ML20137Z396

Discusses Review of W Ltr NSD-NRC-97-4986,dtd 970214,which Requested Relief,Under 10CFR50.12, Specific Exemptions, from Section XI Test Frequency Requirements for ADS Stage 1, 2,3 Valves.Unable to Approve Request for Relief,Per Ssar

ML20137Z396
Person / Time
Site:	05200003
Issue date:	04/22/1997
From:	Quay T NRC (Affiliation Not Assigned)
To:	Liparulo N WESTINGHOUSE ELECTRIC COMPANY, DIV OF CBS CORP.
References
NUDOCS 9704240138
Download: ML20137Z396 (3)

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s p" k UNITED STATE 3

{ ', g j NUCLEAR REGULATORY COMMISSION

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! WASHINGTON, D.C. 3068H001 l

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. April 22, 1997 l

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Mr. Nicholas J. Liparulo, Manager i Nuclear Safety and Regulatory Activities I

Nuclear and Advanced Technology Division j Westinghouse Electric Corporation P.O. Box 355 Pittsburgh, PA 15230 l

SUBJECT:

WESTINGHOUSE AP600 RELIEF REQUEST FOR AUTOMATIC DEPRESSURIZATION SYSTEM (ADS) VALVE TEST FREQUENCY

Dear Mr. Liparulo:

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The Nuclear Regulatory Commission (NRC) Civil Engineering and Geosciences Branch reviewed Westinghouse letter NSD-NRC-97-4986, dated February 14, 1997, i which requests relief, under 10 CFR 50.12, " Specific Exemptions," from the i Section XI test frequency requirements for the ADS stage 1, 2, and 3 valves as j required by 10 CFR 50.55a, " Codes and Standards." This request is also

' l addressed in the standard safety analysis report (SSAR) Subsection 3.9.6.3.1, t

" ADS Valve Exercise Testing," and Note 3 in Table 3.9-16, " Valve Inservice j Test Requirements." Alternate proposals are reviewed and granted by the  !

Commission pursuant to 10 CFR 50.55a(a)(3) or (g)(6). In its letter, Westing- )

house states conflicting factors of increased valve reliability from increased testing, and decreased reliability from increased risk of improper testing.

Westinghouse requests to increase the test frequency from 3-months to 6-months after considering these two apparently conflicting factors. The staff agrees that valve exercising would pose a slightly higher risk of loss of coolant and deprassurization of the reactor coolant system if the proper test sequence is not followed. However, rather than reducing the test frequency, Westinghouse should improve test procedures to minimize the risk of improper testing.

In reviewing this request, the staff considered the importance and the uniqueness of the AP600 ADS valves. In SECY-93-087, the staff-notes that the passive safety systems rely heavily on the proper operation of the ADS valves to mitigate the effects of accidents and to shut down the plant to safe conditions. In SSAR Section 5.4.6, " ADS Valves," Westinghouse states that opening the ADS valves is required for the operation of the passive core cooling systems following postulated accident conditions. For the AP600 design, the staff concludes that the reliability of the AP600 ADS valves to function in the open position should not be compromised. The reliability of the ' valve is a function of test frequency. Extending the test frequency from 3-months to 6-months would reduce the reliability of these valves.

Based upon the above discussion, the staff is unable to approve the request for relief at this time. The staff can not justify the relaxation of the testing requirements without AP600 operational experience or test data to support otherwise. Pending the SSAR revision to delete the 6-month test frequency for the ADS valves, draft safety evaluation report Open Item 3.9.6.3-1 remains open. n kJ @}I 3 o ADON ~

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Mr. Nicholas J. Liparulo April 22, 1997 i

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If you have any questions regarding this matter, you can contact Diane Jackson at (301) 415-8548.

' Sincerely, I

original signed by:

l Theodore R. Quay, Director Standardization Project Directorate Division of Reactor Program Management Office of Nuclear Reactor Regulation Docket No.52-003

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cc: See next page DISTRIBUTION:

Docket File PDST R/F TMartin PUBLIC MSlosson TRQuay TKenyon WHuffman JSebrosky )

DJackson JMoore, 0-15 B18 WDean, 0-17 G21 ACRS (11) GBagchi, 0-7 HIS JHuang, 0-7 H15 l BSheron, 0-7 D24 Glainas, 0-7 D24 i

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T - con wah .n.ch,=.au. ace. v - % con 0FFICE PM:PDST:DRPM l EQCB1)E I By&ETAB:DE l D:PDST:DRPM l l NAME DTJackson:sg W JHuan'g flBagchi TRQuay-T M DATE 04/ W 97 404/p\ /97 & 04/qV97 04/n/97 0FFICIAL RECORD COPY

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, Mr. Nicholas J. Liparulo Docket No.52-003 Westinghouse Electric Corporation AP600

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] cc: Mr. B. A. McIntyre Mr. Ronald Simard, Director l i Advanced Plant Safety & Licensing Advanced Reactor Programs i

Westinghouse Electric Corporation Nuclear Energy Institute J

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 l

! Advanced Plant Safety & Licensing Doc-Search Associates

Westinghouse Electric Corporation Post Office Box 34  ;

j Energy Systems Business Unit Cabin John, MD 20818 '

i Box 355 i Pittsburgh, PA 15230 Mr. James E. Quinn, Projects Manager  !

LMR and SBWR Programs l Mr. M. D. Beaumont GE Nuclear Energy

. Nuclear and Advanceo Technology Division 175 Curtner Avenue, M/C 165 ,

i Westinghouse Electric Corporation San Jose, CA 95125 i One Montrose Metro i

11921 Rockville Pike Mr. Robert H. Buchholz Suite 350 GE Nuclear Energy )

i Rockville, MD 20852 175 Curtner Avenue, MC-781 San Jose, CA 95125 3

Mr. Sterling Franks ]

i U.S. Department of Energy Barton Z. Cowan, Esq.

i NE-50 Eckert Seamans Cherin & Mellott i 19901 Germantown Road 600 Grant Street 42nd. Floor Germantown, MD 20874 Pittsburgh, PA 15219 l Mr. S. M. Modro Mr. Ed Rodwell, Manager

Nuclear Systems Analysis Technologies PWR Design Certification i Lockheed Idaho Technologies Company Electric Power Research Institute

Post Office Box 1625 3412 Hillview Avenue

! Idaho Falls, ID '83415 Palo Alto, CA 94303 l Mr. Frank A. Ross Mr. Charles Thompson, Nuclear Engineer i U.S. Department of Energy, NE-42 AP600 Certification

Office of LWR Safety and Technology NE-50

19901-Germantown Road 19901 Germantown Road j Germantown, MD 20874 Germantown, MD 20874 b

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