ML20041A277
| ML20041A277 | |
| Person / Time | |
|---|---|
| Site: | 07001113 |
| Issue date: | 01/27/1982 |
| From: | Crow W NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| To: | Vaughan C GENERAL ELECTRIC CO. |
| References | |
| NUDOCS 8202190365 | |
| Download: ML20041A277 (2) | |
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. Docket File 70-lll3'}f~L (
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JAN 2 71982 gp f WTCrow LTyson FCUP:WTC RGPage 70-1113 R:II SNM-1097 co a
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q]/ acCEP & D General Electric Company ATTN: Mr. C. M. Vaughan, Acting Manager g
Licensing and Compliance Audits,
. A FEB4 1982 > c M/CJ26 m, m nu:cfm tu r Z Nuclear Energy Products Division
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P.O. Box 780 s %' >-
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Wilmington, North Carolina 28402
.d Gentlemen:
This is to confirm a telephone conversation with your Mr. C. M. Vaughan in September 1981 regarding his letter to me dated August 13,1981 con-cerning radiation or contamination levels of materials to be released for unrestricted use and/or disposal. Equipment containing surface contamination may be released for unrestricted use if the contamination meets the " Guidelines for Decontamination of Facilities and Equipment Prior to Release for Unrestricted Use or Termination of Licenses for Byproduct, Source, or Special Nuclear Material" (copy enclosed);
however, waste materials such as calcium fluoride or materials that will be recycled into the domestic stream, such as aluminum or molybdenum, must be approved on an ad hoc basis and only with the approval of the Commission.
Enclosed is a copy of a recent Branch Technical Position which provides guidance to licensees for disposal of radioactive material in soil.
Although this document was only in conception stage when I spoke to Mr. Vaughan on August 6,1981, it should provide additional information
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B202190365 B20127 om) PDR ADOCK 07001113 C
PDR NRC FORM 318 410 BOI NRCM O240 OFFICIAL RECORD COPY 4-
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s General Electric Company JAN 2 71982 for you when evaluating the alternatives for disposing of contaminated I
materials but, as I infonned Mr. Vaughan, authorization must be l
obtained from the Comission prior to disposal and/or storage of material under Options I through V.
If there are any questions concerning this matter, please feel free to contact me.
Sincerely.
OriGi#
W.y;. T. Crow T. Crow, Section Leader Uranium Process Licensing Section Uranium Fuel Licensing Branch Division of Fuel Cycle and Material Safety, fMSS l
Enclosures:
As stated cc: Mr. D. H. Brown, Stato of NC Radiation Protection Branch 1
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ANNEX GUIDELI!JES FOR DECONTAMIf4ATION OF FACILITIES AtlD EQUIPMENT PRIOR TO RELEASE FOR UllRESTRICTED USE OR TERMINATION OF LICENSES FOR BYPRODUCT, SOURCE, OR SPECIAL NUCLEAR MATERIAL U. S. Nuclear Regulatory Commission Division of Fuel Cycle ano Material Safety Washington, D.C.
20555 NOVEMBER 1976
e gr The instructions in this guide in conjunction with Table I specify the radioactivity and radiation exposure rate limits which should be used in accomplishing the decontamination and survey of surfaces or premises and equipment orior to abandonment or release for unrestricted use.
The limits in Table I do not apply to premises, equipment, or scrap containing induced radioactivity for which the radiological considera-tions pertinent to their use may be different. The release of such f acilities or items from regulatory control will be considered on a case-by-case basis.
1.
The licensee shall make a reasonable effort to eliminate residual con tami nati on.
2.
Radioactivity on equipment er surfaces shall not be covered by paint, plating, or other covering material unless contamination levels, as determined by a survey and documented, are below the limits specified in Table I prior to applying the covering.
A reasonable effort must be made to minimize the contamination prior to use of any covering.
3.
The radioactivity on the interior surfaces of pipes, drain lines, or ductwork shall be determined by making measurements at all traps, and other appropriate access points, provided that contamination at these locations is likely to be representative of contamination on the interior of the pipes, drain lines, or ductwork. Surfaces of premises, equipment, or scrap which are likely to be contaminated but are of such size, construction, or location as to make the surface inaccessible for purposes of measurement shall be presumed to be contaminated in excess of the limits.
4.
Upon request, the Commission may authorize a licensee to relinquish possession or control of premises, equipment, or scrap having,urfaces contaminated with materials in excess of the limits specified.
This may include, but would not be limited to, special circumstances such as razing of buildings, transfer of premises to another organization continuing work with radioactive materials, or conversion of facilities to a long-term storage or standby status.
Such requests must:
a.
Provide detailed, specific information describing the premises, equipment or scrap, radioactive contaminants, and the nature, extent, and degree of residual surface contamination.
b.
Provide a detailed health and safety analysis which reflects that the residual amounts of materials on surface areas, together with other considerations such as prospective use of the premises, equipment or scrap, are unlikely to result in an unreasonable risk to the health and safety of the public.
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Prior to release of premises for unrestricted use, the licensee shall 7
make a comprehensive radiation survey which establishes that contam-
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ination is within the limits specified in Table I.
A copy of the survey report shall be filed with the Division of Fuel Cycle and Material Safety, USNRC, Washington, D.C.
20555, and also the Director of the Regional Office of the Office of Inspection and
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Enforcement, USNRC, having jurisdiction.
The report should be filed M
at least 30 days prior to the planned date of abandonment.
The survey report shall:
a.
Identify the premises.
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Show that reasonable effort has been made to eliminate residual contami nation.
c.
Describe the scope of the survey and general procedures followed.
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State the findings of the survey in units specified in the t-instruction.
Following review of the report, the NRC will consider visiting the facilities to confirm the survey.
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N TABLE I ACCEPTABLE SURFACE CONTAMINATION LEVELS d
bcf bdf bef NUCLIDES AVERAGE MAXIMUM REMOVABLE 2
2 2
U-nat, U-235, U-238, and 5,000 dpm a/100 cm 15,000 dpm a/100 cm 1,000 dpm a/100 cm F
associated decay products 2
2 Transuranics, Ra-226, Ra-228, 100 dpm/100 cm 300 dpm/100 cm 20 dpm/100 cm Th-230, Th-228, Pa-231, Ac-227, I-125,1-129 2
2 Th-nat, Th-232, Sr-90, 1,000 dpm/100 cm 3,000 dpm/100 cm 200 dpm/100 cm Ra-223, Ra-224, U-232, I-126, 1-131, I-133 2
2 2
Beta-gamma emitters (nuclides 5,000 dpm BY/100 cm 15,000 dpm By/100 cm 1,000 dpm BY/100 cm with decay modes other than alpha emission or spontaneous fission) except SR-90 and others noted above.
Where surface contamination by both alpha-and beta-gamma-emitting nuclides exists, the limits established for alpha ~
a and beta-gamma-emitting nuclides should apply independently.
As used in this table, dpm (disintegrations per minute) means the rate of emission by radioactive material as de-termined by correcting the counts per minute observed by an appropriate detector for background, efficiency, and geo-metric factors associated with the instrumentation.
cMeasurements of average contaminant should not be averaged over more than 1 square meter.
For objects of less surface area, the average should be derived for each such object.
2 dThe maximum contamination level applies to an area of not :nore than 100 cm,
TABLE 1 2
2
- The amount of removable radioactive material per 100 cm of surface area should be determined by wiping that area with dry filter or soft absorbent paper, applying moderate pressure, and ascessing the amount of radioactive material I
on the wipe with an appropriate instrument of known efficiency. When removable contamination on objects of less surface area is determined, the pertinent levels should be reduced proportionally and the entire surface should be wiped..
The average and maximum radiation levels associated with surface contamination resulting from beta-gamma emitters should not exceed 0.2 mrad /hr at I cm and 1.0 mrad /hr at 1 cm, :espectively, measured through not more than 7 milli-grams per square centimeter of total absorber.
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October 5, 1981 SECY 81-576 For:
The Commissioners From:
William J. Dircks Executive Director for Operations
Subject:
DISPOSAL OR ONSITE STORAGE OF RESIDUAL THORIUM OR URANIUM (EITHER AS NATURAL ORES OR WITHOUT DAUGHTERS PRESENT) FRCM PAST OPERATIONS Purcose:
To infor:n the Commission of the adoption of a Branch Technical Position for application by the Uranium Fuel Licensing Branch.
Discussion:
Some of the sites formerly used for processing thorium and uranium are known today to be contaminated with residual radioactive materials.
In many cases, the total amount of contaminated soil is large, but the activity concentrations of radioactive materials present are sufficiently low as to justify their disposal on privately owned lands or storage onsite rather than transport them offsite to a licensed radioactive materials disposal (commercial) site.
In many instances, packaging and transporting these Uyd wastes to a licensed disposal site would be too costly and not justified from the standpoints of risk to the public health or cost-benefit. Furthermore, because of the high volume of these wastes, limited commercial waste disposal capacity, and restrictions placed on receipt of long-lived wastes at commercial sites, it is not presently feasible to dispose of these wastes at commercial low-level waste disposal sites.
Effective January 28, 1981, NRC regulations in 10 CFR 20 " Standards for Protection Against Radiation" were amended (45 FR 71761-71762) to delete Section 20.304 which provided general authority for disposal of radioactive material by burial in soil. Under the amended regulations licensees must apply for and obtain specific NRC approval to dispose of radioactive materials in this manner under the provisions of 10 CFR 20.302.
CONTACT:
<c R.G. Page, 'nS
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Guidelines for disposal or storage of low activity concentrations of thorium and uranium or uranium ore bearing wastes on privately owned lands are needed to deal with the contaminated site cases which are presently pending (Enclosure 1). To this end, the staff has identified five acceptable options for disposal (under the provisions of 10 CFR 20.302) or onsite storage which.
the staff intends to apply in processing applications.
A summary discussion of these is provided in Enclosure 2.
An expanded discussion is contained in Enclosure 4. discusses the technical bases for the derived concentration limits for each of the four disposal options. The approach used in establishing the concentration limits is consistent with that used in developing the proposed new Part 61 concerning licensing requirements for land disposal of radioactive wastes. That proposed rule is based on two assumptions that a burial site may some day be intruded; and that buried radioactive materials will not likely present a danger to the public health and safety even if intruded.
In the case of uranium ore residues with daughters present, there will be limited radon emanations; however, with the burial depths required, resultant surface fluxes will be near background levels. Accordingly, the burial of radioactive materials covered by the Branch Technical Position does not present a danger to health and safety.
We believe that the options for disposal or storage of thorium or uranium are fully consistent with disposal standards recommended by EPA. We informally discussed the options with EPA staff members and made some changes to accommodate their suggestions.
Before approving an application to dispose of thorium or uranium under options, 2, 3, or 4, we will solicit the views of appropriate State health officials on a case-by-case basis.
In this connection, we sent the States a copy of the proposed Branch Technical Position. Two States commented; neither of which were negative.
I I
e The Commissioners Enclosure 4 is a Federal Register notice which we plan to have published on this matter.
William J. Ofrcks Executive Director for Operations
Enclosures:
1.
Contaminated Site Cases Presently Pending 2.
Summary of Disposal and Storage Options 3.
Calculation of Allowable Concentrations for Four Disposal Options 4.
Federal Register Notice DISTRIBUTI0ft Commissioners Commission Staff Offices SECY 4
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ENCLOSURE 1 9
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Contaminated Site Cases Presently Pending Disposal or Storage Option Site that May Acoly Stepan Chemical Company 2,3*
Maywood, New Jersey (Thorium ore residues)
Kerr-McGee Corporation 5
West Chicago, Illinois (Thorium ore residues)
McGean Chemical Compar.y 4
Newburg Heights, Ohio (Depleted uranium)
Amax Corporation 4 or 5 Parkersburg, West Virginia (Thorium oxide mixed with zirconium)
Cotter Corporation (former owner) 5 Latty Avenue St. Louis, Missouri (Uranium residues)
Velsicol Chemical (formerly Michigan Chemical) 4 St. Louis, Michigan (Uranium, thorium and radium ore wastes Except for a few hot spots that will need to be removed from the site, the contamination on adjoining property west of Highway 17 appears to fall under options 2 or 3.
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b ENCLOSURE 2 i
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SUMMARY
OF DISPOSAL AND STORAGE OPTIONS The following is a summary of the disposal and storage options which staff intends to apply. The maximum concentrations pennitted under each disposal option are tabulated on the last page of this enclosure.
1.
Disposal of acceptably low concentrations (which meet EPA cleanup standards) of natural thorium, depleted or enriched uranium, and uranium ores with no restriction on burial method.
The concentrations specified for this option are believed acceptably low without restricting the method of burial.
It is expected, however, tha currently licensed operations will be conducted in such a manner as to minimize the possibility of soil contamination and when such occurs the contamination will be reduced to levels as low as reasonably achievable.
2.
Disposal of certain low concentrations of natural thorium and depleted or enriched uranium (with no daughters present) when buried under prescribed conditions with no land use restrictions and no continuing NRC licensing of the material.
Under this option, burial will be pennitted only if it can be demon-strated that the buried materials will be stabilized in place and not be transported away from the site. Acceptability of the site for disposal will depend on topographical, geological, hydrological and meteorological characteristics of t.*e site. At a minimum, burial depth will be at least four feet below the surface.
3.
Disposal of low concentrations of natural uranium cres with daughters in equilibrium, when buried under prescribed conditions in areas zoned for industrial use, and the recorded title documents are amended to state that the specified land contains buried radioactive materials and are conditioned in the manner acceptable under state law to impose a covenant running with the land that the specified land may not be used for residential building. (There is no continuing NRC licensing of the material. )
Disposal will be approved if the burial criteria outlined in option 2 (including burial at a minimum of four feet) are met. Under this option, no residential building would be permitted over land where natural uranium ore residues have been buried.
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Disposal of land-use-limited concentrations.i natural thorium, natural uranium and depleted or enriched uranium wh n buried under prescribed conditions in areas zoned for industrial use and the recorded title documents are amended to state that the land contains buried radioactive materials, and are conditioned in the manner required by state law to impose a covenant running with the land that the land (1) may not be excavated below stated depths in specified areas unless cleared by appropriate health authorities, (2) may not be used for residential or industrial building, and (3) may not be used for agricultural purposes.
(There is no continuing NRC licensing of the disposal site.)
Criteria for disposal under these conditions is predicated upon the assumption that intentional intrusion is less likely to occur if a warning is given in land documents of record not to excavate below burial depths in specified areas of land without clearance by health authorities; not to construct residential or industrial buildings on the site; and not to use specified areas of land for agricultural purposes.
In addition to meeting the burial criteria in option 2, recorded title' documents would be amended to impose these land use restrictions.
5.
Storage of licensed concentrations of thorium and uranium onsite pending the availability of an appropriate disposal site.
When concentrations exceed those specified in option 4, long. term disposal other than at a licensed disposal site will not normally be a viable option under the provisions of 10 CFR 20.302.
In such cases, the thorium and uranium may be permitted to be stored onsite under an NRC license until a suitable method of disposal is found. License conditions will require that radiation doses not exceed those specified in 10 CFR Part 20 and be main-tained as low as reasonbly achievable.
SUMMARY
CF MAXIMUM CONCENTRATIONS PERMITTED UNDER DISPOSAL OPTIONS Disposal Options a
c d
Kind of Material l
2 3
4 Natural Thorium (Th-232 + Th-228) 10 50 500 with daughters present and in equilibrium Natural Uranium (U-238 + U-234) 10 40 200 with daughters present and in equilibrium Depleted Uranium o Soluble 35 100 1000 o Insoluble 35 300 3000 Enriched Uranium o Soluble 30 100 1000 o Insoluble 30 250 2500 a Based on EPA cleanup standards.
b Concentrations based on limiting individual doses to 170 mrem /yr.
Concentration based on limiting equivalent exposure to 0.02 working c
level or less.
d Concentrations based on limiting individual doses to 500 mrem /yr and, in case of natural uranium, limiting exposure to 0.02 working level or less.
ENCLOSURE 3
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CALCULATION OF ALLOWABLE CONCENTRATIONS FOR FOUR DISPOSAL OPTIONS I
Introduction The following sections provide dose calculations for establishing limiting concentrations of thorium and uranium for disposal under four disposal options. The dose tabulation includes various significant pathways to man resulting from the burial of radioactive wastes containing natural thorium, natural uranium, enriched uranium, or depleted uranium. With thesa tables, the concentration limit of a radionuclide or mixture of radionuclides in various types of wastes to be disposed of by these options can be calculated. Tables 7 and 8 summarize the concentration limits of sone typical wastes for each option of disposal. Concentration limits involving other mixtures of these radionuclides can be calculated by the use of these tables.
II Radioactive Characteristics of the Nuclides A.
Thorium The natural thorium decay chain and the characteristics of each nuclide are summarized in Table 1.
The parent Th-232 generally exists in nature with its daughters which are in radioactive equilibrium with the parent. However, in some types of waste such as from processing of thorium ore, the purified metal (Th-232 and Th-228) is removed as the product ano the daughter products can be various wastes. Therefore, it is important to understand the history of the operation and how the wastes are generated.
As shown in Table 1 Th-232 and its daughters consist of alpha, beta, and gamma emitters. The alpha emitters will constitute a significant pathway for dose to man through inhalation and ingestion. The critical organs in the inhalation and ingestion pathways are the lung and the bone depending on the solubility classification of the nuclide. The gamma emitters will contribute external radiation (whole-body) dose to man. Therefore, the pathways for dose to man to be considered for natural thorium are direct radiation, inhalation and ingestion.
Table 1 Thorium Chain c,
, Principal' Radi_ations (MeV)a Isotooe Tl/2 Daughter Alona-Beta
- Gammas Th-232 1.405x1010y Ra-228 4.00 Ra-228 5.75y Ac-228 0.01 0 Ac-228 6.13h Th-228 0.376 0.91 5 Th-228 1.9131y Ra-224 5.40 0.002 Ra-224 3.66d Rn-220 5.67 0.009 i
Rn-220 55.6s Po-216 6,29 Po-216 0.15s Pb-212 6.78 Pb-212 10.64h 81-212 0.100 0.117 Bi-212 60.55m T* -208 6.04(35.93%)
0.003 Po-212
(64.07%)
0.71 7 0.281 T1-208 3.07m Pb-208 0.561 2.37 Po-212 3.05x10'7 s Pb-208 8.78 (Stable)
Branches <1% not included.
Average energ.
. Total Energ emitted per disintegration.
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Uranium The uranium chains including U-238 and U-235 are given in Tables 2 and 3.
For uranium that has been processed through the milling operation, the only nuclides of importance in the dose calculations are U-238 and U-234. The buildup of daughters in the separated uranium is not important, i.e., neither the Th-230 nor the Ra-226 could reach 10% of equilibrium with the separated uranium until i
greater than 10,000 years. The U-234 usually stays in equilibrium with the U-238 parent with the equilibrium between U-238 and Pa-234 reached in a matter of months.
In normal processing of uranium ore, the process separates both the Th-230 and Ra-226 to the same stream of waste; then both nuclides are in secular equilibrium.
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If in~the case of uranium residues Th-230 and Ra-226 are not in equilibrium, particularly if the Th-230 is much higher than Ra-226, a potential source of Ra-226 contamination may exist as radium builds up to equilibrium with the Th-230.
In this case, the primary con-sideration must be given to exposure from radionuclides other than U-238 and U-234.
In some types of operations, other metals are extracted and uranium ore is left in the waste stream as byproducts.
In these cases all uranium daughter products must be considered.
The' parent U-235 occurs to< the extent of only about 0.7% in natural uranium and the chain is generally unimportant compared with the U-238 chain. However, f,n the early years of the Manhattan Project much of the ore'was very high grade pitchblende or carnotite ore. After the uranium was separated and Ra-226 extracted from the wastes, the Ac-227 t
and Pa-231 nuclides remained in the waste stream. These constitute a significant source of contamination.
i.
As shown in Tables 2 and 3, radionuclides in the uranium decay chains emit alpha, beta and gamma radiation. The pathways for dose to man are from direct radiation, inhalation and ingestion. The critical organs are the whole body, the bone and the lung.
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, Princioal Radiations (MeV)a Isotone 1/2 Daughter Alona*
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9 U-238 4.468x10 Th-234 4.20 Th-234 24.10d Pa-234 0.044 0.008 Pa-234 1.17m U-234 0.82 0.011 5
U-234 2.445x10 y Th-230 4.76 4
Ra-226 1600y Rn-222 4.77 0.006 Rn-222 3.8235d Po-218 5.49 Po-218 3.05m Pb-214 6.00 Pb-214 26.8m Bi-214 0.22 0.23 Bi-214 19.9m Po-214 0.63 2.03 Po-214 1.64x10"# s Pb-210 7.69 Pb-210 22.3y B1-210 0.007 0.002 31-210 5.012d Po-210 0.39 Po-210 138.378d Pb-206 5.31 (Stable) 38 ranches <li, not included l
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CTotal energy emitted per disintegration.
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<Princioal Radiations (MeV)a IsotoDe 1/2 Dauchter Alona" Beta" Gamma" 8
U-235 7.1x10 y Th-231 4.28 0.140 Th-231 25.52h Pa-231 0.078 0.017 4
Pa-231 3.248x10 y Ac-227 4.92 0.030 Ac-227 21.773y Fr-223 4.19(1.38%)
Th-227
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0.010 Th-227 18.718d Ra-223 5.67 0.010 Fr-223 21.Sm Ra-223 0.345 0.0 51 Ra-223 ll.434d Rn-219 5.70 0.087 Rn-219 3.96s Po-215 6.81 0.054 Po-215 1.780x10-3s Pb-211 7.39 Pb-211 36.1m 81-211 0.453 0.050 81-211 2.13m T1-207 6.55 0.043 Tl-207 4.77m Pb-207 0.493 0.002 (Stable) a8 ranches <lt not included.
Average energy.
kotal energy emitted per disintegration.
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L III Dose Calculation The following Tables 4-6 summarize the organ doses for various pa2 ways to man based on unit concentration of each nuclide as shown in Tables 1-3.
All internal doses listed in the tables are 50-year dose commitments; that is, the total dose an individual will receive from one year of intake integrated over the next 50 years of his life. For those materials that either have short radioactive half-lives or are eliminated rapidly frem the body, essentially all the dose is received in the same year that the radionuclide entered the body, and the annual dose rate is
- about the same as the 50-year dose commiteent. All external doses are given as annual dose rates.
The factors for converting internal exposure to dose (dose conversion factors) were determined using ICRP-2 and other recognized values and implemented by recent models (Task Group Lung Model) for the lung and GI tract. The dose conversion factors used for external radiation dose determination are given in ORNL-4992. The dose conversion factor for inhalation of radon and its daughters are derived from the BEIR report.
IV Derived Maximum Allowable Concentration for Various Discosal Ootions Tables 7 and 8 sumarize the maximum allowable concentration for the disposal of various types of wastes. Concentrations derived in option 1 are residues of cleanup concentrations which can be disposed of in any manner. The concentra-tions derived in option 2 are such that under the worst modes of exposure including all significant pathways, the maximum individual dose would not exceed 170 arem/yr to any critical organ.- In option 3. the most significant pathway is from the inhalation of radon and its daughter products. With an average concentration of 20 pCi Ra-226 per gm of waste, it is estimated that an individual could be exposed to an average of 0.04 Working Level (WL) from inhalation of radon inside structures built on contaminated land.
This exposure is judged to be too high for residential use of the burial si te. (Compare with 0_.033 WL-10 CFR 20; 0.005-0.02 WL-EPA Florida Phosphate Gui dance. ) Comercial use of the site is allowable because the exposure time to radon is expected to be less than 50% of continuous exposure and consequently no individual will likely be exposed to an average of 0.5 WLM.
The concentrations of uranium, depleted uranium and natural thorium derived in option 4 are higher by approximately a factor of 10 since a limited exposure from an intruder (assuming about 30% of full exposure used in option 2) is assumed and a maximum individual dose of 500 mrem /yr to a critical organ is assumed. For the case of natural uranium, the concentration derived in option 4 is higher by a factor of 5.
The concentration is based on a limited exposure such that no individual will be exposed to a radon dose in excess of 0.5 WLM assuming a maximum exposure time of 2.4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> (i.e.10%) a day. This is equivalent to continuous exposure to 0.02 WL.
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-7 Table 4 Annual Dose from Exposure to External Gamma Radjation Resulting from Contaminated Grcund Surfacetd>
Figures are based on a unit concentrat{gy of 1 pCf /g for each radionuclide in soil l
Whole body dose Whole body dose Whole body dose l
Radionuclides (mrem /yr)
Radionuclides (mrem /yr)
Radionuclides (mres/yr)
Uranium Series Actinium Series Thorium Series U-238 U-235 4.4E-1 Th-232 s'
Th-234 2.5E-2 Th-231 1.9E-1 Ra-228 Pa-234m 1.9E-2 Pa-231 2.7E-1 Ac-228 1.3E-0 i
U-234 Ac-227 Th-228 Th-230 Th-227 4.lE-1 Ra-224 Ra-226 1.4E-2 Ra-223 3.8E-1 Ra-220 Ra-222 Ra-219 1.1E-1 Pb-212 3.0E-1 Po-218 Pb-211 9.4E-2 B1-212 2.3E-1 Pb-214 4.8E-1 B1-211 9.4E-2 T1-208 5.5E-0 81-214 2.8E-0 T1-207 Po-214 Pb-210 3.4E-2 111-210 Po-210 (a) Assumed structural shielding factor of 0.5 and 80% occupancy.
The ground is nodeled as a plane area with uniform distribution of radioactivity.
Assume a soil density of 2.5 g/cc.
U Insignificant compared with other nuclides.
Read as 2.5 x 10~
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Table 5a Dose Commitments (a) From Inhalation of Resusoended Raoionuclioes'-' From contaminatec soil Figures are based on a unit concentration of 1 pCi/g of each radionuclide in soil.
(Clearance rate class Y; particle size ( AMAD) = 1 um)
Racionuclide 00se Commj tment (mrem)if)
Lungs 9)
Bone Working Levei Uranium series
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U-238 6.1E-1(c) 5.2E-3 (d)
Th-234 Pa-234a U-234 6.9E-1 5.8E-3 Th-230 6.7E-1 2.4E-1 Ra-226 7.2E-2 'I 3.6E-2 I
Po-218 Pb-214 Bi-214 Po-214 Pb-210 7.9E-3 'I 3.lE-2 I
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(a) Fifty-year dose commitment for one year of intake.
(b) Assumed resuspension factor 5x10-9 m-I; maximum soil density of 2.5 g/cc; 80i occupancy. This resuspension factor may be conservative. These factors should be based on particle size and densities associated with specific sites.
(c) Read as 6.1x10-1 (d) Insignificant compared with other nuclides.
(e) Ra-226 and Pb-210 are classified as W compounds; Po-210 is classified as W or D compound.
(f) Based on quality factor of 20 for alpha particles.
(9) Pulmonary lung (h) The average Working level (WL) is calculated on the basis of 25 WLM/ year per WL (continuous exposure) and a dose conversion factor of 5 rem per working level month. This mean level of exposure derived from radon inside a structure built en contaminated wastes could be off significantly depending on the input parameters used, such as the ventilation rate, type of floor, etc., which are dependent on the structural design of the building.
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. Table Sa (cont'd)
Radionuclide Dose Commitment (mrem)
Lung Bone Actinium Series U-235 6.2E-1 S.3E-3 Th-231 Pa-231 7.6E-1 7.0E-1 Ac-227 1.3E-0 3.9E-1 Th-227 8.8E-2 2.9E-4 Ra-223 5.9E-2 7.0E-4 Rn-219 Po-215 Pb-211 81-211 T1-207 Thorium Series Th-232 5.8E-1 2.6E-1 Ra-228 6.2E-3 2.1E-2 Ac-228 Th-228 9.2E-1 2.3E-2 Ra-224 Rn-220 Pb-212 Bi-212 T1-208 y.-.
a -
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O r,
. Table Sb Dose Commitments From Inhalatio~n of Resusoended Radionuclides Frcm Contaminated Soil Figures are based on a unit concentration of 1 pCf /g of each radionuclide in soil (clearance rate class W; particle size (AMAD) = 1 um)
Radionuclice Dose Commitment (mrem)
Lung Sone Working Level Uranium Series U-238 6.3E-2 1.5E-2 Th-234 Pa-234a U-234 7.0E-2 1.7E-2 Th-230 6.9E-2 6.0E-1 Ra-226 7.2E-2 3.6E-2 Po-218 Pb-214 81-214 Po-214 Pb-210 7.9E-3 3.1E-2 Bi-210 Po-210 1.3E-3 5.9E-3 Rn-222
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, Table 5b (cont'o)
Radionuclice Dose Commi tment (mrem)
Lung Bone Actinium Series U-235 6.4E-2 1.5E-2 Th-231 Pa-231 1.6E-0 Ac-227 7.4E-2 1.1E-0 Th-227 6.8E-2 2.6E-3 Ra-223 5.9E-2 7.0E-4 Rn-219 Po-215 Pb-211 Bi-211 T1-207 Thorium Series Th-232 6.0E-2 6.2E-1 Ra-228 6.1E-3 2.1E-2 Ac-228 Th-228 1.5E-1 1.3E-1 Ra-224 Rn-220 Pb-212 81-212 T1-208 e
v
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s-
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e 12-Table Sc Dose Commitments from Inhalation of Resuscended Racionuclices from Contaminated Soil Figures are based on a unit concentration of 1 pCi/g of each radionuclide in soil.
(Clearance rate class 0; particle size (AMAD= 1 um))
Radionuclice 00se Commi tment (mrem)
Lung Bone Working Level Uranium Series U-238 1.lE-3 5.0E-2 Th-234 Pa-234a U-234 1.2E-3 5.6E-2 Th-230 6.9E-2 6.0E-1 Ra-226 7.2E-2 3.6E-2 Po-218 Pb-214 81-214 Po-214 Pb-210 7.9E-3 3.lE-2 31-210 Po-210 1.3E-3 1.9E-3 Rn-222
.002 f
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j, 3
, Table Sc (cont'c)
Radionucitae Dose Commitment (mrem)
Lung Bone Actinium Series U-235 1.1E-3 5.0E-2 Th-231 Pa-231 7.4E-2 1.6E-0 Ac-227 1.1E-1 1.1E-0 Th-227 6.8E-2 2.6E-3 Ra-223 5.9E-2 7.0E-4 Rn-219 Po-215 Pb-211 Bf-211 T1-207 Note: Thorium compounds are classified as Y and W compounds, i
a I
.~.
Table 6
' Dose Commitment hesulting from Ingestion (a)
I (vegetation, beef, mild of Radionuclides fr55 tontaminated soll.
Figures based on a unit concentration of 1 pCi/g of each nuclide j
in the soll (the first 15 cm of soil)
Bone Dose Bone Dose Bone Dose Radionuclides (mrem)
Radionuclides (mrem)
Radionuclides (mrem) l Uranium Series Actinium Series Thorium Series l
U-238 1.8E-0 U-235 1.8E-0 Th-232 5.0E-1 i'
Th-234 Th-231 Ra-228 S.4E-0 Pa-234 Pa-231 1.4E+1 Ac-228 U-234 2.0E-0 Ac-227 8.1E-0 Th-228 1.1E-1 Th-230 1.2E-0 Th-227 Ra-224 Ra-226 1.1E-0 Ra-223 Pb-212 Po-218 Pb-211 Bi-212 Pb-214 Bi-211 T1-208 1
Bi-214 T1-207 Po-214 3
Pb-210 8.0E-0 B1-210 Po-210 3.3E-2 (d}It is assumed that an individual would raise 60% of his own food on the burial site. The staff believes this to be a conservative assumption since it is highly unlikely that an individual would raise this amount of his own food on a burial site.
I i
~
Table 7 Stimmary of Radionuc1Tde concentrations in Hastes Under Various Disposal Options J tions 2 and 3 Option 4 O
Type of Wastes Option 1 Whole-Body Lung Bone Whole-Body Lung Bone Whole-Body Lung Bone (10pr/hr)
(Imrad) (3 mrad) (170 mrem)
-(170 mrem) (170 mrem) (500 mrem)
(500 mrem) (500 mrem)
M'aximum Allowable Concentration (PCT /gml
- a. Insoluble 35 300 3,000 1,000
- b. Soluble 35 100 e
- 2. Enriched uranium 2,500
- a. Insoluble 30 250
- b. Soluble 30 100 1,000
(includes all daughters) 500
- a. Insoluble 10 50
- b. Soluble 10 50 500
(includes all daughters) 40(2) 200 (3)
- a. Insoluble 10(1)
- b. Soluble 40 200
\\
}The residual cleanup concentration for natural uranium is based on that set by EPA (46 FR 2556-2563) for radium 226 and its decay poducts.
(
Indoor radon exposure is estimated to be about 0.04 WL for continuous exposure; land restriction for residential use is required.
(3) Radium concentration is based on a limited exposure such that no individual will be exposed to a radon dose in excess of 0.5 ULM assuming a maximum exposure time of 2.4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> a day.
This is equivalent to continuous exposure to.G2 1.'L.
1, s
i l Table 8 Maximum Allowable Concentration in Waste for Ootions 1, 2, 3 and 4 Type of Wastes Maximum All.cwable Concentration (DCf /g)
Option 1 Option 2 & 3 ODtion 4 1.
- a. Insoluble 35 300 3,000
- b. Soluble 35 100 1,000 2.
Enriched Uranium (U-238, U-235, U-234)
- a. Insoluble 30 250 2,500
- b. Soluble 30 100 1,000 3.
Natural Uranium (U-238, U-234)
- a. Insoluble 10 40 200
- b. Soluble 10 40 200 4.
Natural Thorium (Th-232, Th-228)
- a. Insoluble 10 50 500
- b. Soluble 10 50 500 p
6 8N g-
1, ENCLOSURE 4
-~ ~
6 NUCLEAR REGULATORY COMMISSION 7590-01 DISPOSAL OR ONSITE STORAGE OF THORIUM OR URANIUM WASTES FROM PAST OPERATIONS AGENCY:
Nuclear Regulatory Commission (NRC)
ACTION:
Discussion of Options for NRC Approval of Applications for Disposal or Onsite Storage of Thorium or Uranium Wastes -
Interim Use and Public Comment
SUMMARY
- This notice discusses five options for NRC approval of disposal or onsite storage of thorium or uranium wastes from past nuclear operations.
Tiie options are contained in a Branch Technical Position for administration by the Uranium Fuel Licensing Branch, Division of Fuel Cycle and Material Safety. Office of Nuclear Material Safety and Safeguards.
DATES:
Comments on the options for disposal or onsite storage of thorium or uranium are encouraged.
Such ccmments will be considered in any subsequent revision of the Branch Technical Position. Contents are due Note: Comments received after the expiration date will be considered if it is practical to do so, but assurance of consid-eration cannot be given except as to comments filed on or before that date.
FOR ADDITIO.'IAL INFORMATION CONTACT: Ralph G. Page, Chief, Uranium Fuel LicensingSranch,DivisionofFuelCycleandMaterialSafet[,Officeof Nuclear Material Safety and Safeguards, Washington, D.C. 20555, telephone 301-427-4309.
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SUPPLEMENTARY INFORMATION:
I.
Introduction Some of the sites fonnerly used for processing thorium and uranium are known today to be contaminated with residual radioactive materials. Some are currently covered by NRC licenses. Others were once licensed, but the licenses to possess and use material have expired.
In many cases, the total amount of contaminated soil is large, but the activity-concentrations of radioactive materials are believed sufficiently low to justify their disposal on privately owned lands or storage onsite rather than their transport to a licensed radioactive materials disposal (ccmmercial) site.
In many 1
instances packaging and transporting these wastes to a licensed disposal site would be too costly and not justified from the standpoints of risk to the public health or cost-benefit.
Furthermore, because of the total volume of these wastes, limited canmercial waste disposal capacity, and restrictions placed on receipt of long-lived wastes at connercial sites, it is not presently feasible to dispose of these wastes at commercial low-level waste disposal sites.
Effective January 28, 1981, NRC regulations in 10 CFR 20
" Standards for Protection Against Radiation", were amenced (45 FR 71761-71762) to delete Section 20.304 which provided general authority for disposal of radioactive materials by burial in soil. Under the amended regulations, licensees erv f
maair a
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1, 3-must apply for and obtain specific NRC approval to dispose of radioactive materials in this manner under the provisions of 10 CFR 20.302. A case-by-case review was believed needed to assure that burial of radioactive wastes would not present an unreasonable health hazard at some future date.
The deleted provisions of Section 20.304 previously permitted burial of up to 100 millicuries of thorium or natural uranium at 'any one time, with a yearly limitation of 12 burials for each type of material at each site. The only disposal standards specified were (1) burial at a minimum depth of four feet, and (2) successive burials separated by at least six feet. Thus a 1
total of 1.2 curies of these materials were permitted to be disposed of each year by burial in a 12 foot by 18 foot or larger plot of ground.
i Under the amended regulations, it is incumbent on an applicant who wants to bury radioactive wastes to demonstrate that local land burial is. preferable to other disposal alternatives. The evaluation of the application takes into account the following information:
Types and quantities of material to be buried Packaging of waste i
4 4-Burial location Characteristics of burial site Depth of burial Access restrictions to disposal site Radiation safety procedures during disposal operations Recordkeeping Local burial restrictions, if any For applications involving disposal of soils contaminated with low level concentrations of thorium and uranium (other than concentrations not exceeding EPA cleanup standards), the matters of principal importance are:
Concentrations of thorium and uranium (either in secular equilibrium with their daughters or without daughters present)
Volume of contaminated soil Costs for offsite and onsite disposal Availability of offsite burial space Disposal site characteristics Depth of burial and accessibility of buried wastes State and local government views II. Branch Technical Position There are five acceptable options for disposal or casite storage of thorium and uranium contaminated wastes. Applications for disposal or storage will be approved if the guidelines discussed under any option are met. Applications for other methods of
e
. disposal may be submitted and these will be evaluated on their own merits.
1.
Disposal of acceptably Icw concentrations (which meet EPA cleanup standards) of natural thorium with daughters in secular equilibrium, depleted or enriched uranium, and uranium ores with daughters in secular equilibrium with no restriction on burial method.
Under this option, the concentrations of natural thorium and depleted or enriched uranium wastes are set sufficiently low that no member of the public is expected to receive a radiation dose comitment from the disposed materials in excess of 1 millirad per year to the lung or 3 millicads per year to the bone from inhalation and ingestion, under any foreseeable use of the material or property. These radiation dose guidelines were recommended by the Environmental Protection Agency (EPA) for protection against transuranium elements present in the environment as a result of unplanned contamination (42 FR 60956-60959).
In addition, the concentrations are sufficiently low so that no individual may receive an external dose in excess of 10 microrcentgens per hour above background. This is compatible with guidelines EPA proposed as cleanup standards for inactive uranium processing sites (26 FR 2556-2563).
. For natural uran'ium ores having daughters in equilibrium, the concentration limit is equal to that set by the EPA (46 FR 2556-2563) for radium-225 (i.e., 5 pCi/gm, including background) and its decay products.
The concentrations specified belcw are believed appropriate to apply.
It is expected, however, that currently licensed operations will be conducted in such a manner as to minimize the possibility of soil contamination and when such occurs the contamination will be reduced to levels as low as reasonably achievable.
Kind of Material Concentration (pCi/gm)
Natural thorium (Th-232 plus Th-228) if all daughters are present and in equilibrium 10 Depleted Uranium 35 Enriched Uranium 30 Natural Uranium Ores (U-238 plus U-234) 10 if all daughters are present and in equilibrium The analysis upon which the Branch Technical Position is based is available for inspection at the Commission's Public Document Room at 1717 H St., N.W., Washington, D.C.
7-The concentrations specified under this option may be compared with naturally occurring thorium and uranium ore concentrations of 1.3 pCi/gm in igneous rock and uranium concentrations of 120 pCi/gm in Florida phosphate rock and 50-80 pCi/gm in Tennessee bituminous shale.
Concentration limits for natural thorium and natural uranium ore wastes containing daughters not at secular equilibrium can be calculated on a case-by-case basis using the applicable isotopic activities data.
2.
Disposal of certain low concentrations of natural thorium with daughters in secular equilibrium and depleted or enriched uranium with no daughters present when buried under prescribed conditions with no subsequent land use restrictions and no continuing NRC licensing of the material.
Under this option the concentrations of natural thorium and uranium are set sufficiently low so that no member of the public will receive a radiation dose exceeding those discussed under option 1 when the wastes are buried in an approved manner absent intrusion into the burial grounds. This option will require establishing prescribed conditions for disposal in the license, such as depth and distribution of material, to minimize the likelihood of intrusion. Burial will be permitted only if it can be demonstrated that the buried materials will be stabilized in place and not be transported away from the site.
Acceptability of the site.for disposal will depend on 1
topographical, geological, hydrological and meteorological characteristics of the site. At a minimum, burial depth will be at least four feet below the surface.
In the event that there is an intrusion into the burial ground, no member of the public will likely receive a dose in excess of 170 millirems to a critical organ. An average dose not exceeding 170 millirems to the whole body for all members of a general population is recommended by international and national radiation expert bodies to limit population doses. With respect to limiting doses to individual body organs, the concentrations are sufficiently low that no individual will receive a dose in excess of 170 millirems to any organ from exposure to natural thorium, depleted uranium or enriched uranium.
The average activity concentration of radioactive material that may be buried under this option in the case of natural I
thorium (Th-232 plus Th-228) is 50 pCi/gm, if all daughters are l
present and in equilibrium; for enriched uranium it is 100 pCi/gm if the uranium is soluble and 250 pCi/gm if insoluble; for depleted uranium it is 100 pCi/gm if the uranium is soluble and 300 pCi/gm if insoluble. Natural uranium cres containing radium 226 and its daughters are not included under this option, because.of possible radon 222 emanations and resultant higher than acceptable exposure of individuals in private residences if houses were built over buried materiais.
a
. 3.
Disposal of !cw concentrations of natural uranium ores, with all daughters in equilibrium, when buried under prescribed conditions in areas zoned for industrial use and the recorded title documents are amended to state that the specified land contains buried radioactive materials and are conditioned in a manner acceptable under state law to impose.
a covenant running with the land that the specified land may not be used for residential building.
(There is no continuing NRC licensing of the material.)
Disposal will be approved if the burial criteria outlined in option 2 (including burial at a minimum of 4 feet) are met.
Depending upon local soil characteristics, burials at depths greater than 4 feet may be required.
In order to assure protection against radon 222 releases (daughter in decay chain of uranium 238 and uranium 234), it is necessary that the recorded title documents be amended to state in the permanent land records that no residential building should be pennitted over specified areas of land where natural uranium ore residues (U-238 plus U-234) in concentrations exceeding 10 pCi/gm has been buried.
Industrial building is acceptable so long as the concentration of buried material does not exceed 40 pCi/gm of uranium (i.e., Ra-226 shall not exceed 20 pCi/gm).
4.
Disposal of land-use-limited concentrations of natural thorium or natural uranium with daughters in secular equilibrium and depleted or enriched uranium without daughters present when
-=
1, 10 -
buried under prescribed conditions in areas zoned for industrial use and the recorded title documents are amended to state that the land contains buried radioactive material and are conditioned in a manner acceptable under state law to impose a covenant running with land that the land (1) may not be excavated below stated depths in specified areas of land unless cleared by appropriate health authorities, (2) may not be used for residential or industrial structures over specified areas where radioactive materials in concentrations higher than specified in options 2 and 3 are buried, and (3) may not be used for agricultural purposes in the specified areas.
(There is no continuing NRC licensing of the disposal site.)
Under this option, conditions of burial.will be such that no member of the public will receive radiation doses in excess of those discussed under option 1 absent intrusion into the burial ground. Criteria for disposal under these conditions is predicated upon the assumption that intantional intrusion is less likely to occur if a warning is given in land documents of record not to excavate belcw burial depths in specified areas of land without clearance by health authorities; not to construct residential or industrial building cn the site; and not to use specified areas of land for agricultural purposes.
Because of this, we believe it appropriate to apply a maximum critical organ exposure limit of 500 millirems per year to thorium L
4
. and uranium buried under this restriction instead of 170 millirems as used in options 2 and 3.
In addition, any exposure to such materials is likely to be more transient than assumed (essentially continual exposure) under those options. These two factors combine to increase the activity concentration limits calculated under option 2 by about 10. Thus, the average concentration that may be buried under this option for thorium (Th-232 plus Th-228) is 500 pCi/gm if all daughters are present and in equilibrium; for enriched uranium it is 1000 pCi/gm if the uranium is soluble and 2500 pCi/gm if insoluble; and for depleted uranium it is 1000 pCi/gm if the uranium is soluble and 3000 pCi/gm if insoluble.
With respect to natural uranium with daughters present and in equilibrium, the concentration that may be buried under this
. option is 200 pCi/gm of U-238 plus U-234, i.e., 100 pCi/gm Ra-226. This concentration is based on a limited exposure of 2.4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> per day to limit the radon dose to less than 0.5 working level month (WU1) which is equivalent to centinuous exposure to 0.02 working level (WL). Depending upon local soil characteristics, burials at depths greater than 4 feet may be required.
/,
e
SUMMARY
OF MAXD..M CONCENTRATIONS PERMITTED UNDER DISPOSAL OPTIONS Discosal Options a
b c
d Xind of Material l
2 3
4 Natural Thorium (Th-232 + Th-228) 10 50 500 with daughters present and in equilibrium Natural Uranium (U-238 + U-234) 10 40 200 with daughters present and in equilibrimn Depleted Uranium o Soluble 35 100 1000 o Insoluble 35 300 3000 Enriched Uranium o Soluble 30 100 1000 o Insoluble 30 250 2500 a Based on EPA cleanup standards.
b Concentrations based on limiting individual doses to 170 mrem /yr.
Concentration based on limiting equivalent exposure to 0.02 working c
level or less.
d Concentrations based on limiting individual doses to 500 mrem /yr and, in case of natural uranium, limiting exposure to 0.02 working level or less.
O
=....
o 1,
e 13 5.
Storage of licensed concentrations of thorium and uranium onsite pending the availability of an appropriate disposal site.
When concentrations exceed those specified in option 4, long term disposal other than at a license disposal site will'not normally be a viable option under the provisions of 10 CFR 20.302.
In such cases, the thorium and uranium may be permitted to be stored onsite.under an NRC license until a suitable method of disposal is found. License conditions will require that radiation doses not exceed those specified in 10 CFR Part 70 and be maintained as low as reasonably achievable.
Before approving an application to dispose of thorium or uranium under options 2, 3, or 4, NRC will solicit the view of
-appropriate State health officals within the State in which the disposal would be made.
Cated at Silver Spring, Maryland this/rA" da/ of GE&c
, 1981.
[ b b_=-d~
J Richard E. Cunningham Director,- Division of Fuel Cycle and Material Safety Office of Nuclear Material Safety and Safeguards
-.