ML19209C359

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Responds to IE Bulletin 79-06C Re Incident at Tmi.Station Emergency Procedures Have Been Revised to Require Immediate Trip of All Operating Reactor Coolant Pumps
ML19209C359
Person / Time
Site: Beaver Valley
Issue date: 08/28/1979
From: Dunn C
DUQUESNE LIGHT CO.
To: Grier B
NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
References
NUDOCS 7910150150
Download: ML19209C359 (3)


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August 28, 1979 Director of Nuclear Reactor Regulation United States Nuclear Regulatory Commission Atta: Boyce H. Grier, Regional Director Region I 631 Park Avenue King of Prussia, Pennsylvania 19406

.uference: Beaver Valley 2ower Station, Unit No. 1 Dreket No. 50-334 Response to IE Bulletin 79-06C Gentlemen:

The following is submitted as the Duquesne Light Company response to the action items identified in IE Bulletin 79-06C.

Short Term Actions 1.A Station emergency procedures have been revised to require an immediate trip of all operating reactor coolant pumps upon the initiation of a Safety Injection Signal caused by low reactor coolant system pressure.

1.B The Beaver Valley Power Station normal station staffing requirements provide a minimum of two persons with a minimum of a Reactor Operators License to be in the Control Room at all times.

We have issued special instruction to assure that the requirements of this bulletin will be observed during reactor startups in addition to the existing technical specification requirements.

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 Westinghouse Owners' Group. A report summarizing the results of the analysis of delayed Reactor Coolant Pump trip during small loss of coolant accidents for Westinghc1se and NSSS, will be submitted to Mr. D. I'. Cordell Reed on August 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 12 9 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 ruege of break sizes and RCP trip times in all cases 10 minutes or later, which will 1146 124 7910150 {O

.. . Beaver Valley Power Station, Unit No. 1 Docket No. 50-334 Response To IE Bulletin 79-06C Page 2 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 mintues to trip the RCP's following a small break LOCA, especially in light of the conservatisms in the calculations. 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 NRC in Section 6 and Appendix A of WCAP 9600. The analyses provided as the response to Item 2 are consistent with the guidelines in WCAP 9600. No changes to these guidelines are needed for both LOCA and non-LOCA transients.
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 rupture emergency procedures is the following:

Mid-October: Guidlelines 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' Group Subcommittee on Procedures and Westinghouse to provide the background for revising their emergency procedures.

1 to 2 months from Mid-October: Plant specific procedures will be revised.

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

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

Resolution of the requirements for the analyses and an acceptable schedule for oroviding the analyses and guidelines and procedures resulting from the analyses will be arrived at between the Westinghouse Owners' Group and the NRC staff.

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

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, Docket No. 50-334 Response To IE Bulletin 79-06C Page 3 If you have any further questions concerning this response, please contact my office.

Very truly yours,

/e /

L/ / L -

C. N. Dunn Vice President, Operations cc: Director, Office of Inspecton and Enforcement Attn: A. Schwencer Washington, D.C. 20555 1i?.-6 .

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