ML17244A849
| ML17244A849 | |
| Person / Time | |
|---|---|
| Site: | Ginna  |
| Issue date: | 08/29/1979 |
| From: | White L ROCHESTER GAS & ELECTRIC CORP. |
| To: | Grier B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| References | |
| NUDOCS 7910010508 | |
| Download: ML17244A849 (6) | |
Text
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ROCHESTER GAS AND ELECTRIC CORPORATION NEW 414 ~ 0 4>NW
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89 EAST AVENUE, ROCHESTER, N.Y. 14649 LEON D. WHITE, JR.
VECC PRCSIOL'NT TCE.CPHOEEC AREA COOK Tld 546-2700 August'. 29, 1979 Mr. Boyce H. Grier, Director U. S. Nuclear Regulatory Commission Office of Inspection and Enforcement Region I 631 Park Avenue King of Prussia, Pennsylvania 19406
Subject:
IE Bulletin 79-06C, Nuclear Incident at Three Mile Island Supplement R.E.
Ginna Nuclear Power Plant Docket No. 50-244
Dear Mr. Grier:
We have reviewed the Bulletin and, in conjunction with the Westinghouse Owners'roup, have taken the following actions to alleviate the concern over delayed-tripping of the reactor coolant pumps (RCPs) after a loss af coolant accident (LOCA).
lA.
We have instructed the operators to trip all RCPs upon reactor trip and initiation of high pressure injection by low reactor coolant system (RCS) pressure.
Specifically, the operators are instructed to trip the RCPs at an RCS pressure of 1715 psig, the high pressure injection initiation low RCS pressure setpoint.
lB.
We have provided two licensed operators in the control room at all times during plant operation.
2.
A series of 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'roup.
A report summarizing the results of the analysis of delayed Reactor Coolant Pump trip during small.loss of coolant accidents for Westinghouse and NSSS, will be submitted to Mr. D.F.
Ross by Mr. Cordell Reed on August 31, 1979.
In the report, maximum peak clad temperatures (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 6~
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ROCHESTER GAS AND ELECTRIC C oATE August 29, 1979 To Mr. Boyce H. Grier, Director SHEET NO.
2 prior to the reactor coolant system pressure reaching 1250 psig, 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 PCTs 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 RCPs 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'roup 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'roup 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..
We expect, concurrence on the procedure guidelines by the NRC by mid-October.
Appropriate RGGE personnel responsible for preparing the Ginna procedures will meet with the Owners'roup Subcommittee on Procedures and Westinghouse to discuss th' background for revising our procedures.
We expect that several months will be required to revise the plant procedures and to provide the appropriate training for all licensed personnel.
5.
Analyses related to inadequate core cooling and definition of conditions under which a restart of the RCPs 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 resulting from the analyses will be arrived at between the Westinghouse Owners'roup and the NRC staff.
Lon Term As discussed in our response to short-term item 2, we do not believe that automatic tripping of the RCPs is a required
ROCHESTER OAS AND ELECTRIC C oATE August 29, 1979 Mr. Boyce H. Grier, Director SHEET NO.
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'roup Submittal.
Very truly yours,
/
L.D. Whit, Jr.
xc:
Office of Inspection and Enforcement U.S. Nuclear Regulatory Commission Washington, D.C.
20555 Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, D.C.
20555