risk to children assumed in the
ICRP 50 model. Finally, the BEIR IV model was based on the most
updated information, was well documented, and represented the
consensus of a body of established and qualified scientists
(EPA92).
EPA has made two adjustments to the BEIR IV model in esti-
mating radon risks. The first modification, previously de-
scribed, was an adjustment of the age-specific baseline rate of
4-26
-------
lung cancer from all causes by eliminating death due to average
background exposure. This reduced the lifetime risk estimates by
about 15 percent. The second modification was based on findings
cited by the National Research Council in a report completed
under a grant from EPA (Comparative Dosimetry of Radon in Mines
and Homes, NRC91) .
The National Research Council in a companion publication to
its earlier BEIR IV report, compared radon exposures in mines to
those of typical homes. This comparative study identified
physical and biological parameters which uniquely apply to miners
in a mining environment and the general population in a home
environment. Parameter values considered to be significantly
different include age- and sex- dependent respiration rate and
volume/ breathing route, age at exposure, aerosol size distribu-
tion, unattached fraction, cigarette smoking, and effects of
environmental contaminants other than radon. The committee also
explored the consequences of various underlying model assumptions
for the efficiency of nasal deposition, the efficiency of bron-
chial deposition, the solubility of progeny in mucus, and the
growth of aerosols in the respiratory tract. Using the terminol-
ogy of the BEIR IV report (NAS88) , if exposure is expressed in
the commonly used unit working level month (WLM) , the risk per
unit exposure in the home, (Risk) h/ (WLM) h, can be related to that
in mines, (Risk) m/ (WLM) m, by a dimensionless factor K.
where :
K -
* -
(Risk) J (WLM) m
Thus, if the K factor exceeds unity, the risk per unit of
exposure is greater in the home; if it is less than unity, the
risk per unit of exposure is less in the home .
Across a wide range of exposure scenarios considered by the
Committee, most values of K were less than unity. Because
uncertainty remained after the committee's review concerning the
cells of origin of lung cancer, the Committee performed the
calculation separately for basal and secretory cells in the
respiratory epithelium. The K factors for normal people without
respiratory illness are summarized in Table 4-7. The Committee
concluded that the risk per unit exposure to target cells in the
respiratory tract tends to be lower for the home environment by
about 30 percent for adults and by 20 percent or less for infants
and children. Thus, when exposure is chronic (I.e., lifetime),
direct extrapolation of risk estimates from the mining to the
home environment is likely to overestimate the number of radon-
caused lung cancer by about 30 percent.
4-27
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Table 4-7. Summary of K Factors for Bronchial Dose Calculated
for Normal People in the General Environment Rela-
tive to Healthy Underground. Miners
K Factor for the Following
Target Cells:
Sub j ect Category
Infant ,
Child,
Child,
Female
Male
age
age 1
age 5
l mo
yr
-10 yr
Secretory
0
i
0
0
0
.74
.00
.83
.72
.76
Basal
0
0
0
0
0
.64
.87
.72
.62
.69
Using the K value of 0.7 for both sexes and all ages, the
adjusted BEIR IV model can be written as:
r(a) = r0(a) [1 + 0.0175 7(a)(W,) + 0.5W2)] (Eq. 4-18)
where, the parameters are those described previously in equation
4-7 with the difference that S = 0.0175 as a result of the
adjustment for the factor K = 0.7.
The modified BEIR IV model, when used in a standard life
table calculation in conjunction with U.S. 1980 vital statistics,
yields a risk factor of 2.24 x 104 lung cancer deaths per person
WIM.
The assessment of radon risk from uranium mill tailings im-
poundments in this report uses the current EPA risk value of
2.24 x 10"4 lung cancer deaths per person-WLM.
4-28
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CHAPTER 5
70-YEAR RADON EMISSIONS FROM NON-OPERATIONAL TAILINGS
IMPOUNDMENTS AND HEALTH RISKS TO NEARBY POPULATIONS
This chapter provides a quantitative assessment of radon
emissions and risks to nearby populations for the nineteen non-
operational tailings impoundments scheduled for covering as defined
in the Memorandum of Understanding between the EPA and the NRC.
Emission and risk estimates are based on a lifetime exposure of 70
years, beginning December 15, 1991 and ending December 15, 2061.
5.1 THE 70-YEAR ASSESSMENT PERIOD
The Clean Air Act (CAA), 40 CFR 61, Subpart T, specifies that
once a uranium mill tailings pile or impoundment ceases to be
operational, it must be disposed of and brought into compliance
with the emission rate not to exceed 20 pCi/m2-s within two years.
For the nineteen impoundments which had been non-operational at the
time of rulemaking, enforcement of Subpart T of 40 CFR 61 would
have meant emplacement of an earthen cover to meet compliance with
the UMTRCA emission standard as early as December 15, 1991. This
objective, however, was not met, which led the EPA to seek a
revised closure date as defined in the Memorandum of Understanding.
The selection of December 15, 1991 as a start date for the 70-year
assessment period provides a basis for comparing radon emissions
and risks for tailings impoundments under the MOU disposal dates
and the original date specified by 40 CFR 61, Subpart T. Emissions
and risk estimates corresponding to the original December 15, 1991
disposal date represent "baseline values."
A 70-year assessment period of projected radon emissions
corresponds to the total number of years to which an individual may
be at risk from uranium mill tailings emissions. Radon emissions
for the 70-year period may involve three discrete time intervals:
(1) The first interval corresponds to the standby phase which
reflects the current configuration of the tailings impound-
ment.
(2) The second interval encompasses the time needed to dewater,
dry, and cover tailings piles.
(3) The third and final interval is the post-disposal portion of
the 70-year period, when all tailings piles for a given
impoundment have been covered and all tailings piles meet
regulatory emission standards.
5-1
-------
The duration of the three phases is partly linked to the MOU
target date and the need to dewater and dry currently ponded and
wetted tailings before heavy equipment can be used to emplace a
final earthen cover. Previous estimates assumed a five-year period
for the disposal phase (EPA86).
In estimating the duration for each of these three phases
within the 70-year time span starting December 15, 1991 and ending
December 15, 2061 for the nineteen non-operational impoundments,
the following protocol was used:
(1) Disposal period is defined by the five-year period which pre-
cedes the MOU target date. For impoundments with MOU target
dates prior to January 31, 1996, the disposal period is
obviously less than five years and is defined by the time
interval between December 15, 1991 and the MOU target date.
(2) Standby period is defined by that period between December 15,
1991 and the MOU target date minus five years. In order for a
standby period to exist, the MOU target date must be later
than 1996.
(3) The post-disposal period is the balance of time remaining and
is equal to 70 years minus the disposal and standby periods.
Table 5-1 identifies the nineteen facilities, their MOU target
disposal dates, and the corresponding time periods for standby,
disposal, and post-disposal.
5-2
-------
Table 5-1, Assessment Period for Non-Operational Tailings Impoundments
70 Year Assessment Period
Facility Name/Location
ANC (FAP)/Gas Hills, WY
ARCO Coal, Bluewater, NM
Atlas, Moab, OT
Conoco, Conquista, TX
Ford-Dawn Mining, Ford, WA
Helca Mining, Durita, CO
Homestake, NM: large impound.
Homestake, KM: small impound.
Pathfinder -Lucky Me, GH, WY
Petrotomics, Shirley Basin, WY
Quivera, Ambrosia Lake, NM
Rio Algom, Lisbon, DT
Sohio-L-Bar, Cebolleta, NM
OMETCO, Gas Hills, WY
DMETCO, Maybell, CO
UMETCO, Uravan, CO
UNC, Church Rock, NM
Union Pacific, Bear Creek, WY
WNI , Sherwood, WA
WNI, Split Bock, WY
MOU
Target
Date
1995
1995
1996
1996
2010
1997
1996
2001
1998
1995
1997
1996
1992
1995
1997
1997
1997
1996
1996
1995
(12/15/1991 - 12/15/2061)
Standby
(Yrs)
none
none
none
none
14
1
none
5
2
none
1
none
none
none
1
1
1
none
none
none
Disposal Post -Disposal
{Yrs) (Yrs)
4
4
5
5
5
5
5
5
5
4
5
5
none
4
5
5
5
5
5
4
66
66
65
65
51
64
65
60
63
66
64
65
70
66
64
64
64
65
65
66
5-3
-------
5.2 PROTOCOL FOR ESTIMATING RADON EMISSIONS
Radon emission rates for each of the nineteen non-operational
tailings facilities are estimated on the basis of (!) the tailings
status, (2) areas of the tailings, (3) radium-226 concentrations,
and (4) the duration, in years, for the three phases which make up
the 70-year assessment period.
The current status of the nineteen facilities was obtained
from the NRC's Uranium Recovery Field Office and cognizant offi-
cials representing Agreement States. Information included tailings
surface areas, interim cover data, and average radium-226 concen-
trations. The data are summarized in Table 5-2.
Estimated radon emissions from dry tailings are based on the
generic emission relationship of 1 pCi Radon-222/m,2~s per pCi
Radium-226/g of tailings. Emissions from tailings with "a permanent
cover are either assessed at the design flux levels or the UMTRCH
limit of 20 pCi/m2-s. Emissions from tailings that are currently
wet or ponded (i.e., sprayed to mitigate dust and radon emissions)
are assumed to emit no significant levels of radon.
5.2.1 Emissions From Wet and Ponded Areas During Disposal Period
During the five-year disposal phase, however, wet and ponded
areas undergo a thorough drying before heavy equipment can be used
to install a permanent earthen cover. For the five-year disposal
phase, a drying period of four years is assumed with a one-year
period for the installation of a permanent cover. During the four-
year drying-out period, emissions are assumed to linearly increase
from zero to a maximum value defined by the generic relationship of
1 pCi Radon-222/m2-s per l pCi Radium-226/g of tailings. In the
fifth and final year of the disposal phase, covering of all dried
areas (i.e., recently dried and previously dried areas) commences
and progresses throughout the year at a constant rate. During the
fifth, and final year of disposal, radon emissions are assumed to
linearly decrease from the maximum dry level to 20 pCi/m2-s, the
final emission rate assumed for all impoundments that do not now
have a permanent cover.
For impoundments whose MOU target dates do not allow for a
full five-year disposal period, the start date for drying out of
wet or ponded areas is assumed to have begun prior to December 15,
1991 so that a five-year disposal period is achieved. For example,
an impoundment with a MOD" target date of 1995 will be assumed to
have started the dewatering and drying process in 1990, or one year
prior to the start of the 70- year assessment period. Starting
emission rates from tailings areas, which have had one year of
drying as of December 15, 1991, are assumed to be 25 percent of
their maximum dry state (i.e., (0.25} x (1 pci Radon-222/m2-s per 1
pCi Radium-226/g)) .
5-4
-------
Table 5-2. 1992 Status of Non-Operational Tailings Impoundments
FACILITY
ANC, Gas Hill, WY
ARCO Coal, Bluewater, NM
Atlas, Moab, OT
Conoco, Conquista, TX
Ford- Dawn Mining, Ford, WA
Hecla Mining, Durita, CO
Homestake, MM (large impoundment)
Homestake, NM {small impoundment)
Pathfinder -Lucky Me, Gas Hills, WY
Petrotomics, Shirley Basin, WY
Quivera, Ambrosia Lake, NM
Rio Algom, Lisbon, UT
Sohio-L-Bar, KM
DMETCO, Gas Hills, WY
UM1TCO, Maybell, CO
DMETCO, Uravan, CO
me, Church Rock, NM
Union Pacific, Bear Creek, WY
WNI, Sherwood, WA
WNI, Split Rock, WY
TAILINGS SURFACE ARIA (m2 x
Total
445
1214
518
1012
497
142
688
52
821
461
1490
405
324
777
202
283
417
720
380
902
Ponded
0
0
0
0
0
0
0
0
36
0
0
0
0
0
0
0
0
0
0
0
Wet
0
0
40
405
113
0
73
0
24
0
0
0
0
0
0
0
0
0
178
0
Dry
0
607
478
0
0
0
615
28
0
0
146
0
0
0
61
0
0
0
202
0
1000}
Interim
Cover
445
607
0
607
384
142
0
24
761
461
1344
405
324
777
141
2S5/282
417
720
0
902
INTERIM COVER
INFORMATION
Depth Earthen
(cm) Type
15 unknown
75 unknown
N/A N/A
(see footnote ')
150 unknown
60 E-clay
N/A N/A
unknown unknown
unknown unknown
unknown unknown
30 B-soil
90 E-clay
(see footnote ')
120 unknown
15 unknown
3 00/3 O2 unknown
30 unknown
30 E-clay
N/A N/A
300 unknown
Average
Radium -22 6
(pCi/g)
420
620
540
224
240
428
300
300
220
570
237
420
500
310
128
480
290
420
200
430
(n
i
en
Tailings impoundment has a final cover which meets the UMTRCA emission standard.
Represents two discrete areas of 255,000 m2 and 28,000 m2 covered with soil thickness of 300 cm and
30 cm, respectively.
-------
5.2.2 Interim Covered Areas
Tailings with, an interim cover are assumed to remain status
quo during the standby phase and the first four years of the
disposal phase. The installment of a permanent cover is assumed'to
coincide with those of recently and previously dried tailings in
the fifth and final year of disposal,
Of the twenty impoundments, all but three have interim covers
over portions of their tailings. Jta interim cover significantly
reduces radon as well as particulate emission. Its effectiveness
depends mainly on moisture content, porosity, and cover depth
(EPA86). The relationship between the flux from an interim covered
surface to the flux from a bare dry tailings surface is described
by equation 5-1:
•1C
•DT
,-bx
(Bq. 5-1}
where:
PIC
is the flux through interim cover (pCi/m2-s)
is the flux through dry tailings (pCi/m2-s)
b is a coefficient dependent upon the moisture
content, bulk density, specific gravity and
porosity of the soil used
x is the cover thickness in cm
Table 5-3 provides representative values for b for specific earth
types and moisture content.
Table 5-3.
Coefficient b Values for Select Soil Types
and Moisture Content1
Earth Type
A Sandy Soil
B Soil
C Soil
D Compacted Moist
Soil
E-Clay
% Moisture
3.4
7.5
12.6
17.0
21.5
Coefficient b
0.00699
0.00937
0.01350
0.01850
0.02553
Reference: EPA89
5-6
-------
The approximate effectiveness of these various types of earth
covers in reducing radon-222 emissions is 'graphically depicted in
Figure 5-1. The application of almost any type of earth will
initially affect a rapid decrease in radon emission. For example,
an interim cover of 0.5 meter (1.6 feet) or 1 meter (3.3 feet),
which consists of type B soil with a moisture content of 7.5%,
would result in reductions of radon-222 emissions of 37 and 60
percent, respectively. Installed interim covers commonly consist
of local native soil, which can be assumed to represent B soil with
a 7.5 percent moisture content. When the depth of the interim
cover is known, radon-222 emission rates are calculated using
equation 5-1 with the appropriate b coefficient value. When earth
type is not known, the interim cover is assumed to consist of B-
soil with 7.5 percent moisture content having a b-coefficient value
of 0.00937.
100
RADQM PENETRATION (%)
80 -
EAETH TYPE
SOTBY SOIL
B SOIL
c son,
D COMPACT MOIST SOIL
I CLAY
13345
EAETH COVER THICKNESS (meters)
Figure 5-1.
Changes in Radon-222 Penetration with Earth
Cover Thickness (adapted from EPA89).
5-7
-------
For impoundments with tailings where the thickness of the
interim cover was not available, emanation rates are assumed to be
50 percent of their maximum value (i.e., FIC/FDT = 0.5) .
5.2.4 Sample Calculation
JL sample calculation, which estimates radon emissions, is
provided below and serves to illustrate the methodology used to
calculate radon emissions for the nineteen non-operational tailings
facilities:
Problem: Calculate the radon-222 emissions for Pathfinder-Lucky Me
for (1) the 70-year assessment period (12/15/1991 -
12/15/2061) under the revised UMTRCA regulations/MOU
target date and (2) 70-year baseline emissions.
Given;
» MOU target date 1998
» Current tailings characteristics
- Wet = 24,000 m2
Ponded = 36,000 m2
Dry = Om2
Interim Cover = 761.000 m2
Total: = 821,000 m2
• No information was available about the interim
cover with regard to earth type and depth of
cover.
• Average radium-226 concentration in tailings is
220 pCi/g.
Solution: Emissions must be calculated separately for wet, ponded,
and covered areas and for each of the three time periods.
1. Standby Period: During the standby period of two years, the
wet and ponded areas are assumed to be non-fluxing. The
interim covered area of 761,000 m2 can be assessed by the
equation:
FIC = FDT e'bx (see equation 5-1}
Since no information about earth type and cover depth was
available, it will be assumed that FIC/FDT = 0.5. This implies
that the radon flux from the interim covered tailings will be
5-8
-------
one -half of the maximum flux for dry uncovered tailings of 220
pCi/m2-s.
Radon emissions for the two-year standby period for interim
covered tailings are:
Rn-222 Emissionsaaay = (220 pCi/m2-s) (0.5) (3.1536 x 107S/y) (761,000 nta) (2y)
Rn-222 EinissionStaDlBv = 5280 Ci
2. Disposal Period; During the five-year disposal period, wet
and ponded areas will be dewatered and dried for the first
four years. In the fifth and final year, a permanent earthen
cover is installed that meets the DMTRCA emission standard of
20 pCi/m2-s.
During the first four years, emissions are assumed to linearly
increase from 0 to a maximum of 220 pCi/m2-s with an average
value of 110 pCi/m2-s, During the final (fifth) year, emis
sions are assumed to decrease from 220 pCi/m2-s to 20 pCi/m2-s
with an average value of 120
During the disposal period, tailings with interim cover are
conservatively assumed to remain unchanged for the first four
years . A permanent cover is assumed to be installed during
the fifth and final year of the disposal period and coincides
with the permanent cover installation of the previously wet
and ponded areas.
a. Radon emissions from interim covered tailings (i.e.,
^ic/ PDT = 0.5):
Rn-222lc = [{220 pCi/m2-s) (0.5) (3.1S36xl07 s/y) (4y) +
761,000m2
2
Rn-222,c = 12,120 Ci
b. Radon emissions from wet and ponded tailings:
Rn-222w/P = {(110 pCi/m2-s) (3 .1536xl07s/y) (4y) +
(120 pC±/m2-s) {3,1536xl07s/y) (ly) ] 60,000ma
RQ-222W/P = 1059 Ci
c. Radon emission for the five-year disposal period from
all tailings:
= Rn-222K + Rn-222w/P
Rn-222DiiJpo.ial = 12,120 Ci 4- 1059 Ci
Rn-222DbposaJ = 13,179 Ci
5-9
-------
3. Boat.-.Disposal. Period; During the post-disposal period of 63
years, all permanently covered tailings are assumed to be
fluxing at the UMTRC& emission limit of 20 pCi/m2-s.
Radon emissions for the post-disposal period:
Rn-222PD = (20 pCi/rf-s) (3.1536 x 107s/y) (63y) (821,000 m2}
Rn-222PD = 32,634 Ci
Table 5-4 summarizes emissions for the Pathfinder-Lucky Me
Facility.
Table 5-4, Summary of Emissions for the Pathfinder-Lucky Me
Facility
Covered Wet Ponded Dry Total
Period (761,000m2) (24,000m2) (36,000m2) (Om1) (821,000m2)
Standby 5280 Ci 0 00 5280 Ci
{2 years)
Disposal 12,120 Ci 424 Ci 635 Ci 0 13,179 Ci
(5 years)
Post-Disposal 30,249 Ci 954 Ci 1431 Ci 0 32,634 Ci
(63 years)
Total Emission^ = 51,093 Ci
Emissions for the baseline condition involves estimating radon
releases for the 70-year period (i.e., 12/15/1991 - 12/15/2061) if
the tailings had been covered as of 12/15/1991, as required in 40
CPR 61, Subpart T. For baseline conditions, radon emission is
estimated at a constant rate of 20 pCi/m2-s for the full duration
of 70 years.
Rn-2228Mdta> = (20 pCi/rf-s) (3 .1536xlO?s/y) (70y) (821,000 in2)
Sn-222Bjl<.fal = 36,260 Ci
5.3 FROM NON-OPERATIONAL TAILINGS
Estimates of radon emissions for each of the non-operational
impoundments cited in the MOU are provided in Table 5-5, Emissions
are provided where applicable for the standby period, disposal
period, and post-disposal period. Emissions, when summed, provide
an estimate of the cumulative radon that is released over the 70-
year assessment period.
5-10
-------
Table 5-5. Radon Emissions for NoivQperational Tailings Impoundments
FACILITY
ANC, Gas Hill, WY
ARCO Coal, Bluewater, MM
Atlas, «oab, UT
Conoco, Conquista, TX
Ford-Dawn Mining, Ford, WA
Hecla Mining, Durfta, CO
Homestake, NM C targe impoundment)
Homestake, NM (small impoundment)
Pathfinder-Lucky He, Gas Hills, UY
Petrotonics, Shirley Basin, WY
Quivera, Ambrosia Lake, NH
Rio Algom, Lisbon, UT
Sohio-L-Bar, NM
UMETCO, Gas Hills, WY
UMETCO, Maybelt, CO
UMETCO, Uravan, CO
UNC, Church Rock, NM
Union Pacific, Bear Creek, WY
WNI, Sherwood, WA
WNI, Split Rock, WY
TOTALS
HOU
Target
Date
1995
1995
1996
1996
2010
1997
1996
1997
1998
1995
1997
1996
1992
1995
1997
1997
1997
1996
1996
1995
Emissions: Revised UMTRCA Regulations
Standby
(Ci)
N/A
N/A
N/A
N/A
9996
416
N/A
1895
5280
N/A
8678
N/A
N/A
N/A
740
553
2880
N/A
N/A
N/A
30,438
Disposal
(Ci)
18,067
62,507
38,498
9193
5515
1919
28,123
1721
13,179
14,653
39,521
2605
N/A
8920
3395
2582
13,098
20,367
8658
10,753
303,274
Post -Disposal
(Ci)
18,546
50,556
21,255
41,470
15,963
5760
28,210
1980
32,634
19,206
60,160
16,575
14,280
32,340
8128
11,392
16,832
29,510
15,600
37,554
477,951
70 Year Total
CCi)
36,613
113,063
59,753
50,663
31 ,474
8095
56,333
5596
51,093
33,859
108,359
19,180
14,280
41,260
12,263 -
14,527
32,810
49,877
24,258
48,307
811,663
Average Annual
Ci/Year
523
1615
854
724
450
116
805
80
730
484
1548
274
204
589
175
208
469
713
347
690
...
Baseline
70 Year Total
(Ci)
19,670
53,620
22,890
44,660
21,910
6300
30,380
2310
36,260
20,370
65,800
17,850
14,280
34,300
8890
12,460
18,410
31,780
16,800
39,830
Emissions
Average Annual
Ci/Year
281
766
327
638
313
90
434
33
518
291
940
255
204
490
127
178
263
454
240
• 569
518,770
Ul
1
H
-------
Table 5-5 also provides 70-year baseline emissions, which
represent the hypothetical releases that would have been expected
if impoundment facilities had been able to meet the original target
date of December 15, 1991 for permanent disposal, as defined by
Subpart T of 40 CFR 61.
An assessment of these'two disposal schedules reveals that the
collective 70-year emissions corresponding to the MOU disposal
schedule of about 810,000 Ci exceeds the collective 70-year base-
line emissions of about 520,000 Ci by 290,000 Ci. Correspondingly,
this difference in cumulative emissions yields annual average
facility emission rates that differ by a factor of about 1.6 (i.e.,
average annual facility emissions of 610 Ci/y versus 390 Ci/y). •
Based on radium-226 concentrations, the emplacement of a
permanent cover is expected to reduce radon emissions by one to two
orders of magnitude from the maximum emission rate of dry tailings.
Nevertheless, post-disposal releases appear relatively significant.
In fact, for eleven impoundments, the largest cumulative release
occurs during the post-disposal period when a permanent cover has
been installed. This seeming paradox, however, is resolved by
noting that the average post-disposal period represents 64.7 years
or 92.4 percent of the 70-year assessment period. For the same
reason, the average annual emission rate for the 70-year assessment
period'is low since this value is also dominated by the lengthy
post-disposal period.
Variations in emission rates over the 70-year assessment
period are quantitatively and graphically depicted in the illustra-
tion provided below for Pathfinder's Lucky Me facility. During the
two-year standby phase, emissions are estimated at 2640 Ci/y.
Emission rates increase linearly during the first four years of the
disposal phase, reaching a maximum value of 3056 Ci/y. During the
fifth and final year of the disposal phase, the emplacement of the
permanent earthen cover steadily reduces emissions to the final
level of 518 Ci/y. The emission rate of 518 Ci/y meets the UMTRCA
standard and is assumed to remain constant for the full duration of
the 63 year post-disposal phase ending in the year 2061.
5-12
-------
ILLUSTRATION: 70-YEAR EMISSION PROFILE FOR LUCKY MC
Data Elements:
1. MOU target disposal date 1998
2. Average Radium-226 Concentration: 220 pCi/g
3. 70-year Assessment Period:
Standby = 2 yrs; Disposal = 5 yrs; Post-Disposal = 63 yrs
4. Current Tailing Surface Area (m2 x 103) :
Ponded = 36; Wet = 24; Dry =0; Interim Cover = 761; Total
Emission Rates:
E, = Current/Standby Emission Rate
= (Interim Covered Area)(Flux)
= (7.61E+5 m2) (110 pCi/m2-s) = 2640 Ci/v
E2 = Maximum Emission Rate - (Maximum emission rate is the combined
emission of areas with interim cover and those from dried areas
(i.e., currently wet and ponded).
= (7.61E+5 m2) (110 pCi/m2-s) + (6.00E+4 m2) (220 pCi/m2-s)
= 2640 Ci/y + 416 Ci/y = 3056 Ci/y
E3 = Post-Disposal Emission Rate
= (Total Area)(UMTRCA Emission Flux)
= (8.21E+5 m2) (20 pCi/m2-s) = 518 Ci/v
E, + B, E
Total EmissioiLjQy = t^CE,) + t^ ( l —-) + t^( —
= 821
E,
) + t4(E3)
where: t, = 2 yrs; t2 = 4 yrs; t3 = 1 yr; t4 = 63 yrs
Total Emission = 2x2640+(4) ( Ifl2±l°§i ) + ( 1 ) ( 3056+518 } +63x518
Total Einission0991.2Mi) = 51,093 Ci
2 2
Average Emission Rate = 730 Ci/y
4000
3500
3000
2500
2000
1500
1000
500
0
Emission Rate (Ci/yr)
'90 '91 '92 '93 '94 '95 '96 '97 '98 '99 2000
Year
'5B '59 '60 '61 '62 '63
5-13
-------
5.4 POPULATION EXPOSURES AND HEALTH RISKS
The previously described CAPS8-PC model was used to estimate
the down-wind radon exposures from tailings emissions (see Appendix
A) . When public exposure is assessed, the two parameters of
concern are: (1) the lifetime fatal cancer risk to the individu-
al (s) experiencing the maximum risk (MIR) and (2) the annual
collective risk to near-field residents. Exposure estimates are
based on historical site-specific meteorological conditions and
empirical population data which identify residents by distance and
sector.
Due to the prevailing winds, which favor some sectors over
others/ the maximum individual risks are not necessarily experi-
enced by the residents closest to the sites. Prevailing winds also
influence the dose distribution and affect the cumulative popula-
tion exposures to individuals residing within the 0-80 km radii of
the impoundment facilities. All exposures conservatively assume
that individuals spend 100 percent of their time at their residen-
tial location (i.e., 75 percent indoors and 25 percent outdoors).
Table 5-6 provides summary data for each facility based on the
MOU disposal schedule. The values are derived as follows and are
illustrated by using the Pathfinder-Lucky Me facility as an exam-
ple:
* Average Radon Emission (Column #1). This value represents the
yearly average radon emissions (Ci/y) for the 70-year assess-
ment period starting December 15, 1991 and ending in 2061.
For the Lucky-Mc facility, the 70-year assessment period
includes a 2-year standby, a 5-year disposal, and a 63-year
post-disposal period (see Table 5-1). For the 70-year peri-
ods, it was estimated that a total of 51,093 Ci would be
released yielding an average annual value of 730 Ci (see Table
5-5).
• MIR Radon Concentration (Column #2) . The tailings enhanced
average radon-222 concentrations for the MIR is a site-specif-
ic value which is defined by meteorologic and population data.
Appendix B provides a computer generated Synopsis Report for
the Lucky-Mc facility. Based on prevailing wind and air
dispersion, the maximally exposed individual is located 25,000
meters north of the tailings where the radon concentration is
8.77E-4 pCi/1 above prevailing background.
* MIR Decay Product Concentration (Column #3). Radon concentra-
tions in Column #2 are converted to concentration levels of
radon-222 progeny by means of an appropriate equilibrium
fraction. Values for the indoor/ outdoor equilibrium fraction
vary with radon plume travel time and, therefore, distance
from tailings.
5-14
-------
To determine the decay product concentration for the Lucky
Mc's MIR, which is to an individual that is located at 25,000
meters, the effective equilibrium fraction of 0.698 is used
(see Table 4-1):
Decay Prod. Cone.(WL) = (Radon Cone.)(Equil. Fraction)
= (8.77E-4 pCi/1) (0.698) (1WL/100 pCi/1)
= 6.12E-6 WL
MIR Lifetime Fatal Cancer risk (Column #4) . Risk values are
derived by: (1) integrating the exposure to radon progeny
over the 70-year exposure duration, which yields exposure in
the conventional time-integrated unit of WLM, and (2) multi-
plying the derived WLM value times the EPA risk coefficient.
For the Lucky Me MIR, the lifetime fatal risk of cancer is
derived as follows:
= (70 y exposure)(Cancer Risk Coefficient)
= (6.12E-6 WL) (24h/d x 365d/v x 70v) (2.24B-4 cancer/WLM)
170 hr/m
= 4.95E-06 (lifetime)
Population Decay Product Concentration (Column #5) . This
value represents the collective air concentrations of radon
progeny for all residents residing within 80 km of the
facility.
The computer-generated collective exposure of 2.29E-2 WL for
the Lucky Me population is not readily derived manually, and
represents the sum of population weighted air- concentrations
at residential locations defined by sector and distance (see
Table 1 of Appendix B) .
Population Annual Fatal Cancer Risk (Column #6) . The annual
risk to the 0-80 km population is derived by integrating
population exposures to radon progeny over a one year period
and multiplying the derived person-WLM/y times the EPA's risk
coefficient.
The annual fatal cancer risk to the 0-80 km population for the
Lucky-Mc facility is derived as follows:
^.,. = (2.29E-2 person-WL) (24 h/dx365 d/v) (2.24E-4 cancer/WUXI)
170 h/m
/ = 2.64E-04 cancers /y
5-15
-------
Table 5-6, Radon-222 Exposures and Associated Risks For MOU Disposal Schedule
Maximum Individual at Risk
Facility
ANC, Gas Hills, WY
ARCO Coal, Bluewater, NM
Atlas, Moab, UT
Conoco, Conquista, TX
Ford-Dawn Mining, Ford, WA
Hecla Mining, Durita, CO
Homestake, NM*
Pathfinder- Lucky Me, Gas Hills,
Petrotomics, Shirley Basin, WY
T Quivera, Ambrosia Lake, NM
w Rio Algom, Lisbon, UT
Sohio-L-Bar, NM
UMETCO, Gas Hills, WY
UMETCO, Maybell, CO
UMETCO, Uravan, CO
UNC, Church Rock, NM
Union Pacific, Bear Creek, WY
WNI, Sherwood, WA
WNI, Split Rock, WY
Average
Radon Radon
Emission Cone.
(Ci/y) (pCi/1)
523
1615
854
724
450
116
885
WY 730
484
1548
274
204
589
175
208
469
713
347
690
7.21E-4
2.29E-2
3.60E-2
1.39E-2
3.47E-2
1.21E-1
4.77E-2
8.77E-4
5.27E-3
3.82E-3
1.52E-3
3.78E-3
7.13E-4
2.13E-3
1.44E-3
2.20E-2
8.72E-4
3.24E-3
1.47E-2
Decay
Product
Cone.
Cm)
4.69E-6
9.12E-5
1.32E-4
4.59E-5
1.04E-4
3.34E-4
1.57E-4
6.12E-6
2.10E-5
1.95E-5
6.52E-6
1.51E-5
4.98E-6
1.39E-5
7.31E-6
7.29E-5
5.66E-6
1.29E-5
5.37E-5
Lifetime
Fatal
Cancer
Risk
3.79E-6
7.37E-5
1.07E-4
3.71E-5
8.40E-5
2.70E-4
1.27E-4
4.95E-6
1.70E-5
1.57E-5
5.27E-6
1.22E-5
4.02E-6
1.12E-5
5.89E-6
5.89E-5
4.57E-6
1.04E-5
4.34E-5
Population
Per son -
Decay
Prod. Cone.
( Person- WL)
1.76E-2
4.67E-1
1.53E-1
1.04E+0
1.94E-1
1.04E-2
3.19E-1
2.29E-2
3.15E-2
2.31E-1
1.50E-2
1.35E-1
1.82E-2
1.28E-2
2.52E-2
1.40E-1
4.53E-2
1.04E-1
2.92E-2
Total
(0-80 kml
Population
Fatal
Cancer Risk
{deaths/y)
2.03E-4
5.39E-3
1.77E-3
1.20E-2
2.24E-3
1.19E-4
3.68E-3
2.64E-4
3.64E-4
2.67E-3
1.73E-4
1.56E-3
2.10E-4
1.47E-4
2.91E-4
1.61E-3
5.23E-4
1.20E-3
3.37E-4
= 3.48E-2
These values represent the combined releases from both the large and small impoundments.
-------
Variations in exposures and risks among facilities differ by
two to three orders of magnitude. For lifetime fatal risks to
the maximally exposed individuals, values range from a low
probability of 3.791-6 (ANC, Gas Hills) to a high of 2.701-4
(Hecla Mining) among the nineteen facilities under the MOU
disposal schedule (see Table 5-6). Variations in the risks to
the MIR primarily reflect radon emission rates and distances from
the impoundment facilities. The collective annual fatal cancer
risks to the 0-80 km population show a similar variation. The
low annual population cancer risk of 1.19E-4 (Hecla Mining,
Durita) is two orders of magnitude lower than the highest value
of 1.2OS-2 cancer death per year corresponding to Conoco's
Conquista facility. In addition to radon emission rates, the
principal factors affecting variations in population risks are
population size and distribution within the 80 km radii.
The annual population fatal cancer risks for all nineteen
facilities combined are 3.48E-2 deaths per year with an average
value of 1.8E-3 deaths/year. Based on these probabilities, a
single fatal cancer is estimated for the cumulative exposures
from all facilities over a 29 year period. For a single facili-
ty, the average probability of one fatal cancer over the 70-year
assessment period is about 0.13.
For comparison, baseline radon-222 exposures and associated
risks are provided in Table 5-7. Fatal cancer deaths for all
nineteen facilities is 2.26E-2, with an average of 1.19E-3 deaths
per year. The reduced radon emissions and risks representing
baseline values are those that would have been expected had all
nineteen non-operational facilities been able to meet the origi-
nal CAA disposal date of December 15, 1991. A comparison of
values from Table 5-6 and 5-7 show that the baseline emissions
and risks are nearly a factor of two lower than those correspond-
ing to the MOU disposal schedule.
5.5 MEASURED RADON EMISSION LEVELS
There has been relatively little experience with measure-
ments determining the effectiveness actually achieved by the
radon covers placed on uranium mill tailings piles. This is
because few Title II piles have been covered under Subpart T and
because testing the effectiveness of covers was not 'required for
Title II piles under UMTRCA. The available evidence, some of it
from Title I piles that are being reclaimed by the Department of
Energy,' indicates that the actual level of emissions through the
radon covers is considerably lower than the 20 pCi/m2-s flux
standards in Subpart T and UMTRCA, generally lower by a factor of
two to ten. The probable reason is that clay and soil with high
clay content have proven to be more readily available at the mill
tailings sites than was assumed in the cost analyses performed
for the UMTRCA and the 1989 Subpart T rulemakings. The superior-
ity of clay as a cover material can be seen in Figure 5-1; it is
considerably more effective for a given depth of cover than are
other cover materials.
5-17
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Table 5-7. Radon-222 Exposures and Associated Risks For Baseline Emissions
09
Facility
ANC, Gas Hills, WY
ARCO Coal, Bluewater, NM
Atlas, Moab, UT
Conoco, Conquista, TX
Ford -Dawn Mining, Ford, WA
Hecla Mining, Durita, CO
Homestake, NM*
Pathfinder -Lucky Me, Gas Hills,
Petrotomics, Shirley Basin, WY
Quivera, Ambrosia Lake, NM
Rio Algom, Lisbon, UT
Sohio-L-Bar, NM
UMETCO, Gas Hills, WY
UMETCO, Maybell, CO
UMETCO, Uravan, CO
UNC, Church Rock, NM
Union Pacific, Bear Creek, WY
WNI, Sherwood, WA
WNI, Split Rock, WY
Average
Radon
Emission
(Ci/y)
281
766
327
638
313
90
467
WY 518
291
940
255
204
490
127
178
263
454
240
569
Maximum
Individual at Risk
Decay
Radon Product
Cone . Cone .
(pCi/1) (WL)
3.88E-4
1.09E-2
1.38E-2
1.22E-2
2.41E-2
9.37E-2
2.51E-2
6.23E-4
3.17E-3
2.32E-3
1.42E-3
3.78E-3
5.93E-4
1.54E-3
1.24E-3
1.23E-2
5.55E-4
2.24E-3
1.21E-2
2.52E-6
4.32E-5
5.04E-5
4.05E-5
7.22E-5
2.59E-4
8.31E-5
4.35E-6
1.26E-5
1.18E-5
6.07E-6
1.51E-5
4.14E-6
1.01E-5
6.27E-6
4.09E-5
3.61E-6
8.92E-6
4.43E-5
Lifetime
Fatal
Cancer
Risk
2.04E-6
. 3.50E-5
4.07E-5
3.27E-5
5.83E-5
2.09E-4
6.71E-5
3.51E-6
1.02E-5
9.53E-6
4.90E-6
1.22E-5
3.35E-6
8.13E-6
5.06E-6
3.30E-5
2.92E-6
7.21E-6
3.58E-5
Population
(0-80 km)
Person- Population
Decay Fatal
Prod. Cone. Cancer Risk
(Person-WL) (deaths/y)
9.44E-3
2.22E-1
5.85E-2
9.15E-1
1.35E-1
8.04E-3
1.68E-1
1.62E-2
1.89E-2
1.40E-1
1.40E-2
2.57E-3
1.52E-2
9.26E-3
2.16E-2
7.82E-2
2.88E-2
7.16E-2
2.41E-2
Total
1.09E-4
2.56E-3
6.75E-4
1.06E-2
1.56E-3
9.28E-5
1.94E-3
1.87E-4
2.18E-4
1.62E-3
1.62E-4
2.97E-5
1.75E-4
1.06E-4
2.49E-4
9.03E-4
3.32E-4
8.26E-4
2.78E-4
= 2.26E-2
These values represent the combined releases from both the large and small impoundments.
-------
CHAPTER 6
RADON-222 CONTROL TECHNIQUES
This chapter provides a brief discussion of specific tech-
niques employed for interim and long-term control of radon emis-
sions from the tailings piles. Also discussed are methods used to
dewater and dry the tailings impoundment areas before a permanent
cover can be installed.
6.1 INTERIM RADON CONTROL TECHNIQUES
6.1.1 Water Spraying
Saturating tailings with a water sprinkling system effectively
reduces radon-222 emissions to nominal levels. The degree of
radon-222 control increases slightly with the depth of the water.
Factors affecting the effectiveness of this practice include the
mill water recirculation rate (if any), evaporation and precipita-
tion rates, impoundment construction and slope, phreatic levels,
ground water contamination potential, and dike or dam stability.
Some above-grade tailings impoundments minimize the depth of the
water to reduce seepage and possible ground water contamination
through the use of overflow pipes, which direct water to separate
evaporation ponds. (Strict ground water contamination standards,
as specified in 40 CFR Subpart D 192.32, will frequently determine
the degree of water cover maintained in an active area.)
6.1.2 Interim Soil Cover
An application of an interim earthen cover on dry portions of
a tailings impoundment reduces radon-222 emissions prior to final
reclamation. The effectiveness of the interim cover in reducing
radon emissions is determined by the earth-type used and the thick-
ness of the cover (see Chapter 5, Figure 5-2). For example, a 0.3
meter (1 foot) or a 1 meter (3.3 foot) thick soil cover having 8
percent moisture content would theoretically reduce radon-222
emissions by about 25 and 62 percent, respectively.
Site characteristics that control or prohibit the applica-
bility of interim cover include impoundment design and construc-
tion; dam height; stability; phreatic level; permeability; site
water balance; evaporation rates; presence and availability of
suitable earth cover material. Operating factors such as expected
uranium production rate, length and number of standby periods,
impoundment capacity, and expected mill life must also be consid-
ered in determining applicability of interim covers.
6-1
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6.2 DEWATERING OF TAILINGS PILES IN PREPARATION FOR PERMANENT
COVER
During operational and standby phases of uranium milling, a
water cover over the tailings piles is commonly used as a radon
reduction technique. Prior to final reclamation, the tailings
disposal area, however, must be dewatered and dried in order to
permit the use of heavy equipment for permanent cover installation.
Past and current uranium tailings disposal methods have relied
exclusively upon exposure of the surface of the impounded tailings
to sunlight and winds for drying. Rates of evaporation vary
considerably with climate, but are generally very high in those
states which produce most of the uranium.
The time required to dewater a tailings pile can vary consid-
erably, based on many factors such as size of the tailings dispossil
area, the uranium recovery process utilized, the disposal manage-
ment system employed, the method used for dewatering, etc. As
mentioned above, the most commonly used method for dewatering the
tailings piles is natural evaporation. Although evaporation rates
are greatly dependent on climate, the majority of uranium mill
sites are located in semi-arid, dry areas of the country.
In order to expedite site reclamation and consolidation of the
tailings pile, it is common for the owners of the mill to employ
the use of an enhanced evaporation system. The evaporation process
is greatly enhanced through the use of a pumping and spraying
distribution system.
In addition, tailings embankments are generally recontoured
and surface water diversion systems are constructed for the purpose
of directing rain and snow runoff away from the tailings area.
Based on the above consideration and industry/DOE experience
to date, the NRC, in the Final Generic Environmental Impact State-
ment On Uranium Milling (NUREG-0706) , utilized a five-year disposcil
period for the tailings pile in their assessment of the "model"
mill, which was considered to be representative of the milling
industry. This five-year disposal period has been commonly adopted
in other uranium mill environmental assessments (NRC80).
Processes that reduce the liquid content of impounded tailings
also reduce the potential for seepage problems, by reducing the
source of and driving head for seepage. In addition, tailings with
a low moisture content will consolidate more rapidly and add to the
stability of the tailings mass, thus reducing problems associated
with final impoundment drying and reclamation.
The most common engineered method of reducing the water
content in the tailings is in-situ dewatering. This is accom-
plished by permitting gravity draining of liquids to a tailing low
point (sump pit) from which clear decanted liquid is withdrawn and
6-2
-------
recycled and/or transported to an evaporation pond. An underdrain
system, generally consisting of a network of slotted PVC piping
covered by a blanket of sand and/or gravel and supported by the
low-permeability impoundment bottom, is used to withdraw free
liquid from the tailings. Water, which collects in the sump pit,
can then be pumped back to the mill for reuse or directed to an
evaporation pond. This not only reduces the phreatic surface of
the liquids in the tailings (the driving force for seepage), but
also increases the stability of the tailings mass.
6.3 LONG-TERM RADON CONTROL TECHNIQUES
6.3.1 Earth Cover
Covering the dried tailings with soil is a proven effective
method for reducing radon-222 emissions (Ro84). The depth of soil
required for a given amount of control varies with the type of
earth and radon-222 exhalation rate.
Earth covers decrease radon-222 emissions by retaining the
radon-222 released from the tailings long enough so that a major
portion will decay in the cover. A large decrease in radon-222
emissions is achieved by applying almost any type of earth. Radon-
222 diffusion through earth is a complex phenomenon affected by
processes such as molecular diffusion, described mathematically by
Pick's law. These complex parameters have been evaluated by Rogers
and Nielson (Ro81) and were described in Chapter 4. Diffusion
depends greatly on the porosity and moisture content of the medium
through which it occurs. Therefore, high-moisture content soils,
such as clay, provide greater radon-222 emission reduction because
of their smaller diffusion coefficients.
In practice, earthen cover designs must take into account
uncertainties in the measured values of the specific cover mater-
ials used, the tailings to be covered, and predicted long-term
values of equilibrium moisture content for the specific location.
The uncertainty in predicting reductions in radon-222 flux in-
creases rapidly as the radon-222 emission limit is reduced.
6.3.2 Asphalt Covers
Asphalt cover systems have been proposed as a radon-222
control technique because such systems exhibit very low radon-222
diffusion coefficients. The Pacific Northwest Laboratory (PNL) has
investigated controlling the release of radon-222 through use of
asphalt emulsion covers for DOE's Uranium Mill Tailings Remedial
Action Project (UMTRAP). Results have shown asphalt emulsion cover
systems to be effective at substantially reducing radon-222 emis-
sions, and field tests indicate that such systems have the proper-
ties necessary for long-term effectiveness and stability. Of the
various types of asphalt cover systems that were researched, an
6-3
-------
asphalt emulsion admix seal was found to be the most effective
(Ha84; Ba84).
Based on cost estimates for application of a full-scale
asphalt cover (Ba84), asphalt cover systems could prove to be
economically competitive with earthen covers at some existing
sites. These cost estimates are applicable to relatively flat
sites, which may require regrading before these techniques could
be applied. Long-term cover protection, in the form of gravel or
vegetation above an earthen cover applied over the asphalt radon-
222 barrier, may also have to be considered.
6.3.3 Soil Cement Covers
A mixture of soil and Portland cement, called soil cement, is
widely used for stabilizing and conditioning soils (Pc79). The
aggregate sizes of tailings appear suitable for soil cement, which
is relatively tough, withstands freeze/thaw cycles, and has a
compressive strength of 300 to 800 psi. When combined in a dispos-
al system with a 1-meter earth cover, soil (tailings) cement would
likely provide reasonable resistance to erosion and intrusion,
substantially reduce radon releases, and shield against penetrating
radiation. A previous study (EPA82) has estimated that soil cement
covers would control emissions to approximately the same levels as
a 2-meter earth cover. Costs are expected to be comparable to
those of thick earth covers. The long-term performance of soil
cement is unknown, especially as tailings piles shift or subside
with age. When placed over large surface areas, soil cement
typically cracks at various intervals. The importance of this
cracking on the effectiveness of soil cement has not been evalu-
ated, but is expected to be small.
6.3.4 Other Radon Control Techniques
A number of other radon control techniques have been proposed
and subjected to preliminary evaluations for applicability.
Several of these techniques are summarized below.
Synthetic Covers and Chemical Sprays. Synthetic material such
as a polyethylene sheet can reduce radon-222 emissions if carefully
placed and sealed on dry tailings. The overall effectiveness of
synthetic covers is not known since leaks occur around the edges
and at seams and breaks. Synthetic covers also have a limited
life, especially in dry, sunny, windy areas, and will not provide a
long-term barrier to radon-222. Such a barrier would aid, at least
temporarily, in the control of radon-222 if a soil cover material
were subsequently applied.
Chemical stabilization sprays that form coatings on the dry
tailings are effective for controlling dust, but are not effective
in controlling radon-222 since an impermeable cover is not ob-
tained.
6-4
-------
The lack of long-term stability of synthetic covers and the
ineffectiveness of chemical sprays make these options unsuitable
for long-term passive control.
Thermal Stabilization. Thermal stabilization is a process in
which tailings are sintered at high temperatures. The Los Alamos
National Laboratory has conducted a series of tests on tailings
from four different inactive mill sites (Dr81). The results show
that thermal stabilization is effective in preventing the release
(emanation) of radon from tailings. However, before thermal
stabilization can be considered as a practical disposal method,
information is needed on the following: (1) the long-term stability
of the sintered material; (2) the interactions of the tailings and
the refractory materials lining the kiln; (3) the gaseous and
particulate emissions produced during sintering of tailings; and
(4) revised engineering and economic analysis as more information
is developed.
Since gamma radiation is still present, protection against the
misuse of sintered tailings is required. While the potential
health risk from external gamma radiation is not as great as that
from the radon decay products, it can produce unacceptably high
exposure levels in and around occupied buildings. Also, the
potential for groundwater contamination may require the use of
liners in a disposal area.
Chemical Processing. The Los Alamos National Laboratory has
also studied various chemical processes such as nitric acid leach-
ing to extract thorium-230 and radium-226 from the tailings, along
with other materials (Wm81). After removal from the tailings, the
thorium and radium can be concentrated and fixed in a matrix such
as asphalt or concrete. This greatly reduces the volume of these
hazardous materials and allows disposal with a higher degree of
isolation than economically achievable with unextracted tailings.
The major question regarding chemical extraction is whether it
reduces the thorium and radium values in the stripped tailings to
safe levels. If processing efficiencies of 80 to 90 percent were
attained, radium concentrations in tailings would still be in the
30 to 60 pCi/g range. Thus, careful disposal of the stripped
tailings would still be required to prevent misuse. Another
disadvantage of chemical processing is the cost, although some of
the costs might be recovered from the sale of other minerals
recovered in the processing (Th81).
Deep-Mine Disposal. Disposal of tailings in worked-out deep
mines offers several advantages to surface disposal options. The
probability of intrusion into and misuse of tailings in a deep mine
is much less than in the case of surface disposal. Radon releases
to the atmosphere would be eliminated, for practical purposes, as
would erosion and external radiation. The major disadvantage of
deep mine disposal is the potential contamination of groundwater
6-5
-------
resulting from leaching of radionuclides and other toxic chemicals
from the tailings. Overall, while this method can provide a
relatively high level of protection against exposure to radon and
misuse of tailings, it has a high potential for causing serious
groundwater contamination which is very costly to control.
Ca1iche Cover. Caliche (calcium deposits that form within or
on top of soil in arid or semi-arid regions) cover material for
mill tailings piles has been suggested as a control method (Br81).
This material may be effective in precluding excessive mobilization
of certain radionuclides and toxic elements. However, the effec-
tiveness and long-term performance of such covers have not been
adequately assessed.
6.4 COMPARISON OF EARTH COVERS TO OTHER CONTROL TECHNIQUES
In comparison to other control technologies, earth covers have
been shown to be the most cost effective (NRG 80). Apart from cost
considerations, earth covers as a method to control radon-222
emissions also offer several other benefits. For example, syn-
thetic covers, such as plastic sheets, do not reduce gamma radia-
tions. However, earth covers that are thick enough to reduce
radon-222 emissions will reduce gamma radiation to insignificant
levels. Further, chemical and physical stresses over a substantial
period of time destabilize synthetic covers; earth covers are
stable over the long term, provided the erosion caused by rain and
wind is contained with vegetation or rock covers, and appropriate
precautions are taken against natural catastrophes, e.g., floods
and earthquakes.
Earth covers also reduce the likelihood of groundwater contam-
ination resulting from either storing radioactive materials in
underground mines (typically located under the water table) or from
using the leaching process to extract radioactive and nonradioac-
tive contaminants from mill tailings. Moreover, although under-
ground mine disposal is an effective method to protect against
degradation and intrusion by man, it nevertheless incurs a social
cost. For example, storing tailings in underground mines elimi-
nates the future development of the mines' residual resources.
Again, earth covers with proper vegetation and rock covers can
protect against human intrusion, without incurring such social
costs.
Finally, earth covers provide more effective long-term stab-
ilization than either water or soil cement covers. Inasmuch as
soil cement covers are comparable to earth covers in terms of cost
effectiveness, their long-term performance is as yet unknown.
Water covers, on the other hand, depend upon long term institution-
al oversight. Institutional controls cannot be relied upon over
time periods as long as 1000 years or more. Moreover, earth covers
are more practical than water covers in arid regions.
6-6
-------
The standards established for long-term control of residual
radioactive materials from inactive uranium processing sites under
UMTRCA (40 CFR 192, Subpart A.) require the following:
"... Control shall be designed to: (a) Be effective
for up to one thousand years, to the extent reasonably
achievable, and, in any case, for at least 200 years,
and, (b) Provide reasonable assurance that releases of
radon-222 from residual radioactive material to the
atmosphere will not: (1) Exceed an average release rate
of 20 picocuries per square meter per second, or (2)
Increase the annual average concentration of radon-222 in
air at or above any location outside the disposal site by
more than one-half picocurie per liter."
It has been decided that the earth cover will serve as the
radon control technique (specified by 10 CFR 40, Appendix A) which
currently provides the most cost effective means of satisfying the
UMTRCA control standards.
6-7
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Page Intentionally Blank
-------
CHAPTER 7
COSTS AND BENEFITS
The perspective from which the costs and benefits of this
rulemaking are assessed, is addressed in the first section of this
chapter. The costs of covering the piles and the financial burden
this imposes on the mill tailings industry are discussed in Sec-
tions 7.2 through 7.4, and in Section 7.6. Costs and benefits are
compared in Section 7.5. The regulatory flexibility analysis is in
the last section of this chapter.
7.1 THE COSTS AND BENEFITS OF RADON COVER IN PERSPECTIVE
The 20 pCi/m2-s radon emissions limit used throughout this
analysis was established in the 1983 UMTRCA rulemaking. That
rulemaking found that the costs of achieving a 20 pCi/m2-s limit
were justified by the reduction in radon induced fatal cancers.
The 1989 CAA rulemaking reaffirmed the 20 pCi/m2-s limit, finding
that it was safe with an ample margin of safety. The rulemaking
discussed in this BID does not alter those decisions, nor does it
reconsider the results of those rulemakings. The costs and bene-
fits of covering the uranium mill tailings piles in order to
control radon emissions are not changed.
However, there are other costs and benefits specifically
associated with the rulemaking addressed in this BID. They are
separate from the costs- and benefits discussed in the paragraph
above and are dealt with separately. These costs and benefits are
evaluated from the perspective of the situation as it existed at
the end of 1991, after the MOU between EPA, NRC and the Agreement
•States on Subpart T had been signed. The mill tailings piles
'subj ect to the MOU did not have completed radon covers at that
time. Under provisions of Subpart T as enacted, they were to have
had permanent radon covers by December, 1991. The MOU postponed
the time for achieving final cover; effectively reducing the costs
to the mill operators of meeting -the cover requirements because it
delays the time when the expenditures were to have been made. The
MOU also allowed an increase in the overall fatal cancers caused by
emissions from the piles by allowing emissions to continue past the
end of 1991. Prom this perspective, the cost to society of this
rulemaking becomes the increased fatal cancers caused by the
extended period of radon emissions and the benefit to society
becomes the reduction in costs due to the delay in covering the
piles.
The increased fatal cancers resulting from this rulemaking are
presented in Chapter 5 and the cost savings are presented in the
next three sections of this chapter.
7-1
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7.2 COSTS OF COVERING THE PILES
The costs of covering the piles subject to the MOU are devel-
oped in this section. Earthen covers placed on the tops and sides
of uranium mill tailings piles have been demonstrated to be a cost-
effective means of providing long-term control of radon emissions.
This chapter presents cost estimates for the placement of earthen
covers which meet the 20 pCi/m2-s emissions limit for the currently
non-operational tailings impoundments.
The cost of earthen cover varies with the geographic location
of the tailings impoundment, its layout, the topography of the
disposal site and its surroundings, and the thickness of the cover
required to achieve the emission standard. The cost also varies
with the availability of cover material, the distance it must be
hauled, and the ease of its excavation. If the necessary materi-
als, such as gravel, dirt, and clay, are not available locally,
they must be purchased and/or hauled, thereby significantly in-
creasing costs. In general, the more difficult the excavation the
more elaborate and expensive the equipment needed will be, and the
higher the cost will be.
The date of covering the piles affects the present valuation
of the cost of cover. Therefore, the length of the delay, as well
as site specific characteristics of the piles themselves, must be
taken into account in determining the costs of the covers.
Table 7-1 provides estimates of the radon emissions release
rates and cover thickness required on each pile to meet the 20
pCi/m2-s emissions limit. It also gives the pile areas and infor-
mation on any interim cover that may be on the pile. Estimates of
the total volume of earth needed for permanently covering each pile
can be calculated from the information in this table by subtracting
the volume of the interim cover from the volume needed to cover the
entire pile.
The installation of the permanent cover is assumed to take one
year, as is also assumed for calculating estimated radon emissions
in Chapter 5. The permanent cover is assumed to be completed at
the end of the year of the MOU target disposal date.
Cost estimates are generated using the same methods as were
used in estimating the costs for covering the tailings at licensed
mill tailings facilities for the NESHAPs promulgated in 1989. The
methodology is described in detail in Appendix B of the Risk
Assessments Appendixes (Appendix to Volume 2), and the costs are
summarized in Chapter 4 of the Economic Assessment (Volume 3), of
the Background Information Document for those NESHAPs (EPA89c,
EPA89d). The unit costs for individual cover activities were
updated to 1991 dollars for this analysis. The revised costs were
7-2
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Table 7-1. Facility-Specific Release Rates, Cover Depths, and Areas
Facility
ARC, Gas Hill, WY
ARCO Coal, Bluewater, HM
Atlas, Moab, OT
Conoco, Conquista, TX
Ford-Dawn Mining, Ford, WA
Hecla Mining, Durita, CO
Homestake, KM (large impoundment)
Homestake, NM (small impoundment)
Pathfinder -Lucky Me, GH, WY
Petrotomics, Shirley Basin, WY
Quivera, Ambrosia Lake, NM
Rio Algom, Lisbon, OT
Sohio-L-Bar, NM
TOMETCO, Gas Hills, WY
T3METCO, Maybell, CO
IJMETCO, Uravan, CO
UNC, Church Rock, NM
Union Pacific, Bear Creek, WY
WNI , Sherwood, WA
WNI, Split Rock, WY
TOTALS
Release
Rate
(pCi/m2-s)
420
620
540
224
240
428
300
300
220
570
237
420
500
310
128
480
290
420
200
430
Cover
Depth
Required
to Meet
Standard
(m)
3.25
3.66
3.52
2.58
2.65
3.27
2.89
2.89
2.56
3.58
2.64
3.25
3.43
2.92
1.98
3.39
2.85
3.25
2.46
3.27
Current
Interim
Cover
Depth
Cm)
0.15
0.75
N/A
2.58
1.50
0.60
N/A
0.75
0.75
0.75
0.30
0.90
3.43
1.20
2.73
2.73
0.30
0.30
N/A
3.00
Area
Covered
by
Interim
Cover
(m2)
445,000
607,000
0
607,000
384,000
142,000
0
24,000
761,000
461,000
1,344,000
405,000
324,000
777, 000
141,000
283,000
417,000
720,000
0
902,000
8,744,000
Total Area
to be
Covered
(m2}
445,000
1,241,000
518,000
1,012,000
497,000
142,000
688,000
52,000
821,000
461,000
1,490,000
405,000
324,000
777,000
202,000
283,000
417,000
720,000
380,000
902,000
11,777,000
taken from recent versions of the same sources used for the unit
costs in Appendix B (ME91a, ME9lb). The updated unit costs are:
• Hauling — $3.88 per cubic meter,
• Excavating — $1.23 per cubic meter,
• Grading — $2.04 per cubic meter,
• Compacting — $1.63 per cubic meter.
The total cost of covering each tailings pile is estimated
based on these unit costs and the volumes of earth cover calculated
from information in Table 7-1. Excavating and grading costs are
applied for regrading of slopes of each pile and for the reclama-
7-3
-------
tion of the borrow pits. Table 7-2 presents the costs for each
pile for the specific cover activities required to construct earth
covers. A standard overhead cost is applied to arrive at the total
1991 cost to cover each pile to achieve a radon emission rate of 20
pCi/m2-s.
Table 7-2 also shows the present value, or discounted, costs
of covering these piles on the MOU target dates. The present value
costs shown are based on discount rates of 2, 5 and 7 percent.
7.3 COST OF VERIFYING RADON EMISSIONS
Testing the covered piles for radon emissions is a relatively
minor cost. After completing construction of the radon cover, the
owner or operator of each uranium mill tailings pile is required to
measure the radon flux through the permanent radon barrier to
verify the effectiveness of the design of the barrier in ensuring
that the 20 pCi/m2-s standard is not exceeded. The flux is to be
determined after the radon barrier is in place, but before the
placement of gravel and riprap, which are measures for achieving
long-term stabilization of the pile. The necessary measurements
are to be performed in accordance with the procedures described in
40 CFR part 61, Appendix B, Method 115 or any other method proposed
by a licensee and approved by NEC or an affected Agreement State as
being at least as effective as EPA method 115 in demonstrating the
effectiveness of the permanent barrier in achieving compliance with
the standard. Method 115 specifies that the flux be determined
from the mean of a minimum of 100 radon flux measurements made from
the adsorption of radon on activated charcoal in large-area collec-
tors placed at regularly spaced intervals on the surface of the
pile. Radon is to be collected for a 24-hour period. The radon
collected is measured by gamma-ray spectroscopy.
The typical cost of verifying that a covered pile meets the 20
pCi/m2-s limit is in the range of $5,000 to $6,000, but it may be
as high as $10,000. This is the cost to the pile owner or operator
if the task is performed by a firm specializing in this type of
measurement. It covers transportation to and from the pile site,
all labor associated with placing and recovering the large-area
collectors and measuring the radon adsorbed on the charcoal, the
cost of the activated charcoal used in the collectors, and the
capital cost of the canisters and instruments used.
Assuming that it costs $10,000 to test each pile, the total
cost of verifying the emissions for the approximately 34 piles at
the 19 sites is expected to be about $340,000 disregarding
discounting. These costs would be added to the costs shown in
Table 7-2, but they increase overall costs insignificantly.
7-4
-------
Table 7-2. Costs of Achieving the Regulatory Emission Standards
(1991 $, Million)
Present Value Costs
Mill Name
ANC, Gas Hill, WY
ARCO Coal, Bluewater, NM
Atlas, Moab, UT
Conoco, Conquista, TX
Ford-Dawn Mining, Ford, WA
Hecla Mining, Durita, CO
1 Homestake, NM (large impoundment)
Homestake, NM (small impoundment)
Pathfinder- Lucky Me, Gas Hills, UY
Petrotomics, Shirley Basin, UY
Quivera, Ambrosia Lake, NM
Rio Algom, Lisbon, UT
Sohio-L-Bar, NM
UMETCO, Gas Hills, WY
UMETCO, Maybell, CO
UMETCO, Uravan, CO
UNC, Church Rock, NM
Union Pacific, Bear Creek, WY
UNI, Sherwood, WA
WNI, Split Rock, WY
Total
Regrade
Slopes
1.2
4.1
1.5
4.1
1.1
0.2
2.3
0.0
1.7
1.3
4.8
0.7
0.0
2.1
0.4
0.4
1.1
2.5
0.9
3.5
33.9
Dirt
Cover
12.2
35.4
16.1
9.3
6.6
3.4
17.6
1.2
13.6
11.5
31.3
8.4
0.0
11.9
0.1
1.7
9.4
18.8
8.3
2.2
218.9
Reclaim
Borrow
Pit
0.6
1.8
0.8
0.5
0.3
0.2
0.9
0.1
0.7
0.6
1.6
0.4
0.0
0.6
0.0
0.1
0.5
0.9
0.4
0.1
10.9
Total
14.0
41.2
18.5
13.8
8.0
3.7
20.8
1.3
15.9
13.4
37.6
9.6
0.0
14.5
0.5
2.1
11.0
22.2
9.6
5.7
263.7
Total
Including
O&P a 7%
15.0
44.1
19.7
14.8
8.6
4.0
22.3
1.4
17.0
14.3
40.2
10.3
0.0
15.6
0.5
2.3
11.8
23.8
10.3
6.2
282.2
MOU
Target
Date
1995
1995
1996
1996
2010
1997
1996
2001
1998
1995
1997
1996
1992
1995
1997
2001
1997
1996
1996
1995
At Zero
Percent
Real
Interest
Rate
15.0
44.1
19.7
14.8
8.6
4.0
22.3
1.4
17.0
14.3
40.2
10.3
0.0
15.6
0.5
2.3
11.8
23.8
10.3
6.2
282.2
At 2
Percent
Real
Interest
Rate
13.9
40.7
17.8
13.4
5.9
3.6
20.2
1.1
14.9
13.2
35.7
9.3
0.0
14.4
0.4
1.9
10.5
21.6
9.3
5.7
253.5
At 5
Percent
Real
Interest
Rate
12.4
36.3
15.5
11.6
3.4
3.0
17.5
0.8
12.1
11.8
30.0
8.0
0.0
12.8
0.4
1.4
8.8
18.6
8.1
5.1
217.5
At 7
Percent
Real
Interest
Rate
11.4
33.6
14.0
10.6
2.4
2.7
15.9
0.7
10.6
10.9
26.8
7.3
0.0
11.9
0.3
1.2
7.9
17.0
7.3
4.7
197.3
-------
7.4 COST SAVINGS DUE TO POSTPONING THE TIME OF COVER
Under provisions of the CAA, 40 CFR 61, Subpart T, all non-
operational piles were to have been permanently covered by December
15, 1991. The MOU agreement between the EPA, the NRC, and the
affected Agreement States postponed the dates for requiring final
cover; providing specific dates for covering each pile. The dates
were deferred from one to nineteen years. This delay is a savings
to the uranium milling industry and to society as a whole. The
savings, shown in the last column of Table 7-3, are the differences
between the 1991 cost of covering the piles and the discounted
costs of covering the piles on the dates specified in the MOU. The
1991 cost of increasing the cover to the required depth for all
impoundments would have been somewhat less than $300 million.
Postponing covering the piles reduces this cost by about $29, $65,
or $85 million, at 2, 5, or 7 percent discount rates, respectively.
This savings would be increased if the time for covering any of the
piles were delayed beyond the MOU cover dates. The savings would
be reduced if any of the final covers were completed before the
dates established by the MOU, or if additional interim covers were
placed on the piles before the MOU dates.
Table 7-3.
Present Value Costs to Cover by MOU Target Dates
(Millions of 1991 Dollars)
Baseline
Cost to
Cover in
1991
0%
2%
5%
7%
Real
Real
Real
Real
Interest
Interest
Interest
Interest
Rate
Rate
Rate
Rate
282
282
282
282
.2
.2
.2
.2
Present
Value Cost
to Cover
by MOU
Target Date
282
253
217
197
.2
.5
.5
.3
Cost
Savings
From 1991
Baseline
0
28
64
84
.0
.7
.6
.9
7.5 COST SAVINGS AND RISK INCREASES COMPARED
Table 5-7 shows that 2.26E-2 fatal cancers were expected to
have occurred over the 70 year assessment period used for evaluat-
ing risk, had all the piles listed in the MOU been covered by the
end of 1991. The expected number of fatal cancers increases to
3.48E-2 as a result of delaying placement of radon covers until the
dates agreed to in the MOU. The increased number of fatal cancers
resulting from this rulemaking is 1.22E-2 over the 70 year assess-
ment period. This increase in fatal cancers can be compared to the
reduced costs shown In Table 7-3.
7-6
-------
7.6 FINANCIAL BURDEN ON INDUSTRY
A variety of costs are borne by the uranium milling industry
in keeping piles on standby or inactive status rather than taking
them to final closure. They include the costs of keeping personnel
at the pile sites to carry out the variety of duties associated
with the maintenance, upkeep and guarding of the piles, and the
costs associated with management oversight. ' In addition, there are
various fees associated with maintaining NRC or Agreement State
licenses as long as the piles are on standby or inactive status.
The .licensees are also financially liable for the piles as long as
the'y retain title to them.
All of these costs cease when the piles have been covered and
stabilized in accordance with the provisions of UMTRCA, so that
permanent responsibility for their care passes to the Federal
Government. The cessation of these costs is an incentive for the
licensees to close the piles.
There are, however, substantial costs associated with covering
these piles, as shown in Tables 7-2 and 7-3. Further expenditures
are necessary to meet the ground water and stability provisions of
UMTRCA in order to finally close these piles. The costs of these
other provisions are not addressed in this rulemaking because they
do not contribute to the reduction in radon emissions.
EPA has assumed in its previous rulemakings that the piles
could be closed five years after milling operations ended. Five
years is the approximate time it takes to dry out a thoroughly wet
pile and to complete construction of the radon cover. The ,MOU
between NRC, the affected Agreement States, and EPA was negotiated
in Oct. 1991, before this rulemaking was undertaken. The target
dates in the MOU were established expressly so that the licensees
would achieve control of radon emissions as expeditiously as
practicable considering technological feasibility.
The postponement in the dates for requiring cover, past the
December 1991 deadline established by Subpart T, represents a
reduction in the costs of covering the piles. This, in itself,
reduces the cost burden to the pile owners.
The NRC and the affected Agreement States agreed to ensure
that the schedules and conditions for affecting final closure are
flexible enough to consider technological feasibility. A number of
licensees were allowed more than five years from the signing of the
MOU to complete construction of radon covers. Therefore, it is
reasonable to assume that the licensees will be able to meet the
MOU dates without incurring unreasonable costs.
7-7
-------
7.7 REGULATORY FLEXIBILITY ANALYSIS
The Regulatory Flexibility Act (RFA5 requires regulators to
determine whether proposed regulations would have significant
economic impact on a substantial number of small businesses or
other small entities. If so, regulators are required to consider
specific regulatory alternatives that minimize the impacts on these
small entities without compromising the objective of the statute
tinder which the rule is enacted. Alternatives for consideration by
the RFA are tiering regulations, performance rather than design
standards, and small firm exemptions.
Most firms that own uranium mills are divisions or subsidiar-
ies of major U.S. and international corporations. Many of these
uranium milling operations are a part of larger diversified mining
firms which are engaged In a number of raw materials industries;
uranium milling represents only a small portion of their overall
operations., Others are owned by major oil companies and electric
utilities which were engaged in horizontal and vertical integra-
tion, respectively, during the industry's growth phase in the 1960s
and 1970s. In 1977 there were 26 companies operating uranium mills
in the XJ.S. Presently there are approximately three, and these
operate only part time. Future projections for the industry are
bleak; it is unlikely that more than a very few mills will operate
at any one time in the future. The high financial risk and the
large capital requirement needed to enter or to remain viable in
the industry means that the industry will be restricted to large
diversified firms and large electric utilities.
This rulemaking reduces the economic cost to the mill owners
for covering the uranium mill tailings piles subject to the Subpart
T regulation promulgated in 1989 because it effectively postpones
the required expenditures to later dates. It was found in the 1989
rulemaking that there was no significant impact on small business
entities. There has been no change in this, no new tailings piles
have been constructed since 1989.
The result is that no significant impact on small business
entities is expected if this rulemaking is promulgated.
7-8
-------
APPENDIX A
CAP88-PC INFORMATION SHEETS
-------
Page Intentionally Blank
-------
CAP88PC INFORMATION SHEET
Date: April 1992 Source Category: Baseline Emissions Page 1 of
Facility: Federal American Location: Rlverton, Wyoming
X Population Run Input File Name: FED AMER BASE Output File Prefix: AAO
Array Attached Pop. File Name: FEDAMERI
Latitude: 42 ° 47 59 Longitude: 107 ° 38 00
Distances: 500 1,000 2.000 3,000 4.000 5.000 10.000 20,000 40.OOP 60.000
(meters) 80,000
Food Fractions: Fl-Grown at Home F2-Grown Regionally FS-Imported Urban/Low Rural
Meat: Productivity
Milk: X
Vegetables:
Individual Run Input File Name: Output File Prefix:
Distances:_
(meters)
Food Fractions: Fl-Grown at Home F2-Grown Regionally F3-Imported Urban/Low Rural
Meat: m ___^_ Productivity
Milk:
Vegetables:
Meteorological (STAR) Data: Array Attached STAR File Name: LND1100
Location: LANDER WBAN: 24021 HDR: 1100 CODE: LN LND SET//: STAR05
Temperature: 6.0°C Lid Height: 608 m Rainfall: 25.4 cm/yr
Stack Source: 1234 56
Height (m): i
Diameter (m):
X Area Source:
Circular Area (m2): 445,000
Plume Rise:
Buoyant (cal/s):
Momentum (m/s):
Entered (in) :
Pasquill Stability A B
Nuclide Class AMAD Release Rates (Ci/yr)
Rn-222 281
Additional Source Term Attached
Comments:
A-l
-------
CAPS8PC INFORMATION SHEET
Dace: April 1992 Source Category: Baseline Emissions Page 1 of
Facility: Anaconda (ARCO Coal) Location: Bluewater, N.M.
_X Population Run Inpuc File Name: ANACONDA BASE Output File Prefix:
_Array Attached Pop. File Name: BLUEWATE
>^4M. *3 C ® 1 £. i «1 M Y _ J*_.._i__
Lacicude: 35 * 16 12 Longitude:__107_° 56 44
Distances;500 1,000 2,000 3,000 4,000 5,000 10,000 20,000 40,000 60,000
(meters) 80, OOP
Food Fractions: Fl-Grown at Home F2-Grown Regionally F3-Imported Urban/Low Rural
Meat: Productivity
Milk: X
Vegetables:
Individual Run Input File Name: Output File Prefix:
Distances:
(meters)
Food Fractions: Fl-Grovm at Home F2-Grown Regionally F3-Imported Urban/Low Rural
Meat: Productivity
Milk:
Vegetables:
Meteorological (STAR) Data: Array Attached STAR File Name: STARANHM
Location: AMBROSIA LAKE WBAN: HDR: CODE: SET#:_
Temperature: 13.4 °C Lid Height: 767 m Rainfall: 20.6 cm/yr
Stack Source: 1234 5
Height (m):
Diameter (m): ___
X Area Source:
Circular Area (m2): 1,214,000
Plume Rise:
Buoyant (cal/s):
Momentum (m/s):
Entered (m):
Pasquill Stability A B
Nuelide Class AMAD Release Rates (Ci/yr)
Rn-222 766
Additional Source Term Attached
Comments:
A-2
-------
CAP88PC INFORMATION SHEET
Date: April 1992 Source Category: Baseline Emissions Page 1 of
Facility: Moab Location: Moab, Utah
_X Population Run Input File Name: MOAB BASELINE Output File Prefix: AAC
Array Attached Pop. File Name:_MOABATLA_
Latitude: 38 ° 35 59 Longitude: 109 ° 35 44
Distances: 500 1,000 2,000 3,OOP 4,000 5,000 10,000 20,000 40,000 60,000
(meters) 80,000 .
Food Fractions: Fl-Grown at Home F2-Grown Regionally F3-Imported Urban/Low Rural
Meat: Productivity
Milk: X
Vegetables:
Individual Run Input File Name: Output File Prefix:
Distances:_
(meters)
Food Fractions: Fl-Grown at Home F2-Grown Regionally F3-Imported Urban/Low Rural
Meat: Productivity
Milk:
Vegetables:
Meteorological (STAR) Data: Array Attached STAR File Name: GJT0476
Location: GRAND JUNCTION WBAN: 23066 HDR: 0476 CODE: GJT SET#: STAR03
Temperature: 13.7 °C Lid Height: 538 m Rainfall: 20.3cm/yr
Stack Source: 1234 56
Height (m) :
Diameter (m) :
X Area Source:
Circular Area (m2): 518,000
Plume Rise:
Buoyant (cal/s):
Momentum (ra/s):
Entered (m) :
Pasquill Stability A B
Nuclide Class AMAD Release Rates (Ci/yr)
Rn-222 327
Additional Source Term Attached
Comments:
A-3
-------
CAP88PC INFORMATION SHEET
Date: April 1992 Source Category: Baseline Emissions Page 1 of ]
Facility: Conquista Location: Falls City, Texas
X Population Run Input File Name: CONQUISTA BASE Output File Prefix: AAD
_Array Attached Pop. File Name: CONQUIST
Latitude: 28 ° 54 03 Longitude: 98 ° 05 40 "
Distances:_5QQ 1,000 2.OOP 3,000 4,000 5,000 10,OOP 20.0PP 4P.OOP 60,000
(meters) 80.OOP
Food Fractions: Fl-Grown at Home F2-Grown Regionally F3-Imported Urban/Low Rural
Meat: Productivity
Milk: X
Vegetables:
Individual Run Input File Name: Output File Prefix:
Distances:,
(maters)
Food Fractions: Fl-Grown at Home F2-Grown Regionally F3-Imported Urban/Low Rural
Meat: Productivity
Milk:
Vegetables:
Meteorological (STAR) Data: Array Attached STAR File Name: SAT0064
Location: SAN ANTONIO WBAN: 12921 HDR: 0064 CODE: SAT SET//: STAR01
Temperature; 20.4 "G Lid Height: 873 m Rainfall: 68.6 cm/yr
Stack Source: 1234 56
Height (m): _______
Diameter (m):
X Area Source:
Circular Area (m2): 1,012,OOP
Plume Rise:
Buoyant (cal/s):
Momentum (m/s):
Entered (ra):
Pasquill Stability A B
Nuclide Class AMAD Release Rates (Ci/yr)
Rn-222 638
Additional Source Term Attached
Comments:
A-4
-------
CAP88PC INFORMATION SHEET
Date: April 1992 Source Category: Baseline Emissions Page 1 of
Facility: Dawn i Location: Ford, Washington
_X Population Run Input File Name: DAWN BASELINE Output File.Prefix: AAE
_Array Attached Pop.' File Name: DAWNMILL
Latitude: 47 ' 54 06 Longitude: 117 ° _ 49 58
Distances: 500 1,000 2,OOP ' 3,000 4,000 5,000 10.000 20,000 40,OOP 60,000
(meters) 80,000 ,
Food Fractions: Fl-Grown at Home F2-Grown Regionally F3-Imported Urban/Low Rural
Meat: Productivity
Milk: . X
Vegetables: • •
Individual Run Input File Name: Output File Prefix:
Distances:
(meters)
Food Fractions: Fl-Grown at Home F2-Grown Regionally F3-Irnported Urban/Low Rural
Meat: Productivity
Milk:
Vegetables:
Meteorological (STAR) Data: Array Attached STAR File Name: GEG0360
Location: SPOKANE WBAN: 24157 HDR: 0360 CODE: GEG SETtf: STAR03
Temperature: 8.4 °C Lid Height: 640m Rainfall: 42.4 cm/yr
Stack Source: 1 2 3 4 5 6
Height (ra) : , i
Diameter (m) : .
.X Area Source:
Circular Area (m2): 497,000
Plume Rise:
Buoyant (cal/s):
_Momentum (ra/s):
Entered (m):
Pasquill Stability A B
Nuclide Class AMAD Release Rates (Ci/yr)
Rn-222 313
Additional Source Term Attached
Comments:
A-5
-------
CAP88PC INFORMATION SHEET
Date: April 1992 Source Category: Baseline Emissions Page 1 of
Facility: Naturita Location: Naturita,CO
_X Population Run Input File Name: KATURITA BAS E Output File Prefix: AAF
_X Array Attached Pop. File Name: NATURITA
a<"f t"1lHa« ^R • 10 flfl " T ™-i rr-i t-, ,A a •
Latitude: 38 * 12 00 Longitude: 108 ° 37 00
Distances; 500 1.000 2.000 3,000 4.000 5,000 10.OOP 20.000 30.000 40,OOP
(meters) 50,000 60,OOP 80.OOP
Food Fractions: Fl-Grown at Home F2-Grown Regionally FS-Imported Urban/Low Rural
Meat: Productivity
Milk; _X
Vegetables:
Individual Run Input File Name: Output File Prefix:
Distances:
(meters)
Food Fractions: Fl-Grown at Home F2-Grown Regionally F3-Imported Urban/Low Rural
Meat: Productivity
Milk:
Vegetables:
Meteorological (STAR) Data: Array Attached STAR File Name: GJT0476
Location: Grand Junction WBAN: 23066 HDR: 0476 CODE: GJT SET#:STAR03
Temperature: 11.5 °G Lid Height: 538 m Rainfall: 20.3 cm/yr
Stack Source: 1234 56
Height (m):
Diameter (m):
X Area Source:
Circular Area (m2): 142,000
Plume Rise:
Buoyant (cal/s):
Momentum (m/s):
Entered (m):
Pasquill Stability A B
Nuclide Glass AMAD Release Rates (Ci/yr)
Rn-222 9
Additional Source Term Attached
Comments:
A-6
-------
CAP88PC INFORMATION SHEET
Date: April 1992 Source Category: Baseline Emissions
Facility:Homestake (large impoundment) Location: Grants, N.M.
Page 1_
of
_X Population Run Input File Name: LHOMESTAKEBASE
_Array Attached Pop. File Name: HOMESTAK
Output File Prefix: AAI
Latitude:
35
14
31
51
46 "
Distances:
500
1,000 2,000
(meters) 80,000
Longitude: ...107. °
3.000 4,000 5,000 10,000 20,000 40,000 60.000
Food Fractions: Fl-Grown at Home F2-Grown Regionally F3-Imported Urban/Low Rural
Meat: _____ Productivity
Milk:
Vegetables:
X
_Individual Run Input File Name:_
Output File Prefix:_
Distances :_
(meters)
Food Fractions: Fl-Grown at Home F2-Grown Regionally F3-Imported Urban/Low Rural
Meat: Productivity
Milk:
Vegetables:
Meteorological (STAR) Data:
Location: AMBROSIA LAKE WBAN:
_Array Attached STAR File Hame: STARANHM
~ HDR: CODE: SET#:
Temperature: ,13,.4 °C Lid Height: 767 m Rainfall: 20.6 cm/yr
Stack Source: 1234
Height (m):
Diameter (in) :
X Area Source:
Circular Area (m2): 688,000
Plume Rise:
Buoyant (cal/s);
Momentum (m/s):
Entered (m):
Pasquill Stability
B
Nuclide Class AMAD Release Rates (Ci/yr)
Rn-222 434
Additional Source Term Attached
Comments:
A-7
-------
CAP88PC INFORMATION SHEET
Dace; April 1992 Source Category: Baseline Emissions Page
Facility: Homestake (small impoundment) Location: Grants, N.M.
of
_X Population Run Input File Name: SHOMESTAKE BASE
_Array Attached Pop. File Name: HOMESTAK
Output File Prefix: AAJ
Latitude: 35 •
14
31
Longitude: 107
51
46
Distances:
(meters) 80,OOP
500 1.000 2.000 3.000 4.000 5,000 10,000 20,000 40.000 60,000
Food Fractions: Fl-Grown at Home F2-Grown Regionally F3-Imported Urban/Low Rural
Meat: Productivity
Milk: X
Vegetables:
_Individual Run Input File Name:
Output File Prefix:
Distances:
(meters)
Food Fractions: Fl-Grown at Home F2-Grown Regionally F3-Imported Urban/Low Rural
Meat: Productivity
Milk: _____
Vegetables: i
Meteorological (STAR) Data: _____
Location: AMBROSIA LAKE WBAN:
_Array Attached STAR File Name: STARANHM
CODE:
HDR:
SET#:
Temperature: 13.4 "C Lid Height: 767 m Rainfall: 20.6 cm/yr
Stack Source: 1234
Height (m):
Diameter (m) :
X Area Source:
Circular Area (m);
Plume Rise:
Buoyant (cal/s): _
_ Momentum (m/s): _
_ Entered (m) :
Pasquill Stability
52.OOP
B
D
Nuclide Class AMAD Release Rates (Ci/yr)
Rn-222 33
Additional Source Terra Attached
Comments:
A-8
-------
CAP88PC INFORMATION SHEET
Date: April 1992 Source Category: Baseline Emissions Page 1 of 1
Facility: Lucky Me Location: Riverton, Wyoming
X Population Run Input File Name: LUCKY MN BASE Output File Prefix: AAK
_Array Attached Pop. File Name: GASLUCKY
Latitude: 42 ° 49 55 Longitude: 107 ° 37 00
Distances: 500 1,000 2,000 3.000 4,000 5,000 10,000 20,000 40,000 60,000
(meters) 80,OOP
Food Fractions: Fl-Grown at Home F2-Grown Regionally F3-Imported Urban/Low Rural
Meat: Productivity
Milk: X
Vegetables:
Individual Run Input File Name: Output File Prefix:
Distances:
(meters)
Food Fractions: Fl-Grown at Home F2-Grown Regionally F3-Imported Urban/Low Rural
Meat: Productivity
Milk:
Vegetables:
Meteorological (STAR) Data: Array Attached STAR File Name: LND1100
Location: LANDER WBAN: 24021 HDR: 1100 CODE: LND SET#: STAR05
Temperature: 6.0 °C Lid Height: 608 m Rainfall: 22.9 cm/yr
Stack Source: 1234 56
Height (m) :
Diameter (m) :
X Area Source:
Circular Area (m2): 821.000
Plume Rise:
Buoyant (cal/s):
Momentum (m/s):
Entered (m) :
Pasquill Stability A B
Nuclide Class AMAD Release Rates (Ci/yr)
Rn-222 518
Additional Source Term Attached
Comments:
A-9
-------
CAP88PC INFORMATION SHEET
Pace; April 1992 Source Category: Baseline Emissions . Page 1 of 1
Facility: Petrotomics Location: Medicine Bow, Wyoming
X Population Run Input File Name:PETROTOMICS BASE Output File Prefix: AAL
_Array Attached Pop. File Name: PETROTOM
Latitude: 42 * 20 04 ' Longitude: 106 ° 11 49
Distances:500 1,000 2,000 3,000 4,000 5,OOP 10,OOP 20,000 40.000 60.000
(meters) 80,OOP _ ______
Food Fractions: Fl-Grown at Home F2-Grown Regionally FS-Imported Urban/Low Rural
Meat: Productivity
Milk: . ] X
Vegetables:
Individual Run Input File Name: Output File Prefix:
Distances:_
(meters)
Food Fractions: Fl-Grown at Home F2-Grown Regionally F3-Imported Urban/Low Rural
Meat: Productivitvity
Milk:
Vegetables:
Meteorological (STAR) Data: Array Attached STAR File Name: CPR1564
Location: CASPER WBAN:24089 HDR: 1564 CODE: CPR SET//: STAR07
Temperature: 5.3 °C Lid Height: 533 m Rainfall: 30.5 cm/yr
Stack Source: 1234 56
Height (m):
Diameter (m):
X Area Source:
Circular Area (m2): 461,POO
Plume Rise:
Buoyant (cal/s):
Momentum (m/s):
Entered (m):
Pasquill Stability A B
Nuclide Class AMAD Release Rates (Ci/yr)
Rn-222 291
Additional Source Term Attached
Comments:
A-10
-------
CAP88PC INFORMATION SHEET
Date: April 1992 Source Category: Baseline Emissions Page 1 of
Facility: Kerr-licGee (Quivera) • Location: Ambrosia Lake, N.M.
X Population Run Input File Name: KERR-MCGEEBASE Output File Prefix: AAM
_Array Attached Pop. File Name: AMBROSIA
Latitude: 35 ° 23 39 Longitude: 107 " 49 47
Distances: 500 I.OOP 2,000 3.000 4,000 5.OOP 10,000 20.000 40,000 60.000
(meters) 80,000 .
Food Fractions: Fl-Grown at Home F2-Grown Regionally F3-Imported Urban/Low Rural
Meat: Productivity
Milk: X
Vegetables: '
Individual Run Input File Name: Output File Prefix:
Distances:
(meters)
Food Fractions: Fl-Grown at Home F2-Grown Regionally FS-Imported Urban/Low Rural
• Meat: • Productivity
Milk:
Vegetables:
Meteorological (STAR) Data: Array Attached STAR File Name: STARANHM
Location: AMBROSIA LAKE' WBAN: HDR: CODE: SET#:_
Temperature: 13.4°C Lid Height: 7671m Rainfall: 20.6 cm/yr
Stack Source: 12 3 4 5
Height (m) :
Diameter (m) :
X Area Source:
Circular Area (m2): 1,490,POP
Plume Rise:
Buoyant (cal/s): -
Momentum (m/s):
Entered (m) : •__
Pasquill Stability A B C D
Nuclide Class AMAD Release Rates (Ci/yr)
Rn-222 940
Additional Source Term Attached
Comments:
A-ll
-------
CAP88PC INFORMATION SHEET
Dace: April 1992 Source Category: Baseline Emissions Page 1 of
Facility: Rio Algom _____ Location: La Sal, Utah
_X Population Run Input File Name: RIO ALCOM BASE Output File Prefix: AAN_
_Array Attached Pop. File Name: LASALRIO
Latitude: 38 " 15 00 Longitude: 109 " 16 30 ' •
Distances: 500 1,000 2.000 3,000 4,000 5.000 10,000 20.000 40.000 60.000
(meters) 80,000
Food Fractions: Fl-Grown at Home F2-Grown Regionally F3-Imported Urban/Low Rural
Meat: Productivity
Milk: X
Vegetables:
Individual Run Input File Name: Output File Pre'fix-; ;
Distances:_
(meters)
Food Fractions: Fl-Grown at Home F2-Grown Regionally F3-Imported Urban/Low Rural
Meat: . . Productivity
Milk; ' ' ''
Vegetables:
Meteorological (STAR) Data: Array Attached STAR File Name: GJT0476
Location: GRAND JUNCTION WBAN:_23066 HDR: 0476 CODE: GJT SET#: STAR03
Temperature: 13.7 °C Lid Height: 538 m Rainfall: 20.3 cm/yr
Stack Source: 1234 56
Height (»): •
Diameter (m):
X Area Source:
Circular Area (m2): 405,000
Plume Rise:
Buoyant (cal/s): i
Momentum (m/s):
Entered (m) :
Pasquill Stability A B
Nuclide Class AMAD Release Rates (Ci/yr)
En-222 255
Additional Source Term Attached
Comments:
area changed percomments: 0-5 km demography updated.
A-12
-------
CAPB8PC INFORMATION SHEET
Date: April 1992 Source Category: Baseline Emissions Page 1 of
Facility: L-Bar Location: Seyboyeta, N.M.
_X Population Run Input File Name: L BAR BASELINE Output File Prefix: AAV
_Array Attached Pop. File Name: LBARSOHI
Latitude: 35 ° 11 09 Longitude: 107 " 20 09
Distances: 500 1,000 2,000 3,000 4,000 5,000 10,000 20,000 40,000 60,000
(meters) 80, OOP '_
Food Fractions: Fl-Grown at Home F2-Grown Regionally F3-Imported Urban/Low Rural
Meat: Productivity
Milk: X
Vegetables:
Individual Run Input File Name: Output File Prefix:
•istances:
(meters)
""cod Fractions: Fl-Grown at Home F2-Grown Regionally F3-Imported Urban/Low Rural
Meat: Productivity
Milk:
Vegetables:
..eteorological (STAR) Data: Array Attached STAR File Name: ABQ0282
^ocation: ALBUQUERQUE WBAN: 23050 HDR: 0282 CODE: ABQ SET#: STAR03
lemperature: 13.4 °C Lid Height: 767 m Rainfall: 20.6 cm/yr
Stack Source: 1234 56
Height (m):
Diameter (m):
X Area Source:
Circular Area (m2): 324,000
lume RisJe:
Buoyant (cal/s):
Momentum (m/s):
Entered (m):
Pasquill Stability A B
uclide Class AMAD Release Rates (Ci/yr)
.n-222 204
Additional Source Term Attached
Comments:
A-13
-------
CAPS8PC INFORMATION SHEET
DaCe: April 1992 Source Category: Baseline Emissions Page 1 of 1_
Facility: Umetco Gas Hills Location: River ton, Wyoming
X Population Run Input File Name: GAS HILLS BASE Output File Prefix: AAA
_Array Attached Pop. File Name: UCCGASHI
1/*«1 • A 9 ° /. Q /, ^ " T ^,^,rrn f-,i/-lQ •
Latitude: 42 " 49 45 Longitude: 107 " 29 34
Distances: 500 1.000 2.000 3,000 4,000 5,000 10,000 20,000 40,000 60,000
(meters) 80.000
Food Fractions: Fl-Grown at Home F2-Grown Regionally F3-Imported Urban/Low Rural
Meat: Productivity
Milk: _, __X
Vegetables:
Individual Run Input File Name: Output File Prefix:
Distances:
(meters)
Food Fractions: Fl-Grown at Home F2-Grown Regionally F3-Imported Urban/Low Rural
Meat: Productivity
Milk:
Vegetables:
Meteorological (STAR) Data: Array Attached STAR File Name: LND1100
Location: LANDER WBAN: 24021 HDR: 1100 CODE: LND SET//: STAR05
Temperature: 6.0 "C Lid Height: 608 m Rainfall: 25.4 cm/yr
Stack Source: 1234 56
Height (m):
Diameter (m) :
X Area Source:
Circular Area (m2): 777,000
Plume Rise:
_Buoyant (cal/s):
Jiomentum (m/s):
Entered (m):
Pasquill Stability A B
Nuclide Class AMAD Release Rates (Ci/yr)
Rn-222 490
Additional Source Term Attached
Comments:
A-14
-------
CAP88PC INFORMATION SHEET
Date: April 1992 Source Category: Baseline Emissions Page I of
Facility: Maybell Location: Maybe11, CO
_X Population Run Input File Name: MAYBELL BASELINE Output File Prefix: AAP
Array Attached Pop. File Name: MAYBELL
• -- : : 7 "" " -...••".-- - •-••— ...i...,,.,.- „., . ,,-—• ......>,,— .-.-
Latitude: 40 ' 32 36 Longitude: 107 ° 59 36
Distances: 500 1,000 2.000 3.000 4,000 5,000 10.000 20,000 30,000 40.OOP
(meters) 50,000 60,000 80,000
Food Fractions: Fl-Grown at Home F2-Grown Regionally F3-Imported Urban/Low Rural
Meat: Productivity
Milk: X
Vegetables:
Individual Run Input File Name: Output File Prefix:
Distances:
(meters)
Food Fractions: Fl-Grown at Home F2-Grown Regionally FS-Imported Urban/Low Rural
Meat: Productivity
Milk: •
Vegetables:
Meteorological (STAR) Data: Array Attached STAR File Name: EEE1420
Location: Eagle County WBAN: HDR: 1420 CODE: SEE SET#:.
Temperature: 5.8 ° C Lid Height: 538 m Rainfall: 33.8 cm/yr
Stack Source: 1234 5
Height (m):
Diameter (m) :
X Area Source:
Circular Area (m2): 202,000
Plume Rise:
Buoyant (cal/s):
Momentum (m/s):
Entered (m) :
Pasquill Stability A B
Nuclide Class AMAD Release Rates (Ci/yr)
Rn-222 13
Additional Source Term Attached
Comments:
A-15
-------
CAP88PC INFORMATION SHEET
Date; April 1992 Source Category: Baseline Emissions Page 1 of
Facility; Uravan Location: Uravan, Colorado
JC Population Run Input File Name: URAVAN BASELINE Output File Prefix: AAQ
_Array Attached Pop. File Name: URAVANUN
latitude: 38 " 22 00 Longitude: 108 " 45 _ 00
Distances: 500 1,000 2,000 3,000 4.000 5,000 10,OOP 20,000 40,OOP 60,000
(meters) 80,000
Food Fractions: Fl-Grown at Home F2-Grown Regionally F3-Imported Urban/Low Rural
Meat: Productivity
Milk: _X
Vegetables:
Individual Run Input File Name: Output File Prefix:
Distances:
(meters)
Food Fractions: Fl-Grown at Home F2-Grown Regionally F3-Imported Urban/Low Rural
Meat: ______ Productivity
Milk:
Vegetables: i
Meteorological (STAR) Data: Array Attached STAR File Name: GJT0476
Location: GRAND JUNCTION WBAN: 23066 HDR: 0476 CODE: QJT SET#: STAR03
Temperature: 9.4 "C Lid Height: 538 m Rainfall: 29.4 cm/yr
Stack Source: 1234 56
Height (m):
Diameter (m):
X Area Source:
Circular Area (m2): 283,000
Plume Rise:
Buoyant (cal/s):
Momentum (m/s);
Entered (m):
Basquill Stability A B
Nuclide Class AMAD Release Rates (Ci/yr)
Rn-222 18
Additional Source Term Attached
Comments:
A-16
-------
CAP88PC INFORMATION SHEET
Date: April 1992 Source Category: Baseline Emissions Page 1 of
Facility: Church Rock Location: Church Rock, N.M.
XPopulation Run Input File Name: CHURCH ROCK BASE Output File Prefix: AAR
Array Attached Pop. File Name: CHURCHRO
----- - 7 •"—'•'"•'" - - ' " •"•"""- • "•- • •""- - -
Latitude: 35 ° 38 47 Longitude: 108 ° 30 08
Distances: 500 1.000 2,000 3.000 4,000 5,000 10,000 20,000 40.OOP 60,OOP
(meters) 80,000 ,
Food Fractions: Fl-Grown at Home F2-Grown Regionally F3-Imported Urban/Low Rural
Meat: Productivity
Milk; X
Vegetables: ______
Individual Run Input File Name: Output File Prefix:
Distances:
(meters)
Food Fractions: Fl-Grown at Home F2-Grown Regionally F3-Imported Urban/Low Rural
Meat: . Productivity
Milk:
Vegetables:
Meteorological (STAR) Data: Array Attached STAR File Name: GUP1167
Location: GALLUP/SEN WBAN: 23081 HDR: 1167 CODE: GUP SET#: STAR03
Temperature: 10.3 °C Lid Height: 767 m Rainfall: 30..3 cni/yr
Stack Source: 1234 56
Height (m) :
Diameter (m) :
X Area Source:
Circular Area (m2): 417,000
Plume Rise:
Buoyant (cal/s):
Momentum (m/s):
Entered (m) :
Pasquill Stability A B
Nuclide Class AMAD Release Rates (Ci/yr)
Rn-222 263
Additional Source Term Attached
Comments:
A-17
-------
CAP88PC INFORMATION SHEET
Date: April 1992 Source Category: Baseline Emissions Page 1 of
Facility: Bear Creek Location: Douglas, Wyoming
_Populacion Run Input File Name:BEAR CREEK BASE Output File Prefix: AAS
_Array Attached Pop. File Name: BEARCREK
Latitude: 43 a 16 11 Longitude: 105 ° 37 46
Distances; 500 1,000 2.000 3.000 4.000 5,000 10,000 20,000 40,000 60.000
(meters) 80.000 _^_
Food Fractions; Fl-Grown at Home F2-Grown Regionally F3-Imported Urban/Low Rural
Meat: Productivity
Milk: _X
Vegetables:
Individual Run Input File Name: Output File Prefix:
Distances:
(meters)
Food Fractions: Fl-Grown at Home F2-Grown Regionally F3-Imported Urban/Low , Rural
Meat: Productivity
Milk:
Vegetables:
Meteorological (STAR) Data: Array Attached STAR File Name: CPR1564
Location: CASPER WBAN: 24089 HDR: 1564 CODE: CPR SET//: STAR07
femperature: 7.3 °C Lid Height:_ 533 m Rainfall: 30.5 cm/yr
Stack Source: 1234 56
Height (m):
Diameter (m) : i i
X Area Source:
Circular Area (m2): 720,000
Plume Rise:
Buoyant (cal/s):
Momentum (m/s):
Entered (m) :
Pasquill Stability A B
Nuclide Class AMAD Release Rates (Ci/yr)
Rn-222 454
Additional Source Term Attached
Comments:
A-18
-------
CAP88PC INFORMATION SHEET
Dace: April 1992 Source Category: Baseline Emissions Page 1 of
Facility: Sherwood Location: Wellpinit,Washington
X Population Run Input File Name: SHERWOOD BASE Output File Prefix: AAT
_Array Attached Pop. File Name: WELLPINI
Latitude: 47 ° 52 27 Longitude: 118 ° 07 00
Distances: 500 1,000 2,000 3,000 4,000 5.000 10.000 20.000 40,OOP 60.000
(meters) 80,OOP
Food Fractions: Fl-Grown at Home F2-Grown Regionally FS-Imported Urban/Low Rural
Meat: Productivity
Milk: X
Vegetables:
Individual Run Input File Name: Output File Prefix:
Distances:_
(meters)
Food Fractions: Fl-Grown at Home F2-Grown Regionally F3-Imported Urban/Low Rural
Meat: , Productivity
Milk:
Vegetables:
Meteorological (STAR) Data: Array Attached STAR File Name: GEG0360
Location: SPOKANE WEAN: 24157 HDR: 0360 CODE: GEG SET//: STAR03
Temperature: 8,4 °C Lid Height: 640 m Rainfall: 31.7 cm/yr
Stack Source: 1234 56
Height (m) :
Diameter (m) :
X Area Source:
Circular Area (m2): 380,000
Plume Rise:
Buoyant (cal/s):
Momentum (m/s) :
Entered (m) :
Pasquill Stability A B
Nuclide Class AMAD Release Rates (Ci/yr)
Rn-222 240
Additional Source Term Attached
Comments:
A-19
-------
CAP88PC INFORMATION SHEET
Dace; April 1992 Source Category: Baseline Emissions Page 1 of ___
Facility; Split Rock Location: Jeffrey City, Wyoming
X Population Run Input File Name: SPLIT ROCK BASE Output File Prefix: AAU
_Array Attached Pop. File Name: JEFFREYC
Latitude: 42 ° 30 32 Longitude: 107 " 47 14
Distances: 500 1,000 2.000 3.000 4,000 5.000 10,000 20.000 40,OOP 60.000
(meters) 80,000 i _____
Food Fractions: Fl-Grown at Home F2-Grown Regionally F3-lmported Urban/Low Rural
Meat: Productivity
Milk: X
Vegetables: -
Individual Run Input File Name: Output File Prefix:
Distances:
(meters)
Food Fractions: Fl-Grown at Home F2-Grown Regionally F3-Imported Urban/Low Rural
Meat: • Productivity
Milk:
Vegetables:
Meteorological (STAR) Data: Array Attached STAR File Name:LND1100
Location: LANDER WBAN: 24021 HDR: 1100 CODE: LND SET#: STAR05
Temperature: 6.9 "C Lid Height: 608 m Rainfall: 25.4 cm/yr
Stack Source: 1234 56
Height (m):
Diameter (m):
X Area Source:
Circular Area (m2): 902,000
Plume Rise:
Buoyant (cal/s):
Momentum (m/s):
Entered (m) :
Pasquill Stability A B
Nuclide Glass AMAD Release Rates (Ci/yr)
Rn-222 569
Additional Source Term Attached
Comments:
A-20
-------
CAP88PC INFORMATION SHEET
Pace: Aprj.1 1992 Source Category: y ggvlsed UMTRCA Eegulations Page ___ .1 .._.. _ of ____
Facility: Federal American _ Location: _,,Riyertont Wyoming =
X Population Run Input File Mame:Jgg.DERAL_AMggLICA Output File Prefix: AG
Array Attached Pop. File Name:. FEDAMERI
."> _1__ § f\ Q * «•« * f /\ " T
Latitude: 42 ° 47 59 Longitude: 107 " 38 00
Distances: 500 1.000 2.000 3,000 4.000 5.000 10.000 20,OOP 40.000 60.000
(meters) 80,OOP
Food Fractions; Fl-Grown at Home F2-Grown Regionally PS-Imported Urban/Low Eural
Meat; m Productivity
Milk; X
Vegetables: _______ ______ .
Individual Run Input File Name:___ I^-,„„:::= ^.: Output File Prefix: __
Distances:_
(meters)
Food Fractions: Fl-Grown at Hone F2-Grown Regionally F3-lmported Urban/Low Rural
Meat: • ___^ Productivity
. Milk: __ ' .
Vegetables: i ^= ini =jr;
Meteorological (STAR) Data: Array Attached STAR File Name: LND1.1QO
Location: LANDER WBAN; 24021 HDR: 1100 CODE: IM LND SET//: STAR05
Temperature: 6.0 °C Lid Height:608 m Rainfall: 25.4 em/yr
Stack Source: 1234 56
Height (m): ,
Diameter (m): ' -
X Area Source:
Circular Area (m2): 445,OOP
Plume Rise:
Buoyant (cal/s):
Momentum (m/s):
Entered (m): _^
Pasquill Stability A B
Nuclide Class AMAD Release Rates (Ci/yr)
Rn-222 523
Additional Source Term Attached
Comments:
A-21
-------
CAP88PC INFORMATION SHEET
Date: April 1992 Source Category: Revised UMTRCA Regulations Page I of
Facility: Anaconda (ARCO Coal) Location: Bluewater, N.M.
X Population Run Input File Name; ANACONDA Output File Prefix: AS
Array Attached Pop. File Name: BLUEWATE
— •* i, _^ __
Latitude: 35 ° 16 12 Longitude: 107 " 56 44
Distances: 500 1.000 2.000 3,000 4,000 5,000 10,000 20,000 40.OOP 60.000
(meters) 80,OOP
Food Fractions: Fl-Grown at Home F2-Grown Regionally F3-Imported Urban/Low Rural
Meat: Productivity
Milk: ' X
Vegetables:
Individual Run Input File Name: • Output File Prefix:
Distances;,
(meters)
Food Fractions: Fl-Grown at Home F2-Grown Regionally F3-Imported Urban/Low Rural
Meat: Productivity
Milk:
Vegetables:
Meteorological (STAR) Data: Array Attached STAR File Name: STARANHM
Location: AMBROSIA LAKE WBAN: HDR: CODE: SET#:.
Temperature: 13.4 *C Lid Height: 767 m Rainfall: 20.6 cm/yr
Stack Source: 1234 5
Height (m): . i
Diameter (m):
X Area Source:
Circular Area (m2): 1,214,000
Plume Rise;
Buoyant (cal/s): ,__
Momentum (m/s):
Entered (m): ,
Pasquill Stability A B" C D
Nuolide Class AMAD Release Rates (Ci/yr)
Rn-222 1,615
Additional Source Term Attached'
Comments:
A-22
-------
CAP88PC INFORMATION SHEET
Date: April 1992 Source Category: Revised UMTRCA Regulations Page 1 of
Facility: Moab \ Location: Moab, Utah
_X Population Run Input File Name: MOAB ; Output File Prefix: AP
_Array Attached Pop, File Name: MOABATLA
Latitude: 38 " 35 59 Longitude: 109 ° 35 44
Distances: 500 1.000 2,000 3,000 4.000 5,000 10,OOP 20.OOP 40.OOP 60,000
(meters) 80,000
Food Fractions: . Fl-Grown at Home F2-Grown Regionally F3-Imported Urban/Low Rural
Meat: Productivity
Milk: X
Vegetables:
Individual Run Input File Name: Output File Prefix:
Distances:
(meters)
Food Fractions: Fl-Grown at Home F2-Grown Regionally F3-Imported Urban/Low Rural
Meat: _____ Productivity
Milk:
Vegetables:
Meteorological .(STAR) Data: Array Attached STAR File Name: GJT0476
Location: GRAND JUNCTION WBAN: 23066 HDR: 0476 CODE: GJT SET#: STAR03
Temperature: 13.7 °C Lid Height: 538 m Rainfall: 20.3 cm/yr
Stack Source: 1234 56
Height (m) :
Diameter (m) :
X Area Source:
Circular Area (m2): 518,000
Plume Rise:
Buoyant (cal/s): ;
Momentum (m/s): . •
Entered (m) :
Pasquill Stability A B C D
Nuclide Class AMAD Release Rates (Ci/yr)
Rn-222 854 - .
Additional Source Term Attached
Comments:
A-23
-------
CAPSSPG INFORMATION SHEET
Date: April 1992 Source Category: Revised UMTRCA Regulations Page 1 of
Facility: Conquista Location: Falls City, Texas \
X Population Run Input File Name: CONQUISTA Output File Prefix: AF
_Array Attached Pop. File Name: CONQUIST
Latitude; 28 " 54 03 Longitude: 98 " 05 40
Distances; 500 1.000 2.000 3,000 4,000 5,000 10.000 20.000 40,OOP 60,OOP
(maters) 80.000
Pood Fractions: Fl-Grown at Home F2-Grown Regionally F3-Imported Urban/Low Rural
Meat: Productivity
Milk: __x
Vegetables:
Individual Run Input File Name: Output File Prefix:
Distances :^
(meters)
Food Fractions: Fl-Grown at Home F2-Grown Regionally FS-Imported Urban/Low Rural
Meat: Productivity
Milk:
Vegetables:
Meteorological (STAR) Data: Array Attached STAR File Name: SAT0064
Location; SAN ANTONIO WBAN: 12921 HDR: 0064 CODE: SAT SET//: STAR01
Temperature; 20.4 °G Lid Height: 873 m Rainfall: 68.6 cm/yr
Stack Source: 1 2 3 4 5 6
Height (m):
Diameter (m): ^
X Area Source:
Circular Area (m2): 1,012.000
Flume Rise:
Buoyant (cal/s):
Momentum (m/s):
Entered (m):
Pasquill Stability A B
Nuclide Class AMAD Release Rates (Ci/yr)
Rn-222 724
Additional Source Term Attached
Comments:
A-24
-------
'CAP88PC INFORMATION SHEET
Date: April 1992 Source Category: Revised UMTRCA Regulations Page 1 of
Facility: Dawn Location: Ford, Washington
_X Population Run Input File Name: DAWN Output File Prefix: AT_
Array Attached Pop; File Name: DAWNMILL
_ ./ ^
Latitude: 47 ". 54 06 Longitude: 117 ' ° 49 58
Distances: 500 1.000 2,000 3,000 4.000 5,000 10,000 20.000 40.OOP 60.000
(meters) 80,000
Food Fractions: Fl-Grown at Home F2-Grown Regionally F3-Imported Urban/Low Rural
Meat: Productivity
Milk: X
Vegetables:
Individual Run Input File Name: Output File Prefix:
Distances:
(meters)
Food Fractions: Fl-Grown at Home F2-Grown Regionally F3-Imported Urban/Low Rural
Meat: Productivity
Milk:
Vegetables:
Meteorological (STAR) Data: Array Attached STAR File Name:GEGO360
Location: SPOKANE ¥BAN: 24157 HDR: 0360 CODE: GEG SET#: STARQ3
Temperature; 8.4 °C Lid Height: 640 m Rainfall: 42.4 cm/yr
Stack Source: 1234 56
Height (m) :
Diameter (in): ^
X Area Source:
Circular Area (m2): 497,000 _
Plume Rise:
Buoyant (cal/s):
Momentum (m/s):
Entered (m) :
Pasquill Stability ABC
Nuclide Class AMAD Release Rates (Ci/yr)
Rn-222 450
Additional Source Term Attached
Comments:
A-25
-------
CAP88PC INFORMATION SHEET
Date; April 1992 Source Category: Revised IMTRCA Regulations Page 1 of
Facility: Naturita Location: Naturita, CO
_X Population Run Input File Mame: NATURITA Output File Prefix: ADi:
JC Array Attached Pop. File Name: NATURITA
Latitude: 38 " 12 00 Longitude: 108 ° 37 00
Distances: 500 1.000 2.000 3.000 4,000 5.000 10.000 20.000 30,000 40.OOP
(meters) 50,000 60.000 80,000 _____
Food Fractions: Fl-Grown at Home F2-Grown Regionally F3-Imported Urban/Low Rural
Meat; ' , Productivity
Milk: _X
Vegetables:
Individual Run Input File Name: Output File Prefix:
Distances:.
(meters)
Food Fractions: Fl-Grown at Home F2-Grown Regionally FS-Imported Urban/Low Rural
Meat: Productivity
Milk:
Vegetables:
Meteorological (STAR) Data: Array Attached STAR File Name: GJT0476
Location; Grand Junction WBAN; 23066 HDR: 0476 CODE: GJT SET//: STAR03
Temperature: 11.5 "C Lid Height: 538 m Rainfall: 20.3 cm/yr
Stack Source: 1234 56
Height (m):
Diameter (m):
X Area Source:
Circular Area (ra^): 142.OOP
Flume Rise:
Buoyant (cal/s):
Momentum (m/s):
Entered (m):
Pasquill Stability A B C D
Nuclide Class AMAD Release Rates (Ci/yr)
Rn-222 41
Additional Source Term Attached
Comments:
A-26
-------
CAP88PC INFORMATION SHEET
Date: April 1992 Source Category: Revised UMTRCA Regulations Page I of
Facility: Homestake (large Impoundment) Location: Grants, N.M.
_K Population Run Input File Name: HOMESTAKE LARGE Output File Prefix: AAG
_Array Attached Po|>. File Name: HOMESTAK
Latitude: 35 ° 14 31 Longitude: 107" i--; _51 46
Distances: 500 1,000 2.000 3.000 4.000 5.000 10.000 20.OOP 40,000 60.OOP
(meters) 80,000
Food Fractions: Fl-Grown at Home F2-Grown Regionally F3-Imported Urban/Low Rural
Meat; Productivity
Milk: X
Vegetables:
Individual Run Input File Name: Output File Prefix:
Distances:
(meters)
Food Fractions: Fl-Grown at Home F2-Grown Regionally F3-Imported Urban/Low Rural
Meat: Productivity
Milk:
Vegetables:
Meteorological (STAR) Data: Array Attached STAR File Name; STARANHM
Location: AMBROSIA LAKE WBAN: HDR: CODE: SET//:,
Temperature: 13.4 °C Lid Height: 767 m Rainfall: 20.6 cm/yr
Stack Source: 1234 5
Height (m):
Diameter (m):
X Area Source:
Circular Area (m2): 688,000
Plume Rise:
Buoyant (cal/s):
_Momentum (m/s):
Entered (m):
Pasquill Stability A B
Nuclide Class AMAD Release Rates (Ci/yr)
Rn-222 918
Additional Source Term Attached
Comments:
A-27
-------
CAPS8PC INFORMATION SHEET
Dace; April 1992 Source Category: Revised UMTRCA Regulations Page 1 of
Facility; Homestake (small impoundment) Location: Grants, N.M.
_X Population Run Input File Name: HOMESTAKE SMALL Output File Prefix: AAH
_Array Attached Pop. File Name:. HOMESTAK
Latitude: 35 ° 14 31 Longitude: 107 ° 51 46
Distances: 500 1,000 2,000 3.000 4,000 5,000 10.000 20.000 40.OOP 60.000
(meters) 80,000
Food Fractions: Fl-Grown at Home F2-Grown Regionally F3-Imported Urban/Low Rural
Meat: Productivity
Milk: __ X
Vegetables:
Individual Run Input File Name: Output File Prefix: „,„,„_
Distances:.
(meters)
Food Fractions: Fl-Grown at Home F2-Grown Regionally F3-Imported Urban/Low Rural
Meat: Productivity
Milk:
Vegetables:
Meteorological (STAR) Data: Array Attached STAR File Name: STARANHM
Location: AMBROSIA LAKE WBAN: HDR: CODE: SET//:.
femperature: 13.4 °G Lid Height: 767 in Rainfall: 20.6 cm/yr
Stack Source: 1234 5
Height (m):
Diameter (in):
X Area Source:
Circular Area (m2): 52,000
Plume Rise:
Buoyant (cal/s):
Momentum (m/s):
Entered (m):
Pasquill Stability A B
Nuclide Class AMAD Release Rates (Ci/yr)
Rti-222 94
Additional Source Term Attached
Comments;
A-28
-------
CAP88PC INFORMATION SHEET
Date: April 1992 Source Category: Revised UMTRCA Regulations Page 1 of _
Facility: Lucky Me Location: Riverton, Wyoming
X Population Run Input File Name: LUCKY MC Output File Prefix: AU
_Array Attached Pop. File Name: GASLUCKY
Latitude: 42 ° 49 55 Longitude: 107 ° 37 00
Distances: 500 1.000 2,000 3,000 4,000 5,000 10,000 20.000 40,000 60,000
(meters) 80,000
Food Fractions: Fl-Grown at Home F2-Grown Regionally F3-Imported Urban/Low Rural
Meat: Productivity
Milk: X
Vegetables:
Individual Run Input File Name: Output File Prefix:
Distances:_
(meters)
Food Fractions: Fl-Grown at Home F2-Grown Regionally F3-Imported Urban/Low Rural
Meat: Productivity
Milk:
Vegetables:
Meteorological (STAR) Data: Array Attached STAR File Name: LND1100
Location: LANDER WBAN: 24021 HDR: 1100 CODE: LND SET#: STAR05
Temperature: 6.0 °C Lid Height: 608 m Rainfall: 22.9 cm/yr
Stack Source: 1 2 3 4.5 6
Height (m) :
Diameter (m) :
X Area Source:
Circular Area (m2): 821,000
Plume Rise:
Buoyant (cal/s):
_Momentum (m/s):
_Entered (m):
Pasquill Stability A B
Nuclide Class AMAD Release Rates (Ci/yr)
Rn-222 730
Additional Source Term Attached
Comments:
A-29
-------
CAP88PC INFORMATION SHEET
Date; April 1992 Source Category: Revised UMTRCA Regulations Page 1 of
Facility: Petrotomics Location: Medicine Bow, Wyoming
X Population Run Input File Name: PETROTOMICS Output File Prefix: AH_
_Array Attached Pop. File Name:_ PETROTOM
Latitude: 42 6 20 04 Longitude: 106 ° 11 49 "
Distances; 500 1,000 2,000 3,000 4.000 5,000 10.000 20,000 40,000 60.000
(meters) 80,000
Food Fractions: Fl-Grown at Home F2-Grown Regionally F3-Imported Urban/Low Rural
Meat: Productivity
Milk: __X
Vegetables:
Individual Run Input File Name: Output File Prefix:
Distances:_
(meters)
Food Fractions: Fl-Grown at Home F2-Grown Regionally F3-Imported Urban/Low Rural
Meat: Productivitvity
Milk:
Vegetables:
Meteorological (STAR) Data: Array Attached STAR File Name: CPR1564
Location; CASPER WBAN: 24089 HDR: 1564 CODE: CPR SET#: STAR07
Temperature: 5.3 "C Lid Height: 533 m Rainfall: 30.5 cm/yr
Stack Source: 1234 56
Height (m):
Diameter (m):
X Area Source:
Circular Area (m2): 461,000
Plume Rise:
Buoyant (cal/s):
Momentum (m/s):
Entered (m):
Pasquill Stability A B
Nuclide Class AMAD Release Rates (Ci/yr)
Rn-222 484
Additional Source Term Attached
Comments:
A-30
-------
CAP88PC INFORMATION SHEET
Date: April 1992 Source Category: Revised UMTRCA Regulations Page 1 of ]
Facility: Kerr-McGee (Quivera) Location: Ambrosia Lake, N.M.
X Population Run Input File Name: KERR-MCGEE Output File Prefix: AJ
Array Attached Pop. File Name: AMBROSIA
Latitude: 35 " 23 39 " Longitude: 107 ° 49 ' 47
Distances: 500 1,000 2.000 3.000 4.000 5.000 10.000 20.000 40.000 60,000
(meters) 80,000
Food Fractions: Fl-Grown at Home F2-Grown Regionally F3-Imported Urban/Low Rural
Meat: Productivity
Milk: X
Vegetables:
Individual Run Input File Name: Output File Prefix:
Distances:
(meters)
Food Fractions: Fl-Grown at Home F2-Grown Regionally F3-Imported Urban/Low Rural
Meat: Productivity
Milk:
Vegetables:
Meteorological (STAR) Data: Array Attached STAR File Name: STARANHM
Location: AMBROSIA LAKE WBAN: HDR: CODE: SET//:.
Temperature: 13.4 °C Lid Height: 767 m Rainfall: 20.6 cm/yr
Stack Source: 1234 5
Height (m):
Diameter (m) :
X Area Source:
Circular Area (m2): 1,490,000
Plume Rise:
Buoyant (cal/s):
Momentum (m/s):
Entered (m) :
Pasquill Stability A B
Nuclide Class AMAD Release Rates (Ci/yr)
Rn-222 .1.548
Additional Source Term Attached
Comments:
A-31
-------
CAP88PC INFORMATION SHEET
Dace; April 1992 Source Category: Revised. UMTRCA Regulations Page 1 of 1_
Facility; Rio Algom Location: La Sal, Utah
_X Population Run Input File Name: RIO ALGOM Output Pile Prefix: AN
_Array Attached Pop. File Name: LASALRIO
,j_. OOO IET r\/\ ** T • j i _ -
Latitude: 38 ° 15 00 Longitude: 109 ° 16 30
Distances; 500 1,OOP 2.OOP 3,000 4,000 5.000 10,000 20,OOP 40.OOP 60.QPP
(meters) .80,000 , :
Food Fractions: Fl-Grown at Home F2-Grown Regionally F3-Iraported Urban/Low Rural
Meat: Productivity
Milk: . _X
Vegetables:
Individual Run Input File Name: Output File Prefix:
Distances:
(rosters)
Food Fractions: Fl-Grown at Home F2-Grown Regionally F3-Imported Urban/Low Rural
Meat: Productivity
Milk:
Vegetables;
Meteorological (STAR) Data: Array Attached STAR File Name: GJTP476
Location: GRAND JUNCTION WBAN: 23P66 HDR: 0476 CODS: GJT SET//: STAR03
Temperature: 13.-7 °C Lid Height: 538 m Rainfall: 20.3 cm/yr
Stack Source: 1 2 3 4 56
Height (m):
Diameter (m):
X Area Source:
Circular Area (m2): 405,OOP
Plume Rise:
Buoyant (cal/s):
Momentum (m/s):
Entered (ra):
Pasquill Stability A B
Nuclide Class AMAD Release Rates (Ci/yr)
Rn-222 274
Additional Source Terra Attached
Comments:
A-32
-------
CAP88PC INFORMATION SHEET
Date: April 1992 Source Category: Revised UMTRCA Regulations Page 1 of
Facility: L-Bar Location: Seyboyeta, N.M.
_X Population Run Input File Name: L BAR Output File Prefix: AM
_Array Attached Pop. File Name: LBARSOHI
Latitude: 35 ° 11 09 Longitude: 107 ° 20 09
Distances: 500 1.000 2,000 3.000 4.000 5,000 10,000 20.OOP 40.OOP 60.000
(meters) 80,000 •
Food Fractions: Fl-Grown at Home F2-Grown Regionally F3-Imported Urban/Low Rural
Meat: Productivity
Milk: ' ^ X
Vegetables: •
Individual Run Input File Name: Output File Prefix:
Distances:
(meters)
Food Fractions: Fl-Grown at Home F2-Grown Regionally F3-Imported Urban/Low Rural
Meat: Productivity
Milk: .
Vegetables: '
Meteorological (STAR) Data: Array Attached STAR File Name: ABQ0282
Location: ALBUQUERQUE WBAN: 23050 HDR: 0282 CODE: ABQ SET#: STAR03
Temperature: 13.4 °C Lid Height: 767 m Rainfall: 20.6 cm/yr
Stack Source: 1234 56
Height (m):
Diameter (m):
X Area Source:
Circular Area (m2): 324,000
Plume Rise:
Buoyant (cal/s):
_Momentum (m/s):
Entered (m):
Pasquill Stability A B C D E F G
Nuclide Class AMAD Release Rates (Ci/yr)
Rn-222 204
Additional Source Term Attached
Comments:
A-33
-------
CAP88PC INFORMATION SHEET
Date: April 1992 Source Category: Revised UMTRCA Regulations Page 1 of __
Facility; Umetco Gas Hills Location: River ton, Wyoming
X Population Run Input File Name: UMETCO GAS HILLS Output File Prefix: AI_
_Array Attached Pop. File Name: UCCGASHI
tl4o • /I 9 ° /|Q A ^ " T ^1-irr-l +-1./}.= •
Latitude: 42 " 49 45 Longitude: 107 " 29 34
Distances: 500 1,000 2.000 3,000 4,000 5,000 10.000 20.000 40.000 60,000
(meters) 80.000
Food Fractions: Fl-Grown at Home F2-Grown Regionally F3-Imported Urban/Low Rtiral
Meat: Productivity
Milk: __X
Vegetables:
Individual Run Input File Name: Output File Prefix:
Distances:_
(meters)
Food Fractions: Fl-Grown at Home F2-Grown Regionally F3-Imported Urban/Low Rural
Meat: Productivity
Milk:
Vegetables:
Meteorological (STAR) Data: Array Attached STAR File Name: LND1100
Location: LANDER WBAN: 24021 HDR: 1100 CODE: LND SET//: STAR05
Temperature: 6.0 °C Lid Height: 608 m Rainfall: 25.4 cm/yr
Stack Source: 1234 56
Height (m):
Diameter (m):
X Area Source:
Circular Area (m2): 777,000
Plume Rise:
Buoyant (cal/s):
Momentum (m/s):
Entered (m):
Pasquill Stability A B C D
Nuclide Class AMAD Release Rates (Ci/yr)
Rn-222 589
Additional Source Term Attached
Comments:
A-34
-------
CAP88PC INFORMATION SHEET
Date: April 1992 Source Category: Revised UMTRCA Regulations Page 1 of
Facility: Maybe 11 Location: Maybell, CO
_X Population Run Input File Name: MAYBELL Output File Prefix: AC
_Array Attached Pop. File Name: MAYBELL
Latitude: 40 ° 32 36 Longitude: 107 °59 '36 "
Distances: 500 1.000 2,000 3,000 4.000 5.000 10.000 20,000 30.000 40.OOP
(meters) 50,000 60,000 80,000
Food Fractions: Fl-Grown at Home F2-Grown Regionally F3-Imported Urban/Low Rural
Meat: Productivity
Milk: X
Vegetables:
Individual Run Input File Name: Output File Prefix:
Distances:
(meters)
Food Fractions: Fl-Grown at Home F2-Grown Regionally F3-Imported Urban/Low Rural
Meat: Productivity
Milk:
Vegetables:
Meteorological (STAR) Data: Array Attached STAR File Name: EEE1420
Location: Eagle County WBAN: HDR: 1420 CODE: SEE SET#:
Temperature: 5.8 °C Lid Height: 538 m Rainfall: 33.8 cm/yr
Stack Source: 1234 5
Height (m) :
Diameter (m) :
X Area Source:
Circular Area (m2): 202,000
Plume Rise:
Buoyant (cal/s):
_Momentum (m/s):
Entered (m):
Pasquill Stability A B C D
Nuclide Class AMAD Release Rates (Ci/yr)
Rn-222 70
Additional Source Term Attached
Comments:
A-35
-------
CAP88PC INFORMATION
Dace: April 1992 Source Category: Revised TJMTRCA Regulations Page 1 of
facility: Urayan Location: Uravan, Colorado
J{ Population Run Input File Name: UjAgAN Output File Prefix: AL_
Array Attached Pop. File Name: URAVANUN
_ * .„ 7 •• •'• •
Latitude: 38 0 22 00 Longitude: 108 ° 45 __JXL
Distances: 500 1.000 2.000 3. OOP 4,000 5.0.QQ 10,000 20.000 40, OOP 60, OOP
(meters) 80,000
Food Fractions: Fl-Grown at Home F2-Grown Regionally F3-Imported Urban/Low Rural
Meat: _____ iiiim:::==iv.. _____ Productivity
Milk: X
Vegetables: _____ ______
Individual Run. Input File Nane: Output File Prefix:
Distances:.
(meters)
Food Fractions: Fl-Grown at Home F2-Grown Regionally F3-Imported Urban/Low Rural
Meat: ______ , Productivity
Milk:
Vegetables: m
Meteorological (STAR) Data: Array Attached STAR File Name.: GJT0476
Location; GRAND JUNCTION WBAN: 23066 HPR:J)4_?_6CODE; GJT SET#; STAR03
fenperature;.. 9.4 °C Lid Height: 538 m Rainfall: 29.4 cm/yr
Stack Source: 1234 56
Height (m): :
Diameter (m):
X Area Source:
Circular Area (m2): 283.000
Flume Rise:
Buoyant (cal/s): iiio:
Momentum (n/s):
Entered (m) : i
Pasquill Stability A B C D
Nuclide Class AMAD Release Rates (Ci/yr)
Rn-222 60
Additional Source Term Attached
Comments:
A-36
-------
CAP88PC INFORMATION SHEET
Date: April 1992 Source Category: RevisedUMTRCA Regulations Page 1 of
Facility: Church Rock Location: Church Rock, N.M.
X Population Run Input File Name: CHURCH ROCK Output File Prefix: AR
Array Attached Pop. File Name: CHURCHRO
— ____________
Latitude; 35 ° 38 47 Longitude: 108 " 30 08
Distances: 500 1,000 2.000 3,000 4.000 5.000 10,000 20.OOP 40.000 60,000
(meters) 80, OOP . •
Food Fractions; Fl-Grown at Home F2-Grown Regionally F3-Imported Urban/Low Rural
Meat: ^ Productivity
Milk: " X
Vegetables:
Individual Run Input File Hame: Output File Prefix;i
Distances:.
(meters)
Food Fractions: Fl-Grown at Home F2-Grcnm Regionally F3-Imported Urban/Low Rural
Meat: ^ Productivity
Milk: _____
Vegetables:
Meteorological (STAR) Data: Array Attached STAR File Name::GUP1|67
Location: GALLUP/SEN WBAH: 23081 HDR: 1167 CODE: GUP SET//: STAR03
Temperature:..... 10,3 "C Lid Height: 767 m Rainfall: 30^3 _cm/yr
Stack Source: 1 2 3 4 56
Height (m) :
Diameter (m) :
X Area Source:
Circular Area (m2): 417,000
Plume Rise:
Buoyant (cal/s): : ,___
Momentum (m/s):
Entered (is):
Pasquill Stability A B
Nuclide Class AMAD Release Rates (Ci/yr)
Rn-222 469
Additional Source Term Attached
Comments:
A-37
-------
CAP88PC INFORMATION SHEET
Pace;April 1992 Source Category: Revised UMTRCA Regulations Page 1 of
Facility: Bear Creek Location: Douglas, Wyoming
JC Population Run Input File Maine: BEAR CREEK Output File Prefix: AO
_Array Attached Pop. File Name: BEARCREK
Latitude: 43 ° 16 11 Longitude: 105 ° 37 46
Distances; 500 1,000 2,000 3.000 4,000 5,000 10.000 20.000 40.OOP 60,000
(meters) 80, OOP
Food Fractions: Fl-Grown at Home F2-Grown Regionally F3-Imported Urban/Low Rural
Meat; Productivity
Milk: __X
Vegetables:
Individual Run Input File Name: Output File Prefix:
Distances:
(meters)
Food Fractions: Fl-Grown at Home F2-Grown Regionally F3-Imported Urban/Low Rural
Meat: Productivity
Milk:
Vegetables: _____
Meteorological (STAR) Data: Array Attached STAR File Name: CPR1564
Location; GASPER WBAH: 24089 HDR: 1564 CODE: CPR SET#: STAR07
Temperature: 7.3 °C Lid Height: 533 m Rainfall: 30.5 cm/yr
Stack Source: 1234 56
Height (m):
Diameter (m):
Tii:X Area Source:
Circular Area (m2): 720,POO
Plume Rise:
Buoyant (cal/s):
Momentum (m/s):
Entered (m):
Pasquill Stability A B
Nuclide Glass AMAD Release Rates (Ci/yr)
Rn-222 713
Additional Source Term Attached
Comments:
A-38
-------
CAP88PC INFORMATION SHEET
&pxl\ 1992 Source Category: Revised UMTRCA Regulations Page I of ]
Facility: Sherwood Location: Wellplnit, Washington
X Population Run Input File Name: SHERWOOD Output File Prefix: AQ
_Array Attached Pop. File Name: WELLPINI
Latitude: 47 ° 52 27 - Longitude: 118 ° 07 00
Distances: 500 1,OOP 2,000 3,000 4,OOP 5.000 10,000 20,000 40,000 60,OOP
(meters) 80,000
Kood Fractions: Fl-Grown at Home F2-Grown Regionally FS-Imported Urban/Low Rural
Meat: ' Productivity
Milk: X
Vegetables:
Individual Run Input File Name: Output File Prefix:
•istances:
(meters)
'ood Fractions: Fl-Grown at Home F2-Grown Regionally F3-Imported Urban/Low Rural
Meat: Productivity
Milk:
Vegetables:
meteorological (STAR) Data: Array Attached STAR File Name: GEG0360
,o cat ion: SPOKANE WEAK: 24157 HDR._: 0360 CODE: GEG SET#: STARQ3
lemperature: 8.4 °C Lid Height:640 m Rainfall: 31.7 cm/yr
Stack Source: 1234 56
Height (m):
Diameter (m):
X Area Source:
circular Area (m2): 380,000
lume Rise:
Buoyant (cal/s):
Momentum (m/s):
Entered (m):
Pasquill Stability A B
uclide Class AMAD Release Rates (Ci/yr)
ja-222 347
Additional Source Term Attached
]omments:
A-39
-------
CAPS8PC INFORMATION SHEET
Dace; April 1992 Source Category: Revised UMTRCA Regulations Page 1 of 1
Facility; Split Rock Location: Jeffrey City, Wyoming
X Population Run Input File Name: SPLIT ROCK . Output File Prefix: AK
_Array Attached Pop, File Name: JEFFREYC
Latitude; 42 9 30 32 Longitude: 107 * 47 14
Distances: 500 1,000 2,000 3,000 4,000 5.000 10.000 20.000 40.OOP 60.000
(meters) 80,000
Food Fractions: Fl-Grown at Home F2-Grown Regionally F3-Imported Urban/Low Rural
Meat: Productivity
Milk: X
Vegetables:
Individual Run Input File Name: ; Output File" Prefix: __
Distances:_
(meters)
Food Fractions: Fl-Grown at Home F2-Grown Regionally F3-Imported Urban/Low Rural
Meat: ^ Productivity
Milk: .
Vegetables:
Meteorological (STAR) Data: Array Attached STAR File Name: LND1100
Location: LANDER WBAN: 24021 HDR: 1100 CODE: LND SET//: STAR05
Temperature: 6.9 °C Lid Height: 608 m Rainfall: 25.4cm/yr
Stack Source: 1234 56
Height (m) :
Diameter (m):
X Area Source:
Circular Area (ra2): 902,000
Plume Rise:
Buoyant (cal/s):
jMomentum (m/s):
Entered (ra):
Pasquill Stability A B C D
Nuclide Class AMAD Release Rates (Ci/yr)
Rn-222 690
Additional Source Term Attached
Comments:
A-40
-------
Appendix B
CAP88-PC
Version 1.00
Clean Air Act Assessment Package - 1988
SYNOPSIS REPORT
Radon Population Assessment
Facility; LUCKY MC
City: RIVBRTOM
State: WY
B-l
-------
LUCKY MC SYNOPSIS
Effective Dose Equivalent
(mrem/year)
2.491-02
At This Location:
Source Category:
Source Type:
Emission Year:
25000 Meters North
INACTIVE TAILINGS
Area
730 Ci/y
Dataset Name:
Dataset Date:
Wind File:
Population File:
LUCKY MC
Mar 30, 1992 10:00 pm
WNDFILES\LND1100.WND
POPFIL1S\GASLUCKY.POP
SITE INFORMATION
Temperature:
Precipitation:
Mixing Height:
6 degrees C
23 cm/y
608 m
SOURCE INFORMATION
Source Number: 1
Source Height (m): 1.00
Area (sq m): 8.21E+05
Plume Rise
Bouyancy (cal/s): O.OOE+00
(Release Rate)
B-2
-------
LUCKY MC SYNOPSIS
RN-222 MAXIMALLY EXPOSED INDIVIDUAL
Location Of The Individual:
Radon Concentration (pCi/1):
Decay Product Concentration (WL):
Lifetime Fatal Cancer Risk;
25000 Meters North
8.77E-04
5.12E-06
4. 951-06
TABLE I
FREQUENCY DISTRIBUTION OF LIFETIME FATAL CANCER RISKS
Risk Range
Number of
People
Number of People
In This Risk
Range Or Higher
Deaths/Year
In This
Risk Range
Deaths/Year
In This Risk
Range Or Higher
l.OE+00 TO 1,01-01
l.OE-01 TO l.OE-02
l.OE-02 TO 1
l.OE-03. TO
l.OE-04 TO
l.OE-05 TO
01-03
l.OE-04
1.01-05
l.OE-06
LESS THAM l.OE-06
0
0
0
0
37
21420
402
0
0
0
0
3?
21457
21859
O.OOE+00
O.OOE-rOO
O.OOE*QO
Q.OQE+QQ
5.701-06
5.87E-04
4.60E-06
O.OOE+00
O.OOE-i-00
O.OOE+00
Q.QOE-i-QO
5.70E-06
5.72E-04
5.77E-04
Collective Exposure (Person Working Levels): 2.29E-02
RADIONUCLID1 EMISSIONS DURING THE YEAR
Nuclide Class Size
RN-222
0.00
Source
fl
Ci/y .
TOTAL
Ci/y
7.3E+02 7.3E+02
B-3
-------
LUCKY MC SYNOPSIS
TABLE 2
POPULATION DATA
Distance (m)
Direction
N
NNW
NW
WNW
W
WSW
SW
SSW
S
SSE
SE
BSE
E
ENE
NE
NNE
250
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
750
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1500
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
2500
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
3500
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
4500
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
7500
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Distance (m)
Direction
N
NNW
NW
WNW
W
WSW
SW
SSW
S
SSE
SE
ESE
E
ENE
NE
NNE
15000
0
0
0
0
0
451
0
0
0
0
0
0
0
0
0
0
25000
13
0
0
0
0
0
0
0
82
0
11
0
0
0
0
0
35000
0
0
1
34
0
0
0
0
0
0
0
0
0
24
0
0
45000
0
92
0
0
0
0
50
1882
0
0
0
40
0
0
66
0
55000
112
0
0
0
0
355
22
0
489
0
0
0
59
0
0
0
70000
0
140
1364
14704
1362
36
9
11
215
51
35
0
36
100
0
13
B-4
-------
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