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D Standards (Limits) Proposed by Other Organizations AMERICAN NATIONAL STANDARDS INSTITUTE AND HEALTH PHYSICS SOCIETY ANSI/HPS N13.12-1999 Surface and Volume Radioactivity Standards for Clearance The Health Physics Society (HPS) Standards Working Group developed this standard. The standard was consensus balloted1 and approved by the American National Standards Institute (ANSI) accredited HPS N13 Committee on October 19, 1998. Furthermore, ANSI, Inc., itself approved the standard on August 31, 1999. The standard defines primary (dose) and secondary screening (derived) criteria. Primary Dose Criterion The primary criterion of this standard is to provide for the public health and safety of an average member of a critical group such that the dose shall be limited to 10 pSv/yr (1.0 mrem/yr) total effective dose equivalent (TEDE), above back- ground, for clearance of materials from regulatory control. When justified on a case-by-case basis, clearance shall be permitted at higher dose levels when it can be ensured that exposures to multiple sources will be maintained as low as rea- 1A listing of the organizations and government agencies represented on the N13 Committee is listed in an Appendix to the ANSI/HPS standard. 199
200 APPENDIX D sonably achievable (ALARA) and will provide an adequate margin of safety below the public dose limit of 1 mSv/yr (100 mrem/yr) TEDE. Derived Screening Levels Derived screening levels, above background, for the clearance of solid mate- rials or items containing surface or volume activity concentrations of radioactive materials are tabulated in the standard. In that table the radionuclides have been divided into four groups based on similarity of exposure scenario results, with screening levels ranging from 0.1 to 100 Bq/cm2 (or Bq/g), depending on the group considered.2 A generic ALARA process was employed in developing the derived screening levels. However, based on a detailed ALARA evaluation, it shall be permissible to derive less restrictive screening levels on a case-by-case basis using the primary dose criterion. The standard includes a discussion of the collective dose in relation to the screening levels. In reality, concentrations in cleared materials will likely average about an order of magnitude less than the screening levels, which are intended to define upper bounds. From the qualitative evaluation it is concluded that on the average, individuals will likely receive no more than the 10 pSv/yr (1.0 mrem/yr) primary dose criterion because of conservative modeling and assumed maximum concentrations. Assuming an average U.S. background level of 3.0 mSv/yr (300 mrem/yr), the collective doses to the critical group resulting from clearance of items using the criterion from this standard will be no more than 0.3 percent of the dose the same population would receive from natural background radiation in any one year. The magnitude of the potential collective doses to the critical group associated with the items in accordance with this standard is so low that addi- tional ALARA evaluations or analyses, or further reductions in the primary dose standard, are not deemed necessary. INTERNATIONAL ATOMIC ENERGY AGENCY Safety Series No. 89: Principles for the Exemption of Radioactive Sources and Practices from Regulatory Control This document was jointly sponsored by the International Atomic Energy Agency (IAEA) and the Nuclear Energy Agency of the Organization for Eco- nomic Cooperation and Development and was published in 1988. It is based on two principles for exemption: 2Surface and Volume Radioactivity Standards for Clearance: An American National Standard, Health Physics Society Report, ANSI/HPS N13.12-1999.
APPENDIX D 201 1. Individual risk must be sufficiently low as not to warrant regulatory con- cern. 2. Radiation protection, including the cost of regulatory control, must be optimized. Two approaches were followed in determining if the level of risk or dose is trivial;3 first, choose a level of risk and the corresponding dose that is of no significance to individuals; second, use the exposure to natural radiation, to the extent that it is normal and unavoidable, as a relevant reference level. Risk-Based Considerations It is widely recognized that values of individual risk that can be treated as insignificant correspond to a level at which individuals, aware of these risks, would not commit significant resources of their own to reduce them. It is believed that few people would commit their own resources to reduce an annual risk of death of 10-5 and that even fewer would take action at an annual level of 10-6. By considering a rounded risk factor Of 10-2 Sv-i (10-4 remet) for whole-body expo- sure as a broad average over age and gender, the level of trivial individual effec- tive dose equivalent would be in the range of 10 to 100 mSv/yr (1 to 10 mrem/ yr,.4 Natural Background Radiation Considerations The natural background radiation has been estimated to give an average individual dose of about 2.4 mSv/yr (240 mrem/yr).5 This average conceals a wide variation due to different concentrations of radioactive materials in the ground and in building materials, different altitudes, and different habits of people. About half of this dose is due to radon exposure, which may be controlled. The other half comes from cosmic rays, terrestrial gamma rays, and radionuclides in the body for which control is not practical. Individuals do not usually consider variation in exposure to natural background radiation when considering moving 3The word trivial is used extensively by the IAEA in Vienna and the European commission in their safety guides when describing an individual effective dose equivalent in the range of lo to 100 mSv/yr (1 to 10 mrem/yr). 4Principles for the Exemption of Radiation Sources and Practices from Regulatory Control, Safety series No. 89, International Atomic Energy Agency, Vienna, 1988. 5The background radiation varies significantly from country to country and from one location to another within a country. There are several regions in the world where natural background radiation gives doses that exceed the normal ranges by factors of 4 to 6. It is reported that no adverse health effects have been discerned from doses arising from these high natural levels. see, sEIR v, National Academy Press, Washington, D.C., 1990.
202 APPENDIX D from one location to another or when going on a holiday. IAEA believes it can therefore be judged that a dose level that is small in comparison with the variation in natural background radiation can be considered trivial. A figure of whole-body or effective dose equivalent of the order of one to a few percent of the natural background, 20 to 100 mSv/yr (2 to 10 mrem/yr), has been suggested. Conclusion on Individual Related Risk The IAEA concluded that an individual radiation dose, regardless of its origin, is likely to be trivial if it is of the order of some tens of microsieverts per year (some millirems per year). It is noted that this dose corresponds to a few percent of the annual dose limit for members of the public recommended by the International Commission on Radiological Protection (ICRP) in 1977 and is much lower than any upper bound set by competent authorities for practices subject to regulatory control. EUROPEAN COMMISSION Radiation Protection 89: Recommended Radiological Protection Criteria for the Recycling of Metals from the Dismantling of Nuclear Installations This document provides recommended radiological protection criteria for the recycling of metal arising from dismantling nuclear installations. The docu- ment prepared by the Group of Experts established under the terms of Article 31 of the Euratom Treaty confirms and extends its previous recommendations, made in IAEA Safety Series 89 of 1988. It has been demonstrated that metals below the clearance levels specified can be released from regulatory control with negligible risk, from a radiation point of view, for workers in the metals industry and for the population at large. Radiological Protection Criteria The document references the IAEA recommendation in Safety Series 89 that an individual dose of some tens of microsieverts is considered trivial and there- fore the basis for exemption. The Working Group adopted radiation protection levels of 10 ,uSv/yr (1 mrem/yr) and 1 man-Sv/yr (100 man-rem/yr) of practice collective dose criteria. In addition, the skin dose was limited to 50 mSv/yr (5 rem/yr). Relating the dose received by individuals to a practice, and to the levels of radioactivity involved in a practice, is difficult because the clearance criteria must be defined for a largely hypothetical environment. The Working Group constructed a set of exposure scenarios, which relate the activity content of the
APPENDIX D 203 recycled metals to an individual dose. The proposed clearance levels are derived radioactivity levels from the most critical scenario. Tables are provided that specify clearance levels for metal scrap recycling for the radionuclides encountered in decommissioning. A similar table is pro- vided specifying the more stringent clearance levels for direct reuse of the metal. AMERICAN NUCLEAR SOCIETY The American Nuclear Society (ANS) Special Committee on Site Cleanup and Restoration Standards is responsible for reviewing draft regulations from federal organizations related to the decommissioning of nuclear facilities and providing ANS input to the rulemaking process. The ANS is not in the business of writing standards, although it does write position papers and makes comments after reviewing rules. As of this date, the ANS has not endorsed ANSI N13.12. However, in a letter of December 4, 2000, ANS made the following comments regarding the Department of Energy's (DOE's) standard: . ANS considers the 1 mrem/yr standard to be unreasonably low and with- out a firm scientific justification. · Scientific evidence would seem to support a dose limit several times larger than the proposed 1 mrem/yr. The ANS is currently working on a draft position paper on the standard for clearance and expects it to be released in 2002. INTERNATIONAL COMMISSION ON RADIOLOGICAL PROTECTION Publication 60 The ICRP recommends that the maximum permissible dose for occupational exposure should be 20 mSv/yr (2,000 mrem/yr), averaged over five years (i.e., 100 mSv total) with a maximum of 50 mSv in any one year. For public exposure, 1 mSv/yr (100 mrem/yr), averaged over 5 years, is the limit. In both categories, the figures are over and above background levels and exclude medical exposure. The ICRP proposed apportionment of the total allowable dose from all an- thropogenic sources of radiation (excluding medical exposures). Hence for radio- active waste management, authorities could allocate a fraction of the 1 mSv/yr (100 mrem/yr), to establish an exposure limit for low-level radioactive waste (LLRW). For example, the Environmental Protection Agency (EPA) in 40 CFR Part 191 imposed a limit of 0.15 mSv/yr (15 mrem/yr), which is consistent with the ICRP' s concept of apportionment.
204 APPENDIX D THE EUROPEAN UNION Basic Safety Standards The scope of the Basic Safety Standards (BSS) adopted by the European Union (KU) is defined in terms of practices and only indirectly in terms of radioactive substances. Justification of any practice involving radioactivity is required, i.e., determining whether the benefits to individuals and to society from introducing or continuing the practice outweigh the harm (including radiation detriment) resulting from the practice. If such practice is deemed justifiable, a decision is made as to whether it should be placed under the system of reporting and prior authorization as described by the BSS. Exempt practices are those that do not fall under this system. Practices thought to involve appreciable potential risks are put under the regulatory system without exception, including all of the practices associated with the nuclear fuel cycle. However, practices can be ex- empt from control if the associated risks are sufficiently low. Exemption levels have been derived for the BSS that apply to radionuclide levels and activities per unit mass from which the risks are regarded as trivial. All associated activities and material movements are regulated after a prac- tice has been placed within the regulatory system. Regulatory control can be relinquished only by proceeding through the system of reporting and prior autho- rization set out by the BSS. An ad hoc case-by-case procedure is followed for the possible release of materials for recycling, reuse, and disposal, and implementa- tion of this procedure is the responsibility of the competent national authorities. Clearance is defined as the removal from regulatory control of a substance that has radionuclide levels below the recommended specific limits. Cleared sub- stances are automatically exempt from the requirements of reporting and authori- zation. The radiological protection criteria that have been adopted for clearance are 10 pSv/yr (1 mrem/yr), with a collective dose for the practice of 1 man-Sv/yr (100 man-rem/yr).6 Additionally, the skin dose is limited to 50 pSv/yr. European Union Directive 96/29/EURATOM allows clearance of "radioac- tive substances where the concentration of activity per unit mass do not exceed the exemption values set out in Column 3 of Table A to Annex I." Annex I is reproduced at the end of this appendix (see Table D-1), as is a table of derived clearance levels based on a primary dose standard of 10 pSv/yr from NUREG- 1640 (Table D-2. 6European Union Directive 96/29/EURATOM further provides that collective dose can exceed ~ man-sievert, provided that "an assessment of an optimization of protection shows that exemption is the optimum option" (KU, 1996, p. 19).
APPENDIX D 205 UNITED NATIONS United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) Consistent with the current understanding of the related consequences, the ICRP, National Council on Radiation Protection and Measurements (NCRP), IAEA, and UNSCEAR have recommended that radiation doses above back- ground levels to members of the public not exceed 1 mSv/yr (100 mrem/yr), for continuous or frequent exposure from radiation sources other than medial expo- sures. Most countries imposing limits on radiation from anthropogenic sources have endorsed the principle of apportionment of the total allowable dose. Many countries are in the process of endorsing a dose limit of 10 ,uSv/yr (1 mremlyr) for LLRW that is 1 percent of the total allowable dose. MULTIAGENCY RADIATION SURVEY AND SITE INVESTIGATION MANUAL The Multi-Agency Radiation Survey and Site Investigation Manual (MARSSIM) provides a nationally consistent consensus approach to conducting radiation surveys and investigations at potentially contaminated sites. This ap- proach is intended to be both scientifically rigorous and flexible enough to be applied to a diversity of site cleanup conditions. MARSSIM's title includes the term "survey" because it provides information on planning and conducting sur- veys and the term "site investigation" because the process outlined in the manual allows one to begin by investigating any site that may involve radioactive con- tamination. The decommissioning that follows remediation requires a demonstration to the responsible federal or state agency that the cleanup effort was successful and that the release criterion (a specific regulatory limit) was met. This manual assists site personnel or others in performing or assessing such a demonstration. The demonstration of compliance involves three interrelated steps: 1. Translating the cleanup or release criterion (e.g., millisieverts per year, millirem per year, specific risk) into a corresponding derived contaminant concentration level (e.g., becquerels per kilogram or picocuries per gram in soil) through the use of environmental pathway modeling; 2. Acquiring scientifically sound and defensible site-specific data on the levels and distribution of residual contamination, as well as levels and distribution of radionuclides present as background, by employing suit- able measurement techniques; and
206 APPENDIX D 3. Determining that the data obtained from sampling support the claim that the site meets the release criterion, within an acceptable degree of uncer- tainty, by applying a statistically based decision rule. MARS SIM provides standardized and consistent approaches for planning, conducting, evaluating, and documenting environmental radiological surveys, with a specific focus on the final status surveys that are carried out to demonstrate compliance with cleanup regulations. TABLE D-1 Exempt Quantities Established by Council Directive 96/291EURATOM Quantity Concentration Quantity Concentration Nuclide (Bq) (kBq/kg) Nuclide (Bq) (kBq/kg) H-3 109 1o6 Ga-72 105 10 Be-7 107 103 Ge-71 1o8 104 C-14 107 104 As-73 107 103 0-15 109 1o2 As-74 1o6 10 F-18 1o6 10 As-76 105 1o2 Na-22 105 10 As-77 1o6 103 Na-24 105 10 Se-75 1o6 1o2 Si-31 1o6 103 Br-82 1o6 10 P-32 105 103 Kr-74 109 1o2 P-33 108 105 Kr-76 109 1o2 S-35 1o8 105 Kr-77 109 1o2 C1-36 1o6 104 Kr-79 105 103 C1-38 105 10 Kr-81 107 104 Ar-37 1o8 1o6 Kr-83m 1ol2 105 Ar-41 109 1o2 Kr-85 104 105 K-40 1o6 1o2 Kr-85m lolo 103 K-42 1o6 1o2 Kr-87 109 1o2 K-43 1o6 10 Kr-~8 109 1o2 Ca-45 107 104 Rb-86 105 1o2 Ca-47 1o6 10 Sr-85 1o6 1o2 Sc-46 1o6 10 Sr-85m 107 1o2 Sc-47 1o6 1o2 Sr-87m 1o6 1o2 Sc-48 105 10 Sr-89 1o6 103 V-48 105 10 Sr-90+ 104 1o2 Cr-51 107 103 Sr-91 105 10 Mn-51 105 10 Sr-92 1o6 10 Mn-52 105 10 Y-90 105 103 Mn-52m 105 10 Y-91 1o6 103 Mn-53 109 104 Y-9lm 1o6 1o2 Mn-54 1o6 10 Y-92 105 1o2 Mn-56 105 10 Y-93 105 1o2 Fe-52 1o6 10 Zr-93+ 107 103 Fe-55 1o6 104 Zr-95 1o6 10
APPENDIX D TABLE D-1 continued 207 Quantity Concentration Quantity Concentration Nuclide (Bq) (kBq/kg) Nuclide (Bq) (kBq/kg) Fe-59 1o6 10 Zr-97+ 105 10 Co-55 1o6 10 Nb-93m 107 104 Co-56 105 10 Nb-94 1o6 10 Co-57 105 1o2 Nb-95 1o6 10 Co-58 1o6 10 Nb-97 1o6 10 Co-58m 107 104 Nb-98 105 10 Co-60 105 10 Mo-90 1o6 10 Co-60m 1o6 103 Mo-93 1o8 103 Co-61 1o6 1o2 Mo-99 1o6 1o2 Co-62m 105 10 Mo-101 1o6 10 Ni-59 1o8 104 Tc-96 1o6 10 Ni-63 1o8 105 Tc-96m 107 103 Ni-65 1o6 10 Tc-97 1o8 103 Cu-64 1o6 1o2 Tc-97m 107 103 Zn-65 1o6 10 Tc-99 107 104 Zn-69 1o6 104 Tc-99m 107 1o2 Zn-69m 1o6 1o2 Ru-97 107 1o2 Ru-103 1o6 1o2 Cs-134 104 10 Ru-105 1o6 10 Cs-134 107 104 Ru-106+ 105 1o2 Cs-136 105 10 Rh-103m 1o8 104 Cs-137+ 104 10 Rh-105 107 1o2 Cs-138 104 10 Pd-103 1o8 103 Ba-131 1o6 1o2 Pd-109 1o6 103 Ba-140+ 105 10 Ag- 105 1o6 1o2 La- 140 105 10 Ag-108m+ 1o6 10 Ce-139 1o6 1o2 Ag-l lOm 1o6 10 Ce-141 107 1o2 Ag- 111 1o6 103 Ce- 143 1o6 1o2 Cd- 109 1o6 104 Ce- 144+ 105 1o2 Cd-115 1o6 1o2 Pr-142 105 1o2 Cd-115m 1o6 103 Pr-143 1o6 104 In- 111 1o6 1o2 Nd- 147 1o6 1o2 In-113m 1o6 1o2 Pm-147 107 104 In-114m 1o6 1o2 Pm-149 1o6 103 In-115m 1o6 1o2 Sm-151 1o8 1o2 Sn-113 107 103 Sm-153 1o6 1o2 Sn-125 1o6 1o2 Eu-152 1o6 10 Sb-124 1o6 10 Eu-152m 1o6 1o2 Sb-125 1o6 1o2 Eu-154 1o6 10 Te-123m 107 1o2 Eu-155 107 1o2 Te-125m 107 103 Gd-153 107 1o2 Te-127 1o6 103 Gd-159 1o6 103 Te-127m 107 103 Tb-160 1o6 10 Te- 129 1o6 1o2 Dy- 166 1o6 103 continues
208 TABLE D-1 continued APPENDIX D Quantity Concentration Quantity Concentration Nuclide (Bq) (kBq/kg) Nuclide (Bq) (kBq/kg) Te- 129m 1o6 103 Ho- 166 105 103 Te-131 105 1o2 Er-169 107 104 Te-131m 1o6 10 Er-171 1o6 1o2 Te-132 107 1o2 Tm-170 1o6 103 Te-133 105 10 Tm-171 1o8 104 Te-133m 105 10 Yb-175 107 103 Te-134 1o6 10 Lu-177 107 103 I-123 107 10 Hf-181 1o6 10 I-125 1o6 10 Ta-182 104 10 I-126 1o6 1o2 W-181 107 103 I-129 105 1o2 W-185 107 104 I-130 1o6 10 W-187 1o6 1o2 I-131 1o6 1o2 Re-186 1o6 103 I-132 105 10 Re-188 105 1o2 I-133 1o6 10 Os-185 1o6 10 I-135 1o6 10 Os-191 107 1o2 Xe-131m 104 104 Os-19lm 107 103 Xe-133 104 103 Os-193 1o6 1o2 Xe-135 lolo 103 Ir-190 1o6 10 Cs-129 105 1o2 Ir-192 104 10 Cs-131 1o6 103 Ir-194 105 1o2 Cs-132 105 10 Pt-l91 1o6 1o2 Cs-134m 105 103 Pt-193m 1o6 103 Pt-197 1o6 103 U-235+ 104 10 Pt-197m 1o6 1o2 U-236 104 104 Au-198 1o6 1o2 U-237 1o6 1o2 Au-l99 1o6 1o2 U-238+ 104 10 Hg- 197 107 1o2 U-238sec 103 1 Hg- 197m 1o6 1o2 U-239 1o6 1o2 Hg-203 105 1o2 U-240 107 103 T1-200 1o6 10 U-240+ 1o6 10 T1-201 1o6 1o2 Np-237+ 103 1 T1-202 1o6 1o2 Np-239 107 1o2 T1-204 104 104 Np-240 1o6 10 Pb-203 1o6 1o2 Pu-234 107 1o2 Pb-210+ 104 10 Pu-235 104 1o2 Pb-212+ 105 10 Pu-236 104 10 Bi-206 105 10 Pu-237 107 103 Bi-207 1o6 10 Pu-238 104 1 Bi-210 1o6 103 Pu-239 104 1 Bi-212+ 105 10 Pu-240 103 1 Po-203 1o6 10 Pu-241 105 1o2 Po-205 1o6 10 Pu-242 104 1 Po-207 1o6 10 Pu-243 107 103 Po-210 104 10 Pu-244 104 1 At-211 107 103 Am-241 104 103
APPENDIX D TABLE D-1 continued 209 Quantity Concentration Quantity Concentration Nuclide (Bq) (kBq/kg) Nuclide (Bq) (kBq/kg) Rn-220+ 107 104 Am-242 1o6 103 Rn-222+ 1o8 10 Am-242m+ 104 1 Rn-223+ 105 1o2 Am-243+ 103 1 Rn-224+ 105 10 Cm-242 105 1o2 Rn-225 105 1o2 Cm-243 104 1 Rn-226+ 104 10 Cm-244 10 10 Rn-227 1o6 1o2 Cm-245 104 1 Rn-228+ 105 10 Cm-246 103 1 Ac-228 1o6 10 Cm-247 104 1 Th-226+ 107 103 Cm-248 104 1 Th-227 104 10 Bk-249 1o6 103 Th-228+ 104 1 Cf-246 1o6 103 Th-229+ 103 1 Cf-248 104 10 Th-230 104 1 Cf-249 103 1 Th-231 107 103 Cf-250 104 10 Th-232sec 103 1 Cf-251 103 1 Th-234+ 105 103 Cf-252 104 10 Pa-230 1o6 10 Cf-253 105 1o2 Pa-231 103 1 Cf-254 103 1 Pa-233 107 1o2 Es-253 105 1o2 U-230+ 105 10 Es-254 104 10 U-231 107 1o2 Es-254m 104 10 U-232+ 103 1 Fm-254 107 104 U-233 104 10 Fm-255 1o6 103 U-234 104 10 SOURCE: EU (1996).
210 TABLE D-2 Derived USNRC Clearance Levels Assum~ng a 10 ,uSv/yr Primary Dose Standard (All Metals) APPENDIX D Mass Clearance Levels Radi on ucli de Surficial Clearance Levels NRC (Bq/g) Radi on ucli de NRC (Bq/cm2) H-3 2.E+04 H-3 2.E+04 C-14 6.E+02 C-14 7.E+02 Na-22 2.E-02 Na-22 3.E-02 P-32 8.E+O1 P-32 9.E+01 S-35 1.E+03 S-35 2 E+03 C1-36 4.E+OO C1-36 5 E+OO K-40 2.E-O1 K-40 3 E-01 Ca-41 8.E+01 Ca-41 1 E+02 Ca-45 1.E+02 Ca-45 2.E+02 Cr-51 4.E+OO Cr-51 5.E+OO Mn-54 l.E-O1 Mn-54 l.E-01 Fe-55 1.E+04 Fe-55 1 E+04 Co-57 3.E+OO Co-57 3 E+OO Co-58 l.E-O1 Co-58 l.E-01 Fe-59 9.E-02 Fe-59 1 E-01 Ni-59 2.E+04 Ni-59 3 E+04 Co-60 4.E-02 Co-60 5 E-02 Ni-63 8.E+03 Ni-63 1 E+04 Zn-65 5.E-02 Zn-65 6 E-02 Cu-67 5.E+OO Cu-67 6 E+OO Se-75 3.E-O1 Se-75 4.E-01 Sr-85 2.E-O1 Sr-85 2 E-01 Sr-89 9.E+O1 Sr-89 1 E+02 Sr-90 l.E+OO Sr-90 1 E+OO Y-91 3.E+O1 Y-91 3 E+01 Mo-93 7.E+02 Mo-93 9.E+02 Nb-93m 1.E+03 Nb-93m 2 E+03 Nb-94 6.E-02 Nb-94 7 E-02 Nb-95 l.E-O1 Nb-95 2 E-01 Zr-95 l.E-O1 Zr-95 2 E-01 Tc-99 5.E+O1 Tc-99 7.E+01 Ru-103 2.E-O1 Ru-103 3.E-01 Ru-106 5.E-O1 Ru-106 6.E-01 Ag-108m 6.E-02 Ag-108m 7 E-02 Cd- 109 2.E+O1 Cd- 109 3 E+01 Ag-llOm 4.E-02 Ag-llOm 4 E-02 Sb-124 6.E-02 Sb-124 6 E-02 I- 125 4.E+OO I- 125 5.E+OO Sb-125 2.E-O1 Sb-125 3 E-01 I-129 2.E-O1 I-129 2 E-01 I-131 4.E-O1 I-131 5 E-01 Ba-133 4.E-O1 Ba-133 4 E-01 Cs- 134 2.E-02 Cs- 134 2.E-02 Cs- 137 4.E-02 Cs- 137 5.E-02
APPENDIX D 211 TABLE D-2 continued Mass Clearance Levels Radi on ucli de Ce-141 Ce- 144 Pm- 147 Eu-152 Eu-154 Eu-155 Re-186 Ir-192 Pb-210 Po-210 Bi-210 Rn-222 Ra-223 Ra-224 Ac-225 Ra-225 Ra-226 Ac-227 Th-227 Th-228 Ra-228 Th-229 Th-230 Surficial Clearance Levels NRC (Bq/g) 4.E+OO 3.E+OO 9.E+02 9.E-02 8.E-02 9.E+OO 4.E+01 8.E-02 7.E-02 2.E-O1 3.E+02 l.E-O1 6.E-O1 2.E-O1 7.E-O1 6.E+OO 6.E-02 3.E-02 2.E+OO 8.E-02 l.E-O1 2.E-02 2.E-O1 Radi on ucli de NRC (Bq/cm2) Ce-141 Ce- 144 Pm- 147 Eu-152 Eu-154 Eu-155 Re-186 Ir-192 Pb-210 Po-210 Bi-210 Rn-222 Ra-223 Ra-224 Ac-225 Ra-225 Ra-226 Ac-227 Th-227 Th-228 Ra-228 Th-229 Th-230 4.E+OO 4.E+OO 1.E+03 l.E-O1 l.E-O1 l .E+O 1 5.E+01 l.E-O1 9.E-02 2.E-O1 4.E+02 l.E-O1 6.E-O1 2.E-O1 8.E-O1 7.E+OO 7.E-02 4.E-02 2.E+OO 9.E-02 l.E-O1 3.E-02 2.E-O1
