ML20155F282

Informs Commission of Recent & Planned Staff Actions Re Implementing, Final Rule on Radiological Criteria for License Termination

ML20155F282
Person / Time
Issue date:	10/21/1998
From:	Travers W NRC OFFICE OF THE EXECUTIVE DIRECTOR FOR OPERATIONS (EDO)
To:
References
SECY-98-242, SECY-98-242-01, SECY-98-242-1, SECY-98-242-R, NUDOCS 9811050376
Download: ML20155F282 (8)

Text

!*

RELEASED TO THE PDR i

5 1  : hhM JR : ,

! dati initials p <eso...eeeeesesseessess.>

POLICY ISSUE October 21, 1998 (InfOrmation) SECY-98-242 FOR: The Commissioners FROM: William D. Travers Executive Director for Operations l

SUBJECT:

SCREENING TABLE FOR BUILDING SURFACE CONTAMINATION, AS GUIDANCE IN SUPPORT OF THE FINAL RULE ON RADIOLOGICAL CRITERIA FOR LICENSE TERMINATION PURPOSE: 1 To inform the Commission of recent and planned staff actions related to implementing the

" Final Rule on Radiological Criteria for License Termination"[(License Termination Rule (LTR),

62 FR 39058, July 21,1997)]in accordance with the Commission's Staff Requirements Memorandum (SRM) dated July 8,1998 [(SECY-98-051), Attachment 1], especially development of a screening table for building-surface contamination.

BACKGROUND:

On July 8,1998, the Commission cpproved publication of " Guidance in Support of Final Rule on Radiological Criteria for License Termination" for interim use over a period of 2 years. The l

Commission directed staff to: (1) develop a more user friendly format for the guidance; (2) maintain a dialogue with the public during the interim period; (3) address areas of excessive i

conservatism, particularly in the DandD screening code; and (4) develop a standard review plan (SRP) for decommissioning, and provide the Commission with the schedule for the SRP.

In response to Commission direction, the staff has taken prompt actions and made initial progress on each of the following areas:

O/

CONTACT: Boby Abu Eid, NMSS/DWM (301) 415-5811 ')Q Lf

c. %02 Predecisiona' I l

9011050376 981021 '

^L{ -}c DO 3-?

Predecisiona, The Commissioners 2 o

Staff has developed a screening table of unrestricted release values for building-surface contamination. (Attachraent 2) The table would expedite the process of using the draft guidance in a more user-friendly format, during the interim period. The staff coordinated the screening values in the table with other Federal agencies, through the Interagency Steering Committee on Radiation Standards (ISCORS), on September 9,1998.

o Staff conducted a public meeting on August 14,1998, to discuss the format and content of future public workshops on the implementation of the draft guidance for the LTR. The meeting was attended by representatives of the Nuclear Energy institute; Fuel Cycle Facilities Forum; Electric Power Research Institute; Department of Energy; State of New Jersey; Environmental Protection Agency; and other interested organizations. The staff will conduct a second public meeting on October 22,1998, and an expanded workshop  ;

on December 1-2,1998. Staff will continue to conduct such meetings and workshops to receive public input.

o A project plan and workgroup have been established (including Office of Nuclear Material Safety and Safeguards, Office of Nuclear Regulatory Research, Office of State Programs, and Regional staff) to develop the SRP. The staff transmitted the project plan for the SRP to the Commission on September 29,1998. The workgroup is currently addressing the issue of excessive conservatism in the DandD code and developing guidance to be contained in the SRP.

o The staff briefed the Advisory Committee on Nuclear Waste on the subject of the SRP and the screening table.

DISCUSSION:

The staff plans to issue a Federal Register notice (FRN), to be published by October 30,1998, announcing the end of the "grandfathering period,"in 10 CFR 20.1401(b), and the release of the DandD screening code, Version 1. The FRN will also announce: (1) a default screening table of unrestricted release values for building-surface contamination, for the interim use of the guidance; (2) a strategy for future interactions with industry and interested parties, including a combination of workshops, telephone conferences, and release of documents on the U.S.

Nuclear Regulatory Commission's (NRC's) web site; and (3) a plan for developing the SRP for decommissioning within the 2-year comment period. The FRN will also address the status of old decommissioning guidance documents during NRC's transition from the Site Decommissioning Management Plan (SDMP) Action Plan to the LTR.

The screening table for surface contamination of common radionuclides will permit licensees to demonstrate compliance with the LTR as simply as possible, and is consistent with the Commission's direction to develop a more user-friendly format for the guidance. Sites with surface contamination of walle and floors would be acceptable for release for unrestricted use in accordance with 10 CFR 20.1402. The screening values were derived from the DandD screening code, Version 1, using default physical parameters that were selected at the 90th percentile of the dose distribution (Attachment 2).

7 decisional

i 3C t

The Commissioners 3 While site-specific analyses would generally be based on the mean of the dose distribution, the 90th percentile was selected for the default values in DandD to provide high confidence that the

' actual dose at a site will not exceed the standard. Simple screening models, like DandD, that require a minimal amount of site-specific information are easy and inexpensive to use, but will not provide the level of realism and accuracy that is provided by more complex models that require detailed and often more costly site-specific information. The methodology in the draft NUREG-1549 (Using Decision Methods for Dose Assessment to Comply With Radiological Criteria for License Termination) provides licensees with the flexibility to perform their own evaluation of which approach is most reasonable for their specific situation. They can use the simpler screening approach with minimal requirements for site-specific information, and accept a higher level of conservatism which could result in more extensive cleanup. Alternatively, they I can use modeling approaches that use site-specific information, and which support a more realistic estimate of dose.

This differs from current NRC guidance and common staff practices that use the mean of the dpse s as the dose value for demonstrating compliance. For example, the " Branch Technical Position for Low-Level Waste Performance Assessment," (PA), (SECY-96-103), uses the mean of the dose distribution for compliance assessment, provided that the 95th percentile of the distribution is less than 1 mSv (100 mrem). As another example, the staff uses, as the performance objective for postclosure, in the draft proposed 10 CFR Part 63, " Disposal of High-Level Radioactive Wastes in a Proposed Geological Repository at Yucca Mountain, Nevada," .

the mean dose (expected annual dose) to be less than 0.25 mSv/yr (25 mrem /yr) (SECY l 225). The Commission's Final Policy Statement on the use of probabilistic risk assessment j (PRA) methods in nuclear regulatory activities (60 FR 42622) required that PRA evaluations in support of regulatory decisions be as realistic as practicable. In addition, the " Final General Regulatory Guide and Standard Review Plan for Risk-informed Regulation of Power Reactors" (SECY-98 015) contemplates use of best-estimate or mean-risk values. I For the interim period, the staff intends to use the default screening values which result in doses at the 90th percentile because:

o in screening analyses, little information is typically available about an individual site. As such, the degree of uncertainty may not be as well known as in site-specific analyses where a great deal of information is known. Therefore, as stated in the National Council on Radiation Protection and Measurements' Report Number 123, " Screening Models for Releases of Radionuclides to Atmosphere, Surface Water, and Ground," screening models are designed to ensure that there is high confidence that the dose would not be underestimated.

o The default screening levels are consistent with the current default values in the DandD code, Version 1, which already has been released on NRC's web site.

o The DandD screening values at the 90th percentile are only slightly more conservative (within a factor of 2 to 3) of the mean screening values.

l Predecisiona

, Predecisional The Commissioners 4 The staff intends to use the 90th percentile screening values table for building surface contamination during the hterim period, while developing the SRP and testing DandD. The table wili be a useful tool for routine decommissioning cases and will facilitate a smooth transition for simple cases. During the interim period, staff will continue to analyze the pros and cons of selecting the mean versus other confidence levels (e.g., the 90th percentile) in the screening analyses, and will use the mean for demonstrating compliance with the dose criterion for site-specific analyses. The staff plans to develop a new probabilistic version of the DandD code that would enable calculation of the dose based on the mean or other percentile values. If the final SRP and LTR guidance recommend using a decision point for screening or site-specific analyses, based on a percentile value other than the mean, staff will inform the Commission in advance.

The screening values for beta- and gamma-emitters, in Attachment 2, are much higher than the SDMP Action Plan Criteria that staff has been using to make decisions on license terminations.

For alpha-emitters, the surface screening values are generally much lower. This is because the new limit in the LTR is dose-based whereas the Action Plan Criteria are riot in all cases explicitly related to dose. For radionuclides that emit beta / gamma radiation, where the new values are much higher, application of the "as low as is reasonably achievable" rerquirements in 10 CFR 20.1402 may result in contamination levels much lower than the screening values specified in the table. For radionuclides that emit alpha radiation, where the new values are much lower, the calculated screening values are so low that demonstrating compliance would j be complex, very resource-intensive, and not practical. in such cases, refined screening, site-specific data collection, consideration of restricted release, the application of area factors, and other refinements will be employed to implement the license termination rule. The staff will continue to pursue developing more practical guidance for alpha emitters.

]

The staff will announce the availability of the table of screening values, showing only the 90th percentile values for beta and gamma-emitters in an FRN. (Since the alpha values are too restrictive to be useful they will not be included.) Before release of the table to the public, the

staff willinform the Organization of Agreement States.

As recognized in the June 30,1998, SRM, the staff will be refining the regulatory guidance over the next 2 years, so the screening values may change. In the interim, if licensees meet the screening values, they would be deemed to comply with the 25 mrem dose criterion in the LTR without performing dose calculations, using DandD or some other codes.

i e

4 a

Predecisiona

Predecisional The Commissioners 5 The staff will continue to provide updates to the Commission on the progress of developing the j SRP and implementing the LTR. '

h William D. Tr vers Executive Director for Operations Attachments: 1. Staff Requirements Memorandum SECY-98-051, Guidance in Support of Final Rule on Radiological Criteria for License Termination

2. Screening Values of Common Radionuclides for Building Surface Contamination Levels l

DISTRIBUTION:

Commissioners OGC OCAA OIG OPA OCA ACNW CIO CFO EDO REGIONS SECY l

I l

l I

l l

l l

l l

o redecisional

- - - - - - - m

, , Action: Thadani, RES I

=  !'

[ -

o UNITED STATES NUCLEAR REGULATORY COMMISSION Cys: Cal Travers

g WASHINGTON. D.C 20555 Thompson t / Norry ,

July 8, 1998 Blaha l OFFICE OF THE SECRETARY Collins, NRR Trottier, RES MEMORANDUM TO: L. Joseph Callan

,E9cuf e D rector for Operations FROM: C. y , Fecretary

SUBJECT:

1. STAFF REQUIREMENTS - SECY-98-051 - GUIDANCE IN I SUPPORT OF FINAL RULE ON RADIOLOGICAL CRITERIA FOR LICENSE TERMINATION The Commission has approved publication of the guidance and supporting documents and their ,

interim use for a period of two years. The staff should ensure that the Agreement States and I Conference of Radiation Control Program Directors are aware of the issuance of these documents for interim use and public comment.

(EBO) (RES/SP) (SECY Suspense: 7/31/98) 8900194 The staff should go forward with plans to maintain a dialogue with the public during the comment period through use of a website and public workshops provided that they prove to be an efficient use of limited staff resources. The staff should explore the possibility of providing a more detailed flow chart or, at a minimum, a more detailed table of contents or subject index for each guidance document to assist the reader in locating relevant sections of the various guidance documents.

The Commission expressed concern that there may be excessive conservatism, particularly in the screening model (DandD) code. Areas of conservatism that warrant additional review during the public comment penod include, but are not limited to, the following: i the assumption that the resident farmer is the proper screening group scenario in every case where soil contamination is found or where institutional controls fail (perhaps "sub-scenarios" or new scenarios could be developed based on actual i experience)

- the daily drinking water consumption value of 1.3 liters the assumption that 100% of the water used to irrigate the land where food crops ,

are grown is contaminated ground water frem on-site '

more regional or localized data (e.g., rainfall data) should be integrated into DandD when available groundwater model- as mentioned above, the staff should compare the DandD groundwater model against other generic groundwater models or the use of site-specific models to determine the utility of the generic groundwater model. 1 The staff should consider the comments provided to the Commission by the Advisory l l

ATTACHMENT 1 ,

l 1

l

. I i

2-Committee on Nuclear Waste (ACNW) on April 29,1998, when the staff updates the regulatory guidance and supporting documents during the 2-year comment period, in particular, the staff should follow through on the ACNW recommendation to develop a more user-friendly format including development of guidance on standard content and format of information to be

submitted to the NRC for license termination cases. The staff should use a complex site to test the DandD code and serve as a pilot for developing and testing the Standard Review Plan (SRP).

The staff should exercise due diligence to ensure that the more risk-informed and iterative approach outlined in the NUREG-1549 decision framework arid supporting guidance documents is not undermined by the use of outdated methodologies, decision frameworks or guidance that rely on radionuclide-specific concentration limits or other generic values which may not provide a consistent level of protection for the public and environment. Iri developing the SRP, clear guidance should be provided on compliance with the As Low As Reasonably Achievable (ALARA) provision of the final rule, in addition, if the licensee complies with the 25 mrem dose criterion using the screening methodology, the licensee may have met the intended ALARA requirement; therefore, additional demonstration of compliance may not be necessary.

The staff should use a probabilistic approach to calculating a total effective dose equivalent to an average member of the critical group to demonstrate compliance with the license termination rule. The DandD code inherently builds in probabilistic concepts and is consistent with a risk-informed approach to decommissioning that factors in the probability of an individual actually receiving the calculated maximum dose. 1 (EDG) (RES) (SECY Suspense: -7/29A2000-) 8900194 1 7/22/2000 1 The staff should provide the Commission a timeline for development of the SRP and any interim guidance on the SRP. The timeline should include ACNW review of and comment on the SRP during its development. Adequate resources should be provided to NMSS to implement these recommendations.

(EDO) (NMSS) (SECY Suspense: 9/30/98) 9800136 9/23/98 cc- Chairman Jackson Commissioner Diaz Commissioner McGaffigan OGC CIO CFO OCA OlG

, Office Directors, Regions, ACRS, ACNW, ASLDP (via E-Mail)

PDR DCS b

, - - _ _ _ , - . - , , , . , - - . -_ ,- c., - - - --. -.- m -n,__ -- _-- . , - -- - - - y ,-- - -g-

l

• SOfeEENING VALUES OF COMMON MADIONUOLIDES FO'1 F'UILDING SURPAO'T CONTAMINATION LEVELS

"=****** Emissi E'aCD Screening values' Actirn Com s on Plan . mon a=Alph ~

• Value Use*

g,m 90th Percentile Mean s" of the output dose distribution of theoutputdosedistributen y=Omm ma H-3 p 1.2E+08 1.9E+08 SE+03 R, B C-14 p 3.7E+06 5.6E+06 SE+03 B Na-22 p 9.5E+04 9.6E+04 SE+03 B S-35 p 1.3E+07 2.4E+07 SE+03 8 Cl-36 p 5.0E+05 9.8E+05 SE+03 8  ;

Mn-54 p 3.2E+04 3.2E+04 SE+03 R '

Fe-55 p 1.0E+04 ) 5.8E+03 SE+03 R 1

Co-60 py 7.1E+03 7.5E+03 SE+03 R, B Ni-63 p 1.8E+06 3.8E+06 SE+03 R. B Sr-90 p 8.7E+03 1.7E+04 1E+03 R, B Tc-99 p 1.3E+06 2.6E+06 B,FC SE+03 )

1-129 py 3.5E+04 4.8E+04 1E+02 B Cs-137 py 2.8E+04 2.9E+04 SE+03 R Ir-192 0y 7.4E+04 7.6E+04 SE+03 B l

Ac-227 apy 1.8E+00 4.0E+00 1E+02 FC Th-228 - ay. 4.1E+01 9.0E+01 1E+02 FC

. Th-232 ay ' 7.3E+00 1.6E+01 1E+03 FC Pa-231 ay 8.6E+00 1.9E+01 1E+02 FC

. U-235 .

'ay 9.7E+01 : 2.1E+02 SE+03 FC U-238 ay 1.0E+02 2.2E+02 SE+03 FC

~

Pu-239 ay 2.8E+01 6.0E+01 na FC, DOE l Am-241 ay 5.8E+01 2.7E+01 na B l l

l

' Screening vakms (dpm/100 cm2 ) equivalent to 25 mrem /y. Behavioral parameters are set at the mean of the distribution of the assumed critical group. The Metabolic parameters are set at Standard Man or at the mean of the distribution for an average man. The physical parameters were derived as a set to result in a point dose estimate that would be at the percenti',e indicated of the output dose distribution, and would not exceed 100 mrem at 95% confidence.

2 Reg. Guide 1.86 limits (dpm/100 cm2 ); these limits are not explicitly dose-based. .

8 R: Reactor; 8: Broad-Scope; FC: Fuel Cycle