ML20136F827
| ML20136F827 | |
| Person / Time | |
|---|---|
| Site: | Bellefonte  |
| Issue date: | 10/30/1985 |
| From: | Hufham J TENNESSEE VALLEY AUTHORITY |
| To: | Grace J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| References | |
| NUDOCS 8511220195 | |
| Download: ML20136F827 (2) | |
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TENNESSEE VALLEY AUTHORITY CHATTANOCGA. TENNESSEE 37401 400 Ch gu treet Tower II NN October 30, 1985 BLRD-50-438/84-49 BLRD-50-439/84-45 U.S. Nuclear Regulatory Commission Region II Attn Dr. J. Nelson Grace, Regional Administrator 101 Marietta Street, NW, Suite 2900 Atlanta, Georgia 30323
Dear Dr. Grace:
BELLEFONTE NUCLEAR PLANT UNITS 1 AND 2 INCORRECT BOLT STRESS ALLOWABLES USED IN FLANGE QUALIFICATION - BLRD-50-438/84-49 AND BLRD-50-439/84 THIRD INTERIN REPORT The subject deficiency was initially reported to NRC-0IE Inspector P. E. Fredrickson on September 7, 1984 in accordance with 10 CFR 50.55(e) as NCR BLN CEB 8414. Our first interim report was submitted on October 9, 1984.
Later, a related nonconfomance report (NCR) BLN CEB 8419 was issued, and we reported on both NCR's in our second interim report dated July 31, 1985.
Enclosed is our third interim report. We expect to submit our next report no later than six months before unit 1 fuel loading.
If you have any questions, please get in touch with R. H. Shell at FTS 858-2688.
Very truly yours.
TENNESSEE VALLEY AUTHORITY g
. W. Hufham, Nanager Licensing and Risk Protection Enclosure cc:
Mr. James Taylor, Director (Enclosure)
Office of Inspection and Enforcement U.S. Nuclear Regulatory Constission Washington, D.C.
20555 Records Center (Enclosure)
Institute of Nuclear Power Operations 1100 circle 75 Parkway, Suite 1500 Atlanta, Georgia 30339 8511220195 851030 PDR ADOCK 05000438 8
YDR An Equal Opportunity Employer
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ENCLOSURE BELLEFONTE NUCLEAR PLANT UNITS 1 AND 2 INCORRECT BOLT STRESS ALLOWABLES USED IN FLANGE QUALIFICATION BLRD-50-438/84-49. BLRD-50-439/84-45 NCRs BLN CEB 8414 AND DLN CEB 8419 10 CFR 50.55(e)
THIRD INTERIN REPORT Description of Deficiency Nonconformance report (NCR) BLN CEB 8414 (CDRs BLRD-50-438/84-49, BLRD 439/84-45) documented a problem with piping flanges analyzed in problem N4-IKE-0 that were qualifed using incorrect bolt allowables.
The differences between the stress values used and the correct allowables are significant'and 2
range as high as 10,000 lb/in. The analysis was based on preliminary information which was not. verified by the subsequent controlling documentation (i.e., the bill of material). The bill of material did not specify.
high-strength bolts.
This problem is potentially applicable to other Bellefonte Nuclear plant (BLN) piping analysis problems but is not applicable to other TVA plants. This nonconformance may be attributed to a failure by the I
analyst and the checker to verify and document the assumptions factored into.
the analysis.
. Subsequent to the first report on NCR BLN CEB 8414 a related NCR (BLN CEB 8419) was issued. This NCR pertains to incorrect assumptions made by s
the rigorous piping stress analyst as to the strength of flange bolting material.' Some examples are:.(1) Flange bolts for orifice flange element IFE-957-A on mechanical drawing 1BWO453-KE-12 are not specified, yet the analyst assumed high-strength bolts.
(2) Bill of material 3BN0416-NS-00 sheet 5 calls for ASTN SA193 grade B7, B8 or equal bolts.
The allowables for these bolts are not-equal and the analyst assumed the higher strength bolts were used.
(3) The flange bolt material on bill of material 3BN0453KE-05 sheet 8 is to be SA193 grade B7.
This differs from SA307 which is specified on NAVC0 drawing 15-86, contract No. 75K35-86162. The bolt material allowables differ 2
by 18,000 lb/in.
The analysis, which used the erroneous assumptions, is not necessarily conservative.
Interim proaress TVA is proceeding with the replacement of low-strength bolts with high-strength bolts in accordance with the bills of material revised for N4-IKE-0 and the bills of material identified on NCR BLN CEB 8419. To prevent recurrence, the rigorous analysis handbook checklist has been updated to specify that all flange information on the hand calculation sheet and computer output worksheet is complete and correct. Bolt material specifications are included on these documents.
TVA is currently pursuing the disposition of NCR BLN CEB 8419. Further information will be provided when the corrective actions have been finalised but at least six months before unit 1 fuel loading.
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