ML20137L503

Discusses Key Issue 11 Involving Sys Reliability of Hydrogen Mitigation Sys for design-basis Accidents & Severe Accidents

ML20137L503
Person / Time
Site:	05200003
Issue date:	04/03/1997
From:	Martin T NRC (Affiliation Not Assigned)
To:	Liparulo N WESTINGHOUSE ELECTRIC COMPANY, DIV OF CBS CORP.
References
NUDOCS 9704070248
Download: ML20137L503 (3)

Text

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}% p t UNITED STATES j

1 if* NUCLEAR REGULATORY COMMISSION l

'g WASHINGTON, D.C. 30886 4001

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Mr. Nicholas J. Liparulo, Manager Nuclear Safety and Regulatory Analysis .,

Nuclear and Advanced Technology Division Westinghouse Electric Corporation P.O.' Box 355

Pittsburgh, PA 15230 SLG7CT

- AP600 HYDROGEN IGNITER POWER SUPPLY

Dear Mr. Liparulo:

J

, 'In a letter dated December 6,.1996, we sent you a list of. potential critical path' issues in the design certification process for the AP600. One of'the i 1ssues (key issue #11) involves system reliability of hydrogen mitigation

systems for design-basis accidents and severe accidents. For severe acci-dents, the AP600 relies on hydrogen igniters, and the staff expressed concern with the adequacy of the igniter's power supply. In a November 4, 1996, 1etter, and in Revision 11 to the Standard Safety Analysis Report (SSAR),

i- Westinghouse proposed a modification to the design of-the power supply for the

igniters. j j The Containment Systems and Severe Accident Branch (SCSB) has reviewed the )

revised power supplies available to the hydrogen igniters as described in a Revision 11 to the AP600 SSAR. Each igniter power group can now be powered by f the following sources

offsite ac power, one of the two onsite non-essential diesel generators, and the non-Class IE batteries for 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />. After discus- i siens with the Electrical Engineering Branch, SCSB concludes that the proposed power supply design for the hydrogen igniters is consistent with other non-Class IE power supply designs and addresses our concern of igniter

availability during a station blackout event.  !

Section 16.1, " Technical Specifications" of Revision 11 to the AP600 SSAR does not include the hydrogen ignition subsystem (HIS). Operating experience, specifically the accident at Three Mile Island, has shown that a system for j hydrogen control is important to public health and safety as promulgated by i

10 CFR 50.34(f), " Additional TMI-Related Requirements." The Commission

, stated, in its statement of considerations for 10 CFR 50.34(f), that the requirements in the new rule are necessary for protection of the public and i L that their costs are not exorbitant. Westinghouse has used the criteria in '

the Nuclear Regulatory Commission Policy Statement on Technical Specification (TS) Improvement to identify the systems to be included in the AP600 TSs. {

Criterion 4 of the policy statement calls out structures, systems, and compo-nents which operating experience or probabilistic safety assessment has shown

+

to be important to public safety. Based on Criterion 4, the staff has '

-concluded that systems provided to meet the requirements of 10 CFR 50.34(f)(2)(ix) should be included in the AP600's TSs. The precedent for

- ,this decision was made during the evolutionary design certification for the i 05l ,

9704070248 970403 D PDR ADOCK 05200003 l A PDR C _ _!

i Mr. Nicholas J. Liparulo April 3, 1997 Section 14.2.9.1.11, " Containment Hydrogen Control System Testing," of the initial test program (ITP) should be revised to provide or reference specific-  ;

acceptance criteria or functional requirements traceable to specific subsec-tions or numbered paragraphs of the SSAR, the plant TSs, or other appropriate

-references that contain the detailed performance criteria that is being verified by the test. The ability of each igniter power group to be powered by offsite ac power, one of the two onsite non-essential diesel generators, and the non-Class lE batteries should be verified in the inspections, tests, analyses, and acceptance criteria (ITAAC) and the ITP.. The-ITAAC and ITP should verify that the as-built locations of the hydrogen igniters are within 2.5 feet of the locations provided by Figures 6.2.4-5 through 6.2.4-12 of the I SSAR. Because the HIS is included in the Emergency Response Guidelines, it should be included in the Maintenance Rule Program.

If you have any questions regarding this matter, you can contact Joe Sebrosky at (301) 415-1132.

Sincerely, original signed by:

Thomas T. Martin, Director Division of Reactor Program Management '

Office of Nuclear Reactor Regulation i

Docket No.52-003 cc: See next page DISTRIBUTION: SCollins/FMiraglia, 0-12 G18 Docket File PDST R/F PUBLIC AThadani, 0-12 G18 TMartin TRQuay TKenyon MSlosson BHuffman JSebrosky DJackson '

JMoore, 0-15 B18 WDean, 0-17 G21 JKudrick, 0-8 H7 RPalla, 0-8 H7 MSnodderly, 0-8 H7 ACRS (11)

CGrimes, 0-13 HIS

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( 03/27/97 04/01/97 4/1 /97 9'/J5/97 DATE 'f/l/97 0FFICIAL RECORD COPY

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I~ Mr. Nicholas J. Liparulo Docket No.52-003 Westinghouse Electric Corporation AP600 cc: Mr. B. A. McIntyre Mr. Ronald Simard, Director Advanced Plant Safety & Licensing Advanced Reactor Programs Westinghouse Electric Corporation Nuclear Energy Institute Energy Systems Business Unit 1776 Eye Street, N.W.

P.O. Box 355 Suite 300 Pittsburgh, PA 15230 Washington, DC 20006-3706 Ms. Cindy L. Haag Ms. Lynn Connor Advanced Plant Safety & Licensing Doc-Search Associates Westinghouse Electric Corporation Post Office Box 34 Energy Systems Business Unit Cabin John, MD 20818 Box 355 Pittsburgh, PA 15230 Mr. James E. Quinn, Projects Manager LMR and SBWR Programs Mr. M. D. Beaumont GE Nuclear Energy Nuclear and Advanced Technology Division 175 Curtner Avenue, M/C 165 Westinghouse Electric Corporation San Jose, CA 95125 One Montrose Metro 11921 Rockville Pike Mr. Robert H. Buchholz '

Suite 350 GE Nuclear Energy Rockville, MD 20852 175 Curtner Avenue, MC-781 San Jose, CA 95125 Mr. Sterling Franks U.S. Department of Energy Psrton Z. Cowan, Esq.

NE-50 Eckert Seamans Cherin & Mellott 19901 Germantown Road 600 Grant Street 42nd Floor Germantown, MD 20874 Pittsburgh, PA 15219 Mr. S. M. Modro Mr. Ed Rodwell, Manager Nuclear Systems Analysis Technologies PWR Design Certification Lockheed Idaho Technologies Company Electric Power Research Institute Post Office Box 1625 3412 Hillview Avenue Idaho Falls, ID 83415 Palo Alto, CA 94303 Mr. Frank A. Ross Mr. Charles Thompson, Nuclear Engineer U.S. Department of Energy, NE-42 AP600 Certification Office of LWR Safety and Technology NE-50 19901 Germantown Road 19901 Germantown Road Germantown, MD 20874 Germantown, MD 20874