ML20246C943
| ML20246C943 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 05/11/1989 |
| From: | Zech NRC COMMISSION (OCM) |
| To: | Bates J HOUSE OF REP. |
| Shared Package | |
| ML20246C933 | List: |
| References | |
| BATES-890511, CCS, NUDOCS 8907110195 | |
| Download: ML20246C943 (1) | |
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~.c QUESTION 1 Why was.the Connecticut Yankee (Northeast Utilities) reactor j
(Haddam Neck, CN) required by the NRC to make repairs to its thermal heat shield in late 1987 (which had similar broken bolts and cracked supports), but now the NRC is close to allowing So.
Calif. Edison to restart San Onofre I without requiring the repairs to be made?
ANSWER The NRC did not require the repairs made to the Haddam Neck thermal shield in 1987. The repairs were made by the utility on its own initiative, although NRC did review the existing condition of the shield and the licensee's repair plan.
Northeast Utilities' decision to repair the thermal shield was based on the difficulty experienced in removing the lower reactor core support structure, indications of motion (significant vibration) of the shield, evidence of wear at some of the support blocks (indicating that most of the bolts were broken),
and severe wear of the limiter keys. Since the reactor internals were on the inspection stand for the regular 10-year inservice inspection, it was a logical time to accomplish the necessary repairs.
By contrast, none of these conditions existed at San Onofre Unit 1.
Video tapes recorded during tho visual examination at the time of the last outage showed no sign of motion of the thermal shield and no wear at the support blocks. More detailed information on the condition of the San Onofre Unit 1 thermal shield is contained in the May 15, 1989 Safety Evaluation Report included in the attachments to Question 3. -
8907110195 890616 PDR CCt1MS NRCC CORRESPONDENCE PDC
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