United
Environmcnt.il Prut
Agt-i
  of Radiation Programs
   . Facility
PO Box 18416
Las Vegas NV 89114
EPA 520 6 82 021
November 1982
Radi
Emissions Of Naturally
Occurring Radioactivity:
Monsanto Elemental
Phosphorus Plant

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                                                     EPA-520/6-82-021
                                                     November  1982
 EMISSIONS OF NATURALLY OCCURRING RADIOACTIVITY FROM
         MONSANTO ELEMENTAL PHOSPHORUS PLANT
                  Vernon E. Andrews
             Office  of  Radiation Programs
         U.S. Environmental  Protection  Agency
               Las Vegas, Nevada 89114
                   Project Officer

                       Tom Bibb
      Emission  Standards  and  Engineering  Division
         U.S. Environmental  Protection Agency
     Research Triangle Park,  North Carolina 27711
  This  report  was  prepared  with  the  technical  support
of Engineering-Science Inc. under contract 68-02-2815,
   Office of Radiation Programs - Las Vegas Facility
         U.S. Environmental Protection Agency
               Las Vegas, Nevada  89114

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                                  DISCLAIMER


    This report has been reviewed by the Office of Radiation Programs-Las Vegas
Facility,  U.S.  Environmental  Protection  Agency.   Mention  of  trade names  or
commercial  products constitutes  neither  endorsement  nor  recommendation  for
their use.

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                                   FORWARD


    The Office of Radiation Programs  (ORP)  of the U.S.  Environmental  Protection
Agency (EPA) conducts a  national  program for evaluating exposure of humans  to
ionizing and nonionizing radiation.   The goal of this program is to  develop  and
promote protective controls necessary to ensure the public health and safety.

    In response  to the  1977  amendments to  the Clean  Air Act  the Las  Vegas
Facility was given the responsibility to collect field data on emissions to  the
atmosphere  of  natural  radioactivity  from  operations  involved  in the  mining,
milling, and smelting of minerals other  than  uranium and  coal.   This report is
one of a  series  which  describes  an  individual  facility  and   its  associated
radioactive emissions.

    ORP encourages readers of the report to inform the Director, ORP-Las Vegas
Facility, of any omissions or errors.  Comments or requests for further infor-
mation are also invited.
                                       Wayne A. Bliss
                                       Acting Director
                                       Office of Radiation Programs
                                       Las Vegas Facility
                                      iii

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                                   CONTENTS


                                                                           Page

Forward	ii"j
Figures	vi
Tables	vi
Abbreviations and Symbols 	 vii

    1.  Background	   1
    2.  Introduction  	   3
    3.  Summary	   4
    4.  Plant Operations  	   5
            Production Process  	   5
            Airborne Emission Sources 	   7
    5.  Sample Collection and Analysis  	   9
            Sample Collection 	   9
            Sample Analysis 	   9
            Data Reporting	10
    6.  Sample Results	11
            Process Samples 	  11
            Ambient Air  Samples	14
            Emission Samples  	  14
    7.  Discussion of Results	26

References	27

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                                    FIGURES
Number
                                                                           Page
  1  uranium and Thorium Radioactivity Decay Schemes ...........    2
  2  Monsanto Chemical  Plant Flow Diagram  ................    6
                                    TABLES
                                                                           Page
  1   Radioactivity Concentrations  in Process Materials  ..........  12
  2   Ambient Radon-222 Concentrations   ..................  15
  3   Ambient and Stack Particulate Radioactivity Concentrations   .....  16
  4   Radon-222 Stack Emissions ......................  18
  5   Stack Flow and Particulate Emission Rates ..............  20
  6   Particulate Radioactivity Emission Rates  ..............  21
  7  Particulate Radioactivity Annual Emission Rates ...........  23
 8  Aerodynamic Particle Size Distribution  ...............  25
                                     vi

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                      LIST OF ABBREVIATIONS AND SYMBOLS
ABBREVIATIONS

Ci          — curies:   3.7x10^ disintegration  per  second
Ci/y        — curies per year
kg/h        — kilograms per hour
km          — kilometer
mci/y       — millicuries (10~3Ci)  per year
nCi/m^      — nano (10~^Ci) curie per cubic meter
pCi/g       — picocuries (10~12Ci)  per gram
pCi/1       — picocuries per liter
pCi/m^      — picocuries per cubic  meter
ppm         — parts per million
TSP         — total suspended particulates
vm          — micrometer: 10~^meters
SYMBOLS

CO          — carbon monoxide
E-S         — Engineering Science, Inc.
EIC         — Eberline Instrument Company
FeP         — ferrophosphorus
                                      vi i

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                                  SECTION 1


                                  BACKGROUND
    The Clean Air  Act,  as amended in  August  1977, required the  Administrator
of the Environmental Protection Agency  (EPA) to  determine whether  emissions  of
radionuclides into ambient air should be regulated under the Act.   In  December
1979  the  Administrator  listed  radionuclides  as  a hazardous  pollutant  under
Section 112 of the Clean Air Act.

    The naturally occurring radionuclides most likely to be  emitted in signif-
icant  quantities  are  those  in the  uranium-238   and  thorium-232  decay  series
(Figure 1).   These radionuclides  and  their  daughter  products occur  naturally
in widely  varying amounts  in  the soils  and rocks  that make  up  the  earth's
crust.  Average  values for uranium-238 and  thorium-232 in soils  are  approxi-
mately 1.8 ppm  (0.6  pCi/g)  and  9  ppm (1 pCi/g)  respectively  (1).    The radio-
activity concentration  of each  of the daughter  products  in  the  two  series  is
approximately equal to that of the uranium-238 or thorium-232 parent.

    Almost all  operations involving  removal  and  processing of  soils  and rocks
release  some of  these  radionuclides  into  the  air.   These  releases  become
potentially  important  when the materials  being   handled  contain  above-average
radionuclide concentrations  or  when  processing  concentrates  the  radionuclides
significantly above the average amounts in soils  and rocks.

    Because mining and  milling  operations  involve large quantities of ore, and
because there  is little  information  about how  these  activities release radio
active emissions, EPA, in 1978, began to measure  airborne radioactive emissions
from  various mining, milling, and smelting operations.

    Operations were selected for  study on  the  basis  of their potential to emit
significant  quantities  of naturally  occurring  radionuclides  to the atmosphere.
Some  of  the  factors in  the  selection  included typical mine  size, annual U.S.
production,  measured working  levels  of radon  daughters in  underground mines
and  associated  ventilation  rates,  production rate  and process  of individual
facilities,  and previous  association  with naturally  occurring radionuclides.
Usually, we  chose  to look at large facilities in order to improve the  chances
of   obtaining   emission  samples   with  radioactivity  contents   significantly
greater than background.

     These  surveys  were  screening  studies  designed  to  identify  potentially
important  sources  of  emissions   of  radionuclides   into  the  air.   Any such
sources  can  then be studied  in detail to determine whether  or  not a  national
emission standard  for  hazardous pollutants is  needed  under the  Clean  Air Act.

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             URANIUM - 238 DECAY SERIES
THORIUM - 232 DECAY SERIES
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                                  SECTION 2


                                 INTRODUCTION
    As early  as 1908  it  was recognized  that phosphate  rock contained  above
normal concentrations  of  uranium and thorium  (2).   Those concentrations  have
been  observed  in the  United States to  range from  8  to 399  ppm (2.7 to  133
oCi/g) of uranium-238  and 2  to  19  ppm  (0.22  to 2.1  pCi/g) of  thorium-232  (3).
South  Carolina  ores  had  the  highest  concentrations,  while  the lowest  were
found in Tennessee.  During  the  1950's uranium was  recovered  as  a byproduct of
phosphate production.

    Since  1974  the  EPA  has  studied  various  aspects  of  the  radioactivity
released  to plant  environs  during  benefication and  processing  of  phosphate
ores   The  EPA had conducted a  comprehensive radiological survey of  a thermal
nhosphate  (elemental  phosphorus)  plant  in 1974  (4).   However,  problems  with
the analysis of lead-210  had greatly reduced the  accuracy  of the measurements
of both  lead-210 and  polonium-210.  Under  the added emphasis  provided by the
Clean  Air  Act  Amendments   the  decision was  made  to  include  at   least  two
elemental   phosphorus  plants  in  this   series  of   surveys.   The two plants
selected  were  the  Stauffer  Chemical Company plant  in  Silver  Bow, Montana, and
the  Monsanto  Company  plant  in  Columbia, Tennessee.  This  report presents the
results of  the Monsanto facility survey.

    Engineering-Science,  Inc.  (E-S) under contract with the EPA,  conducted the
survey  and  collected samples (5).   Representatives  of  E-S  and EPA visited the
niant before  the  survey to  select sampling   locations.   During  the period
December  4-14, 1979, E-S, accompanied by an  EPA representative,  conducted the
^amoling  and  measurement program.   E-S  collected particulate  and gas samples
from   plant emissions and   ambient  air as  well  as  information   on   plant
operations.  A meteorology  station was  installed at the  ambient  air  monitoring
location.

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                                   SECTION 3


                                    SUMMARY
    Engineering  Science,  Inc.  (E-S)  collected  participate and gaseous emission
samples  from the major  emission points  at  the  Columbia,  Tennessee  plant  of
Monsanto.   Where more  than one stack  served a  process only  one  stack  was
sampled.   Ambient participate  and gaseous samples  were  collected at  a  site 2
km northwest of  the plant.

    The  thorium  decay  chain  radionuclides,  thorium-232  and  -228,  were found at
normal background levels  in  ore  and  emission  samples.   The  uranium decay chain
radionuclides averaged  3.4  pCi/g in Tennessee ores  and  47  pCi/g  in  ores from
Florida.

    Kiln exhaust stacks  were the major point  of  release  of  radioactivity from
the  plant.   Radon   emissions   from  the  kilns   totaled  9.6  Ci/y.   Lead-210
emissions  from  the kilns   were 0.48  Ci/y  and   polpnium-210  emissions  were
0.75 Ci/y.   These  were  probably  all  released  primarily  from  the  molten
materials  in the furnaces and carried to the  kilns along with the CO used as
fuel.

    Except  for  one  source,  the  non-volatile  nuclides,  uranium-238  and -234,
thorium-230,  and radium-226,   produced   annual   releases  of  these  nuclides,
averaging 0.24 to 1.5 mCi.   The  screening plant  dust collectors were estimated
to  release an  average  of   7.2  mCi/y of each  of  these nuclides.   Possible
non-operation of a  scrubber  on  the  discharge  may be the  reason  for  the higher
emissions  from  this source  which accounted  for  over half  of the 13  mCi/y of
each nuclide released from all sources at the plant.

    The majority of the  suspended particulates emitted were  found  to be above
the respirable size range.   This probably holds,  as well, for the non-volatile
radionuclides.

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                                  SECTION 4


                               PLANT OPERATIONS
PRODUCTION PROCESS


    The  Monsanto  Company  plant  is  located  approximately  10  km northwest  of
Columbia, Tennessee.  Most  of  the ore comes from  strip mines in the  vicinity
of the plant, but part of the ore  is  shipped from  Florida.   The  plant  produces
elemental phosphorus.   Ferrophosphorus  (FeP)  is  an important by-product.   At
the time of the survey a portion of the slag produced was sold as an aggregate.

    Figure  2  is  a  schematic of  the plant  operation.   Concentrates  from  the
washer and dust collected from the  kilns  and  screening  plant are stockpiled in
an open,  raw  materials  craneway.  From here the  materials  are sent to  one of
two  stockpiles.   As  one  stockpile is  built  up -  taking  about  1  week  -  the
other  supplies  the  kiln.   Ores  from  various  sources are initially blended by
the  stockpiling  process in  the  craneway  and  are  further blended  by  the kiln
feed operation.

     It   is  necessary to   form   the  finely  divided  ore into   larger,   stable
agglomerates  for  proper operation  of the reduction furnaces.   This is  accom-
plished  by  passing the ore through three rotary  kilns.  The kilns raise the
ore  temperature  to  its  incipient  melting point and the tumbling action forms
it  into  the  desired  nodular form.  The  hot  nodules pass  through  coolers and
are  conveyed by  a  series of  conveyors  to  the  nodule storage  craneway.   A
clamshell bucket  on  an overhead  crane  moves  the nodules to storage bins  from
which  they  pass  through the screening plant on their way to the burden  scales
and  on to the furnace stocking system.   At the burden  scales  coke   is added to
serve  as the reducing agent  and  silica and  lime are  added,   as  needed, to
achieve  the  necessary  balance  of calcium and  silicon  to  form  a proper slag.
The  approximate  reaction  in the  furnace is:

              2  Ca3(P04)2  + 10  C  + 6 SiO£  —*?4 +  10 CO  + 6  CaSiOs

     In addition, the iron  naturally  present  in  ore  reacts with  some   of  the
phosphorus  to produce FeP.  The  blended  furnace  feed enters the furnaces  con-
tinually from the top  and  progresses downward until reaching the  molten layer
on  the  bottom.   Phosphorus and  carbon monoxide  (CO)  are  driven off as gases
 and are  vented  near the  top  of  the  furnace.   The  slag and  FeP which  are
continually  collecting in  the furnace are  periodically "tapped off."   Molten
 slag is  carried  by bucket  to  a dump.   Front-end  loaders  transfer the  cooled
 slag to  a  storage  pile.   At the time  of the  survey,  slag  was  being  sold  from
 storage for use as aggregate.

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                                                                LEGEND

                                                             HM  DAWMATERItl-S
                                                            —«-  PROCESS MAttRlAl FLOW
                                                            —-^ GAS FLOW
                                                            (T)  STACK SAMPLE POINT
FIGURE  2.  MONSANTO CHEMICAL  PLANT  FLOW DIAGRAM

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    Furnace off-gases  pass  through dust  collectors  then  through  water  spray
condensers.  Phosphorus is cooled  to  the  molten state in  the condensers.   The
mix of phosphorus and water  - phossy water - and mud go  to a  processing  system
where phosphorus is separated and  piped to storage.  The clean  off-gases  leav-
ing the condensers contain a high  concentration of CO  and are used as fuel  in
the kilns to supplement the  coal fuel.


AIRBORNE EMISSION SOURCES


    The  Monsanto emission  inventory  includes  54  controlled and  uncontrolled
sources.   Thirty-one  sources   treat  emissions  from   coke handling,  boilers,
short-term  intermittent  operations,  or  emergency  release  emissions.   Open
sources,  such  as  craneways  and  open-belt  conveyors  are not  easily  sampled.
Eight  stacks were  selected  as representing  the  important  emission  sources
based on reported mass emission rates or process involved.   These sources are
shown in Figure  2, keyed to the following descriptions.


Kilns (1)

    The  three  kilns   discharge  emissions through  individual  dust  collection
chambers  and  spray  scrubbers.  Lime  is added  to the  scrubber  spray  to aid in
removal  of fluorine  and sulfur dioxide.  Entrained water in  the exhaust  gases
is  removed in  two demister  stacks.   One  demister stack serves emissions  from
kilns  1 and 2.   The  other  demister  stack  serves kiln  3.   The 5.4-m diameter
stack discharges about 35 m above ground  level.  An existing Monsanto sampling
system  was used  to collect samples from the top of the stack  serving kiln  3.


Nodule  Coolers  (2)

     Each  nodule  cooler has  an emission control  system  and discharge  stack.
Emissions  are controlled by jet  eductors.   The exhaust stack on  the  nodule
cooler  at  kiln 3  was  sampled.   Samples were collected  on  both  inlet   and
exhaust of  the jet  eductor  to  determine  the  fraction removed.   The  4.4-m
diameter stack  discharges 25 m above  ground.


 Nodule  Transfer Points (3)

     Particulate emissions from the  screening  plant  operations are  controlled
by three "Type  R" rotoclones composed of  nine "clones" each.   "Type  R"  roto-
 clones  combine  water scrubbing with multiclone separation.   For purposes  of
 this survey  the screening  plant  dust collectors were  identified by  emission
 source.   One  dust  collector  served the nodule  transfer  points on  the  pan
 conveyors.  The others controlled emissions  from other screening plant points.
 Nodules from the coolers are diverted at several points to other  conveyors for
 delivery to multiple entires into the nodule storage craneway.  Dusts generated
 at  these  transfer points  are  collected by  hooding  systems  and treated for
 removal  of particulates by a "Type  R" rotoclone.   The  1-m diameter  stack
 discharges at a height of 29 m.

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  Screening Plant Dust Collector (4)

      Two dust collectors  control  emissions from the screening plant other  than
  the nodule  transfer  points.   The  two  "Type R"  rotoclone  dust  collectors  and
  their emissions are essentially identical  so only one  source was  sampled    Test
  results indicated  that  the  water to  the  rotoclone  was  off  during  testing
  This has been  corrected  by Monsanto.   The  1-m  diameter  stack  discharges at
  height of  29 m.                                                       s
a
  South Scale Room Dust Collector  (5)

      Nodules,  coke, and  silica  are weighed  and  fed into  the furnace stocking
  system by means of weighing  belt  conveyors.  Two dust  control  systems  are in
  use in this area.  The south scale room  Luhr  baghouse dust collector controls
  emissions  from  the area  where nodules are weighed.   Because of the dissimilar-
  ity of the emissions  this was considered to  be a  single  stack source. The other
  stack was  not sampled.   The 0.9-m  diameter stack  exhausts  at a height of 13 m.


  Stocking System  Belt  Dust Collector (6)

      The stocking  system  belt  conveyor moves the  blended  furnace  feed from the
  scale room to  the furnace stocking system.   The conveyor  and  transfer  points
  are  hooded and  particulate  emissions are controlled  by  two  similar systems
  une  stack   was  selected  as   representative  of  the two  stacks.   Particulate
  emissions  are  controlled  by a  Luhr  baghouse   dust  collector.   The  0.75-m
  diameter stack discharges at a height  of 21 m.


 Central Furnace Stocking System (7)

     The stocking  system belt conveyor  transfers furnace  feed  to the  central
 furnace stocking system.  From there,  three  pivoting belt conveyors  stock  the
 six furnace stocking bins.   Emissions from the central furnace  stocking  system
 are  controlled  by  a  Buell   bag  dust  collector.   The  0.9-m  diameter   stack
 exhausts at a height  of 48 m.


 Furnace Taphole  Fume  Collector (8)

     Each  of the six furnaces  has  a hood, emission  control system,  and  stack.
 Slag  is tapped from  each furnace  for 20  to 25  minutes  with  approximately 20
 minutes  between  taps.  Ferrophosphorus  is  tapped once or twice daily.  Fumes
 in  the stack effluent  are  controlled  by  a  venturi   scrubber.   The  stacks are
 1.1 m in diameter  and  discharge at  a height of 38  m.


 Other  Sampling Points

    In  addition  to the  eight  controlled  sources   sampled,  high-volume  air
samplers were operated near the slag dump  and adjacent  to the Florida ore rail
car  dump  and stockpile.  The  Florida  ore  pile  is  located close to  the slaq
storage pile.

                                       8

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                                  SECTION 5


                        SAMPLE COLLECTION AND ANALYSIS
SAMPLE COLLECTION


    Most  stack  samples  were  collected  using   EPA   reference  methods   for
stationary sources  (6).   Stack  sampling  points were selected according  to  EPA
Method  1,  Sample  and  Velocity Traverses  for  Stationary  Sources.   Stack  gas
velocity and volumetric flow rate were determined by EPA Method  2,  Determina-
tion of Stack Gas  Velocity  and  Volumetric  Flow Rate (Type S  pilot  tube).   Gas
samples for radon-222 analysis were collected  using  EPA Method  3,  Gas  Analysis
for  Carbon  Dioxide,  Oxygen,  Excess   Air,  and  Dry Molecular  Weight.   Total
suspended particulates  (TSP) in ducts  and  exhaust  stacks were determined using
EPA Method  5,  Determination of Particulate Emissions  from  Stationary  Sources,
or  EPA Method  17,  Determination  of Particulate  Emissions  from  Stationary
Sources  (In-stack  Filtration Method).   High  volume ambient  TSP samples  were
collected  in accordance  with  the  Reference  Method for the Determination of
Suspended Particulates  in the Atmosphere (7).

    E-S collected  Method  5  TSP  samples on  7.6-cm (3-inch) diameter glass fiber
filters and  Method 17  TSP samples on  5-  by 12.7-cm  (2- by  5-inch)  glass fiber
filters.   Ambient  TSP  samples  were  collected on  20.3-  by  25.4-cm  (8- by
10-inch)  Microsorban  polystyrene fiber  filters.   Stack gas  and  ambient whole
air samples for radon analysis were collected  in 30-liter Tedlar bags.

    E-S  sampled  each of  the emission points  described in Section  4-B.   They
collected  two  to  four  samples  each  of  TSP  and  gas samples from  each point.
Two  samples  were  collected  simultaneously  on  the   south  scale  room   dust
collector   stack   as   part   of   the  quality  assurance  program.   Two  size-
fractionated samples  were collected  from  each of the  sources  except  the  kiln
demister, nodule cooler,  and furnace  taphole fume  scrubber.

    Samples  of   process   materials  were   collected  to  relate  radionuclide
emission  rates  to the  radioactivity  of  the  material  handled  at each  emission
point  and  to permit a radionuclide  balance through  the process.


SAMPLE ANALYSIS


     E-S made  mass determinations  on TSP samples  before forwarding them  to
Eberline  Instrument Corporation (EIC) for  radiochemical analysis.   Stack and

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 ambient  gas  samples  were  shipped   to  EIC  for  arrival  within  2  days  of
 collection.


     EIC analyzed process  and  TSP samples by  dissolving  the samples  and  sepa-
 rating the elements of interest  by chemical techniques.   The  separated  uranium
 and thorium fractions  were counted  on alpha spectrometers  for  individual  iso-
 topic  quantisation.   An  alpha   scintillation  counter measured  the  polonium-
 210.  Lead was separated and set aside for about 2 weeks  to allow  for ingrowth
 of bismuth-210  from  lead-210.   After the ingrowth  period  the bismuth-210 was
 separated from the lead and was  counted  on  a  beta counter  to quantitate  lead-
 210.   Radium  was  separated and  enclosed as  a  solution  in a  sealed tube  to
 allow for  ingrowth  of  radon from radium-226.   After 3 weeks  of  ingrowth the
 radon  gas  was evolved  and collected  in an  alpha  scintillation  cell  to  be
 counted.   Stack and  ambient gas samples were  transferred to  alpha  scintilla-
 tion cells and counted  for radon.


 DATA REPORTING


     The radioactivity reported  for each  sample,  is  the net radioactivity plus
 or   minus  twice  the  standard   deviation due  to  counting statistics.   Net
 radioactivity  is the gross  sample  radioactivity minus the  counting  equipment
 background  and minus either a)  for  filter samples,  an average  value for the
 radioactivity  content  of  a  blank filter, or b)  for  stack  radon samples, the
 ambient  radon  concentration.  The  standard  deviation is  based  only  on the
 random  variations inherent in radioactivity  counting  and  is propagated  through
 the  various  steps  to  the  final result.   This  random   variation,   plus  the
 variable radioactivity  content of individual  filters,  occasionally results  in
 a  net  radioactivity  of less  than  zero.   Of  course,  there   is  no  negative
 radioactivity.   In  these  cases,   as  with all  others,  the  net  result must  be
considered  along  with  the  standard  deviation.   Averages  of multiple samples
 from a  source  are given with a  standard  deviation due  to  counting  statistics.
This uncertainty is  propagated from the sample  standard deviations.
                                     10

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                                  SECTION 6


                                SAMPLE  RESULTS
PROCESS SAMPLES


        Process sample radioactivity concentrations are given in Table 1.   Ore
from  the  six   Tennessee  sources  had  similar  radioactivity  contents.    The
average  concentration  of  uranium decay  chain  radionuclides was  3.4  pCi/g.
Tailings solids  averaged  3.0  pCi/g.   The washed  ore kiln  feed  averaged  4.0
pCi/g  in the  1st shift sample  and  6.6 pCi/g  in the  2nd  shift sample.   This
indicates that the uranium  and  its  decay  products are more  closely  associated
with the phosphate ore  than with the barren  fines.   As expected, Florida  ore
had a higher radioactivity  content with uranium  decay chain  nuclides averaging
47  pCi/g.   Thorium  decay  chain  nuclide  concentrations of  about 1 pCi/g  in
Tennessee  ores  and  0.5  pCi/g  in  kiln feed  were in  the range  expected  for
normal  rock.   Thorium-232  and -228  were  at normal  concentrations   in ore  and
were generally  not found  at levels significantly different  from  background in
emission samples.  Therefore,  the remainder of  the  sample  results  discussion
will include only  uranium  decay chain nuclides.  Thorium-232 and  -228 results
are included in the data tables, however.

    Nodule samples were collected from the  conveyor  belt  and from the craneway
storage  area  at the  same  time  as  the  1st shift  kiln feed  samples.   Nodules
from the conveyor  had  an  average radionuclide concentration  of 7.4  pCi/g, not
including  the  more   volatile  polonium-210.   The  craneway  composite  sample
averaged 3.5  pCi/g for the same nuclides.   The differences  in concentrations
in  the kiln  feed  and  nodule samples  is probably  due  to  some  inhomogeneity
resulting  from  blending  of  Tennessee  and  Florida  ores.    Although  blending
provides large  scale homogeneity sufficient  for production, it  apparently is
not complete on the small scale of a sample prepared for analysis.

    Coal,  coke,  and  silica  all  had  normal,  background  concentrations  of
radioactivity.   Slag and   FeP  had   approximately  the  same   concentrations  of
uranium, however,  about 90  percent of the total  uranium was  in  slag  due to the
relative amounts produced.   Thorium from  both  decay  chains was  found primarily
in  slag,  as  was  radium.   Lead-210  and polonium-210  were found   in  higher
concentrations  in  the  FeP  (3.9 ± 0.5 and 1.0 ± 0.9 pCi/g) than in  slag (1.5 ±
0.5  and <0.8  pCi/g).   Most of the  lead-210 and  polonium-210 originally in the
ore, however,  is volatilized in  the kiln.   The kiln  emission  control systems
show high  concentrations of these isotopes  in their discharge water.
                                       11

-------
                                  TABLE  1.   RADIOACTIVITY CONCENTRATIONS  IN PROCESS MATERIALS
                                                                Radlonuclide Concentrations (pCi/g)
rv>
Sample
Ore-WcEvens Muck
Ore-Paisley Muck
Ore-Henson's Muck
Ore-Kincaid Tract
Ore-Gilbert's
Ore-Jones Tract
Average
Ore Washer Tailings
Water (pCi/1)
Ore Washer Tailings
Suspended Solids
Ore-Florida ftockb
Ore-Florida Stockpile
Florida Ore Average
Kiln 3 Feed, 1st Shift6
Kiln 3 Feed, 2nd Shiftb
Kiln 3 Feed Average
Nodules'1
Craneway Nodules
Compos i te°
Coal - Kiln Fuel
Silcab
Coke
Slagb
(continued)
U-238
2.6
2.2
2.7
3.2
2.7
2.5
2.7
1.2
3.1
39
46
43
3.5
6.3
4.9
7.5
2.8
0.49
0.32
0.42
11

4 0.4
* 0.3
* 0.3
* 0.4
4 0.4
4 0.3
4 0.3
4 0.4
* 0.4
* 3
* 5
* 5
* 0.3
* 0.5
* 2.0
4 0.6
4 0.3
* 0.15
4 0.1
4 0.10
* 1

U-234
2.5
2.3
2.7
3.5
2.5
2.8
2.7
0.69
2.8
40
47
44
3.7
6.5
5.1
7.7
2.9
0.34
0.38
0.47
11

* 0.4
* 0.3
* 0.3
* 0.5
* 0.4
± 0.4
* 0.4
* 0.29
* 0.4
* 3
4 5
* 5
* 0.3
* 0.5
* 2.0
4 0.6
* 0.3
4 0.12
* 0.07
* 0.11
* 1

Th-230
4.2
1.8
2.6
6.1
2.2
4.8
3.6
2.4
1.3
54
21
38
4.1
7.4
5.8
7.1
4.0
0.46
1.1
0.56
22

4 1.5
* 0.7
* 1.0
4 2.5
4 0.9
* 1.6
* 1.7
* 1.1
* 0.6
4 10
4 7
4 23
4 0.9
4 1.6
4 2.3
4 1.6
4 0.9
40.35
4 0.4
4 0.27
4 4

Ra-226
2.8
2.9
3.1
3.4
3.0
3.2
3.1
1.8
3.7
50
49
50
3.8
6.8
5.3
7.7
3.1
0.39
0.35
0.51
12

4 0.8
* 0.9
4 0.9
* 1.0
4 0.9
4 1.0
4 0.2
4 0.5
4 1.1
4 11
4 15
4 1
4 0.8
4 1.5
4 2.1
4 1.6
4 0.6
* 0.12
4 0.08
4 0.15
4 3

Pt>-210
4.1
5.5
2.0
3,9
5.4
4.5
4.2
26
3.6
44
56
50
4.0
5.0
4.5
7.2
4.6
1.2
0.99
0.91
1.5

* 0.8
4 0.8
4 0.7
4 0.8
* 0.8
4 0.8
4 1.3
4 22
4 0.3
4 1
4 2
4 8
4 0.5
4 0.5
4 0.7
4 0.6
4 0.6
* 0.6
4 0.47
* 0.63
± 0.5

Po-210
4.3 4
4.1 4
2.8 4
5.0 4
3.3 4
5.3 4
4.1 4
<11
3.6 4
57 4
62 4
60 4
4.8 4
7.4 4
6.1 4
3.3 4
3.6 4
1.1 4
<0.
<0.
<0.

1.0
1.0
0.9
_1.1
0.9
1.1
1 0
L
0.9
2
3
4
0.7
0.9
1.8
1.5
1.4
1.0
8
8
8

Th-232
1.4 4Q.7
0.20 4 0.18
0.89 4 Q.51
1.6 * 0.9
0.58 4 0.38
0.23 4 0.24
0.82 4 0.6
0.12 4 o.l7
0.77 4 o.45
0.31 4 0.20
-0.18 4 0.13
0.07 4 o.35
0.57 4 0.25
0.49 4 o.25
0.53 4 0.06
0.57 4 0.27
0.69 4 o.30
0.23 4 0.24
0.26 4 0.15
0.26 4 0.18
0.87 4 0.33

Th-228
1.4 4 0.7
0.72 4 0.37
0.95 4 0.53
1.5 * 0.8
0.58 4 0.38
1.2 4 0.6
1.1 4 0.4
0.12 4 0.17
0.11 4 0.16
0.44 4 0.23
-0.19 4 0.22
0.13 4 0.45
0.40 4 0.20
0.68 4 0.29
0.54 4 0.20
0.62 4 0.30
0.72 4 0.30
0.23 4 0.24
0.65 4 0.47
0.32 4 0.20
1.1 4 0.5


-------
CO
        TABLE  1(continued)



                                                                                Radlonuclide Concentrations (pC1/g)a
Sample
Ferrophosphorusb
Kiln 3 Spray Lime Slurry
Dissolved Solids (pCi/1)
Kiln 3 Spray Lime Slurry
Suspended Solids (pCi/1)
Kiln 3 Spray Lime Slurry
Total Solids (pCi/1)
Kiln 3 Spray Water
Dissolved Solids (pCi/1)
Kiln 3 Spray Water
Suspended Solids (pCi/1)
K1ln 3 Spray Water
Total Solids (pCi/1)
Kiln 3 Spray Discharge
Dissolved Solids (pC1/l)
Kiln 3 Spray Discharge
Suspended Solids (pCi/1)
Kiln 3 Spray Discharge
Total Solids (pCi/1)
U-238
9.7
2.3

.36

38

1.7

3.1

4.8

1.5

54

56

* 1.4
± 0.8

± 13

* 13

± 1.0

* 1.3

* 1.6

* 0.8

* 9

* 9

U-234
9.8
3.5

39

43

1.0

3.5

5.5

2.1

55

57

* 1.4
± 0.9

± 14

* 14

* 1.1

* 1.4

* 1.8

* 0.9

* 9

* 9

Th-230
0.05
1.1

28

28

0.56

2.0

2.6

0.82

24

25

* 0.07
± 0.9

* 19

* 19

* 0.46

* 1.3

* 1.4

* 0.68

* 10

* 10

Ra-226
0.19
4.7

45

50

1.0

4.0

5.0

0.78

59

60

* 0.04
± 1.4

± 13

* 13

± 0.5

* 1.2

* 1.3

* 0.23

± 18

* 18

Pb-210 Po-210
3.9
3.1

-20

-17

1.5

130

130

4.9

990

990

± 0.5 1.0 ± 0.9
* 6.8 <5

* 90 <40

± 90 <45

± 12 <5

* 20 130 * 35

± 23 130 ± 35

* 6.8 <5

* 60 1700 * 170

* 60 1700 * 170

Th-232
0.12
1.4

17

18

0.09

1.5

1.6

0.14

6.5

6.6

* 0.3
± 1.0

± 15

* 15

± 19

* 1.2

* 1.2

± 0.27

± 4.7

* 4.7

Th-228
0.21
1.4

26

27

0.09

1.5

1.6

0.14

5.2

5.3

± 0.14
± 1.0

± 20

± 20

* 0.19

± 1.2

± 1.2

± 0.27

* 4.0

* 4.0

         a)   Picocuries (10~^ curies) per gram plus or minus twice the standard deviation based on counting  statistics.
             Units in plcocuries  per  liter (pC1/l) where  Indicated in sample description.

         b)   The results are derived  from duplicate analyses.

-------
     Waste water from  phossy  water  processing and kiln spray chamber discharges
 is  recycled  through  a  pond,  which  serves  as  a  settling  pond  for  suspended
 solids.  This water  is  used to make  lime  slurry and spray for the  kiln  spray
 chambers.  Uranium-234 and -238, thorium-230, and  radium-226  concentrations  in
 the spray water  averaged  4.5 pCi/1.   Lead-210  and  polonium-210 concentrations
 were  130 pCi/1.   Lime  normally  has uranium-234  and  -238,  thorium-230,  and
 radium-226 concentrations of 0.3  to  0.5 pCi/g  and very  low  concentrations  of
 lead-210 and polonium-210 which  are  volatilized during the calcining  process.
 This  natural  radioactivity  of lime  is reflected  in  the  lime  slurry  which
 averaged 40  pCi/1 for  the  non-volatile  radionuclides.  There  is no  obvious
 reason for the  difference  in lead-210 and polonium-210 concentrations  between
 the kiln spray water  and  lime  slurry  samples.   Radioactivity  concentrations  of
 the kiln spray  chamber  discharge  demonstrate the  removal of radioactivity  at
 that point.   The  average non-volatile  radionuclide content  was  50 pCi/1,  or
 about 38 pCi/1 above  the  weighted  concentration expected from  spray water  and
 slurry alone.  Lead-210, with  990  ±  60 pCi/1,  and  polonium-210,  with  1,700  ±
 170 pCi/1,  were  the major  radionuclides  in  the discharge.


 AMBIENT AIR  SAMPLES


     Airborne  radon concentrations  measured  at the ambient station  are shown  in
 Table  2.  Ambient  radon concentrations  typically  vary  from  less  then  0.1  to
 about  1  nCi/m3, depending  on time of day,  season, and meteorology (1).  All
 ambient radon measurements were within the expected  normal range.

     Ambient  airborne  particulate radioactivity  concentrations are reported  in
 Table  3.  All results  are within the range expected  for  normal ambient air  (1).
 Meteorological measurements  at the ambient  station show  that the station was
 downwind  of  the plant less  than  15 percent  of  the time  during collection of
 the  first particulate  sample  reported  and  less  than 5 percent of  the time for
 the  second sample reported.   No  effect  of  plant  emissions  is   apparent  on
 either  sample.


 EMISSION  SAMPLES
Radon

    Of  four  sources  sampled for  radon only  the kiln  demister was  found  to
release radon  in quantities signficantly  different  than background.   The net
concentration  above  ambient,  shown  in  Table  4,  averaged  1.8  ± 0.3  nCi/m3.
On  this  basis,  the  total  radon  released  annually  from the  three  kilns was
projected to be 9.6 Ci.
                                      14

-------
                   TABLE 2.   AMBIENT  RADON-222  CONCENTRATIONS
                           Time                             Radon-222

pate	On - Off	Concentration  (nCi/m  )a

12/4                   1330 - 1615                         0.14 ±  0.06

12/5                   1130 - 1330                         0.14 ±  0.06

12/6                   1030 - 1300                         0.08 ±  0.04

12/6                   1300 - 1540                         0.17 ±  0.04

12/10                  1130 - 1400                         0.15 ±  0.06

12/10                  1400 - 1600                         0.16 ±  0.05

12/11                  1030 - 1420                         0.09 ±  0.04

12/11                  1430 - 1600                        0.08 ±  0.03

12/12                  0915 - 1215                         0.60 ±  0.07

12/12                  1425 - 1708                          0.34 ±  0.05

12/13                  0800 - 1115                         0.26 ±  0.05

12/13                  1115 - 1630                         0.27 ±  0.07
a)  Nanocuries  (10~9 curies) per cubic meter plus or minus twice the
    standard deviation based on counting statistics.
Total  Suspended Particulates

    Each  of  the   processes  sampled  generates  large  quantities  of  airborne
particulates,  primarily  from  comminution  of materials  during handling.   It
would  be expected, then,  that  particulate emissions would  reflect  the radio-
activity  of  the process materials.   This was found to  be  the  case,  within the
limits of sample  variability and  analytical  accuracy,  for  the  non-volatile
radionuclides for  all sources, with the  possible exception of the furnace tap-
hole fume collector.  The fume  collector emits fumes resulting mainly from the
small  amounts  of  phosphorus released  and which are  very  low  in radioactivity
Stack  exhaust gas  flow  rates and  TSP concentrations are given  in Table 5.


Kiln Emissions

    As shown in  Table  3,  uranium chain  nuclides were  in  approximate equilib-
rium,   with  concentrations  of   about   0.4  pCi/m3,  except for  lead-210 and
polonium-210.   Polonium  was partially volatilized,  as shown  by its depletion
in nodules,  and both lead and  polonium were nearly completely volatilized  in
the furnaces and  returned to the kiln  with  the  CO fuel.  Most  of these two
nuclides was removed in the spray chamber  and demister,  but  they were  still
measured at concentrations  of  33  to  120  pCi/m3  for  lead-210 and  64 to 280
        for polonium-210.  Emission rates determined from individual  samples


                                       15

-------
                      TABLE  3.  AMBIENT  AND STACK PARTICULATE RADIOACTIVITY CONCENTRATIONS
                                                                             .3,a
                                                       Radioactivity Concentration (pCi/m )'
Source
Antoient
Station
Ambient
Station
Florida Ore,
Slag Storage
Slag Dump
Slag Dump
No. 3 Kiln
Demisterb
No. 3 Kiln
Demister15
No. 3 Kiln
Demister6
No. 3 Nodule
Cooler
No. 3 Nodule
Cooler
Nodule Transfer
Point Exhaust
Noifute Transfer
Point Exhaust
Nodule Transfer
Point Exhaust
Screening Plant
Dust Collector
Screening Plant
Oust Collector
Screening plant
Dust Collector
South Scale Room
Oust Collector
South Scale Room
Oust Collector
South Scale Room
Oust Collector
South Scale Room
Collected
1600 - 12/06
1830 - 12/07
0910 - 12/12
1030 - 12714
1440 - 12/07
1915 - 12/08
1200 - 12/10
0800 - 12/12
0800 - 12/12
1220 - 12/12
1340 - 1540
12/06
1720 - 1920
12/06
0952 - 1152
12/07
1338 - 1643
12/11
1012 - 1243
12/14
0922 - 1034
12/06
1208 - 1320
12/06
1505 - 1617
12/06
1057 - 1240
12/07
1408 - 1520
12/07
0933 - 1045
12/10
0913 - 1133
12/04
1522 - 1820
12/04
1524 - 1822
12/04
0928 - 1202
U-238
0.00005
0.00007
0.0022
0.00047
0.0021
0.39
0.43
0.34
0.38
0.42
1.9
3.2
0.93
3.4
13
1.4
1.1
2.0
1.4
2.0
* 0.00011
* 0.00008
* 0.0005
* 0.00016
* 0.0010
* 0.18
* 0.16
* 0.15
* 0.34
* 0.37
* 0.4
* 0.6
* 0.350.
* 0.4
* 1
* 0.5
* 0.4
* 0.5
* 0.4
* 0.5
U-234
-0.00001
0.0
0.0053
0.00071
0.0021
0.42
0.90
0.41
0.19
0.35
2.0
3.5
0.78
4.1
13
1.9
1.6
2.2
1.8
1.8
* 0.00016
* 0.0001
* 0.0005
* 0.00020
* 0.0013
* 0.21
* 0.24
± 0.20
<* 0.39
± 0.45
* 0.5
* 0.8
* 0.41
t 0.7
* 1
* 1.3
* 0.5
* 0.6
* 0.5
* 0.6
Th-i30
0.00015 * 0.00055
0.0002 * 0.0004
0.0086 * 0.0016
0.00077 * 0.00056
0.0025 * 0.0040
0.38 * 0.51
0.21 * 0.40
0.22 * 0.39
0.09 * 0.88
0.6 * 1.1
2.7 * 1.3
5.6 * 2.4
0.50 * 0.89
3.7 * 1.6
15 * 5
1.0 * 0.6
1.7 * 1.0
2.7 * 1.3
1.4 * 0.9
1.0 *1.2
Ra-226
-0.00024 * 0.00056
0.00024 * 0.00032
0.0038 * 0.0009
0.00001 * 0.00035
0.0023 * 0.0038
0.40 * 0.288
0.47 * 0.27
0.26 * 0.22
-0.12 * 0.52
-0.05 * 0.55
1.8 * 0.7
4.3 * 1.5
2.0 * 3.1
4.0 * 1.4
13 * 4
0.9 i 5.5
1.1 * 0.6
2.3 * 1.0
1.2 * 0.6
2.0 * 0.9
Pb-210
0.024 * 0.020
0.0081 * 0.0019
0.0032 * 0.0030
0.017 * 0.002
-0.013 * 0.018
110 * 8
33 * 3
120 * 5
-0.2 * 4.9
-1.6 ± 5.3
-2.7 * 5.0
1.1 * 8.4
-1.0 * 4.8
-3.3 * 5.3
9.0 * 5.3
0.5 * 2.1
-0.5 * 3.2
0.7 * 5.8
-3.5 * 4.9
-1.3 * 5.7
Po-210
0.010 * 0.019
0.006 * 0.003
0.0078 * 0.0042
0.0066 ± 0.0038
0.011 * 0.017
280 ± 15
64 * 9
67 ± 8
0.7 * 2.1
-0.4 * 2.0
0.6 * 1.7
2.1 * 3.2
0.01 * 1.7
1.4 * 2.2
1.6 * 5.1
0.5 * 2.1
-0.03 * 1.7
-1.0 * 2.1
0.3 ± 1.8
-0.4 * 2.3
Th 232
-0.00009 * 0.00029
-0.00004 * 0. 00018
0.0 * 0.00036
-0.00005 * 0.00019
0.0005 * 0.0024
-0.35 ± 0.32
0.02 * 0.25
0.05 * 0.2H
-0.17 * 0.53
-0.14 * 0.58
0.10 * 0.56
-0.05 * 0.55
-0.02 * 0.52
-0.05 ± 0.57
1.6 * 1.5
0.13 * 0.63
-0.16 * 0.48
-0.10 * 0.64
0.13 * 0.52
-0.21 * 0.64
Th-228
-0.00006 * 0.00023
-0.00003 * 0.00015
0.00003 * 0.00030
-0.00003 * 0.00015
0.0007 * 0.0021
0.33 * 0.31
0.04 * 0.24
0.07 * 0.24
-0.10 * 0.51
-0.07 * 0.56
0.01 * 0.50
-1.2 * 1.0
-1.8 * 0.9
-1.1 * 0.8
1.9 * 1.6
0.11 » O.S9
-0.10 * 0.46
-0.03 * 0.59
0.19 ± 0.50
-0.13 * 0.55
(continued)

-------
      TABLE  3.    (Continued)
                                                                               Radioactivity Concentration  (pC1/m3)a
Source
Stocking System
Oust Collector
Stocking System
Dust Collector
Stacking System
Dust Collector
Central Furnace
Stocking System
Central Furnace
Stocking System
Centra] Furnace
Stocking Systen
Furnace Tapehole
Fume Collector
Furnace Tapehole
Fine Collector
Furnace Tapehole
Fine Collector
Furnace Tapehole
Fume Collector
Collected
1040 - 1309
12/04
H53 - 1705
12/04
0905 - 1117
12/05
1351 - 1609
12/06
0658 - 1145
12/07
120S - 15*6
12/07
1355 - 1545
12.04
13S6 -1546
12/04
0844 - 1506

1525 -1808
12/05
0-236
0.80 *

0.95 *

0.66 *

0.51 *

0.90 *

0.93 *

-0.24 *

' -0.15 *

-0.001 *

-0.06 *

0.29

0.31

0.28

0.21

0.27

0.29

0.32

0.36

0.17

0.16

U-234
0.97

0.87

0.98

0.65

0.80

0.73

-0.10

0.05

-0.06

-0.06

* 0.34

* 0.36

* 0.33

* 0.27

* 0.31

* 0.30

* 0.42

* 0.42

* 0.20

* 0.20

Th-230
1.4

0.97

0.55

0.83

1.9

0.47

0.03

-0

-0.10

0.10

* 1.5

* 0.71

* 0.67

* 0.60

* 0.7

* 0.56

* 0.93

« 1.0

* 0.44

* 0.47

Ra-226
0.57

0.81

0.67

0.59

0.78

0.47

-0.04

-0.10

-0.09

-0.04

* 0.43

* 0.46

* 0.43

* 0.36

* 0.43

* 0.35

* 0.54

* 0.58

* 0.26

* 0.26

Pb-210
-0.8

0.1

0.7

-1.4

0.5

-0.3

-3.0

2.4

15

3.2

* 3.5

* 2.6

* 4.3

* 3.0

* 3.3

* 3.0

* 5.8

* 6.9

* 3

* 3.1

Po-210
-0.2

-0.7

-0.4

-0.2

0.3

0.2

0.6

1.5

0.001

1.1

* 1.4

* 1.3

* 1.3

* 1.1

* 1.3

* 1.2

* 2.2

* 2.5

* 0.38

* 1.2

Th-232
0.02

-0.02

0.06

0.07

0.11

0.06

-0.14

0.66

-0.04

-0.07

* 0.40

* 0.39

* 0.40

* 0.34

* 0.36

* 0.34

* 0.57

* 0.69

* 0.29

* 0.28

Th-228
0.04

0.03

0.11

0.11

0.15

0.10

-0.08

-1.2

0.04

-0.53

* 0.37

* 0.38

* 0.39

* 0.32

* 0.35

* 0.33

* 0.55

* 0.8

* 0.26

* 0.33

a) Plcocurlei (10~'2 curies) per actual cubic  meter (volume measured at  ambient or  stack conditions)
   plus or minus twice the standard deviation  based on counting results  only.

b) Plcocuries per dry standard cubic meter (volume of dry air sampled at 21 C. 760  mm Hg).

c) Duplicate sample.

-------
                       TABLE 4.  RADON-222 STACK EMISSIONS

                                         Concentration  (nCi/m3)3       Annual
  Source	Time    Date       Gross             Net
No. 3 Kiln
Demister


Source Average
No. 3 Kiln
Nodule Cooler



Source Average
Screening
Plant Dust
1500-1600
1335-1615
0825-1045
1050-1500

1330-1630
0820-0930
0815-1100
1050-1330
1325-1452
12/6
12/12
12/13
12/13

12/11
12/12
12/13
12/13
12/13
2.0
1.7
2.1
2.1

0.13
0.09
0.32
0.16
0.26
±
±
±
±

±
±
±
±
±
0.1
0.1
0.
0.

0.
0.
0.
0.
0.
,1
,1

06
05
07
04
06
1
1
2
1
1
0
-0
0
-0
-0
.8
.4
.0
.8
.8
.05
.51
.06
.11
.01
-0.10
0910-1200

12/10°

0.30

±

0.

04

0.15


±
±
±
±
±
±
±
±
±
±
±
±

0.1
0.1
0.1
0.1
0.3
0.07
0.09
0.09
0.08
0.09
0.24
0.07





9.6d





-0.19d


                 1330-1530  12/10    0.24 ± 0.05    0.08 ± 0.07
                 0940-1400  12/11    0.08 ±0.04   -0.01 ± Q.06
                 1100-1320  12/12C   0.15 ± 0.03   -0.44 ± 0.08
                 0830-1055  12/13    0.30 ± 0.06    0.04 ± 0.08

   Source Average                                  -0.04 ± 0.23       -0.046

 No.  3 Furnace   0830-1500  12/15C   0.16 ± 0.03    0.02 ± 0.07        0.05f
 Taphole Fume
 Collector
 a)   Nanocuries  (10~9  curies)  per  cubic  meter  plus  or minus  twice  the
     standard  deviation based  on counting  statistics.   Source  average  uncer-
     tainties  are calculated from  the  variance about the mean  of the samples.

 b)   Calculated assuming 24 hour continuous operation for  50 weeks per year.

 c)   The results derived from  duplicate  Samples.

 d)  Annual emissions are for  sum  of three kilns.

 e)  Annual emission is for sum of two stacks.

f)  Annual emission is for sum of six furnaces.
                                      18

-------
are  shown  in Table  6.   Mass emission  rates  measured from  the  three  samples
were  quite  uniform.   This uniformity  is also  evident  in  the  radioactivity
emission  rates  of  the  non-volatile  nuclides.    Lead-210  and  polonium-210
emission rates varied  by factors  of 3 to 4.   The reason for this  is  unknown,
but  it is probably due to the fact that  lead  and  polonium,  as  vapors  or fumes,
are  not  removed  from the exhaust  stream as  consistently as  the particulates.
The  annual  particulate  radioactivity emission rates, calculated for  the  total
number of  stacks from each  type  of source are  shown in Table  7.   Calculated
emissions  of  uranium,  thorium-230,  and  radium-226  from  the  three  kilns
averaged 2.2 mCi/y.  The  annual emission of  lead-210 was 480 mCi  and  that  for
polonium-210 was 750 mCi.


Nodule Cooler Emissions

     Radioactivity  concentrations  in  the  nodule cooler exhaust were essentially
the  same as for the non-volatile  nuclides  in the  kiln demister.   The  over-
lapping  confidence  intervals  for  all  nuclides and the mechanical nature of the
particulate  generation  suggest  that the concentrations  and  emission  rates for
all  nuclides released  from the  coolers  are  approximately  equal.   The annual
emission rates  of about  1  mCi/y  for  uranium-234   and  -238  and thorium-230
probably hold  for  the  other nuclides as  well.   Polonium-210 may actually be
close to  the  0.6  mCi/y  emission  rate  due  to  some depletion in  the  kiln.
Simultaneous  sampling  of  the  inlet  to  and outlet from  the  nodule cooler
scrubber showed  an average removal of uranium chain nuclides of 99.5  percent.
Mass analysis  of the filters showed an average mass  removal efficiency of  98.5
percent.


 Nodule Transfer  Point  Emissions

     Concentrations of  non-volatile nuclides  averaged  from about 1.0 to  5.6
         during  the  three  sampling  periods  (Table  3).    Visible   emissions
 varied noticeably, with  the controlling factor  seeming to be  the temperature
 of  nodules  on  the conveyor.  At times  the nodules  were  still  glowing  and
 generated larger quantities of emissions at  the  transfer points.   Non-volatile
 radionuclide emissions  averaged  1.5 mCi/y (Table  7).   Polonium-210  was  lower
 most likely due  to depletion in the kilns.
                                       19

-------
               TABLE 5.  STACK FLOW AND PARTICIPATE EMISSION RATES
Source
No. 3 Kiln
Demister

No. 3 Nodule
Cooler
Nodule Transfer
Point Exhaust

Screening Plant
Dust Collector

South Scale Room
Dust Collector


Stocking
System Dust
Collector
Central Furnace
Stocking
System
Furnace Taphole
Fume Collector


Collected
Time Date
1340-1540
1720-1920
0952-1152
1338-1643
1012-1242
0922-1034
1208-1320
1505-1617
1057-1240
1408-1520
0933-1045
1913-1133
1522-1820C
1524-1822C
0928-1202
1040-1309
1453-1705
0905-1117
1351-1609
0858-1145
1208-1546
1355-1545°
1356-1546°
0844-1508
1525-1808
12/6
12/6
12/7
12/11
12/14
12/6
12/6
12/6
12/7
12/7
12/10
12/4
12/4
12/4
12/5
12/4
12/4
12/5
12/6
12/7
12/7
12/4
12/4
12/5
12/15
Exhaust Gas
Flow Rate
(m3/min)
3,399
3,554
3,554
1.657
1,571
1,223
1,118
1,224
1,105
1,091
1,104
605.1
606.3
622.7
610.1
394.8
389.1
386.8
578.1
536.1
573.2
823.9
787.1
887.3
840.3
Particulate
Concentration
(mg/m3)3
137. 4b
114. 4b
114. 4b
68.3
64.6
215.6
437.8
247.4
706 3
• *J\J • tj
1,664
176.1
189.1
•* *J •* • 4
207.1
225.8
198.3
135.6
108.9
180.4
179.1
248.6
168.5
17.9
21.6
35.9
15.6
a)  Flow rate and concentration volumes are actual cubic meters at stack
    conditions.


b)  No. 3 kiln volumes are dry, standard cubic meters (at 20°C, 760 mm mercury
    pressure.)

c)  Duplicate samples.
                                      20

-------
                                    TABLE 6.   PARTICULATE  RADIOACTIVITY  ANNUAL EMISSION RATES
                                                             Radioactivity Emission Rates (pCt/s)'
ro
Time-Date
Source 	 Collected
No. 3 Kiln 1340 - 1540
Demister 12/06
1720 - 1920
12/06
0951 - 1152
12/07
Source Average
No. 3 Nodule 1338 - 1643
Cooler 12/11
1012 - 1242
12/14
Source Average
Nodule 0922 - 1034
Transfer 12/06
Point 1208 - 1320
Exhaust 12/06
1505 - 1617
12/06
Source Average
Screening 1057 - 1240
Plant Dust 12/07
Collector 1408 - 1520
12/07
0933 - 1045
12/10
Source Average
South Scale 0913 - 1133
Room Dust 12/04
Collector 1522 - 1820"
12/04
0928 - 1202
12/05
Source Average
Stocking 1040 - 1309
System Oust 12/04
Collector 1453 - 1705
12/04
1905 - 1117
12/05
Source Average
Central 1351 - 1609
Furnace 12/06
Stocking 0858 - 1145
System 12/07
1208 - 1546
12/07
Source Average
(continued)
U-238
22 * 10
26 * 10
20 * 9

23 *3
10 * 9
11 * 10
TT^T-
39 * 9
59 * 11
19 * 7
39 * 20
63 * 7
230 * 20
25 * 9
110 * 110
11 * 4
18 * 3
20 * 5
16 * 5
5.3 * 1.9
6.2 * 2.0
4.3 * 1.8
smrra
4.9 * 2.0
8.0 * 2.4
8.9 * 2.8
7^1

U-234
24 * 12
54 * 14
24 * 12

34 * 17
5 * 11
9 * 12
-T-TT-
41 * 11
65 * 15
16 * 8
41 * 25
75 * 13
230 * 20
29 * 10
110 * 110
16 * 5
22 * 4
18 * 6
IB * 3
6.4 * 2.2
5.6 * 2.3
6.3 * 2.1
6.1 * 0.4
6.3 * 2.6
7.1 * 2.8
7.0 * 2.9
6.8 * 0.4

Th-230
21 * 29
12 * 24
13 * 23

15 * 5
2 * 24
16 * 29
9 * 10
56 * 26
100 * 50
10 * 18
55 * 45
68 * 29
280 * 90
35 * 23
130 * 130
17 * 10
21 * 8
10 * 12
TTST-
9.2 * 9.9
6.3 * 4.6
3.5 * 4.3
B^rrry
8.0 * 5.8
17 * 6
4.5 * 5.3
-nrrr-

Ra-226
23 * 16
28 * 16
16 * 13

2Z*6
-3 * 14
-1 * 14
~^rr
36 * 15
80 * 29
41 * 63
52 * 24
73 * 25
240 * 80
18 * 11
110 * 120
11 * 6
18 * 6
20 * 9
16 *5
3.8 * 2.8
5.3 * 3.0
4.3 * 2.8
4.5 * 0.8
5.7 * 3.5
7.0 * 3.8
4.5 * 3.3
5.7 * 1.3

Pb-210
6300 * 400
1900 * 200
7000 * 300

5100 * 2800
6 * 140
-40 * 140
^TT-inn-
-60 * 100
20 * 160
-20 * 98
-20 * 40
-61 * 97
160 * 100
20 * 100
40 * 110
-5 * 32
-14 * 39
-13 * 57
-11 * 5
-6 * 23
1 * 17
-5 * 28
-3.3 * 3.8
-13 * 29
5 * 29
-3 * 29
-•T^TTO

Po-210
16000 * 900
3800 * 500
4000 * 500

7900 * 7000
20 * 580
-9 * 52
-mr
13 * 34
39 * 60
0 * 35
17 * JO
26 * 40
28 * 92
10 * 38
21 * 10
-3 * 17
-3 * 14
-4 * 23
^rr
-1.6 * 9.2
-4.9 * 8.4
-2.3 * 8.4
-2'9 * U/
-2.0 * 11
3.0 * 12
2.0 * 11
1.0 * 2./

Th-232
-20 * 18
1 * 15
3 * 14

"5 *13
-5 * 15
-4 * 15
I5TT-
2 * 11
-1 * 16
0 * 11
TTTT-
-1 * 10
28 * 27
2 * 12
10 * 16
-2*5
0*4
-2*6
Ti-T
0.1 * 2.6
-0.1 * 2.5
0.4 * 2.6
0-1 *°-*
0.7 * 3.3
1.0 * 3.2
0.6 * 3.2
0.8 * fl.2

Th-228
18 * 18
2 * 14
4 * 14

8i9
3 * 14
-2 * 15
^T
0 * 10
-22 * 19
-36 * 18
-19 * 18
-20 * 14
34 * 28
2 * 11
mi
-1 * 5
1 * 4
-1 * 6
T-TT
0.3 * 2.4
0.2 * 2.5
0.7 * 2.5
0.4 * 0.3
1.1 * 3.1
1.3 * 3.1
1.0 * 3.2
rmr?


-------
ro
ro
              TABLE  6.     (Continued)
                                                                                      Radioactivity Emission Bates (pCi/s)a
Time-Date
Source Collected
Furnace 1355 - 1545
Taphote 12/04
Fume 0644 - 1506
Collector 12/05
1525 - 1S08
12/05
Source Average
U-238
-2.7 * 3.2
0.0 * 2.5
-0.9 * 2.3
-I.Z *1.4
U-234
1.1
-0.5
-0.9
-0.1
* 4.0
* 3.0
* 2.8
* 1.1
Th-230
-2.5
-1.5
1.4
-U.9
« 9.2
* 6.5
* 6.5
* 2.0
Ra-226
-0.5
-1.4
0.5
-0.5
* 5.1
* 3.9
* 3.7
* 1.0
Pb-210
-40
230
44
~75"
* 55
* 50
» 43
* HO
8
0,
5
1-
Po-210
* n
.0 * 5.7
* 17
.3 * 4.0
TH-232
-C.I
-0.5
-1.0

* 5.4
* 4.2
* 3.9
* 0.6
Th-228
-0.1 * 5.2
0.6 * 3.9
-7.4 * 5.3
-?'3 * 4'4
         a)  Picocuries (ICr-l? curies) per second plus or minus  the standard deviation based upon counting statistics.  Source
            average uncertainties are calculated from the variance about  the mean  of the samples.
         b)  Derived fron duplicate samples.
         c)  Exhaust fans were shut down several times.

-------
                                TABLE 7.   PARTICULATE RADIOACTIVITY  ANNUAL EMISSION  RATES
                                                                Radioactivity Emission Rates
Source
Kiln Oemisters
Nodule Coolers
Nodule Transfer
Point Exhaust
Screening Plant
Dust Collector
South Scale Room
ro Dust Collector
U)
Stocking System
Dust Collector
Central Furnace
Stocking System
Furnace Taphole
Fume Col lector
Plant Total
U-238
2.2
1.0
1.2

6.9

0.50


0.33

0.23

-0.32

12
U-234
3.2
1.0
1.3

6.9

0.56


0.38

0.21

0.02

14
Th-230
1.4
0.9
1.7

8.2

0.50


0.40

0.32

-0.13

13
Ka-226
2.1
-0.2
1.6

6.9

-0.50


0.28

0.18

-0.15

11
Pb-210
480
-1.6
-0.6

1.9

-0.35


-0.21

-0.12

15

490
Po-210
750
0.6
0.5

1.3

-0.09


-0.18

0.032

1.4

750
Th-232
-0.5
-0.4
0

0.6

-0.03


0.006

0.025

-0.095

-0.39
Th-228
0.
0.1
0.6

0.3

0.00


0.025

0.035

-0.44

1.4
a)  Mlllicuries  (10~3 curies) per year.  Calculate using concentrations found In Table 3 and emission rates trom Table 5.

-------
Screening Plant Dust Collector Emissions

    As shown in Table 5, the  TSP concentrations  in  emissions  from  the  screen-
ing plant  dust  collector were  the highest of  any source,  and  also the  most
variable.  TSP and  radioactivity concentrations  varied by an order  of  magni-
tude over the three sampling  periods.  This was  the most  significant source  of
non-volatile particulate radioactivity  emissions from the controlled  sources.
Emissions from the two stacks accounted for more than  half of the plant  total.
Other Emission Sources

    Emissions from each of  the  other  sources,  except the furnace  taphole  fume
collector, had  concentrations  similar to  the  preceding  sources.   Stack  flow
rates, however,  were lower  and  emissions of  non-volatile  radionuclides  were
less than 1 mCi/y for all  these  sources.

    Lead-210 emission rates from the  furnace taphole  fume scrubber were highly
variable, ranging from  -40  ± 55 pCi/s to  230  ± 50  pCi/s  in the  four  samples
collected (Table 6).  It had been shown in the earlier  report that the  primary
source of  lead-210  from furnace tapping  is FeP  tapping.   It is probable  that
the  highest  lead-210  sample included  an FeP  tap.   The  polonium-210  annual
average emission rate from furnace tapping was  1.4  mCi.


Particle Size Analysis

    Size-fractionated samples were collected from five stacks using an in-stack
cascade  impactor  sampler.   Two  samples  were  collected  from  each  source.
Sources sampled were the screening plant  dust collector,  south  scale  room dust
collector, stocking  system  dust  collector,  central  furnace stocking  system,
and  furnace  taphole  fume  collector.  Most  of  the  impactor  stages had  such  a
small  mass  of   collected   particulates   that  radiological   analysis  was  not
attempted.  Considering the  sources of particulates  collected it  is reasonable
to assume  that  the  size distribution  of non-volatile  radionuclides  is  similar
to the mass distribution.

    Tne  majority of mass  from each  source was  found on  the  first  impactor
stage.  Cumulative mass analyses  showed  the following  results  for aerodynamic
particulate sizes.
                                      24

-------
                TABLE  8.   AERODYNAMIC  PARTICLE  SIZE  DISTRIBUTIONS
    Source
         Run 1
Size(nm)        less than
         Run 2
Size(ym)       less than
Screening plant
South scale room
Stocking system
Central furnace
stocking system
Taphole fume scrubber
14.1
17.7
14.6

Invalid
12.3
8.7
34
6.8

Sample
18
16.2
17.7
14.2

12.4
12.1
8.9
27
48

6.9
28
High Volume Particulate Samples

    Problems  were  encountered  in  collecting  the  high  volume  particulate
samples  at  the  slag  dump  and  Florida ore  storage  areas.   Samplers  were
unplugged by workers  needing  electrical  outlets or power was  accidentally cut
to  the  circuits  on  several   occasions.   As  a result,  sample  volumes  were
smaller  than  desired and  analytical  uncertainties were  higher.   The  results
are  shown  in  Table  3.   When  compared  to  the  ambient  station  high  volume
samples, the plant  site  samples show generally higher  concentrations  with the
highest  being measured at  the rail car  dump site  adjacent  to the  Florida ore
storage  pile.  While  it  is logical to ascribe these  higher activities  to the
slag dumping  and ore  handling activities no  importance  can  be  laid on  them
because  of the relatively uncontrolled sampling performed.
                                       25

-------
                                   SECTION  7


                             DISCUSSION OF  RESULTS
    As was expected,  several  sources of enhanced radioactivity  emissions  were
found  at  this  elemental  phosphorus  plant.   The gaseous  and volatile  radio-
nuclides  -  radon,  polonium-210,  and lead-210  -  were  driven  off  the  process
materials  in  either  the  kilns  or  furnaces  and  ultimately  exhausted  to  the
atmosphere  via  the  kiln  exhausts.   These  radionuclides  were  also  those
released  in  greatest  quantity.   Annual radon  emissions  from  the kilns  were
measured  at  9.6  Ci/y.   Although  the  kiln  emission  control  system  was  not
designed  to  remove  lead  and  polonium fumes  most  of  them  were  removed  and
annual emission rates  were 0.48  Ci  for lead-210 and 0.75  Ci  for polonium-210,
about an order of magnitude below the radon.

    The  screening  plant  dust  collector emissions  were found  to  account  for
more  than half of  the  non-volatile radioactive  nuclides emitted  from  the
plant's controlled  sources.   The mass emission rates  varied from  11.7  to  109
kg/h,  compared  to  a  rate of  2.9  kg/h  reported by Monsanto.   Mass  emission
rates  measured  at  the other  sources were  generally  about twice  as much  as
reported  by Monsanto  2 years earlier.  The  large amount  of  particulates  from
the screening plant dust  collector,  and their  greatly  varying  quantity suggest
that the  emission control system was  not operating  properly during the survey.
If the average  observed mass  emission rate of 56  kg/h was  reduced  to  2.9  kg/h
the average non volatile  radionuclide  emission  rates would be  reduced from 7.2
mCi/y  to 0.36  mCi/y.  That  would  put  it  in line with  the   other  material
handling  processes  following  the  nodule  transfer  point   control  system  and
would  reduce  the plant  emissions  of  the  non-volatile  nuclides by  about  one
half.

    If  the  screening  plant  dust  collector  was  not  operating  at  design
efficiency, correcting the  problem  would reduce  mass emissions, but  would
probably  not reduce the  respirable  fraction by the  same proportion.   As shown
before only 8.8 percent, on the  average, of  the mass emissions  were below 14.1
to 16.2  urn aerodynamic  diameter.   Large  particles  would   normally be  removed
with more  efficiency  than small  particles.   This is shown to  some  degree  by
the size distributions found for the other sources measured.

    The two major sources of  uncontrolled  emissions, materials  handling in the
kiln-nodule  cooler  area  and  open  nodule  craneway  storage  area,  produce
primarily  large particles  that are  deposited  in   the  immediate  area.   Very
little airborne material  was  visibly evident at  any appreciable distance  from
these sources.
                                      26

-------
                                  REFERENCES


1.  National  Council  on  Radiation  Protection   and   Measurements.    Natural
    Background Radiation in the  United  States,  NCRP  Report  No.  45, Washington,
    D.C., 1975.

2.  Habashi,  Fathi.    Uranium  in   phosphate  rock.   Special  Publication  52,
    Montana  Bureau  of Mines  and Geology,  Montana  College  of  Mineral  Science
    and Technology, Butte, Montana, December 1970.

3.  Menzel,  F.G.   Uranium, radium,  and  thorium content  in  phosphate  rocks and
    their  possible  radiation   hazards.    Journal   of   Agriculture  and  Food
    Chemistry, Vol. 16, No. 2, pp. 231-234, 1968.

4.  Eadie, Greogry G.,  and David E. Bernhardt.   Radiological  surveys of  Idaho
    phosphate ore  processing  - the thermal process  plant.   U.S. Environmental
    Protection Agency, Technical Note OPR/LV-77-3,  Las  Vegas,  Nevada, November
    1977.

5.  Engineering-Science,  Inc.   Collection  of  airborne  radon  and radioactive
    particulates  at   the  Monsanto  Chemical  Intermediates  Columbia  Elemental
    Phosphorus Plant Columbia, Tennessee.  McLean, Virginia, April  1980.

6.  Code of  Federal Regulations, Title 40, Chapter 1, Part 60, Appendix A.

7.  Code of  Federal Regulations, Title 40, Chapter 1, Part 50, Appendix B.
                                      27

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                                   TECHNICAL REPORT DATA
                            (Please read Instructions on the reverse before completing)
1  REPORT NO.

  	EPA-520/6-82-021
4. TITLE AND SUBTITLE
                              2.
  Emissions of Naturally Occurring Radioactivity:
  Monsanto Elemental  Phosphorus Plant
             3. RECIPIENT'S ACCESSION NO.
             5. REPORT DATE
                    November 1982
             6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
  Vernon E. Andrews
             8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
  U.S.  Environmental  Protection Agency
  Office of Radiation Programs-Las Vegas  Facility
  P.O.  Box 18416
  Las  Vegas, Nevada   89114	
              10. PROGRAM ELEMENT NO.



              11. CONTRACT/GRANT NO.
12. SPONSORING AGENCY NAME AND ADDRESS
      Same as above
                                                            13. TYPE OF REPORT AND PERIOD COVERED
              14. SPONSORING AGENCY CODE
15. SUPPLEMENTARY NOTES
  This is the fourth  in a series of  reports covering work  performed in response  to the
  1977 Clean Air Act  Amendments
16. ABSTRACT                                         ~~             '	'	
  Naturally occurring radioactivity was  measured in the atmospheric emissions  and
  process materials  of a thermal phosphate (elemental phosphorus) plant.  Representative
  exhaust stack  samples were collected from each process  in  the plant.  The phosphate
  ore contained  12 to 20 parts per million uranium.  Processes, emission points,  and
  emission controls  are described.  Radioactivity concentrations and emission  rates from
  the sources sampled are given.
17.
                                KEY WORDS AND DOCUMENT ANALYSIS
                  DESCRIPTORS
b.lDENTIFIERS/OPEN ENDED TERMS
                                                                          c.  COSATI Field/Group
    Natural Radioactivity
    Airborne Wastes
    Exhaust Gases
  Technologically
  enhanced
  radioactivity
    1808
    1302
    2102
18. DISTRIBUTION STATEMENT

     Release to Public
19. SECURITY CLASS (TMiReport)
   Unclassified
                                               20. SECURITY CLASS (Tills page)

                                                  Unclassified
21. NO. OF PAGES

	27
                           22. PRICE
EPA Form 2220-1 (R«v. 4-77)   PREVIOUS EDITION is OBSOLETE

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