ML19261C807
| ML19261C807 | |
| Person / Time | |
|---|---|
| Site: | Fermi  |
| Issue date: | 03/20/1979 |
| From: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | Hines E DETROIT EDISON CO. |
| References | |
| NUDOCS 7904030028 | |
| Download: ML19261C807 (1) | |
Text
Et 20.1979.'
t Docket No. 50-341 The Detroit Edison Company ATTN:
Mr. Edward Hines, Assistant Vice President and Manager Quality Assurance 2000 Second Avenue Detroit, MI 48226 Gentlemen:
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/ encl:
Central Files Director, NRR/DPM Director, NRPJDOR PDR Local PDR
~
NSIC TIC Ronald Callen, Michigan Public Service Commission Eugene B. Thomas, Jr.,
Attorney 7904030028 RIII RIII orr CE >
D"U M N
suRu,auc >
3/19/79 oaTE >
bC* Form 33 8A (R321) (5-76) NRCM O2040
- U. 5. GOVERNMENT PRINTING OFFICE:
1978-253-81
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 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 ~1eak.
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 order 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 7903260138 y)upg M
.