ML19351F840
| ML19351F840 | |
| Person / Time | |
|---|---|
| Site: | Clinton  |
| Issue date: | 01/23/1981 |
| From: | Sherwood G GENERAL ELECTRIC CO. |
| To: | Stello V NRC OFFICE OF INSPECTION & ENFORCEMENT (IE) |
| References | |
| REF-PT21-81-350-000 MFN-015-81, MFN-15-81, PT21-81-350, PT21-81-350-000, TRR-6-81, NUDOCS 8102200332 | |
| Download: ML19351F840 (3) | |
Text
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SYSTEMS DIVISION
~ ENERAL ELECTRIC CCMPANY. '75 CURTNER AVE.. SAN JOSE. CA. CORNIA 9s125 TRR-06-81 MC 682, (408) 925-5040 MFN-015-81
%.,yu January 23, 1981 U. S. Nuclear Regulatory Commission Office of Inspection and Enforcement Washington, D. C.
20555 Attention:
Victor Stello, Jr., Director (3 copies)
Gentlemen:
This advises the NRC of a reportable d.fect per 10CFR Part 22 as reported to your office by Walter H. D' Ardenne, Manager, Safety Evaluation Prograin on January 23, 1981.
This defect is a thin wall in an elbow in the reactor pressure vessel bottom head crain line of the Clinton 1 project.
It was judged reportable on January 1, 1981.
The attachment provides further information regarding the defect.
General Electric has issued a Field Deviation Disposition Request to replace the elbow.
The required corrective action has beer completed.
Very truly yours, lf,,,
,s g...ic.l-kf, I'
,i, a -,/
(
Glenn G. Sherwood, Manager i
Safety & Licensing Operation I
udS:1m/1331 cc:
Mr. J. G. Keppler, NRC Region III Mr. U. Potapovs, NRC, Revion IV Mr. J. F. McAllister, General Electric l
DEFECTIVE BWR PRESSURE VESSEL DRAIN LINE ELBOW General Electric, the supplier of t..e reactor pressure vessel and asso-ciated piping for the Clinton 1 Project, discovered that the reactor pressure vessel (RPV) bottom head drain line had an elbow with a thin The defect consists of a one inch oval' area having a minimum wall area.
thickness of 0.250 inches, which is 0.051 inches below the minimum required by the design specification.
The defect was discovered by rsdiography after the elbow was ir. stalled.
There is no valve between the subject elbow and the RPV bottor head.
Therefo.6, the elbow would be exposed to the reactor pressure at all times.
It is General Electric's conclusicn that this defect is reportable within the context of 10CFR Part 21.
Ho.ever, the probability of fail-ure has been assessed as unlikely since the elbow passed the hydro test.
Furthermore, the actual tensile strength of the material is 23% higher than ASME code allowable.
Therefore, tneugh reportable, the plant safety margin would not be signi'icantly affected.
Corrective action, replacement of the elbow in accordance with ASME Code Section XI (1974 edition), has been ini-iated by Field Deviation Dispo-sition Request (FDDR) LNI-il2-80.
Tne eines has been replaced with an
- elbow that meets the design minimum waii thickness.
All elbows, fabricated from the same pipe shipments, that have not been shipped to specific sites have been inspected and found acceptable.
GGS:1m/1333 l
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