ML20005E584

Decommissioning Waste Characteristics

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Issue date:	09/30/1989
From:	Johnson T, Roles G NRC
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l Decommissioning Waste Characteristics i

Timothy C. Johnson, G.W. Roles 1

U.S. Nuclear Regulatory Comission September 1989 i

Abstract

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This paper describes the expected general characteristics of wastes produced from decomissioning nuclear facilities.

For boiling water reactors and pressurized water reactors, we summarize information extracted from studies performed by Pacific National Laboratories (PNL) under contract to the U.S.

Nuclear Regulatory Comission (NRC).

These nuclear facilities will generate the largest volumes and activities of decommissioning wastes.

We also compare these studies with current waste generation information and briefly address decomissioning waste projections for other industries.

j Introduction Decomissioning wastes will be generated by a very broad range of licensees.

These licensees include operators of nuclear fuel cycle facilities such as j

nuclear power reactors, reactor fuel fabrication plants, and uranium hexaflouride conversion plants.

Non-fuel cycle licensees include hospitals, medical research institutions colleges and universities, industrial resecrch laboratories,facilitiesinvolvedwiththeproductionofradiopharmaceuticals, and other industrial users of radioactive material. Wastes produced by these generators n;ill be very diverse in terms of volume, activity, and other physical, radiological, and chemical characteristics.

Decommissioning wastes will range from trash that is only suspected of being contaminated to highly radioactive activated structural components from nuclear power reactors..

In this paper, we present some information on decomissioning waste obtained from studies performed by NRC contractors.

We also compare this information with data on low-level wastes (LLW) currently being disposed at LLW disposal i

facilities.

Our projections of decomissioning wastes are obtained from a series of studies performed Pacific Northwest Laboratories (PNL) for the Nuclear Regulatory Comission NRC).

Two of these PNL studies summarize and classify projected wastes from decomissioning boiling water reactors (BWR's) and pressurized waterreactors(PWR's)(References 1and2). We believe that decommissioning

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waste characteristic data for other fuel-cycle licensees and non-fuel-cycle licensees will be generally similar to the wastes generated during normal operations.

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i Our' data on current caste disposal was extracted from microfiche copies of sh'ipment manifests and computer-generated reports that NRC staff routinely l

obtain from the two existing disposal facility operators (References 3 - 24),

i The two disposal site operators are Chem-Nuclear Systems, Inc., the operator at the Barnwell, SC disposal site NY and the Hanford, WA disposal sites.and U.S. Ecology, the operator of the Beatty, Information compiled from these manifests and reports has been used in various waste characterization studies.

The LLW data is presented in terms of NRC's classification system for LLW.

NRC's regulations require that waste delivered to a low-level waste disposal site be classified into one of three waste classes -- Class A, 8, or C --

depending upon the concentrations of specific radionuclides listed in Tables 1 and 2 of 10 CFR Section 61.55.

Concentration limits are lowest for Class A i

wastes and highest for Class C wastes.

The waste classification system is used to place the most restrictive waste disposal conditions on the most hazardous wastes.

Wastes exceeding Class C concentrations are considered not generally suitable for near-surface disposal.

Below we present some of the key data relative to decommissioning wastes.

_Decomissioning Wastes f rom Huclear Power Plants Assuming a reference 1175-megawatt (electric) (MWe) PWR and a reference 1155-MWe BWR, PNL developed estimates of waste volumes and activity from imediate dismantlement operations.

Each reactor was assumed to have operated for 40 years at a 75 percent capacity factor, resulting in 30 effective full-power-years of operation.

Table 1 shows the )rojected waste stream volumes (in m8) by waste class from dismantlement of t1e reference PWR, Note that virtually all the waste volume is Class A.

ClassCandgreater-than-ClassC(GTCC)wastesareactivated metals from the reactor vessel and internals.

The most voluminous waste stream is Class A contaminated equipment and concrete.

Evaporator bottoms, resins, cartridge filters, and other dry active waste (DAW) are projected to be both Class A and B wastes.

Table 2 shows the projected activities for the reference PWR.

By far t active wastes will be the core shroud and the other GTCC core internals.h Although representing a small volume, these activated metal wastes dominate the PWR decomissioning activity.

We believe that the PNL projections of the activity in evaporator bottoms, resins, cartridge filters, and DAW are overly conservative.

Current waste processing systems generated substantially lower activities then the PNL report predictc. Tables 3 and 4 present 1987 disposal data by waste stream.

Note that overall concentrations for comparable waste streams are significantly lower than those projected by the PNL report.

For example, for PWR resins the PNL report su meter (Ci/m )ggests an average concentration of about 740 curies per cubic s.

This value exceeds the maximum recomended activity loading (350 C1/m*) for organic resins (see Reference 28) by a factor of two.

In actual decommissioning practice, radioactive waste concentrations are more i

likely to be similar to process waste concentrations from normal plant operations.

3 Table 5 pres'ents the projected decommissioning waste volumes for the reference Class C and Note again that virtually all the waste volume is Class A.The most voluminous GTCC wastes are activated metals from reactor internals.

Evaporator

BWR, waste stream is the Class A contaminated equipment and concr other DAW are projected to be both Class A and B wastes.

By far the most Table 6 shows the projected activities for the reference BWR, kithough active wastes will be the core shroud and the other core intern representing a small volumethePNL-projectionsoftheactivityinevaporator decomissioning activity, bottoms, filter sludges, resins, and DAW are considered again to be ve conservative.

Tables 3 and 4 again suggest that activities than the PNL report predicts.overall concentrations of comparable w In actual decomissioning practice, those projected by the PNL report.

radioactive waste concentrations are more likely to be similar to process waste concentrations from normal plant operations.

Table 7 shows a summary distribution of the PNL volume and activity data from PWR and BWR decommissioning.

Tables 8 and 9 present data showing the effects of decay on the Class A, B, C, These data are based on the and GTCC PWR and BWR decommissioning wastes.

The tables clearly radionuclide distributions assumed in the PNL reports.

illustrate how the waste contamination is dominated by short-lived radionuclides such as Fe-55 (2.6-year half-life) and Co-60 (5.26-yr half-life).

Note also that the activated metals that dominate the Class C and GTC are also dominated by the two short lived radionuclides Fe-55 and Co-60.

Decommissioning Wastes from Other Types of Facilities PNL has estimated decommissioning waste volumes for many other fuel cycle an non-fuel cycle facilities (References 29 - 30).The volumes of decommissioning wastes the waste volumes from these facilities.

from non-power reactor facilities will depend on the particular operations of The non-fuel cycle waste projections are for equipment and individual components typically used in non-fuel cycle licensee operations.

the licensee.

Decommissioning wastes from non-utility licensees will contain the sameBecause radionuclides used during operations.

operations are relatively low in activity, the decommissioning wastes will also be relatively low in activity and will be similar to wastes generated during operations.

Table 11 presents overall 1987 waste volume and activity data for disposals by These data show that, in terms of industries generating radioactive waste.

waste volume and activity, the utilities are the principal generators of Except for the industrial -sector, other industries radioactive wastes.

Based on our reviews of shipment generate very little of the activity.

manifests, the industrial sector activity is dominated by shipments from a few Therefore, with the exception of these firms, radioisotope production firms.

Radionuclides the radionuclide concentrations in these wastes are very small.

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fou'nd in non utility wastes are quite varied reflecting the many uses of nuclear piaterials in the commercial sector, t

References 1.

Murphy, E.S., " Technology, Safety and Costs of Decommissioning a Reference Pressurized Water Reactor Power Station," NUREG/CR-0130, i

Addendum 3. September 1984.

Murphy, E.S., ling Water Reactor Pcwer Station," NUREG/CR-0672," Tec 2.

Reference Boi Addendum 2, September 1984.

3.

U.S. Ecology, Radioactive Waste Report by Isotope, 1/1/87 through 12/31/87,- Beatty, NV Facility, Report No. ECF883, May 23,1988.

1 4.

U.S. Ecology, Radioactive Waste Report by Isotope, 1/1/87 through 12/31/87, Richland, WA Facility, Report No. ECF883, May 23,1988.

l S.

U.S. Ecology, Radioactive Waste Report by State, Beatty, NV Facility, i

1/1/87 through 12/31/87, Report No. ECF884, May 23, 1988.

4 6.

U.S. Ecology, Radioactive Waste Report by State, Richland, WA Facility,1/1/87 through 12/31/87, Report No. ECF884, May 23, 1988, t

7.

U.S. Ecology, Volume and Activity by Waste Type, Beatty, NV Facility, 1/1/87 through 12/31/87, Report No. ECF887, May 27, 1988.

8.

U.S. Ecology, Volume and Activity by Waste Type, Richland, WA Facility,1/1/87 through 12/31/87, Report No. ECF887, May 27, 1988.

9.

Utility Data Institute, WASTENET: Radiation Waste Program, Generator i

Activity by Class, Beatty, NV Facility,1/1/87 through 12/31/87, Report No. ECFS10 August 25, 1988.

l 10.

Utility Data Institute, WASTENET: Radiation Waste Program, Generator Activity by Class, Richland, WA Facility,1/1/87 through 12/31/87, Report No. ECF510, August 24, 1988.

11. Chem-Nuclear Systems, Inc., Total of Each Isotope Received per Waste Class for SC DPEC, 1/1/87 to 12/31/87, Report No. 0060705TRR5493033, September 14, 1988.

12. Chem-Nuclear Systems, Inc., Volume Percentage by Class and Activity for Each State for SC DHEC,1/1/87 to 12/31/87, Report No.

0060705TRR5413018, August 30, 1988.

13.

Chem-Nuclear Systems, Inc., Summarized Volume and Activity by State per Class for Generators for SC DHEC,1/1/87 to 12/31/87, Report No.

0060705TRR5563003, September 9, 1988.

14. Chem-Nuclear Systems, Inc., Summarized Volume and Activity by State per Class for Generators for SC DHEC, 1/1/87 to 12/31/87, Report No.

0060705TRR5853048, September 9, 1988.

15.

Chem-Nuclear Systems, Inc., Sumary Breakdown of Isotopes Received for SC DHEC, 1/1/87 to 12/31/87, Report No. 0060705TRR5503007, August 31, 1988.

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16, 4 ChemlNuclear Systems, Inc., Vclume by Waste Description for SC DHEC, 1/1/87 to 1/31/87, Report No. 006070$fRRS383010, September 9, 1988.

17.

Chem-Nuclear Systems, Inc., Volume by Waste Description for SC DHEC, 2/1/87 to 2/28/87, Report No. 0060705TRRS383010, September 9, 1988.

18. Chem-Nuclear Systems, Inc., Volume by Waste Description for SC DHEC, 3/1/87 to 3/31/87, Report No. 0060705TRR5383010, September 12, 1988.

19.

Chem-Nuclear Systems, Inc., Volume by Waste Description for SC DHEC, 4/1/87 to 4/30/87, Report No. 0060705TRR5383010, Septen6er 12,1988.

20.

Chem-Nuclear Systems, Inc., Volume by Waste Description for SC DHEC, S/1/87 to 5/31/87, Report No. 0060705TRRS383010, September 12, 1988.

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21. Chem-Nuclear Systems, Inc., Volume by Waste Description for SC DHEC, 6/1/87 to 6/30/87, Report No. 006070STRR5383010 September 12, 1988.

22. Chem-Nuclear Systems, Inc., Volume by Waste Description for SC DHEC, 7/1/87 to 7/31/87, Report No. 0060705TRRS383010, September 12, 1988.

t 23.

Chem-Nuclear Systems, Inc., Volume by Waste Description for SC DHEC, 8/1/87 to 8/31/87, Report No. 0060705TRRS383010, September 12, 1988.

24. Chem-Nuclear Systems, Inc., Volume by Waste Description for SC DHEC, 9/1/87 to 9/30/87, Report No. 006070STRR5383010, September 12, 1988.

25.

Chem-Nuclear Systems. Inc., Volume by Waste Description for SC DHEC, 10/1/87 to 10/31/87, Report No. 006070STRR5383010, September 12, 1988.

26. Chem-Nuclear Systems, Inc., Volume by Waste Description for SC DHEC, 11/1/87 to 11/30/87, Report No. 006070STRR5383010, September 12, 1988.

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27. Chem-Nuclear Systems, Inc., Volume by Waste Description for SC DHEC, 12/1/87 to 12/31/87, Report No. 0060705TRR5383010, September 12, 1988.

l 28.

U.S. Nuclear Regulatory Commission, Low-Level Waste Licensing Branch Technical Position on Waste Fom, May 1983, I

29.

" Final Generic Environmental Impact Statement on Decommissioning of Nuclear facilities," U.S. Nuclear Regulatory Commission, NUREG-0586, August 1988.

30. Murphy, E.S., " Technology, Safety and Costs of Decommissioning Reference Non-Fuel-Cycle Nuclear Facilities," Pacific Northwest l

Laboratory, NUREG/CR-1754, February 1981.

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lable 1 Waste Stream Volumes (m8) from Dismantlement of a Referenc i

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__ aste Streams Class A Class 8 Class C GTCC Total Neutron Activated Core Shroud and Adjacent Metal Other Internals 39 60 17 133 133 Pressure Vessel 222 116 Concrete 707 222 Metal Cavity Liner 14 707 14 982 60 17 133 1,192 Contaminated Material Equipment, Metal, &

Concrete Surfaces 16,078 Process Waste 16,078 Evaporator Bottoms 266 Resins 266 57 Cartridge Filters 57 9

Dry Activated 9

Waste 195 88 283 461 154 615

Total, 17,521 214 17 133 17,885 t

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Table 2 Waste Stream Activities (C1) from Dismantlement of a Reference PWR t

Waste Streams Class _A Class _B Class C GTCC Total Neutron Activated Core Shroud and Adjacent Metal 4,784,500 4,784,500 Other Internals 212 5,501 34,300 40,013 Pressure Vessel 19,186 19,186 i

Cor. crete 2,121 2,121 Metal Cavity Liner 10 21,529 5,501 34,300 4.784,500 4,845,830 Contaminated Material Equipment, Metal, &

Concrete Surfaces 997 997 Process Waste Evaporator Bottoms 13,812 13,812 Resins 41,998 41,998 Cartridge Filters 5,040 5,040 Dry Activated Waste 234 528 762 14,046 47,566 61,612 Total 36,572 53,067 34,300 4,784,500 4,908,439 l

k Table 3

_1987 Barnwell Waste Volumes and Activities by Weste Type and Class l

3 Waste Type Volume (ft8)

Class A Class B Class C Total Resin 1.920E+5 2.675E+4 4.414E+3 2.231E+5 Solfd Combustibles

1. 733E+ 3 1.190E+2 i

Solid Noncombustibles 1.852E+3 Filter Media

• 5.158E+4 1.866E+2 2.730E+1 5.179E+4 2.193E+4 1.160E+3 Cartridge / Mechanical 2.309E+4 Filters **

5.140E+3 9.044E+2 1.675E+3 7.719E+3 Solidified Liquids ***

5.836E+4 7.836E+2 Equipment, Components 3.849E+2 2.929E+2 9.700E+2 1.648E+3 5.914E+4 8iologfcal Incinerator Ash 5.077E+3 3.000E+1 5.077E+3 Air Filtration Filters 3.045E+3 3.000E+1 Combustibles and Non-S 782E+5 1.016E+3 4.100E+0 5.793E+5 3.045E+3

_ combustibles (Mixed)

Total 9.175E+5 3.121E+4 7.090E+3 9.558E+5 Activity (Cf)

Resin t

1.663E+4 1.717E+4 1.040E+4 4.420E+4 Solfd Combustibles 8.740E+0 1.300E+2 Solid Noncombustibles 3.009E+2 S.977E+3 7.216E+1 6.3SOE+3

1. 387E+ 2 Filter Media

• 3.114E+2 3.489E+2 Cartridge / Mechanical 1.616E+2 4.456E+2 1.165E+3 1.772E+3 6.603E+ 2 Tilters **

Solidified Liquids ***

8.332E+2 2.347E+2 Equipment, Components 3.510E+1 1.177E+3 1.516E+5 1.528E45 1.068E+3

-Biological Incinerator Ash 1.357E+0 7,000E-S 1.357E+0 Air Filtration Filters 5.685E+0 7.000E-S

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Combustibles and Non-5.685E+0 1.237E+3 2.742E+3 4.204E-2 3.979E+3 combustibles (Nfxed)

Total 1.953E+4 2.822E+4 1.633E+5 2.110E+5

• Used in liquids and other than resin or cartridges.

• • Used in liquids.

• • • Includes concentrates and sludges.

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Table 4 1987 Volumes _ and Activities of Richland and Beatty Wastes Richland. WA Site Beatty, NV Site Waste Types Vol. (ft3) Act. (C1)

Vol. (f t3) Act. (Cfl Vials 1.500E+1 1.187E-2 1.158E+2 2.352E+0 Dry solid 4.202E+5 1.927E+4 2.826E+5 9.580E+3

_.E Solidified liquid 2.729E+4 2.284E+4 3.578E+4 6.029E+2 E

Biological waste 2.813E+2 2.606E-2 1.828E+2 5.859E-3 Filter media 3.465E+3 3.455E+2 1.823E+2 6.649E+0 Dewatered resin 3.851E+4 4.002E+3 2.354E+3 8.871E-1 SolidiTied resin 7.184E+ 3 7.481E+2 7.376E+3 9.026E+2 Absorbed aqueous liquid 2.967E+4 2.412E+2 9.721E+2 1.743E+0 Absorbed organic liquid 4.857E+3 1.764E+0 Aqueous liquid in vials 4.700E+3 9.921E+0 2.250E+1 6.011E-3

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Animal carcasses in 1.203E+4 1.527E+1 1.602E+3 7.931E-1 absorbent Gas 2.250E+1 4.051E-3 Compacted dry active waste 5.700E+2 6.264E-1 5.431E+2 2.013E+0 Noncompacted dry active 2.075E+2 6.478E+0 waste Other 7.657E+3

,5.299E+0 6.876E+2 1.239E+0 Total 5.566E+5 4.748E+4 3.324E+5 1.110E+4

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_ Table 5 Waste Stream Volumes (m8) from Dismantlement of a Reference BWR Waste Streams

_ Class A Class 8 Class C GTCC Total Neutron Activated Core Shroud 47 47 Other Internals 15 15 53 Reactor Vessel 8

83 Concrete 90 8

90 113 15 53 47 228 Contaminated Material Equipment, Metal, &

Concrete Surfaces 17,229 17,229 Process Waste Evaporator Bottoms 492 148 Solidified Decon.

640 Solutions 120 Filter Sludge, 120 Resins 54 Dry Activated 54 Waste 468 210 678 1,134 358 1,492 Total 18,476 373 53 47 18,949 I'

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Iable6 Waste Stream Activities (C1) from Dismantlement of a Reference BWR Waste Streams-Class A Class B Class C GTCC Total Neutron Activated Core Shroud 6,301,700 6,301,700 Other Internals 750 10,300 239,000 250,050 Reactor Vessel 2,160 2,160 Concrete 180 180 3,090 10,300 239,000 6,301,700 6,554,180 Contaminated Material Equipment, Metal, &

Concrete Surfaces 8,490 8,490 Process Waste Evaporator Bottoms 1,440 31,200 32,640 ~

Solidified Decon.

Solutions 105 105 Filter Sludges, Resins 227 227 Dry Activated Waste 562 1,260 1,822 2,334 32,460 34,794 Total 13,914 42,760 239,000 6,301,700 6,597,374

12 Table 7 Summary Distribution of Volume and Activity Within Reactor Decommissioning Wastes PWR BWR Class A Volume (m8)(%)

17,521(98) 18,476(97.5)

Activity (C1) (%)

36,600(0.7) 13,900(0.2)

Class B Volume (m8)(%)

214(1.2) 373(2.0)

Activity (C1) (%)

53,100 (1.1) 42,800(0.6)

Class C Yolume(m3)(%)

17(0.1) 53(0.3)

Activity (C1) (%)

34,300 (0.7) 239,000(3.6)

GTCC-Volume (m3)(%)

133(0.7) 47(0.3)

Activity (C1) (%)

4,784,500(97.5) 6,301,700(95.5)

Tota _1 Volume (m3) 17,885 18,949 Activity (Ci) 4,908,400 6,597,400 i

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, Decay o'f Class A, 8. and C Wastes From Reactor Decommissioning (C1)

Time After Total D_isposal (yr)

_ Class A Class B Class C Total or Reference PWR 0

36,600 53,100 34,300 124,000 1

9,480 13,500 9,890 32,900 4

1 45 55 2,300 1,000 0.g 1.7 10.2 12.8 9,700 Reference BWR 0

13,900 42,800 239,000 296,000 1

3,830 11,900 65,100 80,800 4

14 684 5,310 6,180 48 100 64.7 286 3,500 3,850 77 500 10.2 231 242 1,200 1*000 0.

2.8 64.9 68.1 4,300

. Table 9 Decay of GTCC Wastes from Reactor Oecommissioning Reference PWR Reference BWR Time (yr)

Activity (C1)

Red. Factor Activity (C1)

Red. Factor 0

4,780,000 1

6,300,000 1

5 2,530,000 1.9 3,230,000 2

10 1,380,000 3.5 1,710,000 3.7 30 254,000 19 258,000 24 50 159,000 30 147,000 43 100 109,000 44 100,000 63 300 28,300 170 26,200 240 500 8,090 590 7,770 810 1000 1,550 3,100 1,780 3,500

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p Table 10 Decommissioning Waste Volumes from Non-Power Reactor Facilities.

Facility Waste Volume (m8)

Research and Test Reactors 160 - 4,930 Fuel Reprocessing Non-TRU 3,100 TRU 4,600 Uranium Hexafluoride Conversion 1,259 Uranium fuel Fabrication Equipment, Concrete, etc.

1,100 Calcium Fluoride Waste 29,600 Spent Fuel Storage Wet 2,720 Dry Well 6,700 Silo 920 Vault 500 Cask 42 Non-Fuel-Cycle Fume Hood 4

Glove Box 4

Small Hot Cell 2

Laboratory Workbench (4.6m x 0.9m x 0.75m) 7.2 Sink and Drain 0.4 Room (6m x 10m x 3m) 7.5 I

15 Table 11 Low-Level Waste Volume and Activity Sorted by Generic Industry Utilities Hospitals Colleges and and and Electric Health Education Variable Site Services Services Services Government Industry Total Vol.(ft3)B*

6.252E+5 9.740E+2 1.091E+4 5.951E+4 2.592E+5 9.558E+5 R

2.422E+5 2.151E+4 1.827E+4 9.916E+3 2.647E+5 5.566E+5 Be 7.198E+4 9.900E+2 6.125E+4 1.982E+5 3.324E+5 9.394E+5 2.248E+4 3.017E+4 1.307E+ 5 7.221E+5 1.845E+6 (50.9%)

(1.2%)

(1.6%)

(7.1%)

(39.1%)

Act. (C1) B 2.009E+5 1.149E-1 1.591E+1 6.086E+3 3.975E+3 2.110E+5 R

1.721E+4 2.420E+1 5.201E+1 9.855E+2 2.922E+4 4.748E+4 Be 1.632E+3 5.472E-1 5.293E+0 9.463E+3 1.110E+4 2.197E+5 2.431E+1 6.847E+1 7.077E+3 4.266E+4 2.696E+5 (81.5%)

(0.009%)

(0.025%)

(2.6%)

(15.8%)

• B:

Barnwell; R:- Richland; Be:

Beatty.

NRC Residual Contamination Criteria Timothy C. Johnson Division of Low-level Waste Management and Decommissioning U.S. Nuclear Regulatory Comission

. Abstract A basic and important issue is that of allowable levels of contamination on equipment and structures released for unrestricted use.

Resolution of this issue is needed to ensure consistent regulatory and licensee decisions regarding routine operations at facilities using radioactive material, regarding the eventual decommissioning of these facilities,'and regarding disposal of certain low-level wastes by methods other than delivery to a licensed disposal facility.

Introduction The Nuclear Regulatory Commission (NRC) is currently addressing the issue of residual contamination criteria.

A Commission Policy Statement on exemptions from regulatory control is expected in the very near future.

Based on this Policy Statement, NRC plans to publish interim guidance on acceptable levels of residual contamination in early 1990.

Current Criteria'for Reactors The current guidance for terminating nuclear reactor licensees is found in Regulatory Guide 1.86, " Termination of Operating Licenses for Nuclear Reactors" (Reference 1).

This regulatory guide provides methods and procedures considered acceptable by the NRC staff for reactor license termination.

It also contains decontamination guidance for release of equipment and structures for unrestricted use.

This regulatory guide applies to research, test, and power reactor license terminations.

-Prior to terminating a license and releasing the site for unrestricted use, Regulatory Guide 1.86 recommends that the licensee should --

a. Make a reasonable effort to eliminate residual contamination.

b. Not apply coverings (e.g., paint) to radioactive surfaces of equipment and structures until the contaminated levels are below those in Table I of Regulatory Guide 1.86,

c. Determine the radioactivity in the interior surfaces of pipes, drain lines, or ductwork by making measurements at all traps and other appropriate access points if the contamination can be shown to be representative of the actual contamination.

Inaccessible points on structures, equipment, or scrap should be considered contaminated to levels in excess of the limits for unrestricted release.

d. Make a comprehensive radiation survey.

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The NRC staff, and previously the Atomic Energy Commission staff, have used the surface contamination limits given in Table I of Regulatory Guide 1.86 for over twenty years.

(Table I of Regulatory Guide 1.86 is presented below.) These limits were developed based on the variations in natural background and the lower limits of detection of survey instruments, rather than on a dose objective that relates nuclide concentration levels to exposures to the public.

This situation has led to the need for residual contamination criteria based primarily on an individual dose limit that is directly related to put,lic health and safety.

In addition to the structure and equi) ment surface contamination levels in Regulatory Guide 1.86, the NRC staff 1as applied a limit for gama-emitting nuclides of five micro-Roentgens per hour above background as measured at one meter from the surface applicable to radioactive material other than surface contamination (Reference 3). Assuming a reasonably conservative occupancy time of 2,000 hours0 days <br />0 hours <br />0 weeks <br />0 months <br /> per year, the maximum exposure to an individual would be ten millirem per year.

Regulatory Guide 1.86 is currently undergoing revision to make it compatible with the license termination procedures in the new decommissioning rule published in the Federal Register on June 27,1988(Reference 2). The revised regulatory guide will reference updated residual contamination criteria.

We expect to publish a draft regulatory guide for comment after the interim residual contamination limits are issued in early 1990.

Development of New Criteria The NRC is a member of an interagency task force to develop standards for residual criteria.

However, this group is not expected to complete its work until the mid-1990's.

Because the NRC staff recognizes the need for interim guidance in this area, the Commission has committed to providing this guidance by December 1989. This guidance is directly related to NRC activities in the areas of Below Regulatory Concern (BRC) waste disposal practices and other regulatory decisions involving the exemptions of radioactive material from regulatory control. The following discussion presents important background information that will lead to the development of residual contamination criteria.

The Low-Level Radioactive Waste Policy Amendments Act of 1985 was enacted in January 1986 (Reference 4).

Section 10 of this Act requires that, within six months the NRC establish standards and procedures, and the technical capability to act in an expedited manner on petitions to exempt specific waste streams from regulation.

NRC responded with three actions.

First, On August 29, 1986 the NRC published in the Federal Register a Commission Policy Statement and Staff Implementation Plan (Reference 5). These i

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Table I.. Acceptable Surface Contamination Levels Nuclide(a)

Average (b.c)

Maximum (b.d)

Removable (b e)

U-NAT, U-235, U-238, 5,000dpm(alpha) 15,000dpm(alpha) 1,000dpm(31pha) and associated per 100 cm per 100 cm2 per 100 cmt r-decay products Transuranics, 100 dpm/100 cmt 300 dpm/100 cme 20 dpm/100 cm2 Ra-226 Ra-228, Th-230, Th-228 Pa-231, Ac-227, I-125, 1-129 r

200 dpm/100 cm2 Th-NAT, Th-232, 1000 dpm/100 cm2 3000 dpm/100 cm Sr-90, Ra-223, Ra-224, U-232, I-126, I-131, I-133 gamma)pm(beta-Beta-gamma emitters 5,000dpm(beta-15,000dpm(beta-1000 d (nuclides with de-gama) per gama) per per cay modes other than 100 cm2 100 cma 100 cm2 alpha emission or spontaneousfission) except Sr-90 and others noted above.

a.

Where surface contamination by both alpha-and beta-gama-emitting nuclides exists, the limits established for alpha-and beta-gamma-emitting nuclides should apply independently.

b.

As used in this table, dpm (disintegrations per minute) means the rate of emission by radioactive material as determined by correcting the counts per minute observed by an appropriate detector for background, efficiency, and geometric factors associated with the instrumentation.

c.

Measurements of average contamination 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.

d.

The maximum contamination level applies to an area of not more than e

100 cm,

e.

The amount of removable material per 100 cm8 of surface area should be determined by wiping that area with dry filter or soft absorbent paper, applying moderate pressure, and assessing the amount of radioactive material 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.

l 4

4 two documents provide guidance to potential rulemaking petitioners outlining the decision criteria the Comission intends to use to expeditiously process BRC waste stream petitions.

Second, the IMPACTS-BRC computer code for calculating radiological impacts from unregulated disposal was adapted for personal computer use.

A draft user guide for this code was published in July 1986 (Volume 2 of NUREG/CR-3585) (Reference 6). Subsequently, the NRC staff contracted with Sandia National Laboratory for-technical assistance to critique, validate, and verify the computer code.

Third, on December 2, 1986 the NRC published in the Federal _ Register an advanced notice of proposed rulemaking (ANPR) requesting coments on the development of a generic BRC level for wastes (Reference 7). Over 90 coments were received in response to the ANPR reflecting diverse views on how the NRC should proceed. Many commenters opposed the concept of any level of radioactivity being BRC and others urged NRC to proceed promptly on the generic rulemaking. In March 1988 the Comission delayed the rulemaking and directed the staff to first prepare for Commission consideration options for a broad policy statement that establishes a generic limit for exposures that are below regulatory concern.

The policy statement addresses exemption decisions as a whole, not only those BRC issues for waste management, but also licensing applications for consumer products, existing exempt quantity limits, decomissioning, and effluent releases. This policy statement would provide for more efficient and consistent regulatory actions in connection with exemptions from specific NRC requirements. A draf t policy statement was prepared and discussed at the International Workshop on Rules for Exemption from Regulatory Control sponsored by the NRC and the Nuclear Energy Agency in October 1988. An Advance Notice of a policy statement was issued for public comment in the Federal Register on December 12,1988(Reference 8). This Advance Notice recomended a ten millirem per year individual dose criterion as one basis for establishing a floor for curtailment of ALARA activities. This value considered optimum use of Comission resources to address matters of radiological protection, the variations in background, risk perceptions, BRC versus de minimis distinctions, the linear non-threshold hypothesis, and practical implementation. The policy and the comments received are currently being considered by the Comission. We expect the Commission to take action in the very near future.

Based on these dose objectives, NRC plans to publish interim criteria on residual contamination in early 1990.

Included will be guidance on residual contamination levels on a nuclide-by-nuclide basis. These nuclide-by-nuclide data will be develo)ed from pathway analyses performed under a contract with Pacific National La) oratories. These analyses are based on direct exposure, ingestion, inhalation, and groundwater pathways.

5 References 1.

U.S. Nuclear Regulatory Commission Regulatory Guide 1.86, " Termination of Operating Licenses for Nuclear Reactors," June 1974.

2.

" General Requirements for Decommissioning Nuclear Facilities," Final Rule, Federal Register, Vol. 53, No. 123, pp. 24018 - 24056, June 27, 1988.

3.

Letter to Dr. Roland A. Finston, Stanford University, from John A. Stolz, NRC, March 17, 1981.

4.

Low-Level Radioactive Waste Policy Amendments Act of 1985, Public Law 99-240, January 15, 1985.

5.

" Radioactive Waste Below Regulatory Concern; Policy Statement," Federal Register, Vol. 51, No. 168, pp. 30839 -30847, August 29, 1986._

6.

Forstom, J.M and D.J. Goode, "De Minimis Waste Impacts Analysis Methodology, NUREG/CR-3585, VoTume 2, July 1986.

7.

" Radioactive Waste Below Regulatory Concern, Generic Rulemaking," Federal Register, Vol. 51, No. 231, pp. 43367 - 43369, December 2, 1986.

8.

" Policy Statement on Exemptions from Regulatory Control," Federal Register, Vol. 53, No. 238, pp. 49886 - 49891, December 12, 1988.

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ELIMINATION OF ESIDUAL CONTAMINATION 2.

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u. cept Sr-90 and others noted above.

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'As u:ed in thh 9ble, dpm Idisintegrations per minute) ameans the rate of emission by radioective snaterial ad dgermined by correcting the counts per minute observed bP an appropriate detector for background, efficiency, and g,,.,/aic fictWes associated with the i

iwtrumentation.

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average shodid be derived for each such object.

2

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The snaximdm contamination level applies to an stea of not mose than 100 cm,

2 Ti'e amount of removable radioactive material per 100 can of surface area should be deterndeed by wiping that area with dry filter or '

sof absorbent paper, applying nooderate psessure, and assessing the amount of radioactive material.on the wipe with as appropriate instnament of known efficiency. When sessovalde consam3== siam on objects of less surface ases is determined, she partinent levels.

stiould be seduced proportionaBy and the entire surface sbomad be wipod. -

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LOW-1 BEL WASTE POLICY APOEPENTS ACT PIAISATED SDERAL lEC ACTIONS.

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