ML19253C941
| ML19253C941 | |
| Person / Time | |
|---|---|
| Site: | Brunswick  |
| Issue date: | 12/07/1979 |
| From: | Utley E CAROLINA POWER & LIGHT CO. |
| To: | Ippolito T Office of Nuclear Reactor Regulation |
| References | |
| GD-79-3155, NUDOCS 7912120409 | |
| Download: ML19253C941 (2) | |
Text
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s December 7, 1979 FILE: NG-3514(B)
SERIAL NO.:
GD-79-3155 Office of Nuclear Reactor Regulation Attention:
Mr. T. A. Ippolito, Chief Operating Reactors Branch No. 3 United States Nuclear Regulatory Commission Washington, D.C.
20555 BRUNSWICK STEAM ELECTRIC PLANT, UNIT NOS 1 AND 2 DOCKET NOS. 50-325 AND 50-324 LICENSE NOS. DPR-71 AND DPR-62 INTERIM POSITION FOR CONTALNMENT PURGE AND VENT VALVE OPERATION PENDING RESOLUTION OF ISOLATION VALVE OPERABILITY
Dear Mr. Ippolito:
In response to your letter of October 22, 1979, Carolina Power & Light Company (CP&L) submits the following information:
1.
Drywell inerting and deinerting are infrequent operations controlled by plant procedures and Technical Specifications.
The drywell is required by Technical Specifications to be inerted within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> after exceeding 15% rated thermal power and remain inerted until within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> of a scheduled reduction of power to less than 15% of rated thermal power.
Deinerting occurs only when a drywell entry is required in order to provide a safe working atmosphere.
If deinerting were delayed until the unit reached cold shutdown and if inerting were required prior to leaving cold shutdown, outage downtime would be significantly increased and drywell inspections at rated temperature and pressure would be impossible. Limited venting and purging must be allowed during operation to maintain Technical Specification limits for oxygen concentration less than 4% and drywell pressure less than 1.75 psi, both resulting from small instrument air leaks occurring within the drywell.
2a.
It is our intent to verify the operability of the subject valves at the Brunswick Steam Electric Plant by analysis.
The results of these analyses shall be available by January 7, 1980.
In the interim, a plant modification is being prepared to limit the travel of all butterfly valves greater than three inches nominal diameter to less than 50* open. The valve vendor is being contacted and his 1535 248 AoB Y
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- Sw-Mr. T. A. Ippolito recommendations will be used to determine the exact amount of valve travel established. This modification should be implemented by December 17, 1979.
The four-inch head vent valves cannot be modified at present due to their inaccessibility. These valves will not be operated until the modification has been installed or the analyses prove their operability.
2b.
A review of our CAC isolation logic indicated that extensive engineering will be required to integrate the requested changes in design philosophy with the modification work currently in progress on CAC valve switches and override circuitry. Modifications to the CAC system to segregate the isolation signals will be completed by the end of the 1980 refueling outages scheduled for the spring of 1980.
Yours very truly,
.i
< :X, ? ij E. E. Utley Executive Vice President Power Supply & Customer Services RMP/CSB/j eb Sworn to and subscribed before me this 7th day of December 1979 b -tct b N Y h u Vta /
Notary Public
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My Commission expires October 4,1981.
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