July, 1980
IMPACTS ON HUMAN HEALTH FROM THE COAL AND
NUCLEAR FUEL CYCLES AND OTHER TECHNOLOGIES
ASSOCIATED WITH ELECTRIC POWER
GENERATION AND TRANSMISSION
By
Edward P. Radford, M.D.
University of Pittsburgh
Pittsburgh, Pennsylvania 15261
Prepared for
Ohio River Basin Energy Study (ORBES)
Subcontract under Prime Contract R805588
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
WASHINGTON, D.C. 20460
-------
ABSTRACT
This report evaluates major public health impacts of electric power
generation and transmission associated with the nuclear fuel cycle and
with coal use. Only existing technology is evaluated; for the nuclear
cycle effects of future use of fuel reprocessing and long-term radioactive
waste disposal are briefly considered. The health effects of concern are
those leading to definable human disease and injury; subjective factors,
effects of pollutants on visibility, or effects on agriculture and aquatic
life forms are outside the scope of this report.
Health effects are scaled to numbers of persons and activities associated
with a nominal 1000 Megawatt (electric) plant fueled by either option. Com-
parison of the total health effects to the general public from the nuclear
and coal cycles gives: nuclear, 0.03-0.05 major health effects per 1000
MWe per year; coal, 0.7-3.7 per 1000 MWe per year. Thus for the general
public the health risks from the coal cycle are about 50 times greater than
for the nuclear cycle. Health effects to workers in the industry are currently
quite high. For the nuclear cycle, 4.6-5.1 major health impacts per 1000 MWe
per year; for coal, 6.5-10.9. The two-fold greater risk for the coal cycle is
primarily due to high injury rates in coal miners.
There is no evidence that electrical transmission, common to both fuel
cycles, contributes any health effects to the general public, except for
episodes where broken power lines come in contact with people. For power
line workers, the risk is estimated at 0.1 serious injury per 1000 MWe per
year.
ii
-------
CONTENTS
-\
Abstract r . ii
Tables. v
Acknowledgements vi
1. Introduction 1
2. Human Health Impacts from the Nuclear Fuel Cycle 2
Mining 2
Uranium Milling 8
Uranium Hexafluoride Production 11
Enrichment 13
Fuel Fabrication 15
Mixed Oxide (MOX) Fuel Fabrication 16
Nuclear Power Plants 16
Fuel Reprocessing 20
Waste Management 22
Transportation 23
Summary of Exposures 24
Health Effects from Nuclear Cycle 24
References 30
3. Human Health Impacts from the Coal Cycle 31
Coal Mining 32
Coal Processing 34
Coal Transportation 34
iii
-------
Coal-Fired Power Plants 36
Summary of Health Impacts from Coal Cycle 41
References 43
4. Power Transmission and Its Health Effects 44
References 49
iv
-------
TABLES
Number Page
1. Radioactive Materials Handled per Year to Supply
1000 MWe Plant 3
2. 1977 Uranium Mine Exposure to Radon Daughters (Company
Records) 6
3. Uranium Milling Airborne Releases of Radioactive Materials
(Excluding Tailings) 7
4. Radioactive Effluents from UF6 Production (Curies) per
1000 MWe LWR Requirements/Yr 14
5. Personnel Radiation Exposure for Light Water Reactors
Licensed by U. S. Nuclear Regulatory Commission 19
6. Effluents Discharged from Nuclear Fuel Services
Reprocessing Plant 21
7A. Exposures to General Public in Nuclear Fuel Cycle per
1000 MWe Power Generation/Yr 25
7B. Exposures to Workers in Nuclear Fuel Cycles per 1000
MWe Generated/Yr 26
8. Health Impacts of Nuclear Fuel Cycle per 1000 MWe-Yr of
Power Production 29
9. Circuit Miles of High Voltage Transmission Lines in U. S.,
1970 45
-------
ACKNOWLEDGMENTS
In the preparation of this report, I acknowledge the great assistance
of my colleagues, Professors Maurice Shapiro, Satl Mazumdar, and Julian
Andelman of the Graduate School of Public Health. Especially valuable have
been the literature searches and draft reports prepared by my student
assistants, Carol Godfrey, Dennis Cosmatos, Irene Goldberger, Stephan
Lanes, and Eugene Takahashi. Finally, 1 acknowledge valuable discussions
of the Issues with a great number of professional experts in a wide range
of topics in this large and rapidly evolving field.
vi
-------
SECTION 1
INTRODUCTION
In this report I have summarized my assessment of the potential human
health problems associated with electric power generation and transmission.
I deal here only with existing technologies for power production. Because
oil has never been a significant fuel for electric power generation in the
Ohio River Basin area, this report has been limited to the coal and nuclear
options. Obviously introduction of new technology, such as breeder nuclear
reactors or coal gasification, will modify the relative importance of some
of the health impacts.
The report deals only with health effects that lead to definable human
disease or injury, and does not attempt to quantitate subjective factors
such as esthetics, nor does it deal with effects of pollutants on plant or
animal life. Thus the possible role of acid rain in producing detrimental
effects on aquatic or other biota is not included in this study.
With the limited resources available for this evaluation, it has been
necessary to depend on a number of reviews of relevant subjects to obtain
data in a concise form, but I have attempted to rely on more than one in
each specific area of interest in order to provide a divergence of viewpoint.
This final product is strictly based on my own perception of the scientific
evidence and is not necessarily in accord with views of the authors of reports
from which I have taken data.
In presenting the health impact results, I have attempted where possible
to scale these to fuel use or other quantities required for operation of
nominal 1000 Megawatt-electric plants of current design. Because control of
future exposures of workers and the general public to hazardous conditions
may significantly affect health risks over the period of interest to the
ORBES study, some attention is paid to the possible impact of reduction in
exposures to occupational or public groups on future projections of risks to
the year 2000.
-------
SECTION 2
HUMAN HEALTH IMPACTS FROM THE NUCLEAR FUEL CYCLE
We consider here health effects from "normal" operations of all aspects
of the nuclear cycle, even though in the ORBES region only certain phases of
the cycle are actually carried out. These latter include uranium enrichment
and fuel fabrication plants, as well as power reactors. The fuel reprocessing
and high level storage stages are not now operating commercially in the U. S.,
storage of fuel elements mainly being done at power plant sites. For this
reason it is currently difficult to assess health effects from this phase of
the fuel cycle. It appears from experience with previous commercial reprocess-
ing plants, as well as those now operating in foreign countries, that re-
processing might contribute significant exposures to radiation, both for
workers and for the general public in the vicinity of the plants. With re-
gard to high level waste storage, it is presently not possible to assign any
exposure to be expected from the current long-term disposal options.
Table 1 gives the throughput of radioactive materials in the steps of
the nuclear cycle, scaled for a typical 1000 Mwe reactor (1).
MINING
The two major types of uranium recovery practiced in the U. S. are strip
or pit mining and underground mining. Open pit mining is used when the ore
body lies under relatively soft material at depths up to a few hundred feet;
underground mining is employed when the ore body is at depths greater than
400 feet or when it lies under rock which requires a great deal of blasting
to remove. Although there are considerably more underground mines operating
today than open pit mines, the latter generally have higher production
capacities and slightly more than half of the uranium mined in the U. S. is
from open pit mines. The size of open pit and underground mines varies over
a wide range. The average capacity of operating open pit mines in the U. S.
is about 1.5 x 105MT of ore per year, and the average capacity of operating
underground mines is about 2 x lO^MT of ore annually. The ore requirements
for a 1000 Mwe light water reactor (LWR) are about 105MT (Table 1) per year.
Sources of Radiation Exposure
1). Direct radiation from the ore. The principal exposure is to gamma
radiation from decay of the uranium or thorium series of heavy elements. The
extent of exposure will depend on the richness of the ore. For open pit
mining the workers receive less radiation (about half) compared to underground
-------
u>
TABLE 1
RADIOACTIVE MATERIALS HANDLED PER YEAR TO SUPPLY 1000 MWE PLANT
Operation
Mining
Milling
Conversion
i Enrichment
Fabrication
Reactor
Reprocessing
Nature of Product
Uranium ore
U3°8
UF6
Enriched UF,
D
Power plant fuel
Spent fuel
High level solid waste
Throughput /yr
Metric tons (MT)
90,000
182
270
52
35*
35*
7
Other Waste
Radioactive rubble in mine
Tailings of % 9000 MT/yr
Depleted uranium tails
Low-level waste 230 MT
Plutonium for recycle
* Metric tons of heavy metals.
-------
miners because they are more distant from the ore and are not surrounded by
it. In general, with typical uranium ore conditions, underground miners
accumulate about 1 rad/yr from gamma ray exposure (2). Because underground
exposures to radon daughters range from one to several working level months
(WLM)*/yr, and the working level month gives rise to a dose to the bronchial
epithelium of about 6 rem on the average (3). In terms of lung cancer in the
contribution of the whole body gamma exposure to risk is minor. A risk of
cancer at other organ sites may be contributed by the gamma radiation in
underground miners, but should be insignificant for surface miners except
under unusual circumstances.
2), Airborne particulates. and gases,. Uranium and £ts daughters are
released to the atmosphere when the ore body is exposed and broken up during
either underground or open pit mining operations. The airborne particulate
radionuclides discharged from the mines are rapidly reduced by atmospheric
dispersion and approach normal background levels at the site boundaries.
U, S. Bureau of Mines measurements of radon concentrations in existing open
pit mines revealed no significant alpha concentrations, but for very rich
ore bodies some elevation of radon daughters can occur in the working area.
A report by the Atomic Energy Commission also estimated that atmospheric
concentrations of radon from open pit mining were minimal outside the work
area; where scaled to 1000 MWe production requirement these emissions are
less than 10% of the underground mines. For an underground mine with a
capacity of 1.5 x 105MT of ore per year, the amount of radon gas emitted to
the open air is estimated to be approximately 18 Ci per day (4), or about
4,500 curies/yr scaled to the production for a 1000 MWe LWR. This release
rate is about 10 times greater than that due to the final tailings release,
as discussed below. If, in fact, this amount of radon resulted in exposure
to the general population of radon daughters at about 70% equilibrium, the
bronchial dose would be on the order of 800 person-rem. Such an exposure
would be by far the greatest in the entire fuel cycle.
The mines are generally remote from population centers, however, and
there is the question of dispersion of radon (physical half-life 3.8 days,
which governs the short half-life daughters) before it can affect people
who bay breathe the daughters (see discussion below for mill tailings).
From current estimates it appears that nearly all of the exposure to radon
daughters occurs locally within tens or hundreds of miles from release. In
view of the low population density in mining areas, the exposure to the
general population is likely to be much less than the projection cited above.
Even If one assumes that an estimate of only 10% would be applicable, however,
the contribution of dose to human populations from mines is still very signif-
icant, even if one ignores any contribution of the Po-210 daughter of long-
lived Pb-210 resulting from radon decay. I use the estimate of 80 person-
rem per nominal plant for lack of a better value.
*The "working level" is a concentration of short-lived radon daughters giving
rise to 1.3 x 105Mev of alpha radiation per liter of air. The Working Level
Month is a measure of cumulative exposure and is defined as exposure to one
Working Level for 170 hours (hours worked/mo).
-------
3). Solid and liquid waste. The solid waste from underground mining
is estimated to be about equal to the volume of the processed ore. The
gamma radioactivity associated with the solid waste is very small, but
rubble present in mine areas can contribute to the radon present. The
water pumped from both open pit and underground mines will contain dissolved
and suspended uranium and its daughters. The radioactivity in the mine
water is estimated at 1% of that in the ore, but it is removed from the
water and returned to the ground by ion exchange during seepage through the
soil. Therefore, the radioactivity reaching surface drainage is not expected
to reach any significant levels.
Occupational Exposure
A major source of health effects associated with the mining of uranium
is the occupational exposure to radiation incurred by the underground uranium
miners. These miners are exposed to radon-222 and Its daughter products, which
are short-lived radioactive isotopes that emit alpha radiation and are potential
cancer-causing agents when inhaled.
The Mining Enforcement and Safety Administration (MESA) increased its
radiation exposure monitoring during 1977. Inspectors collected 1857 radon
daughter samples at 153 uranium mines (compared to 1976 figures of 1180 samples
at 142 mines). Average concentrations of radon daughters have consistently
decreased in uranium mines, with the average falling from 0.71 WL In 1975, to
0.58 Wl in 1976, to 0.51 WL in 1977, but still well above the standard of 0.3 WL.
Table 2 presents data collected from uranium mining companies of radiation
exposures to miners in 1977. The records also show a decrease in exposure
from 1.07 WLM in 1975 to 0-99 WLM in 1976 to 0.91 WLM in 1977. A discrepancy
exists, however, between federal sampling results and company records. When
the federal data of concentration of radon daughters measured in WL is con-
verted into exposure data measured in WLM, the average exposure is 5.68 WLM
in 1975, 4.64 WLM in 1976, and 4.08 WLM in 1977.
A special radiation exposures and recordkeeping audit to investigate this
discrepancy was initiated in 1975, and continued until its completion in 1977,
Twenty underground uranium mines employing 1604 miners were visited by MESA
auditing teams. The results from the investigation are also summarized in
Table 2, which confirmed that uranium miner exposure was significantly greater
than indicated by company records, with an average exposure of 4.64 WLM.
According to this audit, only about 1/3 of the mines were actually in
compliance with the exposure standard (3.6 WLM/yr).
Film badge surveys in open pit mines indicate that external whole-body
radiation doses are generally less than 0.6 rem/yr. Radon-daughter con-
centrations are generally less than 0.3 WL, with the average concentration
being 0.06 WL, or less than 10% of that found in underground mines.
-------
TABLE 2
1977 URANIUM MINE EXPOSURE TO RADON DAUGHTERS
(COMPANY RECORDS)
Total
employment
5,315
Average
exposure
.91 WLM
Miners having exposure in indicated
intervals , percent
o-i WLM
61.8
1-2 WLM
21.7
2-3 WLM
12.4
3-4 WLM
3.8
>4 WLM
0.2
Radon daughter concentration in underground uranium
mines 1976-1977 (MESA Audit)
Total number
of samples
1,882
Average
concentrations
0.58 WL
Maximum
concentr at ions
24.0 WL
Number and percent of samples in
designated range of annual exposure
0-4
WLM
653
34.7%
4-8
WLM
473
25.1%
8-12
WLM
329
17.5%
12-24
WLM
291
15.5%
>24
WLM
136
7.2%
-------
TABLE 3
URANIUM MILLING
AIRBORNE RELEASES OF RADIOACTIVE MATERIALS
(EXCLUDING TAILINGS)
Site Boundary*
Release Rate Air Concentration
Radionuclide Ci/day pCi/m3
Uranium .0005 -079
Thorium 230 .00027 .043
Radium 226 .00013 .043
Radon 222 1.13 11. (-v 0.1 WL)
*Dlstance to site boundary assumed to be 600 meters.
-------
In assessing current and future exposure, the number of underground
uranium miners is assumed to be 6000 at the present time, and the average
occupational exposure per year is assumed to be 4 WLM.
It is difficult to take account of significant changes in these ex-
posure levels in future operations if the ore continues to be worked in
small veins, with 50% or more from underground operations, A realistic
appraisal suggests that with better controls demanded, 2 WLM/yr could
probably be readily achieved with better mine ventilation. If a more
restrictive standard than this were required, it could probably be achieved
in some mines only by restricting individual exposure times, thus increasing
the number of miners and not changing the total cancers resulting. It
should be noted that projections of mining activity and exposures are not
greatly influenced by decisions concerning use of plutonium recycle in
power production.
In calculating the maximal lifetime lung-cancer risk from occupational
exposure, we assume the miner works underground 40 years, beginning at age
20. A lower average exposure would undoubtedly occur, but would be
accompanied by a larger number of miners exposed.
URANIUM MILLING
The next stage in the uranium fuel cycle is the conversion of the mined
ore containing about 0.2% V^OQ into a compound feontaihing 80 to 83% U308
(yellowcake). This process takes place at uranium mills, which are located
near the mines in order to minimize ore haulage distances. As of January 1,
1976, there were 17 uranium mills in operation in the U. S. The majority
of the mills are conventional acid leach or alkaline leach mills, but
several obtain the uranium by solution mining or from phosphoric acid
treatment.
Although the uranium extraction process may vary between mills due to
the chemical composition of the ores, steps common to all mills processing
conventionally mined ores include crushing, grinding, chemical leaching and
recovery of the uraniuir from the leach solutions. The problem of radio-
logical controls is present throughout this entire process, primarily because
uranium and uranium daughter products are released to the atmosphere in the
form of dust and radon gas (Rn-222).
After the uranium is extracted from the ore, mere than 99% of the ore
material becomes the mill wastes or tailings, a slurry of sandlike material
in waste solutions. The tailings are pumped to nearby sites where the solids
settle out and soon accumulate to form a tailings pile.
Radiological Effluents
The radioactivity associated with uranium mill effluents are emitted from
natural uranium and its daughter products (thorium-230 and radium-226) present
in the ore. The milling process removes and concentrates the bulk of the
-------
natural uranium, while the majority of the radioactive daughter products
remains in the uranium-depleted solid wastes which are piped to the tailings
retention system.
A). Airborne. Radioactive airborne effluents consisting of uranium and
its daughter products are released primarily from the ore crushing and grinding
ventilation system, and from the yellowcake drying operations in the form
of dust. Additional particulates and radon gas are also released from the
tailing piles near the mill, which will be discussed in a later section.
Table 3 shows the airborne effluents which are estimated to be released from
milling operations.
It is estimated that each mill is associated with about 5000 MWe
generating capacity, therefore the mill radon output (excluding tailings)
per 1000 MWe nominal plant is about 85 Ci/year, very much lower than for
the mine or tailings releases.
B). Liquid. The liquid effluents from a mill (acid-leach) consists of
waste solutions from the leaching, grinding, extraction and washing operations
of the mill. This liquid is discharged with the solids into the tailing pond,
which is designed to prevent contamination of ground or surface waters.
About 4300 nr of waste solutions are generated per day, and the amounts of
heavy radionuclides released in this waste water would be about 2 m Ci of
natural uranium, 1 m Ci of Ra-226 and 50 m Ci of Th-230 per day. The tailings
are composed mainly of sandstone and clay particles, and constitute about
1/3 of the weight of the slurry.
C). Releases from the mill tailing piles. The mill tailing piles are
the major source of radioaative materials released to the environment
from mill sites. The solid waste tailings contain about 75-85% of the radio-
active materials originally in the ore. While stored in the tailings retention
pond, low-level activity continues to decay naturally, resulting in further
discharge of radioactive effluents to the atmosphere. Radon-222 generated
by the decay of Ra-226 parent and Th-230 grandparent ^represents a~signi£icant
localized source of radon frpm annual fuel requirements for a 1000 MWe plant,
although not all of it will reach the atmosphere.
Studies of concentrations in air near mill tailing piles have indicated
that at distances beyond 0.5 mile in the prevailing wind direction, radon
concentrations are not significantly higher than background levels in these
areas. The rate of radon gas escape to the atmosphere from the tailings site
of a 1500 MT yellowcake mill after 10 years of operation is estimated to be
about 3000 Ci/yr. Scaled to a nominal plant this is about 400 Ci/yr per
1000 MWe. The rate may vary with location, however, due to the effects of
weather conditions such as wind or precipitation. A pile saturated with water
may have its radon release rate decreased by a factor of 25 because of decay
during diffusion to the surface. Unlike the radon releases from underground
uranium mines, which for all practical purposes end when the mine is shut
down and sealed off, releases from mill tailings continue after the mill has
been closed. This is because one source of the radon gas, thorium-230, has
a very long radioactive half-life (8 x 101* years).
-------
The tailing piles also release radioactive materials such as waterborne
radionuclides leached out by precipitation, surface runoff and waste solutions.
Although the movement of radioactive materials through seepage can be expected
to be very slow, seepage surveillance Is required to prevent unacceptable
contamination of local water sources. Leaching into human water supplies
can constitute a significant human exposure route.
Occupational Exposures
Film badge surveys conducted in uranium mills indicate that external
whole body radiation doses to employees are generally less than 600 mretn per
year. Although there are only a limited number of surveys measuring internal
exposure received by mill workers, the indication is that significant radon
daughter concentrations are usually not found. There exist a few exceptions
in which the concentrations approach those experienced in underground mines,
but with improved ventilation it is assumed that future exposure to radon
daughters in uranium mills should be low. Nevertheless, projections to date
indicate that total lung exposures to radon daughters and other alphas-emitters
in milling operations could be similar to that for mining.
Population Exposures
EPA has estimated the population weighted exposure from radon daughters
arising from uranium mill tailings using two different models for atmospheric
transport (5). The simplest model, which treats radon diffusion on the basis
of gross meteorology, yields an annual exposure of 6.5 x lO"1* person WL per
curie/yr released. A more detailed meteorological model developed for EPA
by the National Oceanic and Atmospheric Administration (NOAA) has been used to
calculate the exposure due to radon daughters from four release sites in the
western U. S. These exposures range from 4.2 x 10 ^ to 7.6 x JLO ** person-WL
per curie per year released, yielding an average of 5.6 x 10 **. A population
exposure due to radon daughters of 6 x 10 ^ person-WL per curie released per
year is used in this analysis. It is based on the assumption that exposure
from the emitted radon and its daughters occur at seven tenths of the equil-
ibrium concentration. This average applies to the entire Ur^S. population,
although it appears that the local population is primarily affected. In 1974,
EPA estimated the annual release from twenty-two known Inactive uranium mill
tailings piles as about 80,000 Ci per year. The population exposure from this
release would be estimated as
6 x 10i~k person-WL x 8 x 10^ Ci/yr = 48 person-WL
Ci/yr
10
-------
The Individual exposures to persons working or residing near the point
of release are of course substantially larger than the national average.
Because the local population density is markedly different near various
tailings piles, the regional impact from each should be considered on a
site specific basis. When it is arbitrarily assumed that tailings piles
are located in a low-population area, 7.5 persons per square mile, the
population exposure to a uniformly distributed local population is about
1 x lOT1* person-WL per curie/yr released, significantly lower than estimated
above. However, a preliminary EPA analysis of the actual population dis-
tribution around tailings piles located at Salt Lake City, Utah, and Grand
Junction, Colorado, indicates that the regional population exposures from
these sources account for almost all the exposure.
In those cases where the local population density is high and the
tailings pile large, the magnitude of regional health impact projections
approach those for the national total from all inactive tailings piles.
For example, the Vitro pile in Salt Lake City, which produces a large
fraction (16%) of the total radon emissions in the U. S. from inactive
piles, results in an exposure of about 100 person-working levels to the
800,000 persons who reside locally. For Grand Junction, Colorado, the
estimated exposure to the regional population is about 40 person-working
levels per year.
To convert person-working levels to person-rem, we assume continual
exposure to radon daughters to calculate WLJjt, and a value of 6 rem/WLM
(3). On this basis 1 person-working level = 300 person-rem dose to the
bronchial epithelium per year.
URANIUM HEXAFLUORIDE PRODUCTION
The yellowcake extracted from the ore in the milling process is
shipped to conversion plants, where the U^OQ concentrate is converted into
the volatile compound uranium hexafluoride (UF6). The UF6 is then used as
feed to an enrichment facility. The total domestic commercial industry
produces about 17,300 MT of uranium per year as UF6, with a typical con-
version plant having a capacity of 7000 MT of UF6 annually. This capacity
is sufficient to produce 24,000 MWe-yr of electric energy.
There are two different industrial processes involved in the production
of UFg. In the dry hydrofluor process, the uranium concentrate is passed
through successfive reduction, hydrofluorination and fluorination steps
11
-------
followed by fractional distillation of the crude uranium hexafluoride to
obtain a pure product. The second method begins with a wet chemical solvent
extraction step to produce a highly purified uranium oxide feed prior to
the reduction, hydrofluorination and fluorination steps. In this process,
a flame reactor is used instead of a fluidized bed unit to carry out the
fluorination step. Approximately equal quantities of UFg feed are produced
by each method, although waste effluents differ somewhat between the two
methods.
Radiological Effluents
In the dry hydrofluor process the radioactivity released is primarily
in the gaseous and solid states, while the wet solvent process discharges
radioactivity into liquid streams.
1). Gaseous effluents. A minimal amount of radioactive effluents are
released into the atmosphere from exhaust air as dust. The quantity of
natural uranium emitted in this fashion from all processes associated with
the wet procedure is approximately 100 mCi per year. The calculated con-
centration of natural uranium in the air at the site boundary is about
700 pCi/m3. The total industry airborne emissions are estimated to be
about 8 Ci for the period 1975-2000.
2). Liquid effluents. Radioactivity in liquid effluents, originating
primarily from natural uranium, has averaged less than 2yCi/m3, The radio-
nuclide concentration in the water retention pond of the wet solvent process
would be about 1 mCi/m3 of Ra-226 and lesser amounts of Th-230 and natural
uranium. The radioactivity in a neutralized pond is usually found in the
settled sludge, with only about 2% of its total activity present in the
liquids. After evaporation, the remaining sludge is expected to be disposed
of at licensed burial grounds or reprocessed at a mill to recover the uranium,
with transfer of the waste material to the mill tailings pond,
The wet process UF6 facility has a river adjacent to it, whose flow has
been measured monthly. The flow would be expected to provide enough
dilution of any radionuclides in it to reduce their concentration to below
maximum permissable levels.
Estimated waterborne radiological emissions for all heavy elements
(mainly U-238, U-234,and Th-234) from the projected UFg industry range
from 340 Ci to about 451 Ci, depending on whether plutonium recycle is used
or not.
3) Solid effluents. The primary source of solid radioactive wastes
is the ash residue from the fluidized bed fluorinators formed during the dry
12
-------
hydrofluor process. The residue is packaged and consigned for burial at
a licensed commercial disposal site. The principal constituent is Th-230
(18 Ci/yr) with about 3 Ci/yr of uranium isotopes in equilibrium with their
daughters, and about 2 Ci/yr of Ra-226. Much smaller amounts of solid ash
wastes are produced in the flame fluorination stage of the UFg wet solvent
process. The total quantity of radioactive solids estimated to be emitted
by the UF6 industry over the period from 1975-2000 ranges from 21,000 CI
to 28,000 Ci.
Table 4 summarizes the radiological effluents from hexafluoride pro-
duction of both types, normalized to a model 1000 MWe-yr LWR annual fuel
requirement.
Occupational Exposure
Employees of the UFg portion of the uranium fuel cycle are exposed to
external beta and gamma radiation, as well as to natural uranium and uranium
daughters in the atmosphere, Domestic UFe plant operations have conducted
plant measurement surveys, and their results indicate that external ex-
posure to beta and gamma radiation averages about 0.5 rem/yr, but most of
this is from the beta component and thus does not apply to the whole body
problem.
Internal body doses are the result of inhalation of air containing radio-
nuclides in addition to penetrating external gamma radiation. An average
whole body dose commitment per individual worker is expected to be about
0.2- rems/yr with critical organ dose commitments of about 1.5 rems to
the lung and about 2.2 rems to the bone. These figures can be used to
compute an integrated whole body dose commitment for the entire industry
population over the period 1975-2000 of 3500 to 4400 person-rems,
ENRICHMENT
Enrichment of uranium is presently being carried out at 3 large govern-
ment-owned and contracted gaseous diffusion plants, located at Oak Ridge,
Tennessee, Paducah, Kentucky and Portsmouth, Ohio. The total capacity of
the 3 plants have an output which is sufficient to produce about 90,000
MWe-yr of electrical energy from LWRs. The federal government is currently
planning to increase the capacities of the 3 plants by a factor of 2.5
to meet projected domestic and foreign demands. Conversion to the gas
centrifuge method is being considered.
Radiological Effluents
Small amounts of uranium are released from the enrichment plants during
normal operations in both gaseous and liquid forms. The bulk of the radio-
active effluents are discharged to holding ponds as a liquid and then dis-
persed to streams, while a small portion of the effluents are released to
the atmosphere. Releases from uranium enrichment normalized to a 1000
MWe-yr model LWR annual fuel requirement is about 0.002 Ci/yr of uranium
in gaseous forms and 0.01 Ci/yr of uranium in liquids.
13
-------
TABLE 4
RADIOACTIVE EFFLUENTS FROM UF6 PRODUCTION (CURIES)
PER 1000 MWE LWR REQUIREMENT/YR.
Gases
Uranium 0.003
Liquids
Ra-226 0.0034
Th-230 0.0015
Uranium 0.044
Solids (buried)
Other than high-level 0.86
14
-------
Occupational Exposure
Personnel employed in the uranium enrichment industry will be exposed
to small quantities of beta and gamma radiation, as well as radioactivity
from airborne particles. Annual monitoring of personnel at the Oak Ridge
Gaseous Diffusion Plant was made over the five-year period, 1970-1974,
Exposure to gamma radiation has remained at about 50 mrem/yr on the average,
but the beta doses have declined sharply from 1970 to 1974 and now add little
to the effective dose. Internal exposure can result from inhalation of
radionuclides in the air. The level of the radionuclldes does not exceed
5.5 pCi/tn3, which will produce an annual critical organ dose commitment
of about 0.7 rems/individual.
Predictions for the year 2000 indicate that the occupational doses will
not change significantly for the gaseous diffusion operations, For plants
using the centrifuge procedure, however, the whole body occupational dose
commitments are expected to increase because of the increased number of
employees at these facilities,
FUEL FABRICATION
The enriched uranium hexafluoride is used as feed material in the
fabrication of fuel for LWRs. It is converted to U02 powder, which is formed
into pellets, sintered and then loaded and sealed into zircaloy or stainless
steel tubes. The process that is currently being used to produce the fuel
is a wet ammonium diuranate (ADU) process. The present fuel fabrication
industry consists of 9 commercial operations, each performing either a
specific step of the fabrication process, or the entire process.
Radiological Effluents
Very small quantities of airborne radionuclides are emitted from fabri-
cation operations. The annual atmospheric releases for a plant with an
annual throughput of 1000 MT or uranium are estimated to be about 0.008 Ci/yr.
About one-third of the uranium losses are liquid and are discharged to a
waste lagoon. Liquid releases include uranium and thorium-234 (which grows
back after being separated from the uranium products at the milling plant).
The solid wastes are made up of CaF2 containing small amounts of uranium,
and account for almost two-thirds of the uranium losses. These solid effluents
are normally buried within the plant site, or may be sent to licensed
commercial burial grounds. The radiological effluents from a fabrication
plant normalized to a model 1000 MWe-yr LWR annual fuel requirement are about
0.002 Ci/yr of uranium in gas form, 0.013 Ci/yr of uranium and thorium-234
in liquids, and 0.23 Ci of uranium in solids.
The estimated radioactive emissions from the fuel fabrication industry
over the period 1975-2000 are predicted at 1.3 curies from airborne effluents
and 3.0 curies from liquid effluents if no recycle is implemented, and a
slight reduction if both uranium and plutonium are recycled.
15
-------
Occupational Exposure
Personnel employed by the fuel fabrication industry are exposed to
external radiation, as well as to internal radiation from airborne radio-
nuclides. These exposures are estimated to produce an annual whole body
dose commitment of about 0.20 rem per individual, in addition to a critical
organ dose commitment of about 10 rems to the lung.
MIXED OXIDE (MOX) FUEL FABRICATION
If plutonium recycle is incorporated into the uranium fuel cycle, then
fabrication of mixed oxide fuel from uranium and recovered plutonium will be
required. It is estimated that 8 model plants employing 24,000 persons would
be needed for this to occur by the year 2000. It is assumed that plutonium
recycle will not begin before the year 1981.
Radiological Effluents
Estimates of radiological effluents emitted from a MOX fabrication
industry are about 0.034 Ci of uranium, plutonium and americium in the gas
phase, and about 0.007 Ci of the same mixture as liquid waste,
Occupational Exposure
Employees of a MOX fuel fabrication plant may receive an average annual
whole body dose commitment of about 1.2 rems from external radiation and
0.2 rems from internal radiation.
NUCLEAR POWER PLANTS
Within the reactor radioactive materials are generated as a result of
the fissioning of uranium, and by neutron absorption in the coolant and
structural materials. The products of uranium fission include a large
number of elements in both their stable and radioactive forms. In the
operation of nuclear reactors, a small amount of these created radioactive
materials is expelled to the atmosphere or to nearby waters, but the majority
are contained within fuel rods. After a period of operation, the spent
fuel rods must be removed from the reactor, stored for a cooling period and
then shipped to a fuel reprocessing plant. The amount of radioactive
effluents released to the environment at the reactor site depends on several
factors, such as the type and size of the reactor, reactor design, percent
of fuel failures, and the control measures used.
Almost all of the current nuclear power plants in operation in the U. S.
today employ light water reactors to generate power. There are 2 types of
LWRs—the Boiling Water Reactor (BWR) which allows the water in the reactor
to boil, and the Pressurized Water Reactor (PWR) where the water inside the
reactor is prevented from boiling by pressures of about 150 times atmospheric
pressure. These differences in processes result in different types and
quantities of radioactive materials being emitted from PWRs and BWRs.
16
-------
Radiological Effluents
Radlonuclides may enter the environment through either the gaseous or
liquid effluent streams. The airborne effluents consist of fission noble
gases (krypton and xenon isotopes), activation gases (Ar-41, C-14, N-16,
S-35), tritium, radioactive halogens and particulates. In the liquid effluents
are found tritium, fission products and activated corrosion products.
A). Fission noble gases. Several isotopes of the noble gases Kr and
Xe are created by fission in the nuclear fuel. The amount and composition
of Kr and Xe escaping to the coolant and eventually to the environment
depends on the rate of their escape and the hold-up time prior to release.
In PWRs the gas volume buildup in the coolant (water flowing through the
core) is relatively slow, and therefore gases can be held up for a relatively
long time (more than 30 days) before being released. A 30-day delay would
reduce all the short-lived radionuclides to an insignificant level and only
Kr-85 and Xe-133 would be released in any measurable quantities. The gas
production rate in the BWR coolant, however, requires continuous removal of
non-condensable gases and, because of its large volume, the time between
gas removal and release must be shorter. The current hold-up time for krypton
from BWRs is about one day. In addition to Kr-85, Xe-133 and Xe-135 comprise
an important part of the noble gas effluents from BWRs. The total emission
of noble gases from PWRs during 1976 varied from a few up to 15,000 Ci/1000
MWe/yr, whereas from BWRs the range was from 30,000 to more than 1,000,000
Ci/ 1000 MWe/yr.
B). Tritium. Tritium is produced in both BWRs and PWRs from tertiary
fission, but most is produced as an activation product in the primary coolant.
Approximately 90% of the tritium is released as a liquid effluent and the
remainder in the form of a gaseous water vapor. About 1000 Ci/1000 MWe-yr was
released from PWRs and 100 Ci/1000 MWe-yr from BWRs.
C). Radioiodine. Several isotopes of iodine are produced in reactors
by fission and by decay of other fission products. 1-131 with a half-life
of 8 days is the isotope which is of main concern from an environmental
standpoint. It is released as both a liquid and gaseous effluent. The
measured releases of this radioactive halogen vary from several millicuries
to up to 100 curies per 1000 MWe-yr of power production.
D). Particulates in airborne effluents. Particulates can arise either
indirectly or as decay products of fission noble gases. Almost all of the
particulates are prevented from escaping to the atmosphere by high efficiency
particulate air filters. Only the smallest particles can escape, which results
in very low levels of particulate activity. It is estimated that in 1974
from PWRs, there was 0.5 Ci per 1000 MWe/yr emitted, and 1.1 Ci per 1000
MWe/yr from BWRs in the U. S.
E). Radionuclides in liquid effluents. Tritium and 1-131 comprise the
major portion of the liquid effluents from reactors, but there are other
radionuclides which can be found in significant quantities. These include
a number of fission and activation corrosion products, such as cesium-137,
17
-------
cesium-134, cobalt-58, cobalt-60, chromium-51, magnesium-54, raolybdenum-99,
and iron-55,
The U. S. Nuclear Regulatory Commission annually presents measured data
on radioactive materials in effluents from licensed commercial LWR power
plants. EPA has studied time trends of releases, which indicate the
fluctuations which have occurred in the release of radioactive effluents
over a 5-year time span from 1970 to 1975. There is also great variability
in releases from one reactor to another of the same type.
Occupational Radiation Exposure at Power Reactors
Table 5 is a summary of the number of annual whole body exposures to
workers at LWRs for the years 1969 through 1977. The total number of
individuals monitored for radiation exposure has increased steadily, as
has the number of personnel receiving measureable exposure. The percent
of individuals with measurable dose receiving exposures exceeding 5 rems
has remained about 1% over recent years.
An average of 669 persons per reactor received measurable exposure at
commercial LWRs in 1976, a number which represents a progressive increase
during the past several years. Since 1972 the average exposure to workers
has remained about 0.7-0.8 rem/yr. The number of persons receiving ex-
posures in excess of the short-term limits established by 10 CFR 20 at
commercial reactors is also reported for the years 1971 through 1977 in
Table 5. It is apparent from Table 5 that both in terms of short-term
overexposures (most of which result in partial body exposure from inhaled
radionuclides, generally of a few rads), or in terms of average annual ex-
posures, the current standards are frequently exceeded.
The data shown in Table 5 are for all reactors operating in each year.
Analysis by specific reactor shows that while the average dose per exposed
worker for all reactors is about 0.75 rem/yr, for individual reactors the
averages show a wide range. In 1976, the range of average exposures for
BWRs was 0.4 to 2.2 rems, while for PWRs the range was 0.2 to 1.7 rems.
In part this range reflects the number of years the reactor has been in
operation, the older plants having higher exposures to the workers, but
the large range shows that control of worker exposure is much less effective
in some plants than in others.
Within a particular plant there is also variability in radiation ex-
posure by the type of work carried out. Evidence indicates that maintenance
workers and the health physicists responsible for radiation protection have
higher individual doses than operating personnel in the reactors. The
significance of this variation is that simply giving an average annual
exposure cannot indicate the potential risk to individual workers in a
facility, although it is a useful datum for analysis of total societal
cost of nuclear operation. The consistency of the pattern of exposure
shows that definition of individual risk by job category and by reactor
can be done, but there remains the question of the appropriate level to
assume, especially when projecting to the year 2000.
18
-------
TABLE 5
PERSONNEL RADIATION EXPOSURE FOR LIGHT WATER REACTORS LICENSED
BY U.S. NUCLEAR REGULATORY COMMISSION
SUMMARY OF ANNUAL WHOLE BODY EXPOSURE BY INCREMENT
YEAR
1969
1970
1971
1972
1973
1974
1975
1976
1977
TOTAL
MONITORED
2854
7518
10269
15730
35918
38379
45659
61151
70904
i
NOT
MEASURABLE
0-1
NUMBER OF INDIVIDUALS
EXPOSURE INCREMENT - REM
1-2
2607
6953
9660
14783
20717
20240
20188
25704
27671
10249
13455
18277
26636
33252
2449
2491
3892
4880
6174
2-3
144
184
328
536
1585
1375
1903
2354
2838
3-4
70
175
146
205
432
470
707
789
1130
4-5
26
92
107
114
237
226
426
487
569
5-6
5
102
17
47
117
86
169
188
141
6-7-
2
11
11
23
71
30
60
70
66
7-8
0
1
0
10
38
6
24
26
36
8-9
0
0
0
6
16
0
12
11
21
9-10
0
0
0
6
7
0
0
5
6
>10
0
0
0
0
0
0
1
1
0
NUMBER
OF OVER-
EXPOSURES
2
16
19
43
14
20
27
SOURCES: 1969-1975:
1977:
NUREG-0323 Occupational Radiation Exposure at Light Water Cooled Power
NUREG-0463 "Occupational Radiation Exposure" Tenth Annual Report 1977
Reactors 1976
-------
FUEL REPROCESSING
Spent fuel from uranium-fueled LWRs can be reprocessed to recover
usable fissionable material (both uranium and plutonium). The fuel elements
removed from the reactor still contain about one-quarter of the original
U-235, in addition to Pu-239 produced from the absorption of a neutron by
U-238. If plutonium recycle is implemented, a portion of the original
plutonium content will also remain in the spent fuel. The recovered uranium
is converted to UF6, shipped to enrichment plants and eventually recycled
to nuclear reactors. The recovered plutonium can be converted to PuC>2 and
then mixed with U02 for recycle in reactors. The reprocessing operation
involves the separation of the fission products from the uranium and
plutonium. The fissionable uranium and plutonium are recovered as purified
nitrate solutions. Radioactive wastes must be converted into forms suitable
for transfer to federal waste repositories, which will be the ultimate con-
finement location for various types of radioactive wastes.
Three commercial nuclear fuel separation facilities have been built in
the U. S., none of which are in operation at the present time. Reprocessing
and recycling have been controversial subjects because of the potential health
problems which can result from the widespread use of plutonium, and because
plutonium can be used in the production of nuclear explosives.
Radiological Effluents
After the fuel rods with the spent fuel are removed from the reactor,
they are stored for about 150 days to allow significant reduction of the
radioactivity of the shorter half-life radionuclides. Despite this re-
duction in radioactivity, however, large quantities of natural and reactor-
generated radioactive materials are still found in fuel rods at reprocessing,
A significant portion of the radioactive effluents from the entire fuel cycle
is encountered in the reprocessing stage.
The Nuclear Fuel Services Reprocessing Plant (NFS) was in operation
from 1966 to 1972, and was then shut down for alterations and expansion.
The plant released to the atmosphere all the Kr-85 and C-14, about 60% of the
H-3, and very small quantities of radioiodine and other fission products
present in the spent fuel. Additional tritium and other radioactive materials
were released to streams as liquid effluents. The following data in Table 6
show the effluents discharged from the NFS plant, normalized to a 1000 MWe-yr
of uranium processed.
If plutonium is recycled in LWRs over the period from 1975 to 2000, the
amount of MOX reprocessed is expected to total about 11% of the total fuel
reprocessed, mostly to be processed in plants not yet designed. The re-
cycling of plutonium will not affect the amount of fuel reprocessed, but
will primarily change the mixture of radioactive effluents.
Determination of the population or occupational exposures from fuel
reprocessing is difficult at this time. From the nature of the isotopes
released at NFS (Table 6) exposures to the general population would be
20
-------
TABLE 6
EFFLUENTS DISCHARGED FROM NUCLEAR FUEL SERVICES
REPROCESSING PLANT
Radlonuclide Cl/1000 Mwe-yr
Gases
Krypton-85, 340,000
Tritium (H ) 220,000
Carbon-14 10
Iodine-129 0.003
Iodine-131 0.06
Other fission products 0.9
Actinides 0.004
Liquid
Tritium (H ) 4,000
Ruthenium-106 4
21
-------
largely to krypton-85, tritium and transuranic actinides, and thus would affect
mainly people living near the plants. Estimates of occupational exposures are
generally low, but experience with the reprocessing plant in England, which has
been operating commercially for more than a decade, shows average occupational
exposures of about 1.3 rads/yr.
WASTE MANAGEMENT
The disposal of radioactive wastes is one of the most controversial
aspects of the uranium fuel cycle. The major problem is presented by the
highly radioactive fission products created in the nuclear reactors, as well
as the plutonium and other heavy elements produced there.
The Nuclear Regulatory Commission has grouped the wastes from the nuclear
fuel cycle into six major categories. Four of these arise from either uranium-
only recycle or both uranium and plutonium recycle: high-level wastes, tran-
suranium-contaminated wastes, non-transuranium-contaminated wastes (usually
called low-level wastes), and contaminated facilities and large equipment.
In addition, the uranium fuel cycles give rise to two other classes or wastes:
spent fuel from the no-recycle option and unused plutonium from the uranium-
recycle option.
High-level wastes (HLW) are produced at fuel reprocessing plants, and
contain most of the highly radioactive fission products separated from fissile
material. These wastes are perhaps the most difficult to handle in terms of
containment because of the need for shielding and heat dissipation. According
to Appendix F of 10 CFR 50, HLW must be converted to solids within 5 years
after being generated, which then must be transferred to a federal repository
for storage within an additional 5 years. The fission products that are found
in HLW include the transplutonium elements and about 0.5% of the uranium and
plutonium that were originally in the spent fuels.
Transuranic wastes are determined by their concentration of transuranic
elements (i.e., a minimum of 10 nCi/g being emitted from elements with atomic
numbers larger than 92). Transuranic wastes are generated primarily after
fuel reprocessing operations. Waste materials included in this category are
solidified liquids, cladding hulls and other fuel hardware, and general trash.
Non-transuranic low-level wastes are defined as any radioactive waste
material which contains less than the minimum amount of transuranium elements
(as defined in the previous paragraph), These materials are contaminated with
fission products with relatively short half-lives, the maximum being around
30 years.
Contaminated equipment and large facilities are taken out of service by
a procedure termed decommissioning, which varies depending on the type of
facility. Some of the actions involved in decommissioning include equipment
removal, removal of contaminated concrete, chemical scrubbing and removal of
cell liners.
22
-------
Wastes containing radioactive isotopes are produced at each segment of
the uranium fuel cycle. Much of the waste is low-level and can be dealt with
by storage in licensed repositories, but the principal problem is potential
exposure to the general public from solidified high-level wastes and the
transuranics. The bulk volume of this waste is relatively low, .about 10 m3
of spent fuel per 1000 MWe-yr for current reactors, and less for solidified
fission products from reprocessing. Long-term storage in a location from
which negligible activity can reach human contact is required.
At the present time, the plan most carefully researched for long-term
disposal of HLW calls for placement in geologically stable salt beds. The
Department of Energy is in the process of selecting a suitable site for this
disposal. If one assumes that a repository for HLW or spent fuel can be
built which will adequately cope with the long-lived radionuclides generated
in the production of nuclear fuel, the environmental impact of nuclear waste
management should be relatively small, but at present this problem is un-
resolved.
TRANSPORTATION
Throughout the nuclear cycle, transportation of potentially hazardous
radioactive materials is required, and for this reason the total number of
miles of transport is higher than for coal, In general, however, the volume
of material transported is much less than for the coal cycle, but the potential
hazard to the general public or the workers is greater than for coal, especially
if the containment of these materials is breached. In addition, there is the
potential for injury due to accidents even if the containment of activity is
maintained.
The most significant source of exposure is from spent fuel or reprocessed
fission products after the fuel is used in energy production. The risks from
spent fuel will predominate in the short run, but in the long run transportation
of the reprocessed waste will probably lead to greater population risks than
for spent fuel. Transportation of these highly radioactive sources is carried
out in lead-shielded casks designed to withstand significant impact. Shipment
is primarily by truck, but some by rail. To the present, we can only speculate
on the health impact on the general population of transportation of nuclear
materials, except from gamma ray exposures in transit, which are less than 1
mrem per person, or negligible in relation to natural background. An individual
who stood next to a cask for several minutes could receive about 1 mrem/2 min.
Exposures of the general population from accidental breaching of the containment
casks could be much higher or not, depending on where the accident occurred,
but it is difficult to forecast these kinds of exposures.
Occupational radiation exposures are relatively low. Estimates of exposure
for the truck drivers are about 15 mrem for a 500-mile haul, including time
spent working adjacent to the cask. Spent fuel haulage is estimated to re-
quire about 20 shipments per year per 1000 MWe, or a total of 10,000 miles
per year per nominal plant. Thus at the present rate, exposures of drivers
should be well within acceptable limits, unless relatively few drivers handle
the entire nuclear industry. If plutonium recycle is undertaken, some additional
exposure would occur, particularly from transport of the solidified high-level
23
-------
waste to a final repository. Finally, risks to the drivers from road accidents
exist, but they are likely to be much lower per shipment than for coal ship-
ments because the progress of the shipment will be very closely supervised.
The above discussion has assumed that shipments of ore or unirradiated
fuel contribute negligible population or worker exposures. Low-level waste
shipments may contribute some occupational exposures because of the larger
volume and greater number of shipments required per 1000 MWe/yr.
An accident occurred in Colorado in 1977 in which several tons of yellow-
cake (UsOg) were spilled. This incident did not produce a significant general
exposure to radiation, but it did emphasize the importance of plans for clean-
up operations from a major spill, especially if the material had a much higher
radiation risk than yellowcake.
SUMMARY OF EXPOSURES
From the preceding discussion we may summarize the radiation exposures
in the nuclear fuel cycle. The following data are reasonably consistent with
the recent EPA estimates of airborne exposure (4). In considering health
impacts, obviously hazards not related to radiation must also be considered.
In Table 7, these exposure factors are summarized for the nuclear cycle.
Table 7A gives general population exposures and Table 7B gives occupational
exposures.
These exposures are on a yearly basis. For some of the long-lived
radionuclides the integrated total dose, or dose commitment, is used to
express exposure. This is a necessary approach to an individual when the
exposure leads to a continuous integral dose from nuclides present in the
body over many years, and it has been used here. In the sense, however,
that annual releases of radiation exposure sources sum over time to give a
very long exposure, as in the case of uranium mill tailings, it is evident
that single individuals will not experience the entire cumulative effect
which may last for centuries. For this reason, I have elected to emphasize
the dose relevant to individuals, but this approach does not give stress to
the very long-range impact of the nuclear cycle. The situation is analogous
to the long-range effects of strip-mining for coal, which may alter the
environment permanently, conceivably with health impacts a century hence.
If there were significant gonadal dose from the mine tailings, the long-range
genetic effects of radiation could be important, but there is no evidence
that this is the case.
HEALTH EFFECTS FROM NUCLEAR CYCLE
In this section I have applied risk estimates based on the linear no-
threshold dose-response relationship, derived from the draft 1979 BEIR report
(3). These risk coefficients are applied to the exposure data in Tables 7A & 7B
which are normalized to a nominal plant.
24
-------
TABLE 7A
EXPOSURES TO GENERAL PUBLIC IN NUCLEAR FUEL CYCLE
PER 1000 MWE POWER GENERATION/YR.
N3
01
Location
Mining
Milling (tailings)
Conversion
Enrichment
Fabrication
Power plants
Reprocessing
Waste management
Transportation
Total (person-rem)
80 (lung)
70 (lung)
2 (lung)
Minimal (<1)
Minimal (<1)
20
200 (est)
10 (est)
3
Individual Maximum (rem/yr.)
very low
0.035 (lung)
0.001 (lung)
0.006 (lung)
0.005 (lung)
O.OM (thyroid)
0.1 (lung)
unknown
0.001 (whole body)
-------
TABLE 7B
EXPOSURES TO WORKERS IN NUCLEAR FUEL CYCLE
PER 1000 MWE GENERATED/YEAR
NJ
0\
Location
Mining
Underground
Conversion
No. of
workers
^2 00
^80
800
Enrichment ^500
Fuel fabrication
Power plants
Reprocessing
Waste management
Transportation ^5
Total ^ 2000
Total exposure Individual average
person-rem of exposed group
(whole body) (rem/yr.) Other hazards
200
Surface
Milling
MOO
^30
50
5
16
25
100
800
unknown
unknown
1
1200
25 (lung)
1 (whole body)
Accidents, Silicosis
0.5 (whole body) Accidents
10 (lung)
0.2 (whole body)
3 (lung)
0.2 (whole body)
0.05 (whole body)
10 (lung)
0.2 (whole body)
1 (whole body) Accidents
^1 (whole body)
0.2 (whole body) Accidents
-------
General Population
For these exposures (Table 7A)» health effects are mainly from effluents
of mining, mill tailings, fuel reprocessing and power plants, A single-dose
exposure lifetime-risk model is appropriate. This model has been applied to
a population of all ages and both sexes, by application of life-stable methods.
The principal health effect of radiation 1& cancer production. It is not
possible to quantitate in health terms genetic effects. Thus no attempt is
made to do so, but it should be borne in mind that estimates for cancer alone
do not fully indicate the health implications of radiation exposure. In
deriving cancer incidence, projection of lifetime risk has a range of un-
certainty because the appropriate model for lifetime projection is unknown
at this time.
Because fuel reprocessing is not currently under way, this phase and
waste disposal are considered separately. For those stages of the cycle
currently operating, most exposure is from mining and milling effluents,
although there is considerable uncertainty about the contribution of mining.
The total incident life-time cancers expected from a single year of exposure
would be about 0.028-0.048 cases per year. For fuel reprocessing, the
excess cancer incidence from a single year's exposure would be about 0.08-
0.25 cases per year, probably in a smaller exposed population.
Occupational Health Effects
Occupational health effects can be more definitely specified than for
the general population. In this case the assumption is made that workers
begin at age 20 and retire at age 65, and most of the workers are likely to
be male. In this case no estimate is made for the reprocessing workers,
although it is likely that they will contribute significantly in the future.
In addition, for mining we assume 2/3 of the miners are underground, and
the lung cancer risks in fuel fabrication are comparable per rem to that
in the mining and milling operations, an assumption which ultimately may be
found to overestimate risks.
The effect of whole-body exposure in all workers is about 0.2-0.8 excess
lifetime cancers/1000 MWe-yr. For the groups with significant lung dose from
alpha radiation (mining, milling and fuel fabrication), additional lung cancers
will occur from this exposure. These would be about 1.3 excess lung cancers
from a year's exposure, about 3X as many as from whole-body exposures
in the current cycle. These additional lung cancers Indicate that mining
and fuel fabrication especially contribute a large portion of the total occu-
pational cancer impact from radiation.
To the 1.5-2.1 excess lifetime cancers arising from annual exposures
must be added a component from lung disease and accidents. Preferably, these
should be in terms of morbidity, but no data for morbidity exist for uranium
miners. About 150 excess deaths from chronic respiratory disease and accidents
occurred in the cohort studied by Archer et al, (6), consisting of nearly
4000 underground miners exposed for about 20 years. Scaled to 200 miner-yr/
1000 MWe-yr this excess mortality is about 0.4/yr. On the assumption that
serious morbidity frequency is at least 8 times mortality, the added health
27
-------
effects are about 3, 2 from accidents and l from respiratory disease, This
estimate is based on past practices and may be reduced in the future, but it
indicates that injuries and respiratory disease contribute significantly to
total morbidity in uranium mining. Morbidity from accidents in the rest of
the cycle has been minimal by comparison.
We may summarize the health impacts of the nuclear cycle as in Table 8.
The risk estimates are based on current or anticipated normal operations of
the nuclear fuel cycle. Occupational on-the-job injury has been included,
but no attempt to quantitate risks from accidental releases, such as from
criticality accidents or reactor core malfunctions has been Included, In
my view, the Three Mile Island episode supports the view that if the primary
containment vessel remains intact, population exposures from a reactor
accident should contribute minimal added risk to the above figures. On the
other hand, if a reactor accident led to loss of primary containment, I
believe that the political and social consequences would be so severe that
the fission nuclear option would be terminated,
28
-------
TABLE 8
HEALTH IMPACTS OF NUCLEAR FUEL CYCLE
PER 1000 MWE-YR OF POWER PRODUCTION
Ni
Occupational
Total
Current
Projected for year 2000
opulation 0.
nal 1.
upational 4.
4.
028-0.048
5-2;
2,
0.
0.
6-5.
6-5.
1
0
5
5
1
1.
Cancer
Cancer
Trauma
Silicosis
Chronic lung
disease
0
1
1
0
2
3
.11-0
..4-1.
.0+
+
.5
.9-3.
.0-3,
.31*
7**
2
5
Cancer
Cancer
Trauma
Chronic
lung
disease
*0n assumption of recycle of plutonium.
**0n assumption whole-body exposures are reduced by one-half, reprocessing not included.
+0n assumption injury morbidity is reduced by one-half and silicosis is eliminated.
-------
REFERENCES
1. The Nuclear Industry. U. S. Atomic Energy Commission, WASH 1174-74, 1974.
2. Sources and Effects of Ionizing Radiation Report of the United Nations
Scientific Committee on the Effects of Atomic Radiation (UNSCEAR),
United Nations, New York 1977.
3. Advisory Committee on the Biological Effects of Ionizing Radiation (BEIR
Committee), U. S. National Academy of Sciences. Draft Report May, 1979.
4. Radiological Impact Caused by Emissions of Radionuclides into the Air in
the United States, Preliminary Report EPA 520/7-79-006, U. S. Environ-
mental Protection Agency, August, 1979.
5. The Health Risk from Inactive Uranium Mill Tailings Piles. Bioeffects
Analysis Branch, Criteria and Standards Division, Office of Radiation
Programs, U. S. Environmental Protection Agency, Sept. 1979.
6. Archer, V.E., J. D. Gillam, and J. K. Wagoner. Respiratory Disease
Mortality Among Uranium Miners. Symposium on Occupational Carcinogenesis,
Ann. N.Y. Acad. Sci. 271:280-293, 1976.
30
-------
SECTION 3
HUMAN HEALTH IMPACTS FROM THE COAL CYCLE
Wtthin the industry providing coal for electric power generation, con-
siderable differences in types of mining, transportation and other factors
that can influence health impacts exist throughout the country. As a result
one would anticipate that the health impacts of the coal cycle could be sub-
stantially influenced by conditions modifying local practices. An example
is the extent to which western coal will be used in eastern power plants,
because long transportation distances will increase the probability of
accidents affecting both workers and the general public. In this presentation
I shall consider practices in the ORBES region. In this case, a large pro-
portion of coal used is mined in the ORBES area, although the fraction of
western coal used has recently increased because of the high sulfur content
of eastern coal. Because the ORBES region has extensive coal deposits, mine
mouth power plants are feasible and are currently operating on a limited
scale. Furthermore, the mix of transportation modes includes in this area
more use of trucks and barges than elsewhere in the U, S«
As in the case of the nuclear cycle, we consider current technology as
the basis for projections of health impact, but it is pertinent to note that
the use of coal for power has involved an industry of long-standing, with
practices rooted in a past when concern for public and worker health was
minimal. This fact is in sharp contrast to the development of nuclear power.
One result of the long history of the use of coal for power is that the
industry is now in transition, with new technology and regulations which
are correcting many of the abuses of the past. Because of rapid changes
occurring within the past decade, the health impacts that may be discerned
in recent years may not be applicable to the current situation, reflecting
as they do a legacy from previous conditions no longer present.
Current evaluations of the health impacts of the coal cycle are character-
ized by controversies which in large part are based on the reliability of
forecasts based on past conditions, with differing projections of the future
impacts of current practices. In what follows I have considered both sides
of these controversial issues, the most important of which involves the
occupational health impacts of coal mining and the impact on public health
from airborne stack emissions from coal-fired power plants.
Currently somewhat over 100 gigawatts of electric power are generated
each year by coal combustion. A gigawatt is 1000 MW, thus the total power
31
-------
generation is equivalent to about 110 nominal plants, but because many coal-
burning plants are quite small the number of actual plants is large.
On the basis that 4,000,000 metric tons (MT) of coal are required per
year for 1000 MWe power generation, of the total 1977 coal mining production
of about 600 million MT (1), approximately 2/3 was utilized for electric power
production. Additional steps in the coal cycle include coal processing,
transportation to the power plant, combustion at the plant, and waste disposal.
Because figures related to health effects are often given as totals for the
entire coal industry, the fraction of 2/3 of coal use for power generation
is used wherever applicable.
COAL MINING
Surface mining of coal Is now the dominant mode of coal mining, accounting
for over 60% of the total production. In the ORBES region the proportion
varies considerably by area, with more underground mining in West Virginia and
western Pennsylvania. Surface mining is not only more labor-efficient, with
less than 30% as many miners required per unit production as Is required for
underground mining, but it also has less health impacts per miner. Despite
economic advantages for surface mining, estimates are that the proportion of
coal mined from underground operations will continue about the same as at
present, at least into the immediate future in the ORBES area, because of
limitations on coal deposits accessible to surface mining and new regulations
for such mining. Surface mining Is primarily done by the "strip'1 mining
method, in which overburden is removed, the coal taken out, and the over-
burden is replaced.
Underground mines vary greatly in size, degree of mechanization and
techniques of mining. For the large mines, long-wall mining is now becoming
very widely applied, but in small mines, sometimes family owned and operated,
resort to manual methods is still extensive. These small mines are gradually
being forced out of production, in part because of regulatory pressure to
prevent accidents and exposure to dust in the mines.
Occupational Health Impacts; Injury
Coal mining has traditionally been one of the most hazardous of all
occupations, with frequent episodes of multiple deaths or serious injuries
due to cave-ins or explosions. These latter episodes have largely been
eliminated by regulations and proper inspection procedures, but the problems
of injuries among coal miners remains serious, nevertheless, especially
among the smaller mines. In 1977 there were 100 deaths reported from under-
ground mines and 29 from surface mining (1). When these deaths are scaled
to production requirements for a nominal power plant, they give 0.7 deaths
from underground mining and 0.2 deaths from surface mining, or a total of 0.9
deaths per 1000 MWe per year. A similar calculation for disabling Injuries
gives about 96/yr, but these are all injuries with lost time greater than an
arbitrary limit, without regard to severity or permanent disablement. A
32
-------
difficult problem, also present in assessing the health impacts of uranium
mining, is the extent to which these non-fatal injuries contribute to the
total health cost.
Occupational Health Impacts; Disease
Coal workers pneumoconiosis (CWP) is now well-recognized as a clinical
entity. With continuing exposure to dust in the mines,the process may progress
in a small percent of cases to progressive massive fibrosis, a chronic and
disabling disease whose course is independent of continuing exposure. Simple
CWP is, on the other hand, not disabling and shows little functional impairment.
In addition, Morgan (2) believes that there is a form of industrial bronchitis
associated with inhalation of dust, which subsides on removal from exposure.
All of these clinical conditions are confounded by cigarette smoking, and the
question of whether inhalation of coal dust accelerates or adds to the disease
processes associated with smoking has been a source of great debate.
Another complication in assessing the disease impacts of coal mining is
the improvement of dust conditions in the mines in recent years. Much of the
disease present among miners, especially the more disabling forms, reflects
working conditions that are now rare. For this reason the projections of
present and future health impacts are difficult; in addition the controversy
over the health significance of simple CWP is another source of uncertainty.
For these reasons estimates vary considerably of the new cases of signifi-
cant lung disease generated per year in a population of 1000 underground and
400 surface miners required for production of coal for a nominal plant. Pre-
valence rates for CWP must be corrected to take account of the time required
for the disease to develop at current exposure levels. If we take the
prevalence of CWP as 10% for underground miners (the prevalence of 4% for
surface miners is believed to be due to previous underground work), then the
prevalence would be 100 cases/nominal plant. On the assumptions that 20 years'
exposure are required to develop evidence of the disease, and no more than
20% of the simple CWP cases will progress to functional disability, the new
cases per 1000 MWe/yr would be 1.0, This is a relatively crude estimate,
perhaps too high if the proportion of cases that progress to massive fibrosis
or bronchitis is overestimated for current exposure conditions, and perhaps
too low if subsequent evidence supports the view that simple CWP is associated
with acceleration of onset of chronic lung disease and eventual disability,
at least in smokers.
Health Impacts on General Public
Coal mining has significant effects on populations living nearby, but
the long-term health significance of these effects is not well understood.
Normal operations result in fugitive dust exposure, especially from strip
mining, and siltation of streams. The latter is believed to contribute
significantly to flooding, which can have public health significance. In
addition, tailings and slag have been used to create earthen dams, which
have given way and caused major loss of life. Acid mine drainage in the
33
-------
coal fields is extensive, but aside from esthetic effects and loss of
recreational use of streams, public health impacts have not been demonstrated.
Abandoned underground mines may catch fire and smolder for long periods
of time, releasing gases at the surface, especially sulfur dioxide, to local
areas. Subsidance from collapse of supports in underground mines also fre-
quently occurs, with substantial effects on property values, at least.
It is not possible to assign a value for health impacts from the above
effects created by coal mining, particularly because of the episodic and
localized nature of some of them. The potential exists for significant
public health impacts from mining on local communities, but many of these
conditions reflect past practices which presumably are being corrected, and
in any case no quantitative assessment of health risks can be made at this
time.
COAL PROCESSING
As mined, coal contains about 20% contamination with rocks and other
debris. In addition, mechanical crushing or grinding is necessary for some
uses. As a result, about 90% of mined coal undergoes processing of some kind,
although the best grades of coal are reserved primarily for industrial uses,
and power plants can use lower grades for combustion purposes.
Coal processing is a significant source (about 25% of the total from all
mining operations) of acid residues which can leach into water, and is a
major source of trace elements in leachates. Moreover, tailings from processing
must be handled by various waste disposal methods. Thus processing shares with
mining some of the same potential public health impacts, but again there is
as yet no basis for providing quantitative estimates of health impacts on the
general public.
Data for the period 1972-77 indicate that in coal processing plants, when
scaled to coal production for a nominal 1000 MWe plant, the fatality rate for
workers is 0.05/yr (mostly from haulage or machinery accidents), and the dis-
abling injury rate is about 5.0/yr. In other words, while coal processing is
somewhat less hazardous to workers than strip mining, the health impacts from
processing are not negligible.
COAL TRANSPORTATION
Coal transportation is a very significant part of the coal cycle, as trans-
portation of coal by rail accounts for almost one-third of all tonnage of freight
transported by rail in the U, S. Rail transportation accounts for about 2/3
of all shipments of coal to power plants in the U. S., but in the ORBES region
the proportion is probably somewhat less because of the greater contribution
of shipment to ORBES plants by water and by truck, as well as the larger
proportion of mine mouth plants which utilize conveyor systems for transport
of coal.
34
-------
Exposure tp dusts or contamination of the environment is not a significant
factor in coal transportation, thus the health effects aris,e from injuries,
For the general public these injuries are related to railway grade-crossing
and switching and yard accidents, and truck collisions on the highways.
Rail Transport
Coal may be transported either mixed with standard freight trains, or as
unit trains carrying coal alone. The use of unit trains has been increasing,
but thus far there are no statistics which permit separation of injury ratio
by type of train. On the basis of ton-miles transported, the proportion of
health impacts assigned to coal is relatively high because of the density of
coal compared to most freight moved by rail. On a train-mile basis, coal
accounts for a lesser proportion of total freight movement. Finally, unit
trains for coal may have a lower risk for injury, to the general public at
least, because of the lower train velocity commonly present. In calculating
the health impacts of rail transportation by coal, 1 have used the train-mile
basis as the best indicator of risk to the public as well as to the railroad
workers. The latter assumption may somewhat underestimate the occupational
risk because the heavy weight of coal cars may lead to greater probability
of injuries associated with switching and coupling operations.
On the assumptions that 4xl06 MT of coal are required per 1000 MWe, and
in the ORBES region there are an average 1,5 x lQk MT carried per train for
a round trip distance of 400 miles, the train-miles required per 1000 MWe/yr
would be approximately 100,000, From data summarized by Morris (3), the
fatality rate to the general public from all rail operations in the U, S.
in the period 1966-74 was about 3 per 106 train-miles, and the injury rate was
about 6 per 106 train-miles.
From the above estimates, and on the assumption that in the ORBES region
60% of coal transport is by rail, one would calculate that for the general
public there would be about 0.2 fatalities and 0,4 injuries/1000 MWe/yr.
Similarly for occupational risks the values would be 0,006 fatalities and
0.5 injuries/1000 MWe/yr.
Truck Transport
Hazard estimates for truck transport are based on vehicle-wiles, The
same assumption is made as for rail transport that the tonnage transported
makes no difference in the accident rate, an assumption that is reasonable
because the tons of coal transported per truck (about 20 MT) are similar to
other large truck loads. At 20 MT per load, and on the assumptions that in
the ORBES region 15% of coal for power consumption is transported by truck
and each round trip is 100 miles, the total vehicle-miles per year per nominal
plant would be 3 x 106. Statistics for the truck industry for 1973-76 (4)
indicate that for truck fleets the fatality rate is 0.009 per 106 vehicle-
miles. If these values are applied to coal transport, the fatalities would
be about 0.03 deaths and 0.1 injuries per 1000 MWe/yr. These deaths and
injuries apply both to the general public and to truck drivers, and it is
35
-------
not possible to apportion them exactly. On the assumption that trucks are
more frequently involved in single-vehicle accidents than in multiple-vehicle
crashes, but the multiple-vehicle accidents will produce a higher proportion
of fatalities or injuries to the general public than to the drivers, we may
estimate crudely that about half of the casualties will be distributed to
the drivers and half to the genera^ public,
Water Transport
In the ORBES region about 15% of coal is moved by water to power plants,
nearly all in barges. Data are available for casualty rates per ton trans-
ported by water routes. On the assumptions that the load per barge is the
same for coal as for all freight, but that the distance coal is transported
to power plants is one-half that for all freight, then rates may be applied
to coal transport. From U, S. Department of Transportation data for 1975-76
(4), the casualty rates for freight transport are 0.037 deaths and 0.034
injuries/106 ton transported, On this basis and taking account of the shorter
transport distance for coal, the fatality and injury rates both would be about
0,01 per 1000 MWe per year. These would apply to the workers only.
We may summarize the health impacts of coal transport in the ORBES region
as follows:
Fatalities
per 1000 MWe
Mode of % General Occupational
Transport Use Public
Rail 60 0.2 0.006
Truck 15 0.015 0.015
Water 15 0 0.01
Injuries
generated
General Occupational
Public
0.4 0.5
0.05 0.05
0 0.01
It should be emphasized that while the fatalities can be added, the
injuries may vary in severity from one transport mode to the other. The
health impacts will be discussed later. It is evident that for the general
public rail transport is the principal problem, but for the workers, truck
and barge transport also contribute significantly.
COAL-FIRED POWER PLANTS
The possible health effects of emissions from coal-fired power plants
have been very extensively studied in some aspects, in others they have not.
Examples of the latter are our uncertain knowledge about health effects on
the general public from waste leachates, or the lack of occupational health
data on plant workers. Because of early interest in possible health effects
of airborne sulfur oxides, and because power plants produce in the U, S. a
large fraction of the sulfur oxides emitted into the air, very extensive
36
-------
studies of effects of air pollution, both in animals and in human populations.
have been done in the last two decades<
Health Effects on the General Public
Early interest in the effects of sulfur oxides on public health came
from the well-known smog episodes in the 1950s in London, England, the Meuse
valley in Belgium and in Donora, PA. These episodes, which were associated
with prolonged meteorologic temperature inversions and closely packed local
concentrations of fixed sources burning soft coal with relatively high sulfur
content, established clearly that when air pollution reached high levels
sustained for several days, lethal effects on the populations exposed could
be demonstrated. The 1952 London episode, as well as subsequent ones a few
years later, has been most extensively studied, and from this analysis it
is evident that an increased risk of mortality from cardiopulmonary diseases
occurred when both suspended particulates and sulfur oxides both exceeded
500 micrograms per meter3, with the likelihood that transient elevations
above 1000 micrograms/m3 accounted for most of the excess mortality. The
potential public health seriousness of exposure of people with varying sus-
ceptibilities to air concentrations of soft coal effluents of this amount
is generally accepted and has formed an important bench mark in the political
process of air pollution control.
Such high concentrations of these pollutants have rarely ever been
observed in the U. S., and now with relatively little coal used for home
heating and even minimal controls on emissions from .coal-burning plants,
they are a thing of the past. For this reason, research in the past decade
has been directed toward defining the health impacts from lower concentrations
of a number of pollutants, arising from coal combustion with particular
emphasis on sulfur oxides. Animal studies have generally been of limited
value in defining chronic effects in special populations at risk, and thus
epidemiologic research has been extensive. A number of conclusions of these
studies can now be drawn (see e.g., summaries by Ferris (5) and Higgins
(6)).
1. Except for the London studies, research on the specific effects of
coal combustion effluents prior to 1970 cannot be relied upon to give any
quantitative estimates of risk, primarily because of inadequacies in the
air pollution measurements, and also because of confounding effects of
cigarette smoking and exposure to indoor pollutants.
2. Recent studies, both experimental and epidemiologic, have shown that
concentrations of sulfur dioxide, by Itself, in the range of less than 500
micrograms/m3 have no significant short-term effect on respiratory mechanics,
symptoms or disease.
3, If acid derivatives of sulfur dioxide, such as arise from chemical
reactions in stack plumes or during long-range transport of effluents,
contribute to health effects observed in population studies, their contribution
cannot as yet be isolated from the possible Influence of other elements in
37
-------
the suspended participates present in the alrbprne mix, such as oxides of
nitrogen (largely derived from combustion sources other than power plants),
and trace metals,
4. It has been possible to relate acute morbidity and mortality from
cardiovascular disease, but not respiratory disease, .to local concentrations
of total suspended particulates in the range of 300 yg/m3 or more (Mazumdar,
personal communication), and the recent analysis of New York mortality data
by Schimmel (7) suggests that excess total mortality is correlated with
suspended particulates, but not sulfur dioxide, in a reasonably dose-related
fashion. The fact that in this study respiratory disease mortality is much
less strongly correlated with airborne particulates, a phenomenon also
observed in the early London studies, strongly supports the view that cardio-
vascular disease, which accounts for most of the remaining non-cancer deaths,
is the principal cause of mortality associated with acute air pollution effects.
The biological mechanisms by which inhalation of airborne particulates in-
fluences cardiovascular disease mortality remain obscure,
5. The role of airborne irritants in exacerbating asthmatic attacks
has received some support from epidemiologic studies, but the particular
contribution of effluents from coal-burning is far from clear, especially
in view of the large number of irritants in addition to sulfur oxide derivatives
that are present in urban air, and the role of indoor pollution in such
studies. Some contribution of urban airborne particulates on morbidity and
mortality in severely affected asthmatic patients cannot be ruled out, but
there is no quantitative basis for assessing risk at this time.
6. From studies of lung cancer in occupational groups, such as coke-
oven workers, roofers, and gas-plant workers, exposed to high concentrations
of polynuclear aromatic hydrocarbons, it is evident that the concentrations
of these combustion products in urban air (about three orders of magnitude
lower than the concentrations present in the above occupations) cannot be
given any significance in excess rates of lung cancer in urban populations.
Weinberg (doctoral thesis, University of Pittsburgh, 1980) has shown that all
of the differences in lung cancer rates between census tracts of the Pittsburgh
metropolitan area, where considerable variations in coal-derived suspended
particulates exist, can be accounted for by differences in cigarette smoking
habits. One component of particulate effluents from coal combustion that has
not yet been evaluated for a role in urban lung cancer rates is radioactive
lead-210 and polonium-210, but at the present time the evidence indicates
that there is no association of urban air pollution, including coal-combustion
effluents, with excess lung cancer risk,
7. Contributions of sulfur oxide pollution to acid rain, visibility
reduction and corrosion of materials are outside the scope of this discussion.
In assessing the public health impacts of power plant stack emissions,
therefore, at current levels of pollution we are left with only the relation-
ship of gross airborne particulates to cardiovascular disease mortality as a
reasonably firm conclusion at this time. The contribution of sulfur emissions
38
-------
to this relationship is obscure, Allegations of much more significant health
impacts from urban air pollution, which are based on multiple regression
techniques, simply display the clear inadequacy of this method for evaluating
health effects in complex social groups where major confounding variables
such as cigarette smoking cannot be taken into account. Radioactive heavy
elements are part of the particulate phase from coal-fired plants, but
estimates of risk depend on their route of exposure to human populations.
For uranium, thorium and radium isotopes, ingestion from this source Is
negligible compared to normal soil sources of these elements In food. As
mentioned above, however, by the inhalation route particularly, Pb-210 and its
alpha-emitting granddaughter Po-210 could contribute to lung cancer risk, This
component of the radioactive emissions from coal-fired plants has not yet been
evaluated adequately,
My analysis of the recent data Indicates that cardiovascular disease
mortality (morbidity should reasonably closely correlate with mortality
for these diseases) is Increased by 5% with sustained exposure to airborne
parttculates at a concentration of about 350 yg/m3 • With a proportional
extrapolation to higher doses, this figure Is in reasonable agreement with
the earlier London data. We may now estimate the public health impact of
the usual concentrations of urban particulates, and the contribution of power"
plants, but only on the assumption that the fraction of urban particulate
pollution from coal-fired power plants contributes proportionally to these
effects. Until we know more about the mechanisms responsible for this relation-
ship, it is difficult to say whether this assumption leads to over- or under-
estimates of the role of power-plant emissions.
To apply the above risk relationship to usual population exposures to
suspended particulates which are no more than an annual average of about
100 yg/m3 for comparatively heavily polluted urban areas, some dose-response
relationship must be assumed, A more difficult problem is presented if one
assumes that peak concentrations are the primary factors contributing to
mortality, but because the assumption of an effect from sustained exposure
leads to higher risk estimates in general, it has been adopted. The linear
model can be applied to calculate excess risk by assumption of a background
exposure from non-combustion and industrial sources, which 1 take here to
be about 50 yg/m3,which is found in rural areas isolated from human activities,
and assumption of a value of 50 probably again will slightly overestimate
the risk.
Assumption of a straight-line dose-response model must be considered
the upper limit case because Internal exposure to cells from inhaled
particulates would be expected to be under biochemical influences that would
reduce the effects of low doses relative to higher doses. In particular,
these influences include intestinal and respiratory uptake and excretion,
as well as the toxic effects of cell interactions with the offending agents,
whatever they are.
39
-------
Calculations of health effects per 100Q MWe generation may be done as
follows:
The total cardiovascular mortality in the U, S, is about
600,000 per year. Exposure to particulates at levels of 100
Hg/m3 is estimated to be to no more than 1/2 the urban population,
which is 2/3 of the total U, S. population. On the basis of the
straight-line dose-response hypothesis,, if 5% increased risk
occurs at a sustained exposure to 350 pg/m3, or 300 wg/m3 above
background, at 100 ng/m3, or 50 yg/m3 above background, the in^
creased risk is 3^8" x 5% = 0,83%, But coal-fired power plants
contribute only part of the total urban particulate load, and I
assume for the ORBES region 1/5 for this purpose. The maximum
total excess cardiovascular mortality contributed per year by
coal-burning power plants is therefore:
600,000 x 1/3 x 0.0083 x 0,2 - 333 deaths
The maximum contribution per 1000 MWe per year, based on current
production of 110 GWe./yr from coal plants, is thus 3,0 deaths or
potentially lethal incident cases.
This estimate is clearly very uncertain, as the above assumptions attest,
but I believe it is a defensible upper limit based on current epidemiologic
evidence. The lower limit is zero, because the straight-line estimate of
dose response may well not hold at low doses, as defense mechanisms of the
body may be able to cope with low-dose exposures without any significant effect
on cardiovascular disease.
Although the upper limit estimate of risk to fhe general public is lower
than others have claimed, it is by no means negligible. Indeed, if subsequent
work supports a risk estimate close to the upper limit, it is evident that
this problem is the principal source of health impacts to the general public
from either the coal or nuclear cycles, a conclusion consistent with con-
ventional wisdom in this field.
Occupational Health Impacts
Disease specifically related to occupational exposures in coal^fired
plant workers has not been investigated. In conventional modern plants with
negative pressure coal feed, exposures to dusts and gases in the workplace
should be minimal. The possibility of exposure to fugitive dusts from coal
and waste storage exists, but their potential effects are unknown.
With regard to injuries among these workers, Rom, (8) reports that for
all power plants the fatality rate per 1000 MWe was estimated to be about
0.02 per year and injuries about 1,2 per year, It is not clear whether these
rates include transmission linemen; if they did, transmission line injuries
would account for a high percentage of the serious Injuries estimated for
power plant workers (see transmission section 4).
40
-------
Waste Disposal
Coal-fired power plants generate ash and scrubber sludge that must be
disposed of. Although some waste Is held temporarily in the plant area,
permanent disposal is to sites generally near the plants. Current plans
include use of slurry pipelines for transport. Although there is the
possibility of leaching of potentially hazardous wastes from storage areas
into water supplies, there is as yet no evidence of public health impacts
into water systems from power plant or waste effluents (9).
SUMMARY OF HEALTH IMPACTS FROM COAL CYCLE
It is evident from the above discussion that, in contrast to the nuclear
cycle, the coal cycle injuries' constitute major public health impacts for
both the general public and workers. While fatality rates from injuries can
be clearly assigned a public health importance, non-fatal injuries are some-
what more difficult to assess in quantitative terms. For example, an injury
that is associated with permanent disability, -such as. quadrlplegia, is obviously
comparable in its effects on the individuals involved as a fatality may be.
In contrast, a broken bone, which may require a long period of loss of work
capacity and thus be included as a serious injury, nevertheless may heal
completely with no permanent loss of function.
It is a remarkable fact that the ratios of serious lost-time injuries
to fatalities among most of the occupational groups discussed above is quite
constant at about 80 to 120. But most of these injuries, while significant,
produce public health impacts which are substantially less than a fatality
or permanently disabling Injury. Some adjustment is therefore required to
bring these relatively minor injuries into some sort of balance with the
more serious ones. On the assumption that occupational injuries are 100
times the fatality rate (a ratio that does not hold for motor vehicle or barge
accidents), if one assigns an arbitrary "coefficient of harm" to the range
of effects of injury, then it is possible to integrate these and produce a
total health impact estimate which is related to the fatality data. In what
follows I have used a range of 5 to 10 times the fatality rate as the total
non-fatal injury impact equivalent in terms of total health effects to a
fatality. It is apparent that on this basis, calculation of health impacts
based solely on fatality rates would seriously underestimate the total effect.
For those cases where the ratio of injury to fatalities is much lower than
100, I have used either the total injury rate or 5x the fatality rate,
whichever is less, to estimate the total health impacts.
41
-------
On the above assumptions we may summarize the health impacts of the
coal cycle:
Health Impacts per 1000 MWe/yr
from the Coal Cycle
Mining
Processing
Transportation
Power Plants
Waste disposal
Total
Current
General
Public
None known
None known
0.7 (injury)
0-3.0 (Cardio-
vascular disease)
None known
0.7-3.7
Occupational
5-9 (injury)
0.5 (CWP)
0.5 (Bronchitis)
0.3-0.5 (injury)
0.1-0.15 (injury)
0.1-0.2 (injury)
Negligible
6.5-10.9
Projected to year 2000
General
Public Occupational
2-5*
0.3*
0.2*
0.1-0.3*
0.4* 0.1*
0-1.5* 0.1
_
0.4-1.9* 2.8-6.0*
*0n assumption of a 50% reduction by control techniques.
Comparison of the health impacts from the coal and nuclear cycles leads
to the following conclusions:
1. Risks to the general public from the coal cycle are substantially
greater (currently by a factor of at least 50) than risks from normal operations
of the nuclear fuel cycle, per unit energy produced. This difference is due to
public health costs of coal transportation and the possibility of significant
health effects from coal-fired power plant stack emissions. If plutonium
recycle is adopted, and with improvement in transportation accidents and
stack emissions from coal-fired plants, the two cycles become more nearly
comparable.
2. Occupational health impacts from the coal cycle are about twice as
great for coal use as for the nuclear cycle, per unit energy production,
mainly due to the high costs in human health impacts estimated for coal
mining. Vigorous efforts should be made to reduce these Impacts for both
the cycles.
42
-------
REFERENCES
!• Coal Mine Injuries and Worktime. U.S. Mine Safety and Health Admini-
stration Report, 1978 p4.
2. Morgan, W.K.C. Industrial Bronchitis. Brit, J. Ind. Med. _285_:35, 1978.
3. Morris, S.C. Health Aspects of Fuel and Waste Transport. ORBES Symposium
on Energy and Human Health: Human Costs of Electric Power Generation.
U.S. Environmental Protection Agency, Washington, B.C., 1979, pp 260-284.
4- Summary of National Transportation Statistics. U.S. Dept. of Transportation
Yearly Reports, Washington, D.C. 1974-77. Also Statistical Abstract of the
U.S., 1979.
5. Ferris, B.C., Jr. Health Effects of Exposure to Low Levels of Regulated
Air Pollutants: A Critical Review. Journal of the Air Pollution Control
Association. 28:5, pp 482-497, 1978.
6. Higgins, I.T.T., Welch, K. and Classman, J. Epidemiological.Studies of Human
Health Effects. ORBES Symposium on Energy and Human Health: Human Costs
of Electric Power Generation. U. S. Environmental Protection Agency,
Washington, D.C., 1979, pp. 260-284.
7. Schimmel, H. Evidence for Possible Acute Health Effects of Ambient Air
Pollution from Time Series Analysis. Bull. N.Y. Acad. Sci. 54:1052-1108,
1978.
8. Rom, W.N. Occupational Health Aspects of Fossil-Fuel Electric Power Plants.
ORBES Symposium on Energy and Human Health: Human Costs of Electric Power
Generation. U.S. Environmental Protection Agency, Washington, D.C., 1979,
pp 221-245.
9. Andelman, J.B. Human Exposures to Waterborne Pollutants from Coal-fired
Steam Electric Plants. ORBES Symposium on Energy and Human Health: Human
Costs of Electric Power Generation. U.S. Environmental Protection Agency
Washington, D.C, 1979, pp 195-220.
43
-------
SECTION 4
POWER TRANSMISSION AND ITS HEALTH EFFECTS
Power transmission is common to all kinds of electric power generation
and fuel types. Electricity is transmitted by alternating current at both
high and low voltages, high voltages being used for energy transfer for long
distances from a generating source to a population center. Lower voltages
are used within the population center to distribute electricity to individual
consumers. The effects of electricity carried in wires are electric and
magnetic fields, and corona effect around the transmission lines. In con-
sidering health effects, risks occur to the general public from exposure to
the above fields, as well as accidental injury or death from broken or falling
transmission lines as a result of wind or ice damage, earthquakes, etc.
Occupational hazards also exist from working closer to the lines, not only
to the electromagnetic fields but also from direct contact with high-voltage
terminals or other low-resistance pathways.
The transmission of electricity from a remote generating source to load
centers is accomplished by means of Extremely High Voltage (EHV) lines. EHV
levels vary from 230-800 kilovolts (kV). There are advantages to the use of
higher voltages within this range. For example, one 765 kV line has the
equivalent load carrying capability of five 345 kV lines and its right-of-way
requires 145 feet less. With the growth of electric power consumption, the
trend has been to use higher voltage transmission. As of January 1, 1970, the
circuit miles of AC EHV lines existing in the United States are as in Table 9.
Accurate measurements of the induced currents and power absorbed by a
human body from the electromagnetic fields around power lines have been
difficult to obtain. Electric field measurements provide the basis for
calculating the induced human body current from transmission lines. Practical
measurements with a dosimeter show much lower electric field exposure than
that calculated on the basis of the maximum field in a work area. Power
frequency currents are induced in the body of people who are in the presence
of the electric field produced by high voltage transmission lines and sub-
stations. Over flat ground the electric field is vertical and uniform over
the dimensions of a human being (1), The electric field is not uniform close
to non-flat boundaries like vehicles, towers, trees, bushes, and transformers.
The induction field or uniform electric field produced in a human being
whose head is 1.76 meters above ground and is walking occasionally through
a 20 kV/m field is 5.75 kV/m and corresponds to a space potential of 10 kV
44
-------
TABLE 9
CIRCUIT MILES OF HIGH VOLTAGE TRANSMISSION LINES IN
U.S., 1970
Voltage Levels (kV) Approx. Circuit Miles
230 1420
287 1020
345 14070
500 6840
700 (765) 66
45
-------
at the center of the head and the induced current is about 35 microamperes
(uA). The body current perception level is about 1000 yA and is larger than
the calculated total induced current in either a man on the ground or a line-
man. The electric field recognition level and corona (ozone) forming level
are 236 Kv/m and 1968 kV/m respectively (2).
Environmental Mortality and Morbidity
Electrical accidents not directly related to linemen working in the trans-
mission industry account for no more than 4% of all fatal accidents and 0.4%
of all non-fatal accidents. Statistics for 1962 submitted to the International
Symposium on Electrical Accidents showed that of 1118 electrical fatalities,
40% involved high voltages. Of the low voltage fatalities, 43% were industrial,
17% were agricultural, and 39% were domestic. Most HV accidents are occupa-
tionally related to electrical generation, transmission, or distribution;
while more than half of the low voltage deaths occur during use of portable
electrical equipment. Thus the exposure of the general public to Injury from
transmission line failures is very low.
Reviews of the biological effects of high voltage electric fields have
been published. Four studies on short-term exposures to electrical fields
involved the medical treatment experience of people living within 25 meters
of a transmission line, the experience of farm workers on 18 farms traversed
by a 765 kV line, and a physiologic state study involving lineworkers inter-
mittently exposed to intense electric fields during maintenance work. No
immediate, acute, or permanent effects were found; however, only 2 of these
studies looked at long-term exposure (3).
In contrast, studies on workers exposed to electric fields in Soviet
and Spanish high-voltage switchyards report effects such as excitability,
headaches, drowsiness, fatigue, and nausea, but these effects may be related
more to acoustical noise in the switchyard environment.
No immediate or acute effects were noted in laboratory animals exposed
to electric fields. A small reduction in weight gain was observed in the
progeny of mice exposed to intense fields (100 kV/m), and there was evidence
of behavioral changes. Cell-mediated immunity changes were reported for
rodents exposed to intense fields up to 100 kV/m (3).
Corona Effects
Corona is an electrical discharge occurring at the surface of a trans-
mission line conductor when the electric field intensity at the surface of
the conductor exceeds the breakdown strength of the air. Corona effects
associated with transmission lines could generate ozone and nitrogen oxides.
According to one study, emissions due to a 765 kV line would result in
concentrations of 2 to 3 ppb of ozone not to be exceeded more than one hour
per year. Ozone is believed to produce adverse health effects at about 100
ppb, but the effects of exposure to 2-3 ppb over a long period of time are
46
-------
unknown. On a linear dose-response hypothesis, the effects should be
negligible. Nitrogen oxide would be at about the same concentration as
ozone, also considerably below concentrations at which any effects would
occur.
On the basis of the above data, the conclusion seems warranted that
health effects to the general public from electric transmission are not
yet demonstrated, and in any case are likely to be negligible in relation to
the hazards from parts of the electric power generating system and the fuel
cycles on which it depends.
Occupational Risks: Injury
Persons employed in electrical generation, transmission, and
distribution are exposed to additional hazards as well as the normal work
exposure of falls, lifting, etc. Many electrical accidents involve contact
with A.C. 50 or 60 Hertz currents and most high-voltage accidents are
occupationally related. Since linemen working on high and low voltage
distribution equipment are working at elevated height, many electrical
accidents cause severe injuries as a shock causes the body to involuntarily
react and the worker falls from a pylon.
The various effects of accidental contact with electric currents include
asphyxia from respiratory arrest caused when the electric current passes
through the head. Very few of these accidents are fatal, since the head is
not a common path for the current to take. Ventricular fibrillation occurs
less when the current is over several amperes, so victims of HV accidents
often survive, though severely burned. Electric burns and flash burns occur
from HV accidents. Finally, secondary effects, such as angina electrlca,
are clinically undistinguishable from angina pectoris, but clear up after a
few months; chromoproteinuria and renal function disturbances and various
neurological sequelae have been described (4).
Analysis of the injury and illness rates for the electrical industry
in 1974 showed no difference from industrial experience as a whole, but in
1976 the death rate for all industries was 14 per 100,000 workers, while
for Transportation and Public Utilities was 31 per 100,000, How much of this
excess was related to transmission-line workers is not clear,
In a study done by the Society of Actuaries in 1967, mortality ratios
and extra deaths were calculated for occupations considered substandard
by most companies for either life insurance or accidental death benefits;
other occupations were included if there was reason to expect mortality
somewhat above that for standard risks. Based on U, S. Bureau of Labor
Statistics data for 1963 on-job occupational deaths, the on-job accidental
rate for employed persons is 0.15 per 1000. The Standardized Mortality
Ratio for violent deaths among transmission workers was 243 for non-climbing
workers, but 425 for climbing workers. Thus the excess mortality for
climbing linemen is about 0.27 per 1000. On the assumption that serious
injuries could be four times the mortality, total injury would be about
1 per 1000 workers/yr.
47
-------
To determine possible long-term health effects of electric fields, a
medical follow-up study of high voltage linemen working in AC electric fields
over a period of nine years was carried out. No disease states which could
be in any way related to HV line exposure were found-. Examinations consisted
of complete medical history, physical, hemotological and blood chemistry
studies, thyroid test, kidney and liver function tests, electrocardiograms,
electroencephalograms, hearing test, x-rays, sperm count, and psychiatric
evaluation. This is relatively short exposure, however, and the end points
studied were non-specific.
It is difficult to convert occupational risks from injuries to a nominal
plant requirement, but from Bureau of Labor Statistics about 100 line workers
are required per 1000 MWe generation plant. On this basis, the risk per
1000 MWe/yr is about 0.1 serious injury per year per nominal plant.
48
-------
REFERENCES
1. Deno, D. W. Currents Induced in the Human Body by High Voltage Transmission
Line Electric Fields—Measurement and Calculation of Distribution of Dose.
IEEE Transactions on Power Apparatus and Systems. Vol PAS-96 No. 5
Sept/Oct 1977, pp 1517-1527.
2. Spiegel, R.J. High Voltage Electric Field Coupling to Humans Using Moment
Method Techniques. Biological Effects of Electromagnetic Waves. Vol.11
HEW 77-8011, U.S. Govt Printing Off., Washington, B.C., 1975.
3. Task Force Report, National Institute of Environmental Health Sciences.
Env. Health Perspectives ^0:0ctober, 1977.
4. Electricity—physiology, pathology. In Encyclopedia of Occupational
Health and Safety, Vol I, Int. Labor Org. Geneva, 1971, pp 449-451.
49
------- |