ML18065A543
| ML18065A543 | |
| Person / Time | |
|---|---|
| Site: | Palisades  |
| Issue date: | 02/28/1996 |
| From: | Smedley R CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NUDOCS 9603120487 | |
| Download: ML18065A543 (2) | |
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MICHl&AN"S l'RO&RESS Palisades Nuclear Plant: 27780 Blue Star Memorial Highway, Covert, Ml 49043 February 28, -1996 U S Nuclear Regulatory Commission Document Control Desk Washington, DC 20555 DOCKET 50-255 - LICENSE DPR PALISADES PLANT WITHDRAWAL OF COMMITMENT FOR REDUCING THE DEAD BUS TRANSFER TIME DURING A FAST TRANSFER In correspondence dated January 7, 1994, Consumers Power Company made the following commitment_:
"A modification is being considered to reduce the dead bus time during a fast transfer. The modification, if implemented, is targeted for completion in the 1996 refueling outage."
The above commitment is hereby withdrawn. Further evaluation has shown that the modification would be of little value (dead bus time is presently only 7.5 cycles) and would not be cost effective based on the following:
- 1.
No critical safety concern has been identified that warrants implementation of this modification. While the present fast transfer operations have not met all of the design performance expectations, no safety significant components have failed to operate during experienced fast transfers.
Evaluation has shown that, although various non-safety-related loads coulc;l be lost during this transfer, all safety-related systems will operate as designed and operability requirements will be met.
- 2.
Fast transfers rarely occur at Palisades.
A fast transfer does not occur following a Palisades reactor trip (since it normally relies on off site power),
while a fast transfer will occur following a reactor trip at plants that rely on station power.
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- 3.
Palisades has experienced minimal equipment problems during the two fast transfers that have occurred since the installation of the second source of off site power. Neither of these transfers had an effect on safety-related equipment, and neither"'Of these transfers resulted in a reactor trip.
- 4.
The impact on safety made by improving the dead bus time is insignificant.
2 The worst event analyzed has been the occurrence of a fast transfer following a Loss of Coolant Accident (LOCA).. The probability of a fault on a switchyard bus, subsequent to a LOCA, was judged to. be low. If this event did occur, the electrical transient would result in a loss of offsite power and is considered in the plant design basis.
- 5.
The decrease in dead bus time during a fast transfer, using currently available technology, would be minimal without a significant and costly redesign of the system.
SUMMARY
OF COMMITMENTS This letter contains no new commitments. The following commitment is withdrawn:
11 A modification is being considered to reduce the dead bus time during a fast transfer. The modification, if implemented, is targeted for completion in the 1996 refueling outage.
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Richard W Smedley Manager, Licensing CC Administrator, Region Ill, USNRC Project Manager, NRR, USNRC NBC Resident Inspector - Palisades