ML19208D682

Forwards Response to IE Bulletins79-05C & 06C, Nuclear Incident at TMI-Suppl. Two Licensed Operators Required to Be in Control Room During Unit Operation & Three During Two Unit Operation

ML19208D682
Person / Time
Site:	North Anna
Issue date:	08/31/1979
From:	Stallings C VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
References
NUDOCS 7909290310
Download: ML19208D682 (3)

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<bC- 339 k VraorwrA Er.ncra C AND Powan CourAN? 3eW Rrenwonn,VamorwzA sossa August 31, 1979 Mr. James P. O'Reilly, Director Serial No. 621A Office of Inspection and Enforcement P0/DLB:sej U. S. NuclearcRegulatory Commission Docket Nos. 50-338 Region II 50-339 101 Marietta Street, Suite 3100 License Nos. NPF-4 Atlanta, Georgis 30303 CPPR-78

Subject:

IE Bulletin 79-05C and 06C This is in response to IE Bulletin Nos.79-05C and 79-06C, " Nuclear Incident at Three Mile Island - Supplement". Our response for North Anna Power Station Unit Nos. 1 and 2 is attached.

Very truly yours, MT C. M. Stallings Vice President-Preet- Supply and Production Operations ec: Director, Off'.ce of I spec +1on and Enforcement U. S. NRC, Washington, D. C. 20555 Director, Office of Nuclear Reactor Regulation U. S. NRC, Washington, D. C. 20555 D T9 D d "

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$ D D RESPONSE TO IE BULLETIN OSC and 06C g f NORTH ANNA POWER STATION UNIT NOS. 1 AND 2 h3I A Re8ponses are numbered as in the Bulletin abb_ J

1. a. A Standing Order has been issued which requires immediate tripping of all operating RCP's upon reactor trip and initiation of safety injec-tion caused by low reactor coolant systen pressure.

b. Two licensed operators will be in the control room at all times during single unit operation to accomplish this action and other immediate and followup actions required during such an occurrence. During two unit operation a total of three licensed operators will be in the control room at all times.

2. A series of Loss of Coolant Accident (LOCA) analyses for a range of break sizes and a range of time lapses between initiation of break and pump trip applicable to the 2, 3 and 4 loop plants has been performed by the Westing-house Owner's Group. A report summarizing the results of the s-Nysis of delayed Reactor Coolant Pump trip during small loss of coolant accidents for Westinghouse NSSS, will be submitted to Mr. D. F. Ross by Mr. Cordell Reed on Austist 31, 1979. In the report, maximum PCT's for each break size considered and pump shutoff times have been provided. The report concludes that if the reactor coolant pumps are tripped prior to the reactor coolant system pressure reaching 1250 psia, the resulting peak' clad temperatures are less than or equal to those reported in the FSAR. In addition, it is shown that there is a finite range of break sizes and RCP trip times (in all cases 10 minutes or later) which will result in PCT's in excess of 2200 F as calculated with conservative Appendix K models. The operator in any event would have at least 10 minutes to trip the RCP's following a small break LOCA, especially in light of the conservatism in the calcula-tions. This is appropriate for manual rather than automatic action, based on the guidelines for termination of RCP operation presented in WCAP-9600.

3. The Westinghouse Owners' Group has developed guidelines which were submitted to the ERC in Section 6 and Appendix A of WCAP 9600. The analyses provided as the response to item 2 are consistent with the guidelines f.n WCAP 9600.

No changes to these guidelines are needed for either LOCA or non-LOCA transi-ents.

4. The Owners' Group effort to revise emergency procedures covers many issues, including operation of the Reactor Coolant Pumps. The action taken in response to item 1 is sufficient as an interim measure and no immediate need exists for changing our emergency procedures to include the tripping of the Reactor Coolant Pumps. The expected schedule for revising the LOCA, steamline break and steam generator tube ruptur a emergency procedures is the following:

Mid-October: Guidelines which have been reviewed by the NRC will be provided to each utility. Appropriate utility personnel associated with writing procedures will meet with the Owners' Croup Subcommittee on Pro-c cedures and Westinghouse will provide the background for revising their emergency procedures.

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DNN- _3 1 to 2 months from: Plant specific procedures will be revised.

Mid-October 3 to 4 months from: Revised procedures will be implemented and operators Mid-October trained.

5. Analyses related to inadequate core cooling and definition of conditions under which a restart of the RCP's should be attemp*>,d will be performed.

Resolution of the requirements for the analyses god an acceptable schedule for providing the analyses and guidelines and rrccedures resulting from the an;ilyses will be arrived at between the Wor,i;inghouse Owners' Group and the NRC staff.

Iong Term As discussed in our response to short-term item 2, we do not believe that auto-matic tripping of the RCF's is a required function based on the analyses that have been performed and the guidelines that have been developed for manual RCP tripping. We propose that this item be discussed with the NRC staff following their review of the Owners' Group Submittal.

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