ML19261C804
| ML19261C804 | |
| Person / Time | |
|---|---|
| Site: | Midland |
| Issue date: | 03/20/1979 |
| From: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | Howell S CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| References | |
| NUDOCS 7904030024 | |
| Download: ML19261C804 (1) | |
Text
N Te4A s
_ laut 20.1979 Docket No. 50-329 Docket No. 50-330 Const mers Power Cotapany ATTN:
Mr. Stephen H. Howell Vice President 1945 West Parnall Road Jackson, MI 49201 Centle:nen:
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, NRR/ DOR PDR I.ocal PDR
~
NSIC TIC Ronald Callen, Michigan Public Service Cor=r.ission Dr. Wayne E. North Myron M. Cherry, Chicago 7904030024 RIII RII OF FICE >
Fierelli/bk Kcppler suRwguE m 3/19/79
- oug, NRC korm 318A (R2II) (5-76) NRCM 02040
- U. S. GOVERNMENT PRINTING OFFICE: 1978-253 81f
i U.S. NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION AND ENFORCEMENT REGION III March 20, 1979 IE Circular No. 79-05 MOISIVRE LEAKAGE IN STRANDED WIRE CONDUCTORS Description c. 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 staf f determined it to be prudent to investi-gate this phenomenon and initiated an equipment checkout test at Sandia Laboratcries 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 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 Y
- e. eau me**
7903260138
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