ML20207D259
| ML20207D259 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 12/23/1986 |
| From: | Hukill H GENERAL PUBLIC UTILITIES CORP. |
| To: | Stolz J Office of Nuclear Reactor Regulation |
| References | |
| 5211-86-2214, NUDOCS 8612300361 | |
| Download: ML20207D259 (2) | |
Text
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Nuclear
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Route 441 South Middletown, Pennsylvania 17057 0191 717 944-7621 TELEX 84 2386 Writer's Direct Dial Number:
December 23, 1986 5211-86-2214 Office of Nuclear Reactor Regulation Attn: Mr. John F. Stolz, Director PWR Projects Directorate No. 6 US Nuclear Regulatory Commission Washington, DC 20555
Dear Mr. Stolz:
Three Mile Island Nuclear Station Unit 1 (TMI-1)
Operating License No. DPR-50 Docket No. 50-289 10 CFR 50 Appendix R - Associated Circuits In response to your verbal request concerning the TMI-1 statistical sample analysis performed for associated circuits by common enclosure, the following additional information is provided.
We will make the following additional studies to assure that fire induced failure of associated common enclosure circuits will not prevent safe shutdown. The new approach, which we understand was found acceptable to the NRC for other nuclear stations, will show that all power cables requiring electrical AC and DC power at TMI-1 are protected by circuit breakers, fuses, or similar interrupting devices. This approach requires rigorous electrical analyses of auxiliary electrical systems by performance of an interrupting device coordination study and a fault study.
These studies will verify that all circuits that have the potential of being associated by common enclosure are being adequately protected.
This will be accomplished by checking each breaker or fuse on AC and DC distribution panels, motor control centers, buses and switchgear in the plant and verifying that the protective device protects the cable.
Any deficiencies found will be corrected by providing an adequately sized breaker or fuse.
Coordination of safety related AC and DC protective devices will be verified to be acceptable to perform their safety function. Coordination of non-safety related interrupting devices is not considered a requirement to resolve this issue if circuit protection is demonstrated.
8612300361 861223 PDR ADOCK 05000289 fc PDR (a
GPU Nuclear Corporation is a subs' diary of the General Public Utilities Corporation
r.
a 5211-86-2214 We believe that this approach will resolve the concern re. lated to safety related and non-safety related circuits associated by c.cmon enclosure as required by NRC Generic Letter 81-12.
Si cerely,
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H D. Hukill Vice President & Director, TMI-l HDH/DJD/spb:0736A cc:
J. Thoma F. Young D. Kubicki A. Krasopoulos i
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