ML20101M103
| ML20101M103 | |
| Person / Time | |
|---|---|
| Site: | Wolf Creek  |
| Issue date: | 12/07/1984 |
| From: | Koester G KANSAS GAS & ELECTRIC CO. |
| To: | Denise R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| References | |
| KLMNRC-84-220, NUDOCS 8501020482 | |
| Download: ML20101M103 (2) | |
Text
e KANSAS GAS AND ELECTRIC COMPANY CLENN L MOESTER nce Peaboteer esm:Laan December 7, 1984 Mr. R.P. Denise, Director Wolf Creek Task Force c_
U.S. Nuclear Regulatory Cceznission
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Region IV p
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Arlington, Texas 76011 l
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KMLNRC 84-220 et,,
Ret Docket No. STN 50-482 Ref: Interim Report KMLNRC 84-061 dated 4/11/84 from GLKoester, KG&E, to EHJohnson, NRC Subj: Final 10CFR50.55(e) Report - Containment Cooling Fan Mechanical Interlocks (53564-K128)
Dear Mr. Denise:
This letter provides the final report submitted pursuant to 10CFR50.55(e) concerning ITE-Gould Aotor Control Center Two-Speed Starters for the Containment Cooling Fan Motors. This matter was reported by Messrs. O.
Maynard and H. Chernoff of Kansas Gas and Electric Company (KG&E) to Mr. W. Johnson of the Nuclear Regulatory Commission, Region IV, on March 16, 1984, with supplemental information provided in the Reference.
The mechanical interlocks in the two-speed starters have periodically failed to operate properly.
" Sticking" between contactors 42T and 42S in all four Fan Motor Starters could prevent the fans from transferring from high speed to low speed. The manufacturer initially determined that the interlock problem was a result of coil failures in the starter assemblies.
The coil failures were thought to be caused by a lack of maintenance. The interlock mechanism on starters NG0lTAFl and NG03TAFl were removed and thoroughly cleaned using water and compressed air. The interlocks were then reinstalled and appeared to function normally. Subsequently, however, the interlock in NG03TAFl prevented the 42S coil from closing properly.
The subject mechanical interlock assemblies were inspected by the manufacturers ' representative. Based on this inspection, all of the interlock assemblies were replaced with new assemblies of the same type and catalog number. During testing of the newly installed mechanical interlock assemblies binding was determined to be a continuing problem.
8501020402 041207 DRADOCK05000g
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201 N. Market - MNta, Kansas - mar Address: RO. Boit 208 I Mtuta, Kansas 67201 - Telephone: Area Code (316) 2616451 L
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e Mr. R.P. Denise KMLNRC 84-220 December 7, 1984 Af ter further investigation, it was found that the actuator extension
- of the size 5 starter was exerting slight pressure on the interlock assembly of the de-energized starter coil. This presure could cause the interlock assembly to bind and not allow for automatic transfer of the cooling fan from high speed to low speed.
To alleviate this pressure, the portion of the actuator extension which contacts the interlock assembly was shortened by approximately one-eighth inch on all size 5 starters. Instruction Manual 10466-E-018-0190 will be revised, within 90 days after fuel load, to change the installation instructions of the size 5 mechanical interlock assembly to reflect this modification.
If you have any questions concerning this subject, please contact me or Mr. Otto Maynard of my staff.
Yours very truly, fN Glenn L. Koester Vice President - Nuclear GLK:bb xc:RCDeYoung PO'Connor (2)
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