ML18052A264
| ML18052A264 | |
| Person / Time | |
|---|---|
| Site: | Palisades  |
| Issue date: | 01/29/1986 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML18052A263 | List: |
| References | |
| NUDOCS 8602030440 | |
| Download: ML18052A264 (2) | |
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e UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION INSTALLATION OF ISOLATION SWITCHES FOR APPENDIX R To lo CFR so CONSUMERS POWER COMPANY PALISADES PLANT DOCKET NO. 50-255 By letter dated May 26, I983, the staff issued a post-fire alternate shutdown safety evaluation for the Palisades Plant using the criteria of IO CFR 50, Appendix R.
Included in the items found acceptable was the installation of isolation switches consisting of terminal block slide links.
In a later submittal (August IO, I984) the licensee requested an exemption from the requirements of Appendix R in order to provide an electrician from offsite to operate these slide links. This exemption was denied on two bases:
(I) reliance on an electrician from offsite to perform hot shutdown functions can not provide a capability equivalent to the criteria of Section 111.L.4 and (2) both diesel generators would be inoperable for approximately two hours which would not provide the necessary safe shutdown capability per the criterion of III.G.1.a.
In order to overcome this difficulty, the licensee proposed, by submittal dated October 29, I985, to install isolation switches in the following circuits:
I. Control circuit for voltage control of diesel generator I-I.
- 2. Control circuit for speed control of diesel generator I-I.
- 3. Control circuit of breaker I52-I07 which connects diesel generator I-I to tpe 2400 V IC.bus.
- 4. Control circuit of breaker I52-I03 which connects the IC bus to the service water pump P-7B.
- 5. Control circuit.of breaker I52-I10 which connects the IC bus to Station Power Transformer No. I3, located in the Turbine Room, which can be used to supply 480 volt power to charging pumps P-55 B and C.
These switches are intended to ensure operability of the attendant equipment independent of damage which may cause a malfunction in the normal control circuits as a result of a fire. The switches provide local control for required hot shutdown equipment (diesel generator, service water pump and charging pump) in the event of a fire in the control room, cable spreading room, auxiliary building corridor at elevation 590 ft. or engineered safeguards panel room.
The isolation switches in the voltage and speed control circuits for diesel generator 1-I are located in the diesel generator room while the remaining isolation switches are located in the IC switchgear room.
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'. "' The isolation switches are designed to seismic Category I standards in order
- to prevent-occurrence of an unacceptable failure (transfer) after a seismic -
event. These switches have two positions, "remote" and "local." In the remote position, operation will be in the normal mode (control from the control room).
When the switches are thrown to the "local" position, all control circuits outside the local equipment panels a~e electrically isolated. These switches have unique handles which may be removed when in the "remote" position in order to avoid unnecessary switch operation.
When moved to the local position, the switch handles cannot be removed until the switch is again moved to the 11 remote 11 position.
Additional information was provided in the licensee's submittals dated December 3 and December 20, 1985 and January 17, 1986.
We conclude, based on the foregoing, that the design of the isolation switches satisfies the criteria of Appendix R to 10 CFR 50 and is, th~refore, acceptable.
Date:
January _29, 1986 Principal Contributors:
I. Ahmed N. Wagner