ML19261C808
| ML19261C808 | |
| Person / Time | |
|---|---|
| Site: | Clinton  |
| Issue date: | 03/20/1979 |
| From: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | Gerstner W ILLINOIS POWER CO. |
| References | |
| NUDOCS 7904030030 | |
| Download: ML19261C808 (1) | |
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ya 20. H79 Docket No. 50-461 Docket No. 50-462 Illinois Power Company ATTN:
Mr. W. C. Gerstner Executive Vice President 500 South 27th Street Decatur, IL 62525 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 C. Keppler Director
Enclosure:
IE Circular No. 79-05 cc w/ enc 1:
Central Files Director, NRR/DPM Director, NRR/ DOR PDR Local PDR NSIC TIC Mr. Dean Hansell, Office of Assistant Attorney General 7904030030 RIII RII OFFICE >
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3/19/79 oavE >
NRc Form 318A (RIII) (5-76) NRCM 02040
- U. S. GOVERNMENT PRINTING OFFICE:
1978-253-
t U.S. NUCLEAR REGELATORY COMMISSION OFFICE OF INSPECTIOS AND ESFORCEMENT 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 investi-gate this phenomenon and initiated an equipment checkout test at Sandia Laboratories using a few typical conductors used in nuclear plants.
The equipment checkout test for cable leaks performed at Sandia Laborato-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 fro = the environ-ment (typically, inside a sealed co=ponent such as a sensor / transmitter).
In order to deter =ine 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 ccnductors, ir.spection visits by NRC personnel were made in October to twe nuclear plants, (one under construction, and the other operatingi.
During the inspections the detailed configuration of stranded conductor cables, and their te mina-tions at splices, penetrations, junction boxes, trannmitters, motors, motor
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