ML19206A357
| ML19206A357 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 03/19/1976 |
| From: | Arnold R Metropolitan Edison Co |
| To: | Knuth D Office of Nuclear Reactor Regulation |
| References | |
| GQL-0401, GQL-401, NUDOCS 7904190381 | |
| Download: ML19206A357 (2) | |
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March 19, 1976
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Director of ::uclear Reacter Regulation
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U.S. ! uclear Regulatory Cc:rtission 3
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Washington, D.C.
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Attention:
Dr. D. F.
Knuth, Director s'
Subject:
This e Mile Island ::uclear Staticn Unit 2 Cocket ::o. 50-320
Dear Dr. Knuth:
Cn February 20, 1976, Mr. L. :: arrow of your of fice was verbally notified of a situation which Metropolitan Edison Ccmpany then censidered may be reportable in accordance with the requirements of 10 CFR 50.55 (e).
This letter constitutes a thirty day follcw-up letter, althcugh as is no,ted belcw we new believe that this situation is not in fact rescreable.
Cescriptien As part of the construction of the shield walls and slabs 3rcund the fuel transfer tubes, holes were drilled into the south extension wall of the Fuel Handling Building for reinforcing dowels. Cne cf these holes exposed a void approximately eight inches into the concrete and extended to a depth of abcut three feet.
The void is located in a section of wall that had initially been a blockcut for the fuel transfer tube installatien. When concrete was subsequently placed in the blockout after the tube installation, *he inner tcp section of the blockout failed to fill cenpletely, leaving the recently discovered void.
A similar incident invclving the east fuel transfer tube was reported to your Mr. ::arrcw in Cctcher 1975.
Analysis of Safety Implications The Fuel Handling Building was designed and ccnstructed as a Seismic Class I structure. Had the void remained undetected, it is possible that during a seismic event, cracks : tight cccur at the high stress concentratien corner areas of the void; these cracks could then propagate through the structure. Because of its small relative sice, this would not have a significant effect On the structural integrity of the building.
Also, since this area is adjacent to the reactor building containment wall and is protected with radiatien shield walls, no possibility of radiation streaming could have existed. For these reasons this situation could not have ccrpremised the health and safety cf the public cr the plant staff, therefore, this situatien dces net constitute a situatien repcrtable pursuant to 10 CFR 50.55 (e),
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Corrective Action The above condition was documented on a site deviation report.
Exploratory holes were czillad ae =rproximately one foot centers across the tcp of the blockcut construction joint angling down into the joint. The depth of the holes through sound concrete wan about 30 inches before reaching the void area.
The length of the void was deter =ined to be about 5 feet.
The engineer has prepared a repair precedure for fil'ing the veid utilizing the previously mentioned exploratory holes.
It is estimated that the repair of the void will be cceplete by March 30, 1976.
Documentation associated with the repair activities will be available at the site for your inspection.
Very truly ycurs, s
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R. C. Ar'nold Vice President RCA:JJM:cas cc:
Mr. J.
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