ML20154E188
| ML20154E188 | |
| Person / Time | |
|---|---|
| Site: | Diablo Canyon, 05000000 |
| Issue date: | 08/17/1970 |
| From: | Peterson R PACIFIC GAS & ELECTRIC CO. |
| To: | Rich Smith US ATOMIC ENERGY COMMISSION (AEC) |
| Shared Package | |
| ML20154C370 | List:
|
| References | |
| FOIA-88-156 NUDOCS 8805200122 | |
| Download: ML20154E188 (2) | |
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U. S. Atomic Energy Commission 7
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Re:
Construction Permit CPPR-39 pg 4
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Dear Mr. Smith:
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This is in reply to your letter da*..ed July 21, 1970 regarding an apparent deficiency in preparation of welds for radiography during fabrication of the containment structure liner at our Diablo Canyon site.
1970youraudittehindicatedto On June 23, P G and E representatives that weld reinforcement appeared to be in excess of that specified in Paragraph UW-51, Sec-tion VIII, ASME Boiler and Pressure Vessel Code.
P G and E, in conjunction with its contractors, immediately initiated an investigation to determine the facts in this matter.
The investigation included detailed examination of the full length of both inside and outside welds of the second, third, and fourth horizontal seams, and the vertical seams on rings one, two, three, and four.
The examination revealed intermittent lengths of weld having excessive reinforcement.
The first horizontal seam represented a special situation.
At the time of investigation, the inside weld had been covered with a leak chase channel and had been leak tested.
P G and E inspectors' reports indicate that the con-tractor had exercised special care with the inside weld of the first horizontal seam, with grinding in evidence as the work progressed.
The outside weld, being completely visible, was fully examined and was found to have an aggregate of approxi-mately 25 feet with excessive reinforcement.
To investigate the inside weld covered by the leak chase channel the channel directly opposite these 25 feet was removed.
The inside weld thus exposed was found to be all within Code requirements.
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Smith U.
S. Atomic Energy Commission 2
August 17, 1970 Having thus confirmed P G and E inspectors' reports, we concluded that removal of additional leak chase channel was not warranted.
All seams found to have excessive reinforcement were ground to Code requirements and reradiographed, The results of this work show that all welds are sound and in conformance with the Code.
To prevent recurrence of this type of problem P G and E now requires the contractor to measure the weld reinforcement with a gage when making the required visual inspection.
This will as-sure conformance with Paragraph UW-51 of the Code at weld locations where radiographs are taken and with Paragraph UW-35 at other lo-cations.
Very truly yours, cud llfAwM
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