ML20236L489
| ML20236L489 | |
| Person / Time | |
|---|---|
| Issue date: | 06/25/1998 |
| From: | Mcgaffigan E NRC COMMISSION (OCM) |
| To: | Hoyle J NRC OFFICE OF THE SECRETARY (SECY) |
| Shared Package | |
| ML20236L475 | List: |
| References | |
| SECY-98-051-C, SECY-98-51-C, NUDOCS 9807130025 | |
| Download: ML20236L489 (4) | |
Text
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NOT ATIO N VOTE RESPONSE SHEET TO:
' John C. Hoyle, Secretary FROM:
COMMISSIONER MCGAFFIGAN
SUBJECT:
SECY-98-051 - GUIDANCE IN SUPPORT OF FINAL RULE ON RADIOLOGICAL CRITERIA FOR LICENSE TERMINATION Approved (
Disapproved Abstain l
Not Participating Request Discussion COMMENTS:
See attached comments.
/*t' SIGNATURE l/6' 'd U Release Vote / v /
}3,
(392 l
DA(d Withhold Vote /
/
Entered on "AS" Yes Y
No E N E 3 !-
Commissioner McGaffinan's Comments on SECY-98-051:
I approve publication of Regulatory Guide DG-4006 and supporting guidance documents for a public' comment period of two years and offer the following for the staff's consideration.
I commend the staff for meeting an extremely aggressive schedule while utilizing an open and j
innovative process that included several public workshops which were preceded by the availability of draft guidance documents on the Intemet. The staff should ensure that the +
Agreement States and Conference of Radiation Contml Program Directors am aware of the -
issuance of these documents for interim use and public comment.
y I agree with the staff's proposed approach to maintain a dialogue with the public during the lL
. comment period through the website and I support the conduct of public workshops provided that they prove to be an efficient use oflimited staff resources. I also suggest that the staff explore the possibility of providing a more detailed flow chart or, at a minimum, a more detailed table ofcontents or subject index for each guidance document to assist the reader in locating relevant sections of the various guidance documents.
L
' After reviewing the guidance documents, receiving a briefing by the staff, and reviewing the
- April 29,1998 letter report from the Advisory Committee on Nuclear Waste to the Chairman, I have two primary areas of concem--the conservatism associated with dose modeling and development of the standard review plan to implement the rule. I will address each of these areas in tum.
Dose Modelino I recognize that the use of various modeling codes such as RESRAD, PRESTO and DandD (currently under final development by the staff and contractor) to demonstrate compliance with a radiation dose limit can result in significantly different calculated doses due to differences in i
underlying assumptions, pathway analyses, default parameter values, etc. I also recognize that DandD is a screening tool that provides for an iterative process using a risk-informed approach and its use by licensees is strictly voluntary. Nevertheless, I am sensitive to the concem by some individuals that certain DandD parameter values (e.g., soil-to-plant transfer rates) are more conservative than necessary. As a result, the calculated potential dose to members of the public from residual contamination could be significantly overestimated, particularly in cases where the default parameter value is conservative and there is no corresponding site-specific data on which to rely. In these cases, it is conceivable that licensees using only the generic screening model might perform costly and unnecessary additional cleanup oflicensed sites for little or no public benefit. Therefore, I strongly agree with the staff's plan to continue reviewing the DandD code l
during the public comment period to identify areas where conservatism can be reduced and to test and compare DandD with other models in use to better determine its applicability for NRC licensees. This is particularly important for the conservative groundwater model in DandD for the resident farmer scenario. I understand that it is very difficult to generically model groundwater, but it would be preferrable if a specific groundwater mods! did not have to be developed in almost every instance involving groundwater contamination.
a 2
I also approve the staff's use of 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. Indeed, probabilistic concepts are inherently built into dose models including -
the DandD code by using generic, probabilisticly derived default parameters and providing for the integration of site specific data on certain pawneters based on their probability of positively affecting the outcome. Therefore, in using a risk-informed approach to decommissioning, I believe that it is necessary to factor in the probability of an individual actually receiving the calculated maximum dose and making license termination decisions accordingly.
w Based on the information provided, areas of conservatism that warrant additional review during Lthe public comment period include, but are not limited to, the following:
. 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 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 from on-site the assumption that 100% of the animal feed and food crops are grown on-site in contaminated soil more regional or localized data (e.g., rainfall data) should be integrated into DandD when D
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.
Standard Review Plan To some' degree, the development and use of the Standard Review Plan (SRP) to review license termination plans submitted by licensees is where the " rubber meets the road" in terms of -
implementing the final rule on radiological criteria for license termination. Because ofits significance, the staff must exercise due diligence to ensure that the more risk-informed and iterative approach outlined in the NUREG-1549 decision framework and suppo'rting guidance 4
- documents is not undermined by the use of outdated methodologies, decision frameworks or guidance that rely on radionuclides-specific concentration limits or other generic values which may not provide'a consistent level of protection for the public and environment. I am concerned that efforts to develop the SRP are not yet underway and I suggest that the staff be directed to I
l provide the Commission a timeline for development of the SRP. The timeline should include
' ACNW review of and comment on the SRP during its development. In developing the SRP, it is
- also important that clear guidance be provided on compliance with the As Low As Reasonably L
4 Achievable (ALARA) provision of the final rule. For example, the Generic Environmental j'
Impact Statement for the final rule finds that, for soil, doses that meet the 25 millirem per year R
3 dose limit are ALARA. Is. these cases, additional demonstration of compliance may not be necessary.
While I recognize that this is a resource constrained era, it would be useful for the staff and NRC licensees if an existing complex site were used as a pilot case for the purposes of developing and testing the SRP.
l l
4.
[pnseat UNITED STATES
'n NUCLEAR REGULATORY COMMISSION l
{
I W ASHIN GTON. D.C. 20555 July 8, 1998 OFFICE OF THE l
SECR ET ARY j
MEMORANDUM TO:
L. Joseph Callan cu ' e Di ector for Operations l
FROM:
C.
y, cretah ySTAFF REQUIREMENTS - SECY-98-051 - GUIDANCE IN l
SUBJECT:
SUPPORT OF FINAL RULE ON RADIOLOGICAL CRITERIA l
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 Conference of Radiation Control Program Directors are aware of the issuance of these l
documents for interim use and public comment.
(EDO)
(SECY Suspense:
7/31/98)
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 nL guidance documents.
h Ll} '
The Commission expressed concem that there may be excessive conservatism, particularly in the screening model (DandD) code. Areas of conservatism that warrant additional review Og)
. during the public comment period include, but are not limited to, the following:
f-t the assumption that the resident farmer is the proper screening group scenario in overy case where soil contamination is found or where institutional controls fail i
(perhaps "sub-scenarios" or new scenarios could be developed based on actual experience) j 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 from 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.
The staff should consider the comments provided to the Commission by the Advisory C@Wim-n - 2RO
.s
- '. 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 outi;ned in the NUREG-1549 decision framework and supporting guidance documents is not undermined by the use of outdated methodologies, decision frameworks or guidance that rely on radionuclice-specific concentration limits u other generic values which may not provide -
a consistent level of protection for the public and environment. In 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.
(EDO)
. (SECY Suspense:
7/29/2000)
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 -
E recommendations.
(EDO)
(SECY Suspense:
9/30/98)'
1 cc:
Chairman Jackson l
Commissioner Diaz Commissioner McGaffigan OGC-CIO o
CFO l
OCA i
l OlG 1
l-Office Directors, Regions, ACRS, ACNW, ASLBP (vi. 2-Mail) l PDR DCS i
b
-