ML13308A298
| ML13308A298 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 11/01/1983 |
| From: | Rood H Office of Nuclear Reactor Regulation |
| To: | Carter J, Case E, Harold Denton Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8311140205 | |
| Download: ML13308A298 (2) | |
Text
November 1, 1983 MEMORANDUM FOR:
H, Dton E. Case
.. Carter D. Eisenhut R. Purple H. Thompson R. Mattson T. Spels R. Vol1mer T. Novak F. Miraclia J. Sniezek G. Lainas T. Ippolito THRU:
George W. Knighton, Chief Licensing Branch No. 3 Division of Licensing FROM:
Harry Rood, Project Manager Licensing Branch No. 3 Division of Licensing
SUBJECT:
DAILY HIGHICHT SAN ON0FRE UNITS 2 AND 3 On October 28, 1983, during monthly urveillance testing of the San Onofre Unit 3 reactor trip breakers, two of the eight breakers were found with the undervoltage trip attachment inoperable.
Specifically, the undervoltage armature was observed to be in the mid-range of its normal travel, rather than fully cocked and ready to trip the breaker upon de-energization of the UV coil.
These breakers were reset, were observed to operate properly, and were left with the undervoltage armatures properly positioned.
On October 31, 1983, the armature position of all 16 UV devices on both Units 2 and 3 were checked, and the sa-me two Unit 3 breakers weae again found to be in operable for the same reason.
Also, one Unit 2 breaker was found in the same condition, with the UV armature improperly positioned and, therefore, inoperable.
All breakers were reset, observed to operate properly, and left with the UV arature properly positioned.
The shunt trip device for all Unit 2 and 3 breakers was found to be operable, as has always been the case in the past.
Therefore, plant opi(tifaseconin The licensee is continuing to investigate the problem, and has reached the pre liminary conclusion that the improper UV armature position resulted from mechancial 631140205 83110 PDR ADOCK 05000361
interference between the armature and the copper shading ring around the core of the UV coil.
An IE Bulletin advising other plants with GE AK trip breakers of these events is being issued, and staff follow up will be undertaken to determine the cause and implications of these failures.
Harry Rood, Project Manager Licensing Branch No. 3 Division of Licensing cc: G. W. Knighton S. Black DL BC's DISTIBTUION Document Control L PDR NRC PDR LB#3 Reading Attorney OELD JLee GWKnighton HRood PRC System LB#3:DL L
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