ML19275B649

Interim Deficiency Rept Re DNBR Limit & Nuclear Instrumentation Reactor Rate Trip Circuit,Reported Previously in Separate Submittals.Administrative Reduction in Control Rod Insertion Limits Implemented

ML19275B649
Person / Time
Site:	North Anna
Issue date:	01/04/1980
From:	Brown S VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:
References
REF-PT21-79-181-001 1116A, NUDOCS 8001080467
Download: ML19275B649 (3)

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PCO VIRGINI A ELECTRIC AND POWER COMP ANY, RICMMONO, VIRGINI A 23261 J muary 4, 1980 Mr. James P. O'Reilly, Director Seri al No.11." A Office of Inspection L Erforcement PSEAC/JCHjr:mac: wang U. S. *!uclear Regulatory Commission Region II Oceket No c0 "?

101 Marietts Street, Suite ?100 Atlanta, Georgia 30303

Dear Mr. O'Reilly:

On December 7, 1979. two -eocrts were made unter tha orovisions n#

d ICCFREO.55(e) for North .bna 'fnit 0; one concerning the Dacar+;re f*om Nucleate Soiling Ratio (DN'R) Limit and the other concerning the Nucles" Instrumentation Rutter Ra:e Trio Circuit. In accor13rce 'vith 10CFR?l, ae sucmitted on Decem::er 11,1979 5-day 1.*tters Serial Nos.1116 and 112 7, resoectively. Since ther, ve have su%itted another letter (cooy enclosedi Seri al No. 97? dated Dec'm5er 17,1979 which represents ou* position on tS's subject for North Anna Units 1 and 2.

This letter (with er. closure) is an interim report on this subject. A finsi recort will he submitted after we complete our evaluation of

'destin950use's Drocosed oermanent solutions Dresently beinn deVelooed. Should you recuire further information, please contact this office.

Very truly voors, S ?9 C . E rTvn . -7" .

Senior Vice president Dewer Statice Enclosure Engineering and Construction cc: Mr. Victor Stello, Director Office of Inspection & Enforcement Mr. Harold R. Denton, Director

' Office of Nuclear Reactor Regulation (30I9 SEIll J /

6 8001 080

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December 17, 1979 Mr. Itarold R.'Denton, Director .

Office of Nuclear Reactor Regulation Serial No. 973 .

L Attn: Mr. A. Schwencer, Chief .

FR/RWC: mye  ! ,

Operating Reactors Branch No.1 ,

Division of Operating Reactors Docket No.: 50-338 U. S. Huelcar Regulatory Commission 50-339 Washington, DC 20555 '"

License No. NPF-4 '

Dear Mr. Denton:

3 . x /.  :

~ PROCEDURAL CHANGES .

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REQUIRED TO ADDRESS CONTROL '

ROD DROP ANALYSIS CONCERNS Westinghouse question en November Electric Carperation notified Vepco .of an unroviewed safety 15, 1979 results for single dropped rod events. Discussions with Westinghouse conf only Vepco plants affceted were North Anna Units 1 and 2.

' appropriate Nuclear Regu'atory Commission (NRC) notifications were mace.Ccnsequently, the The event was investigated further by Vepco through detailed discussions with Westinghouse and the NRC Staff at a meeting in Bethesda, Maryland on Novemb 1979. The interim sclutien ag: eed upon at tne meeting is provided in Attachmen 1 and wul be incorporatec in tha appropriate Operating Procedures applicable to botn North Anna Units 1 and 2 prior to cperatien. Since the current Technical Specifications limit on centrol rod insertion is. ncnconservative, we are immediately implementing an ad:nini;trative recuction in the control rod insertion limits consistent with Attachme.nt 1.

Operation in compliance with tnis solution will climinate any safety concerns associated with potential dropped rod events. Westinghouse is Obntinuing to addrecs the issue, and we will evaluate their proposed permanent solutions for applicability to No Anna Units 1 and 2 when the solutions are finalized.

Technical 1979, Serial Nc. 504. Specifications Change No. 21 transmitted by m are no longer apprep.-iate.As discussed at the meeting on November 19,1979, these changes

. e.

The proposed solution has been reviewed and approved by the Station Nuclear Safety anc Operating Committee and the System Nuclear Safety and Oper& ting Committee. If you require additional info.mation, please contact us. -

Very truly yours, {,

NTC/ alM/j~d C. M. StcIling:

Vice-Prc.cident-Power Supply

[g end Production Operations ,

i Attachment 9

cc: Mr. Jumt.s P. O'Ryilly. Diredor Ou.ee oc un ce u sa a..a t.....ae m ent 08-an.wa u i

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l ATTACHMENT 1 INTERIM PROCEDURAL CHANGES REQUIRED FOR NORTH ANNA UNITS 1 AND 2 AS A RESULT OF CONTROL ROD DROP CONCERNS

- MANUAL ROD CONTROL

- O TO 100% POWER: NO CHANGE FROM CURRENT ROD INSERTION LDIITS (RIL)

- AUTOMATIC ROD CONTROL

- O to 90% POWER: NO CHANGE FROM CURRENT RIL

-90 TO 100% POWER: D BANK GREATER THAN 215 STEPS .

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