ML20148E067

Informs That After Further Review on W AP600 Request to Change ADS Valve Test Frequency,Staff Has Determined That Addl Info Needed & Request Denied at This Time

ML20148E067
Person / Time
Site:	05200003
Issue date:	05/29/1997
From:	Slosson M NRC (Affiliation Not Assigned)
To:	Liparulo N WESTINGHOUSE ELECTRIC COMPANY, DIV OF CBS CORP.
References
NUDOCS 9706020262
Download: ML20148E067 (3)

Text

O N hte+ Glle, gacg g 1- UNITED STATES j NUCLEAR REGULATORY COMMISSION 2 WASHINGTON, D.C. 30666 4001

% May 29, 1997 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

SUBJECT:

ADDITIONAL GUIDANCE ON WESTINGHOUSE AP600 REQUEST TO CHANGE AUTO-MATIC DEPRESSURIZATION. SYSTEM (ADS) VALVE TEST FREQUENCY

Dear Mr. Liparulo:

After further review, the staff has reconsidered its guidance regarding the AP600 request to change the test frequency of ADS Stage 1, 2, and 3 valves.

As indicated previously, the staff is unable to approve your request at this time. In its February 14, 1997, letter, Westinghouse stated that the frequency of the ADS valve exercise testing should be minimized to reduce the risk of improper testing, and that the probablistic risk assessment results demonstrate that the AP600 meets its safety goal. The staff cannot justify the relaxation of the testing requirements based on this statement because increasing the test interval might reduce the valve reliability and increase the risk. Additional information is required to evaluate the reduction in risk from less frequent testing compared to the increase in risk due to reduced valve reliability from an increased test interval.

Westinghoure may present a quantitative probabilistic or deterministic justificatiin to demonstrate equal or improved reliability from testing ADS valves at 6 month intervals, rather than 3-month intervals. If Westinghouse chooses a probabilistic justification as intended in your February 14, 1997, '

letter, please provide a detailed explanation for the basis of the probabilistic values, how the information is used, a description of the methodology, and the quantitative results.

The heavy reliance on the ADS valves for the operation of the safety-related [f) systems to safely shut down the plant after a postulated accident is unique to I the AP600. The staff believes that the reliability of the AP600 ADS valves to open on demand should not be compromised. Westinghouse's analysis results y?))

must show that the reliability of the valves and the overall safety of the plant is equal or improved by testing the ADS valves at a frequency of 6 months versus 3 months. Westinghouse is also requested to explain why improved test procedures cannot accomplish the same result without extending the test frequency. Without additional justification, the staff believes that the ASME Code Section XI requirement for a 3-month testing frequency is  !

appropriate.  ;

escale NBC HLE CENTER COPY  :

9706020262 970529 PDR ADOCK 05200003 K PDR

,.,_,,n, , . - . ,--

l Mr. Nicholas J. Liparulo May 29, 1997 l

l To resolve this issue, Westinghouse must either submit additional information as discussed above, or revise the standard safety analysis report to comply with the ASME 3-month test frequency. If you have any questions regarding this information, please contact Diane Jackson at (301) 415-8548.

Sincerely, original signed by:

Marylee M. Slosson, Acting Director Division of Reactor Program Management Office of Nuclear Reactor Regulation Docket No.52-003 cc: See next page DISTRIBUTION:

Docket File PDST R/F MSlosson PUBLIC SWeiss TQuay TKenyon BHuffman JSebrosky DJackson JMoore, 0-15 B18 WDean, 0-17 G21 ACRS (11) l 1,

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0FFICE PM:PDST:DRPM D:PDST:DRPM $;D( 4 (A)D:DRPM ., ,

NAME DTJackson:sg i4k TRQuay P24; $ herl # MMSlossondftv DATE 05/b /97 '(I 05/ (, /97 65/$97 05/f/97 (Mi 0FFICIAL RECORD COPY L I

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1 Mr. Nicholas J. Liparulo Socket No. o2-003 Westinghouse Electric Corporation OP600 l l

cc: Mr. B. A. McIntyre Mr. Ronald Simard, Director '

Advanced Plant Safety & Licensing Advanced Reactor Programs Westin5h ouse Electric Corporation Nuclear Energy Institute Energy Systems Business Unit 1776-Eye Street, N.W. l

. P.O. Box 355 Suite 300 '

l Pittsburgh, PA 15230 Washington, DC 20006-3706 Ms. Cindy L. Haag Ms. Lynn Connor Advanced Plant Safety & Licensing Doc-Search Associates Westinghocse 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 i LHR 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 Barton 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 l

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