ML20237L289

Forwards Requests for Addl Info Re Item 4.2 (Parts 3 & 4) of Generic Ltr 83-28,requiring Licensees to Describe Preventive Maint & Surveillance Program for Ensuring Reliable Reactor Trip Breaker Operation

ML20237L289
Person / Time
Site:	Zion  File:ZionSolutions icon.png
Issue date:	09/01/1987
From:	Muller D Office of Nuclear Reactor Regulation
To:	Butterfield L COMMONWEALTH EDISON CO.
References
GL-83-28, TAC-53950, TAC-53951, NUDOCS 8709080329
Download: ML20237L289 (5)

Text

.a . l September 1 0 1987 i

Distribution:

' Docket FHeo Plant File i Docket Nos. 50-295 NRC & Local PDRs l and 50-304 PDIII.2 r/f )'

GHolahan LLuther Mr. L. D. Butterfield, Jr. JNorris )

Nuclear Licensing Manager OGC-Beth, j Commonwealth Edison Company Edordan i Post Office Box 767 JPartlow I Chicago, Illinois 60690 ACRS (10) j 1

Dear Mr. Butterfield- J 1

SUBJECT:

REQUEST FOR ADDITIONAL INFORMATION - ITEM 4.2 (PARTS 3 & 4) 0F GENERIC LETTER 83-28, ZION STATION, UNITS 1 AND 2 TAC NOS.: 53950 AND 53951 Item 4.2 of Generic Letter 83-28 requires licensees to describe their preventive maintenance and surveillance program for ensuring reliable reactor trip breaker i operation. Parts 3 and 4 of Item 4.2 pertain to life testing of an acceptable sample size of the breakers, and periodic replacement of the breakers or compo-nents consistent with demonstrated life cycles. The Commonwealth Edison Company submitted responses to Item 4.2 (Parts 3 & 4) by letters dated November 5, 1983; February 29, 1984; June 1, 1984; and October 10, 1984. Our review of these responses finds them to be inadequate as indicated in the enclosed Request for Additional Information. 4 Sincerely, Danis 15CfAn S l Daniel R. Muller, Director Project Directorate III-2 Division of Reacto.* Projects - III, IV, V ar.J Special Projects

Enclosure:

As stated cc: A. Toalston ,

8709080329 870901 PDR ADOCK 05000295 P PDR m i 0FC  : PDIII-2  : PDII 2  : PDIII  :  :  : 1

______:.___..4d....:(......y NAME : LLuther/ww  :

JNo ris\  : r  :  :  :

l

)

......:.....________..:.__.._7._..._:_p...._______:______._______:____________.:.__

i i DATE : 9 /o e /87  : / h/bl /87 :@/ / /87 :  :  :

l l l '

. 4 Mr. L. D..Butterfield, Jr.

Commonwealth Edison Company Zion Station cc:

Robert J. Vollen, Esquire Mr. Michael C. Parker, Chief ,

109 North Dearborn Street Division of Engineering- **

Chicago, Illinois 60602 Illinois Department of Nuclear. 1 Safety Dr. Cecil Lue-Hing 1035 Outer Park Drive 5th Floor Director of Research and Development- Springfield, Illinois 62704 Metropolitan Sanitary District

~

of Greater Chicago 100 East Erie Street Chicago, Illinois 60611 Mr. P. Steptoe.

Isham, Lincoln and Beale Counselors at Law Three First National Plaza 51st Floor Chicago, Illinois 60602 Mayor of Zion Zion, Illinois. 60099 Illinois Department of Nuclear Safety ATTN: Manager, Nuclear Facility Safety 1035 Outer Park Drive, 5th Floor Springfield, Illinois 62704 U.S. Nuclear Regulatory Commission Resident Inspectors Office 105 Shiloh Blvd.

Zion, Illinois 60099 Regional Administrator, Region III U.S. Nuclear Regulatory Commission 799 Roosevelt Road Glen Ellyn, Illinois 60137 i

1 l

REQUEST FOR ADDITIONAL INFORMATION ITEM 4.2 (PART5 3&4) DF GENERIC Lt11ER 83-28 ZION STATION, UNITS 1,2 y

.- T'  ;

l Item 4.2 of Generic Letter 83-28 requires licensees or applicants to describe their preventive maintenance and surveillance program for~ ensuring reliable reactor trit breaker operation. Parts 3 and 4 of Item 4.2 pertains to life testing of an acceptable sample size of the breakers, and periodic replacement ,

of the breakers or components consistent with demonstrated life cycles. The licensee st.bmitted responses to Item 4.2 (Parts 384) by letters dated November 5,1983; February 29,1984; June 1,1984; and October 10, 1984.

The licensee referenced the Westinghouse Owners Group' activities toward establish-1 ing the service life of the reactor trip breakers and components, and indicated that the life testing and replacement of the breakers and components would be based on the Westinghouse recommendations.

Westinghouse has presented the results of cyclic testing on the RTB DB-50 and DS-416 in WCAP-10852 and 10835, respectively. These reports address cyclic testing of the RTB trip attachments. They neither address life qualification of the RTBs nor noneyclic life-limiting or performance-degrading phenomena (e.g.,

aging)forthetripattachments. Therefore, WCAP-10852 and WCAP-10835 do not 1 constitute an acceptable response to the concern of the generic letter. l If it can be demonstrated that the qualified life of the RTB exceeds the life of the plant, then the specific qualified life need not be identified. In a practical sense, the intent of the life testing requirement of the generic letter would be satisfied by demonstrating that the qualified life of the breaker (for the tripping function) exceeds the expected use projected to the next refueling.

Cycle testing by the various owners groups, although it does not consider the effects of aging, may provide evidence to support continued use of the RTBs for one additional refueling cycle, provided that the individual breaker has not shown a sign of degradation based on the licensee's Parametric Trend Monitoring

.)

a

(

l. .

l l

Program. In this approach; the actual qualified.ldfe is not specifically identi- g fie but is"only demonstrated to be adequate. [

Ophoing life testing is an acceptable alternative to ' formal life testing for the purpose of. establishing a specific qualified life for RTBs. Ongoing life testing will demonstrate that the qualifiedlife, though not specifically known, is longer (in terms of cycles and time) than the integrated service that will be accumulated through the next refueling interval. The description of an ongoing qualification-program should include the following:

(1) an estimate of the number of demands between refueling outages to which the RTB must respond, and the basis for the estimate. 1 (2) a definition of relevant, end-of-life related failures (Note thaf random failures occurring durin_q the constant hazard rate portion of the " bathtub curve" (plot of failure rate vs. time) are not relevant to a life test).

The licensee should (a) identify the possible failure modes, (b) categorize eachfailuremodeasanend-of-lifetypeornot,and(c)presentageneral methodology for categorizing future failure modes that may not be included in(a).

(3) the action to be taken u?on any failure.

The staff finds that the licensee has not committed to a life testing program.

The licensee should qualify their breakers by (a) actual life testing of the breakers, including aging, on an acceptable sample size or (b) establishing an ongoing life testing program. If the first alternative is selected, the licensee should present the results of the life testing to the staff for review. If the second alternative is selected, the licensee should describe their ongoing life testing program, including the three items identified above.

l l

1

1

. J

.. 1 I

I The licensee should'also present 701 staff review a replacement p<agram for the g {

breaker and breaker components based on the results of their life qualification [ l program. For ongoing qualification, the licensee should describe how the ongoing qualification results will be used to establish replacement cycles and times. i l

i I

i i

I I

- _ _ - _ _ _ _ _