ML19259D336
| ML19259D336 | |
| Person / Time | |
|---|---|
| Site: | Yankee Rowe |
| Issue date: | 09/14/1979 |
| From: | Groce R YANKEE ATOMIC ELECTRIC CO. |
| To: | Grier B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| References | |
| IEB-79-06C, IEB-79-6C, WYR-79-107, NUDOCS 7910180149 | |
| Download: ML19259D336 (3) | |
Text
%
Telephone 617 366-90ll rwx 710-390-0739 YANKEE ATOMIC ELECTRIC COMPAHY m.
20 Turnpike Road Westborough, Massachusetts 01581
,Y 5KEE
's B.4.1.1 WYR-79-107 September 14, 1979 United States Nuclear Regulatory commission Office of Inspection and Enforcement Region I 631 Park Avenue King of Prussia, PA 19406 Attention: Boyce H. Grier, Director
Reference:
(1) License No. DPR-3 (Docket No. 50-29)
(2) WCAP-9584 Analysis of Delayed Reactor Coolant Pump Trip During Small Loss of Coolant Accidents for Westi.ighouse Nuclear Steam Supply Systems, August 30, 1979.
Dear Sir:
Subject:
Response to I&E Bulletin 79-06C A response to the subject bulletin has been made in our behalf by the Westinghouse Operating Plant Owners' Group via the report detailed in Reference (2). We request that your staff place a copy of this report (WCAP-9584) on the Yankee Atomic Electric Company, Docket No. 50-29.
The individual items of I&E Bulletin 79-06C were addressed as follows:
1.
Procedures have been revised to assure manual tripping of RCP's upon reactor trip and SIAS caused by low RCS pressure and to assure the presence of two licensed operators in the control room at all times during operation as requested in Bulletin 79-06C.
2.
A series of loss of Coolant Accident (LOCA) analyses for a range of break sizes and a rang ~e 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. The report, Reference (2), summarizing the results of the analysis of delayed Reactor Coolant Pump trip during small loss of coolant accidents for Westinghouse NSSS has been submitted to Mr. D. F. Ross by Mr. 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 1r -
>rq 7910180I M
B.4.1.1 WYR-79-107 Page 2.
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 0
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 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: Guidelines which have been reviewed by the NRC will be provided to each utility. Appropropriate 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 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 condition 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 providing the analyses and guidelines and procedures re-sulting from the analyses will be arrived at between the Westinghouse owners' Group and the NRC staff.
4 e,
k
B.4.1.1.
WYR-79-107 Page 3.
Long Term As discussed in our response to short-term item 2, we do not believe that autotuatic tripping of the RCP's ic a required function based on the analyses that have 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.
Very truly yours, YANKEE ATOMIC ELECTRIC COMPANY h
Robert H. Groce Licensing Engineer WJS: dis IM 361
.