ML20148D998

Expresses Appreciation for Re Concerns Raised on Risk Posed by low-power & Shutdown Operations at Npps.Staff Concluded That New Rulemaking on Risk During low-power Operations Not Warranted,Due to Existing Regulations & TSs

ML20148D998
Person / Time
Issue date:	05/28/1997
From:	Callan L NRC OFFICE OF THE EXECUTIVE DIRECTOR FOR OPERATIONS (EDO)
To:	Seale R Advisory Committee on Reactor Safeguards
References
ACRS-GENERAL, FACA, NUDOCS 9706020220
Download: ML20148D998 (6)

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NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 s*****/ May 28, 1997 R. L. Seale, Chairman Advisory Committee on Reactor Safeguards U.S. Nuclear Regulatory Commission l

Washington, D.C. 20555-0001 l

SUBJECT:

ESTABLISHING A BENCHMARK ON RISK DURING LOW-PO'NER AND SHUTDOWN OPERATIONS

Dear Chairman Seale:

Thank you for your letter of April 18,1997, in which yo, aised a number of concerns related I to the risk posed by low-power and shutdown operations at nuclear power plants. You ,

recommended that the staff undertake a well-planned, de!iberate effort, with extensive peer I review, to develop technologies needed to benchmark risk, and address in the benchmarking a representative range of plant types as well as all phases of low-power and shutdown operations. '

I share the concerns you raised regarding repeated events during shutdown operations and the changes being made in plant operations due to economic forces. The staff is being guided by risk insights in its efforts to develop a rule to address shutdown operations. I intend to forward a proposed rule to the Commission by the end of July 1997 and have directed the staff to meet with the ACRS following resolution of public comments to discuss the final rule.

In addition, substantial domestic and international work has been done in this area that can provide valuable input to our future course of action. In determining whether further work is needed, we have looked at what was learned from the two NRC studies (see References 1 and 2) and other NRC activities. We have concluded that the timely issuance of a rule addressing shutdown risks is warranted. To that end, we are developing a revised proposed shutdown rule that will account for public comments received on the previously proposed rule.

The considerable effort entailed in developing a benchmark for shutdown risk would expend significant agency resources. Further, we tt 'mve that mere detailed benchmarking is not necessary to support a rulemaking on shutcc. a Finally, the staff has concluded that a new ruiemaking on the risk dunng low-power operations is not warranted, because existing regulations and technical specifications already ensure the availability of critical systems during low-power operations.

Sincerely,

'f I k gdD L. J bseph Callan

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References:

l 1. U.S. Nuclear Regulatory Commission, NUREG/CR-6144, BNL-NUREG-52399, l Vol.1, Brookhaven National Laboratory, " Evaluation of Potential Severe Accidents L

During Low Power and Shutdown Operations at Surry, Unit 1," Summary of Results, October 1995. l l

2. U.S. Nuclear Regulatory Commission, NUREG/CR-6143, SAND 93-2440, Vol.1, l Sandia National Laboratories, " Evaluation of Potential Severe Accidents During Low Power and Shutdown Operations at Grand Gulf, Unit 1," Summary of Results, July 1995.

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R. L. Scale, Chairman Advisory Committee on Reactor Safeguards May 28, 1997 U.S. Nuclear Regulatory Commission Washington, D.C. 20555-0001

SUBJECT:

ESTABLISHING A BENCHMARK ON RISK DURING LOW-POWER AND SHUTDOWN OPERATIONS 4

Dear Chairman Seale:

Thank you for your letter of April 18,1997, in which you raised a number of concerns related to the risk posed by low-power and shutdown operations at nuclear power 4

plants. You recommended that the staff undertake a well planned, deliberate effort, with extensive peer review, to develop technologies needed to benchmark risk, and address in the benchmarking a representative range of plant types as well as all phases or low power and shutdown operations.

I share the concerns you raised regarding repeated events during shutdown operations and the changes being made in plant operations due to economic forces.

. The staff is being guided by risk insights in its efforts to develop a rule to address shutdown operations. I intend to forward a proposed rule to the Commission by the end of July 1997 and have directed the staff to meet with the ACRS following resolution of public comments to discuss the final rule.

In addition, substantial domestic and international work has been done in this area that can provide valuable input to our future course of action in determining whether further work is needed, we have looked at what was learned from the two NRC studies (see References 1 and 2) and other NRC activities. W3 have concluded that the timely issuance of a rule addressing shutdown risks is warranted. To that end, we are developing a revised proposed shutdown rule that will account for public comments received on the previously proposed rule.

The considerable effort entailed in developing a benchmark for shutdown risk would expend significant agency resources. Further, we believe that more detailed

benchmarking is not necessary to support a rulemaking on shutdown.

4 Finally, the staff has concluded that a new rulemaking on the risk during low power operations is not warranted, because existing regulations and technical specifications already ensure the availability of critical systems during low power operations.

Sincere @iginal Signed by L J. f'allan L. Joseph Callan 4

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R. L. Seale, Chairman l Advisory Committee on Reactor Safeguards .

! U.S. Nuclear Regulatory Commission l Washington, D.C. 20555-0001 i

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SUBJECT:

ESTABLISHING A BENCHMARK ON RISK DURING LOW-POWE AND SHUTDOWN l OPERATIONS

Dear Chairman Seale:

Thank you for your letter of April 18, 1997, in wh you raised a number of concerns related to the risk posed by low-power d shutdown operations at nuclear power plants. You recommended that the staff undertake a well planned, deliberate effort with extensive peer review to develop technologies needed to benchmark risk, and then include i the benchmarking a representative range of plant types and al phases of low-power and shutdown operations.

I share the concerns you raised with r ard to repeated events during shutdown operations, and the changes being mad in plant operations due to economic forces. The staff has included thes risk-significant considerations in its efforts to develop a rule to addre shutdown operations. I have asked that a proposed rule for public comment sent to the Commission by the end of July 1997. I understand that followl g resolution of public comments, the staff will meet with the ACRS to disc ss the final rule.

In addition, substantial dom tic and international work has been done in this area, which can provide val ble input to our future course of actions.

Therefore, we plan to look at what was learned from the two NRC studies

[ References 1 and 2] and rom other NRC activities in deciding if any further work is needed. This pl n is in accordance with what the staff briefed the ACRS in February 1997 the next activity in low power shutdown risk. We welcome discussions w h the ACRS as we move forward in this area and propose that these discussio be held following public comment on the proposed low-power and shutdown le. Further, specific questions will be included in the proposed rulemakin package that solicit information on the need for additional low-po ' r and shutdown risk studier.

Sincerely, Shirley Ann Jackson cc: Commissioner Rogers Commissioner Dicus OCM Commissioner Diaz SJackson Commissioner McGaffigan 05/ /97 SECY n

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