ML19261C803
| ML19261C803 | |
| Person / Time | |
|---|---|
| Site: | Perry  |
| Issue date: | 03/20/1979 |
| From: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | Davidson D CLEVELAND ELECTRIC ILLUMINATING CO. |
| References | |
| NUDOCS 7904030022 | |
| Download: ML19261C803 (1) | |
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y NR 20.1979 Docket No. 50-440 Docket No. 50-441 The Cleveland Electric Illuminating Company ATTN: Mr. Dalwyn R. Davidson Vice President - Engineering P. O. Box 5000 Cleveland, OH 44101 Centlemen:
The enclosed IE Circular No. 79-05 is forwarded to you for infor-mation.
If there are any questions related to your understanding of the suggested actions, please contact this office.
Sincerely, James G. Keppler Director
Enclosure:
IE Circular No. 79-05 cc v/ encl:
Central Files Director, NRR/DPM Director, NRR/ DOR PDR local PDR NSIC TIC U. Young Park, Power Siting Commission Mr. Daniel D. Vilt, Attorney 7904030022 I
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- U. S. GOVERNMENT PRINTING OFFICE: 1978-253 NRC Form 318A (R2IE) (5-76) NRCM O2040
i U.S. NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION AND ENFORCEMENT REGION III March 20, 1979 IE Circular No. 79-05 MOISTURE LEAKAGE IN STRANDED WIRE CONDUCTORS Description of Circumstances:
During a staff review of the results of environmental qualification test of certain electrical equipment, the phenomenon of water penetration between an electrical conductor and its loosely fitting insulation sleeve was identified. The staff determined it to be prudent to im 1sti-gate this phenomenon and initiated an equipment checkout test at Sanaia Laboratories using a few typical conductors used in nuclear plants.
The equipment checkout test for cable leaks performed at Sandia Labcrato-ries in August 1978, has shown that most stranded wire conductors, when subjected to a differential pressure across the conductor ends, will leak steam or moisture through the interstices of the strands of wire.
The test has also shown that solid conductors, under similar conditions, do not' leak.
Steam / moisture leakage through stranded conductors can occur during a Loss of Coolant Accident / Main Steam Line Break (LOCA/MSLB), if a differential pressure were to develop across the conductor ends; e.g., one end of the conductor is exposed to the accident environment (typically, in an
, - unsealed junction box) and the other end is isolated from the environ-ment (typically, inside a sealed component such as a sensor / transmitter).
In erder to determine whether as-installed configurations exist in nuclear Power plants which may result in degradation of safety-related functions due to moisture leakage in stranded wire conductors, inspection visits by NRC personnel were made in October to two nuclear plants, (one under construction, and the other operating). During the inspections the detailed configuration of stranded conductor cables, and their termina-tions at splices, penetrations, junction boxes, transmitters, motors, motor T)"f" 790sgeo,y9
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