ML20137E241
| ML20137E241 | |
| Person / Time | |
|---|---|
| Site: | Calvert Cliffs  |
| Issue date: | 11/25/1985 |
| From: | Williams J BALTIMORE GAS & ELECTRIC CO. |
| To: | Jaffe D Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8511270225 | |
| Download: ML20137E241 (3) | |
Text
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9 B ALTIMORE G AS AND ELECTRIC COMPANY P.O. BO X 14 7 5 B A LTIM O R E. M A R YL A N D 21203 NUCLEAR POWER DEPARTMENT BY, MARYLAND 20657 November 25,1985 U.S. Nuclear Regulatory Commission Division of Licensing Washington, D.C. 20555 ATTENTION:
Mr. David H. Jaffe, Project Manager Operating Reactors Branch #3
SUBJECT:
Calvert Cliffs Nuclear Power Plant Unit No. 2, Docket No. 50-318 As-Found Main Steam Safety Valve Setpoints
Dear Mr. Jaffe:
Attached are replies to three questions you gave to Mr. J. A. Mihaleik concerning effects of the out-of-specification main steam safety valve setpoints discovered during surveillance testing on Calvert Cliffs Unit 2.
If I can provide additional information, please call me at (301) 260-4027.
Very truly yours,
/
/
Joseph F. Williams Incore Fuel Management JFW:bsb Attachment ec:
R. E. Denton L. B. Russell J. A. Mihaleik M. E. Bowman T. Foley, NRC e511270225 851125 j
F DR ADOCK 0500 8
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QUESTION:
What assumptions are made in safety analyses for main steam safety valve (MSSV) setpoints and operability?
RESPONSE
Eight MSSV are assumed operable for each steam generator. Non-LOCA safety analyses assume 4 valves per steam generator open at 1050 PSIA, and the remaining 4 valves open at 1080 PSIA. Small break LOCA analyses'are identical except that 2 valves per steam generator are assumed to open at 1010 PSIA rather than 1050 PSIA. Safety analyses
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were redone for the Calvert Cliffs Unit 1 Cycle 8 reload submittal to reflect the revised MSSV setpoint technical specification. Combustion 3
Engineering has shown the revised setpoint configuration to be 1
applicable to Calvert Cliffs Unit 2 Cycle 6. The revised configuration was explicitly included in the Unit 2 Cycle 7 reload analyses.
QUESTION:
Which accident analyses result in MSSV operation?
RESPONSE
Accident analysis predicts MSSV operation for the following non-LOCA events:
'"h Loss of Load Loss of Non-Emergency AC Power CEA Withdrawal Loss of Load to One Steam Generator Loss of Feedwater Feed Line Break In addition, small break LOCA analysis assumes operation of the MSSV.
QUESTION:
What effect does the as-found setpoint configuration have on the safety
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analyses described above?
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RESPONSE
Combustion Engineering determined that Non-LOCA safety analyses are 3,
bounded by the Loss of Load event. The parameter of concern is the peak secondary system pressure, which should be limited to 110% of the design pressure of 1000 PSIA, or 1100 PSIA. C-E reanalyzed the Loss of Load, conservatively modeling the as-found setpoint configuration. The g
setpoint configuration used is shown in the attached Table. This analysis predicted a peak secondary system pressure of 1093 PSIA.
For small break LOCA, there is more High Pressure Safety Injection (IIPSI) flow actually available than is assumed in the analysis. The additional HPSI flow is more than is required to compensate for the higher MSSV setpoints.
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-e MAIN STEAM SAFETY VALVE SAFETY ANALYSE Nominal As-Found As-Found UIC8*
Setpoint Setpoint Analysis Analysis PSIG PSIG PSIG.
PSIG RV-3992/4000 985 991/1037 1037/1037 1035**
RV-3993/4001 985 1015/1040 1040/1040 1035**
RV-3994/4002 995 1001/1059 1059/1059 1035 RV-3995/4003 995 1035/1047 1047/1047 1035 RV-3996/4004 1015 1024/1070 1070/1070 1065 RV-3997/4005 1015 1020/1054 1054/1054 1065 RV-3998/4006 1035 1044/1104 1104/1104+
1065 RV-3999/4007 1035 1057/1106 1106/1106+
1065 i
This configuration has been shown to be applicable for U2C6.
+ RV-4006 and RV-4007 were assumed stuck closed for Loss of Load analysis.
RV-3908 and RV-3999 opened at 991 and 1001 PSIG, respectively.
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