ML19256E972
| ML19256E972 | |
| Person / Time | |
|---|---|
| Issue date: | 10/31/1979 |
| From: | Eadie G, Gnugnoli G, Miller H NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
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| REF-WM-28 NUDOCS 7911160283 | |
| Download: ML19256E972 (25) | |
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,J CHURCH ROCK URAtlIUM MILL TAILINGS SPILL UtilTED flVCLEAR CORPORATIO!!
CHURCH ROCK, NEW '4EXICO Prepared by Staff of Uranium Recovery Licensing Branch Division of Waste Management Office of fluclear Material Safety and Safeguards U. S. Iluclear Regulatory Commission G. G. Gnugnoli G. G. Eadie H. J. Miller D D
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October, 1979 340 325 7911160 ifg
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. C u u.l e u._, n SACKGROUND On July 16, 1979, a tailings dam at the Church Rock uranium mill of United Muclear Corporation failed.
Estimates of the amount of tailings released from the failure have varied, but it appears that at least about 100 million gallons of acidic tailings solutions and 11 hundred tons of tailings solids escaped from the tailings impoundrent area before the break in the dam could be closed. Most of the solids were deposited in an area very near the impoundment in a backup containment area on operator property and in an adjacent stream, the so-called "Pipeli ne Arroyo. " The solutions were carried in the Pipelire Arroyo to the Rio Puerco which flows through Gallup, New Mexico, a town about 20 miles southwest of the mill site, and into Arizona. By evaporation and percolation into the stream bottom, the spilled solutions eventually dissipated at a point estirated by visual observations to be about 20 miles into Arizona.
The Pipeline Arroyo stream and the Rio Puerco run in channels which, except for periods of heavy rain, are very small streams.
The release of tailings solutions resulted in a flow which filled the entire channel, contaminating the normally cry bottom portions, or " terraces," as they passed.
The result u.
as indicated by early measurements was widespread contamination of the terraces wnicn were wetted by the released solutions. The contamination levels appeared as a result of deposition of fine particles suspended in the tailings solution and 1,240 326 s
. of sorption of soluble contaminants from the solution into the terraced soils and stream sediments.
There were isolated areas on the terraces where contamination is quite concentrated, being as high as 100 to 500 times background levels.
These were, in many cases, areas where solutions became stranded in isolated pools af ter the spilled solutions passed.
In a letter dated Aegust 23, 1979, the iRC staff advised the State of New Mexico of acceptable cleanup criteria for this particular case (letter attacned).
This letter fornalized conversations the staff had,sith State of New i'exico Environmental Improvement Division prior to the State's letter (signed by T. E. Baca) of August 13, 1979, to the operator concerning monitoring ar.d cleanup requi rements.
CLEANUP LIMITS The levels for cleanup specified by the NRC staff as being acceptable for the Church Rock case are:
levels which are no greater than 10 pCi/gm Ra-226 dnd 30 pCi/gm Th-230 (both inclusive of background).
These criteria were selected on the basis of (1) the evaluation oi OL results of the limited sarrpling and analysis conducted at the time the criterf a were set, (2) the evaluation of potential radiological exposure pathways, and (3) the desirability of reducing exposures to the maximum extent reasonably achievable.
The objective of selecting the cleanup levels was to assure that the areas of concentrated radioactivity are cleaned up.
However, the cleanup of large portions of arroyos, which are contaminated above background radiation levels, but not at levels which pose a threat to public health, snould be 1340 327
. mi nimi zed.
The latter case, in the extreme might result in atterrpting to clean up the entire 60 mile stretch of contamination, an unreasonable burden to require of the operator.
The 10 pCi/gm activity for radium was specified as consistent with the cleanup cbjective of reducing contamination to as low as reasonably achievable (ALARA). A few measurements of Ra-226 using the highly accurate radon emanation reasurement technique, appeared at the time the criteria were set to show that radium levels in areas below the dam breach were on the average of a few pCi/gm. Earlier measurements made by the operator were much higher (as nuch as 10 pCi/gm and higher).
The staff proposed that radium measurement techniques should be checked closely and that, if it was confirmed that the lower Ra-226 measurements were representative of the contaminated area, a limit of 5 pCi/gm Ra-226 (inclusive of background) would be more consistent wits the ALARA principle and should be specified.
(Recent data from soil sa.ple analyses strongly indicate soil concentrations far belcw 5 pCi/gm Radium-226, and that thc cleanup should be performed to this level.)
The staff chose not to apply in this case, the criteria that it had previously issued for land cleanup (" Staff Technical Position Fuel Processing and Fabrication Branch--Interin Land Cleanup Criteria for Decommissioning Uranium Mill Sites" May,1978). The land cleanup criteria, in the staff position documentec, are based en situations where radon and direct ganna exposure pathways are dominant due to the building of structures on such decommissioned sites. Because the contamination in this ca.se is located in an arroyo where structures will not be constructed, the land c'.5anup criterla are not appropriate and have not been
',9, 0 328 used.
In terms of deses from the realistic pathways existing in each case, the criteria adopted for this cleanup operation are more protective than those for decommissioning mill sites, even though permissible residual concentrations are higher.
Various potential exposure paths which affect human health were evaluated with respect to the levels of radioactive contamination remaining in the arroyo following cleanup. Specifically, the staff looked at four major pathways:
inhalation of radon daughters, direct gamma exposure, inhalation of contaminated windblown particulates, and ingestion of beef cattle and sheep which graze near an:1 drink from the Rio Puerco.
(From discussions with the State and people residing in the area, it is understood that there is no direct cor.sumption of water from the affected streans). Using conservative assumptions about such f actors as the location and occupancy of structures near the contaminated arroyo, the staff found, that for each of the above pathways, the exposures were below levels which would pose a threat to public health after decontamination of the arroyo, using the above mentioned cleanup criteria.
Specifically, calculated exposures which are attributable to contamination of soils at or below the cleanup level for a person living next to the arroyo, are fractions of the linit set by the EPA (40 CFR 190) for exposures to persons in the pubiic from roukine releases from fuel cycle facilities. While the EPA limit would not be directly applicable to this accident case, it is a convenient bench mark to use for judging the risks involved.
The most difficult, and pernaps the most limiting, pathway is the meat ingesticq pathway where animals drink contaminated stream water. However, it is difficult to relate strean water quality to soil contanination levels, cecause 1340 329 the rate at which the contaminants are leached or scoured from tt:a soil cannot be quantitatively predicted. To evaluate this pat' ay, the staff has investigated several cases which are based on available data in order to bound the potential exposures occurring from this pathway. Table 2 presents these concentrations and the associateo doses. Total doses from all pathways, including this water-meat ingestion, vary frcm 6 to 18 mrem /yr (See Table 3).
As was stated in the letter advising the State of the cleanup criteria, it is extremely important to get a comprehensive understanding of the contamination present in the af fected arroyo.
The NRC, together with the State, and with some assistar.ce from the operator, has undertaken a comprehensive sampling program (procedure attached). This has included setting up a specially equipped mobile laboratory (Battelle Pac 1fic Northwest Laboratory) on-site to rapidly process soil samoles.
The full nature of the cleanup effort will not be known until the comprehensive sampling program is completed, and cleanup has progressed for a time.
The staf f set the cleanup limits to be clearly protective of public health and environment.
This report documents the radiological assessments performd by the staff in selecting the cleanup criteria.
The detailed radiological assessment is summarized in the following material.
RADIOLOGICAL ASSESSMENT The Uranium Recovery Licensing Branch's computer code, MILDOS, was used to evaluate environmental doses for potential nearby residents.
This code is used to perform radiological impacts for licensing casework (Ref.1).
marg l )y(
The MILDOS code permits radiological 3ssessment of doses to man through the following pathways:
1)
Inhalation of:
a) Particulates.
b) Radon Gas and daughters.
- 2) External exposure from:
a) Ground.
b) Cloud immersion.
3)
Ingestion of:
a) Vegetation grown locally.
b) Meat from local animals.
An additional pathway was considered separately.
This was the meat pathway resulting from the ingestion of meat from animals drinking water frcm the Pipeline Arroyo and the Rio Puerco. Appendix I documents the assumptions and calculations made in estimating the corresponding effect on man.
These pathways were, at first, considered for 30 potential individuals living along the Pipeline Arroyo or Rio Puerco. This assumption was conserva-tive in that no individual dwelling actually exists there. Three locations were finally chosen to be reflective of all possibilities:
- 1) Living at the edge of the Pipeline Arroyo.
2)
Living ten meters removed from the Pipeline Arroyo.
3)
Living downstream in the direction of the prevailing wind.
Modeling Assumotions Figure 1 models the flow of the Pipeline Arroyo.
The water flows from the northeast. The pictured portion is assumed to represent a portion of the stream such as might occur in Pipeline Arroyo downstream from the dam 1340 331
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breach and upstream of the intersection with the fiorth Fork of the Rio Puerco.
Spe'ifically, this portion was modeled as an elongated area source made up of twenty contiguous squares. The prevailing wind direction is WSW-SW, which explains the choice of the three receptors A, B, and C.
Further assumptions are:
- 1) Each of the twenty segments is assumed to be totally dry and subject to fugitive dust emission. This is presently conservative since there is a portion covered with muddy water, but this case would be representative of conditions in the arroyo upon subsequent termination of mining and milling operations in the affected area.
- 2) The cleanup criteria specify the following specific activity in the fugitive dust.
Radionuclides oCi/gm U-234 )
12.0 8
U-238 )
12.0 Th-230 30.0 Ra-226 10.0 Pb-210 )
10.0 b
') Staff estimate of uranium contamination at the time criteria were set.
Later sample analysis indicated it may be higher than 12.0 pCi/gm (as much as 20-25 pCi/gm), but the model assessment shows that doses are very insensitive to the amount of uranium present versus the other radionuclides.
b)Pb-210 is assumed to be about in equiblibrium with P.a-226.
1340 333 3)
The total length of the Pipeline Arroyo under consideration is approximately 700 meters. Considering the proximity of the potential individuals, doses resulting further downstream would have little, if any, effect on the critical individuals, as far as atmospheric transpcrt is concerned.
- 4) 140 on site meteorology was available in the form required for the MILDOS code.
Lack of information on the reduction of the Gallup Meteorology into atmospheric classes, forced the staff to search for a suitable replacement.
Meteorological data for the La Polvadeva Valley, flew Mexico, located near Gallup proved to de extremely compatible when compared with the Gallup wind rose.
Tne two wind roses are included as Figure 2.
5)
Individuals at each of the three locations, A, B, and C, are assumed to-a) Breath the air continuously, b) Eat vegetables grown at the location.
c) Eat meat animals raised at location B.3)
- 6) More specific data on tha models used in the MILDOS code are available in Reference 1.
Radiation Exposure Pathways Inhalation Airborne radioactive emissions resulting fron the contaminated soils are in the form of:
d) Highest mat ingestion doses result from cattle and sheep for aging at this location.
1340 334
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9 a) Particulates resuspe.1ed in the air by the wind blowing mechanism.
b) Radon and daughters.
Individuals in the source vicinity will inhale these radiocative materials and thus will received to internal doses.
Table 1 lists the inhalation doses to the potential individuals at locations A, B, and C, previously specified (see Figure 1). Total inhalaticn doses to the bone are greater than those to any other organ. The adult bone inhalation dose to individuals at locations A, B, and C are 1.E0 mrem /yr,1.65 mrem /yr and 0.94 mrem /yr, respectively.
External Exposure Individuals in the affected area are exposed to iceersion from the following sources:
a) Resuspended particulates in the air frcm the centaminated soil.
b) Radon and daughters in the air.
c) Radioactive emissions directly from the soil.
Individuals are assumed to be exposed to these materials at the cleanup levels previously mentioned.
The resulting maximum doses are negligible.
The results show that bone doses fall below 0.1 mrem /yr (see Table 1).
Ingestion The MILDOS computer code was employed to compute doses from ingestion of vegetables and ceat, both of which are assumed to be produced locally.
The mechanisms for radioactive uptake by humans are as follows:
p.,4 0 G
. 1)
Ingestion dose from vegetable intake:
a) Foliar deposition of radioactive particles.
b) Root uptake of radioactive materials.
2)
Ingestion dose from meat animals:
a) Animals eating vegetation contaminated as in 1 cbove.
b) Animals drinking water from the contaminated stream.3)
Doses from these pathways are listed in Tables 1 - 3.
The staff understanas that there is no drinking of the water from the Pipeline Arroyo and Rio Puerco by humans; this pathway was, therefore, not considered.
The milk pathway was also not considered due to the lack of milk cattle in the nearby area.
Although humans do not drink the water in the Rio Puerco and the Pipeline Arroyo, the sheep and cattle do water themselves in the Rio Puerco. Doses to various organs from water ingestion by animals are list,ed in Table 2.
It should, again, be noted that this pathway cannot be rigorously related to the cleanup criteria, because the leaching and scouring mechanisms, which move the contamination from the soils and sediments into the stream, cannot be quantitatively estimated at this time. Instead, estimates of exposures attributable to contaminated stream waters were based on available stream water data.
Such data on r dioactivity I
in water has been, at best, sparse and scattered. Hence, several cases of water contamination levels were considered, in order to bound the situaticn.U) u)Not performed by the MILDOS code.
b)Widely varying data has been reported by the State of ilew Mexico, the mill operator, and the EPA Las Vegas Facility Laboratory.
1340 337 The following water concentrations were chosen to place some limits on the effects of the stream contamination caused by the dam breach:
Concentration pCi/ liter Radionuclides Case Ia)
Case Il )
Case III )
d b
U-238 25 25 25 U-234 25 25 25 Th-230 2000 500 10 Ra-22o 50 25 2
Pb-210 100 100 10 Appendix I documents the assumptions, parameter values, and calculations used to obtain the doses to humans by way of the water-meat pathway.
The doses are included in Table 2 for completeness.
Until analysis of the stream contamination is completed, the staff presents a reasonably corservative range of water concentrations in order to give a more complete profile of the potential human dose.
Over time it is likely that the levels of contamination in stream water will decrease on the average. Cleanup of soils will help to assure that this is true. The same leaching and scouring mechanisms, which will tend to bring the contamination into the stream, will also be dispersing such contamination over time, thereby reducing the average concentrations.
Therefore, while the above mechanisms cannot be quantitatively evaluated in terms of relating exposures through the water-meat pathways to the soil cleanup criteria, the staff considers that use of existing water concentrations places upper bounds on potential future exposures.
- 3) Cases I and II are based on the limited water concentraticn data available, as reported by the State of.New Mexico. Analysis was performed at Eberline.
b) Case II? is based on data reported oy the State of New Mexico, the mill operator (UNC) and the EPA /LVF Laboratory.
1340 338 The staff has learned that there is direct human consumption of groundwater f rom local wells. This pathway was not included by the staff in the radiological assessment.
The primary reasons for this omission is that there is no quantitative, rigorous way to relate water concentrations to those in the soil. The soil cleanup criteria establish no levels for surface water or groundwater.
The staff believes that the primary contribution to contamination of the groundwater is attributable to the initial slug of radioactive material released immediately following the dam breach. Although the concentrations in the slug were high, the sorption of radioactivity into the ground and the diffusion of the contamination in the groundwater should reduce the overall contamination over time.
However, the staff realizes that this pathway should not be lightly dismissed.
Groundwater monitoring efforts of other agencies, such as the Indian Health Service and the State of flew Mexico, are being supplemented by collection and analysis of well water sanples by the ilRC during the arroyo decontamination efforts. The llRC will continue this monitorint, as long as deemeo necessary to protect the public health.
It should also be noted that if in the future by whatever soil and water mechanisms, such as saltation or percolation of contaminated or leached water, the soils in and around the arroyo should come to exceed the levels set by the cleanup criteria, the operator would still be subject to return the affected areas to the cleanup levels established.
The evaluation of the effect of the water pathway suffers from adaitional complications. The primary source of water in the arroyo is f rom mine dewatering activities upstream of the mill.
This water already has elevated levels of 1340 339
SS uranium before it passes the mill location. Any assessment must consider what contribution is attributable to the existing flow of mine water down the arroyo.
In addition to the contamination attributable to the dam breach and initial slug, and to the mine water, a third source of " technically enhanced" contamination is the appreciable seepage from the tailings impoundment. Presently, the contributions of these three sources to the groundwater contamination have not been determined.
In spite of these complications, the staff believes that consumption of potable well water in the affected area would not immediately impose any additional radiological exposure due to the relatively slow migration in the groundwater system. The possible contamination of the groundwater system requires well monitoring for some extended period of time, to fully determine the effects of the dam breach on it.
1340 340
TABLE 1 ADULT DOSE COMMITMENTS (mrem /yr) TO INDIVIDUALS FROM RESIDUAL CONTAMINATION AFTER CLEANUP ORGAN Location Pathway Whole Body Bone Lung A
Inhalation 0.05 1.50 0.69 External Exp.
0.08 0.08 0.08 Ingestjon-Veg.
0.24 2.98 0.24 Meat-Veg.a) 0.04 0.46 0.04 TOTAL 0.41 5.02 1.05 B
Inhalation 0.05 1.65 0.75 External Exp.
0.09 0.09 0.09 Ingestjon -
Veg.
0.26 3.27 0.26 Meat-Veg.g 0.04 0.46 0.04 TOTAL 0.44 5.47 1.14 C
Inhalation 0.03 0.94 0.43 External Exp.
0.05 0.05 0.05 Ingestjon-Veg.
0.15 1.84 0.15 Mea t-Veg.a) 0.04 0.46 0.04 TOTAL 0.27 3.29 0.67 kngestion doses result from ingestion of vegetation grown at the respective location. Meat ingestion doses result from cattle grazing i740 34I at location B.
TABLE 2 ADULT DOSES FROM THE MEAT-WATER INGESTION PATHWAY a)
Water Concentrations Doses (mrem /yr)
(pCi/ liter)
Beef Mutton Case U-238 U-234 Ra-226 Th-230 Pb-210 Whole Body Bone Whole Body Bone I
25 25 50 2000 100 0.70 12.1 0.62 7.04 II 25 25 25 500 100 0.41 7.40 0.32 3.78 III 25 25 2
10 10 0.04 0.68 0.03 0.32
- 8) Doses are broken down by organ, nuclide and type of meat in Appendix I.
1340 342
co TABLE 3 een
SUMMARY
OF TOTAL DOSES TO THE MAXIMUM EXPOSED INDIVIDUAL (LOCATION B) FROM RESIDUAL co COMIAMINATION AFTER CLEANUP ) (mrem /yr) a
~
Beef Mutton b
b Case Whole Body Bone Lung Whole Body Bone Lung I
1.14 17.57 1.84 1.06 12.51 1.76 II 0.85 12.87 1.5" 0.76 9.25 1.46 Ill 0.48 6.15 1.18 0.47 5.79 1.17 a) Doses from Table 1 and 2 are added.
)lngestion doses to the lung are considered not to exceed whole body doses for all ingestion pathways.
RE FEP,ENCES 1.
U. S. Nuclear Regulatory Comission Draft Regulatory Guide, " Calculational Models for Estimating Radiation Doses to Man from Airborne Radioactive Materials Resulting from Uranium Milling Operations." Division 3, Task RH-802-4, May 1979.
2.
G. G. Eadie and R. S. Kaufmann, " Radiological Evaluation of the Effect of Uranium Mining and Milling Operation on Selected Groundwater Supplies in the Grants Mineral Belt, New Mexico." Health Physics, Pergamon Press, Vol. 32, April 1977.
1340 344
Appendix I.
Water to Meat Pathway and Ingestion Doses to Humans.
As mentioned in the body of the Radiological Assessment, the water to meat pathway is handled separately. There are two reasons for this decision:
1.
The MILDOS code does not include this particular pathway.
2.
The cleanup criteria are stipulated in terms of soil contamination.
However, to present a complete profile of doses to humans, this pathway was investigated because of the wide variation in reported water data.
These cases are discussed in the Radiological Assessment and the reader is directed to it for further details.
The calculational model for this pathway is taken from References 1 and 2.
The computation consists of two steps:
1.
The meat concentration is the product of the following:
- Animal uptake of liquid (liters / day).
- Environmental transfer coefficients
.pCi/ka s
(pCi/ day /
- Water concentration of the nuclide of interest (pCi/ liter).
2.
The dose commitment to a given organ is computed as a product of the following:
- Annual rate of meat consumption (kg/yr).
- Meat concentration of the nuclide (pCi/kg).
This was computed in 1 above.
- The dose conver sion factor for the particular nuclide and organ
'7 mrem /yr N
(pCiingested)
To permit flexibility, the parameters in Table 1 and 2 are computed so as to leave the initial water concentration variable. Table 3 lists factors whicn convert water concentration directly to dose. Using Table 3 and the concentrations for cases I, II, and III, doses to the various organs are computed and listed in Table 4.
It should be noted that the maximum doses are to the bone; 12.1 mrem /yr from beef and 7.04 mrem /yr from mutton ingestion.
1340 345
TABLE 1 Pertinent environmental parameters Description
'alue Reference Uptake rate of water 50 (cattle)
Ref. 1 (li ters/ day) 8 (sheep)
Transfer coefficients pCi/kg meat i
V 3.4 x 10-(cattle)
Ref.1, 2, 3 pCi/ day ingested 3.4 x 10-4 (sheep)
Ref. 1, 2, 3
\\
Th 2.0 x 10-4 (cattle)
Ref. 1, 2, 3 2.0 x 10' (sheep)
Ref. 1, 2, 3 Ra 5.1 x 10-4 (cattle)
Ref. 3 4.0 x 10-3 (sheep)
Ref. 4 Pb 7.1 x 10-4 (cattle)
Ref. 3 8.0 x 10-4 (sheep)
Ref. 4 Adult Meat Ingestion Rate
', kg/yr')
78.3 (meat)
Ref. 3 1340 346
TABLE 2 ADULT DOSE CONVERSION FACTORS FOR MEAT INGESTION (REF. 3) mrem /pCi ingested U-238 U-234 Ra-226 Th-230 Pb-210
-5
-5
-3
-4 Whole Body i4.54x10 5.17x10 4.60x10 5.70x10-5 5.44x10
-4
-2
-3
-2 Bone 7.67x10-8.36x10 4.60x10 2.06x10 1.53x10
-6
-4
-3 Liver 0.0 0.0 5.74x10 1.17x10 4.37x10
-4
-4
-4
-4
-2 Kidney 1.75x10 1.99x10 1.63x10 5.65x10 1.23x10 1340 347
TABLE 3 ADULT DOSE FACTOR MULTIPLIERS C
er Beef U-238 U-234 Ra-226 Th-230 Pb-210 Whole Body 6.04x10-5 6.88x10-5 9.18x10-3 4,46x10-5 1.51 x10-3 Bone 1.02x10-3 1.lix10-3 9.18x10-2
- 1. 61 x10-3 4.25x10-2 Liver 0.0 0.0 1.15x10-5 9.16x10-5
- 1. 21 x10-2 Kidney 2.33x10-4 2.65x10-4 3.25x10-4 4.42x10-4 3.42x10-2 Mutton U-238 U-234 Ra-226 Th-230 Pb-210 Whole Body 9.67x10-6 1.10x10-5 1.15x10-2 7.14x10-6 2.73x10-4 Bone 1.63x10-4
- 1. 78 x10-4 1.15x10-1 2.58x10-4 7.67x10-3 Liver 0.0 0.0 1.44x10-5 1.47x10-5 2.19x10-3 Kidney 3.73x10-5 4.24x10-5 4.08x10-4 7.08x10-5 6.16x10-3 l.
1340 348
TABLE 4 c.d ADULT ORGAN DOSES (mrem /yr) RESULTING FROM
-er TliE WATER / MEAT INGESTION PATHWAY a)
'1 c- >
Case I "P
r< 3 UbbU,n_
~
Water Concentration Whole Body Bone Liver Kidney Whole Body Bone Liver Kidney pCi/ liter U-238 25 0.0+
0.03 0.0 0.01 0.0+
0.0+
0.0 0.0&
U-234 25 0.0&
0.03 0.0 0.01 0.0+
0.0&
0.0 0.0&
Ra-226 50 0.46 4.59 0.0&
0.02 0.58 5.75 0.0+
0.02 Th-230 2000 0.09 3.22 0.18 0.88 0.01 0.52 0.03 0.14 Pb-210 100 0.15 4.25 1.21 3.42 0.03 0.77 0.22 0.62 TOTAL 0.70 12.1 1.39 4.33 0.62 7.04 0.25 0.78 Case II Beef Mutton Water Concentration Whole Body Bone Liver Kidney Whole Body Bone Liver Kidney pCi/ liter U-238 25 0.0&
0.03 0.0 0.01 0.0&
0.0t 0.0 0.0+
U-234 25 0.0+
0.03 0.0 0.01 0.0+
0.0t 0.0 0.0+
Ra-226 25 0.23 2.30 0.0&
0.01 0.29 2.88 0.0+
0.01 Th-230 500 0.02 0.81 0.05 0.22 0.0+
0.13 0.01 0.04 Pb-210 100 0.15 4.25 1.21 3.42 0.03 0.77 0.22 0.62 TOTAL 0.41 7.40 1.26 3.66 0.32 3.78 0.23 0.66
TABLE 4 (cont'd.)
c:)
tn rn Case Ill cD
[f(
Beef flu tton Water Concentration Whole Body Bone Liver Kidney Whole Body Bone Liver Kidney
~
pCi/ liter U-238 25 0.0+
0.03 0.0 0.01 0.0&
0.0+
0.0 0.0+
U-234 25 0.0F 0.03 0.0 0.01 0.0+
0.0F 0.0 0.0+
Ra-226 2 0.02 0.18 0.0+
0.0+
0.02 0.23 0.0+
0.0+
Th-230 10 0.0+
0.02 0.0&
0.0+
0.0&
0.0&
0.0&
0.0&
Pb-210 10 0.02 0.43 0.12 0.34 0.0&
0.08 0.02 0.06 TOTAL 0.04 0.68 0.12 0.36 0.03 0.32 0.02 0.07
} The "+" after 0.0 indicates positive numbers which are less than 0.005.
Rounding off to two decimal places accounts for any discrepancy in the to tal s.
APPENDIX REFERENCES 1.
U.S. Nuclear Regulatory Commission Regulatory Guide 1.109,
" Calculation of Annual Doses to Man From Routine Releases of Reactor Effluents for the Purpose of Evaluating Compliance with 10 CFR 50", Appendix R, March, 1976.
2.
Reference 2, Revision 1, October 1977.
3.
U.S. Nuclear Regulatory Commission Draft Regulatory Guide,
" Calculational Models for Estimating Radiation Doses to Man from Airborne Radioactive Materials Resulting from Uranium Milling Operations", Division 3, Task RH-802-4, May 1979.
4.
L.M. McDowell-Boger, A.P. Watson, C.C. Travis.
Review and Recommendations of Dose Conversion Factors and Environmental Transport Parameters for Pb-210 and Ra-226, NUREG/CR-0574.
ORNL/NUREG-56, March 1979.
1340 35i