ML20006E153
| ML20006E153 | |
| Person / Time | |
|---|---|
| Site: | Trojan File:Portland General Electric icon.png |
| Issue date: | 01/31/1990 |
| From: | Cockfield D PORTLAND GENERAL ELECTRIC CO. |
| To: | Martin J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| References | |
| NUDOCS 9002220186 | |
| Download: ML20006E153 (2) | |
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M LM D Portland GeneralElecticConpany ht a
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David W. Cockfield Vice President. Nuclear CD FEB 5 nll : 0 8 1
l January 31, 1990
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Trojan Nuclear Plant Docket 50-344 License NPF-1 l
I Mr. John B. Martin 4
Regional Administrator, Region V l
U.S. Nuc1M r Regulatory Commission j
1450 Marie; 'uane, suite 210 l
f Walnut Creek CA 94596-5368 Dear Mr. Martint Portland General Electric Company (pCE) Submittal I
Ef the Results of the Multiple Hith Ins >edance Fault Analysis This. letter provides the results of the Multiple High Impedance Fault (HIF)
Analysis recently completed for the Trojan Nuclear Plant.
This letter responds to your letter of October 24, 1989, which summarized PCE's commitment to address the multiple HIF concern for Trojan, j
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The HIF analysis is based on the conservative assusption that all cables in a given fire area are affectet simultaneously. Based on this assumption-the results of the HIF analysis identified several safe shutdown buses-which may potentially be lost in the event multiple high isqpedance f aults were to occur due to a fire. The buses of concern are the Engineered-Safety Features (ESF) 400-Volt load centers and motor control centers.
Manual operatoe actions will be relied upon to de-energize specific components not required for safe shutdown at their respective power feeder breakers to mitigate the effects of a high impedance fault.
Currently, Rmergency Fire Procedure (EFP)-0, " Procedure in the Event of a Fire" and RFP-1, " Alternative Shutdown for Evacuation of Control Room caused by Fire", include a caution statement on multiple grounds induced by i
a fire which may cause the loss of;the RSF power supplies. The caution t
9002220186 900131 PDR ADOCK 05000344 l
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W W M Cof14MNW John B. Martin January 31, 1990 P.91e 2 statement states that if multiple faults are suspected, then ESF buses should be stripped and safe shutdown loads re-energised. To address the results of the HIF analysis, an attachment will be added to EFp-0 which will identify individual components that can be doenergized. The caution i
statement will be revised to direct the operators to this attachment. This j
revision to trP-0 will be completed by July 1, 1990.
A revision to ErP-1 will not be necessary because specific steps are already included in the procedure to open the power feeder breaker for j
components not required for safe shutdown.
PGE is evaluating the desirability of reducing the conservatism in the HIF j
analysis to reduce the number of manual operator actions required. This effort would involve, as one option, performing detailed cable routing reviews to limit the number of cables assumed to fault, pot will advise the PRC of any planned revisions to the HIP analysis.
Sincerely, N
c-c U.S. Nuclear Regulatory Commission Attnt Document Control Desk Washington DC Mr.- David Stewart-Smith State of Oregon Department of Energy Mr. R. C. Barr NRC Resident Inspector Trojan Nuclear Plant i
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