ML20072G689
| ML20072G689 | |
| Person / Time | |
|---|---|
| Site: | Nine Mile Point  |
| Issue date: | 06/13/1983 |
| From: | Dise D NIAGARA MOHAWK POWER CORP. |
| To: | Starostecki R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| References | |
| 10CFR-050.55E, 10CFR-50.55E, 6830, NUDOCS 8306280597 | |
| Download: ML20072G689 (2) | |
Text
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NuMOHAWK Y NIAGARA NIAGARA MOHAWK POWER CORPORATION /300 ERIE BOULEVARD WEST, SYRACUSE. N.Y.13202/ TELEPHONE (315) 4741511 June 13, 1983 (6830)
Mr. R. W. Starostecki, Director U.S. Nuclear Regulatory Commission Region I Division of Project and Resident Programs 631 Park Avenue King of Prussia, PA 19406 Re: Nine Mile Point Unit 2 Docket No. 50-410
Dear Mr. Starostecki:
Enclosed is a final report in accordance with 10CFR50.55(e) for the deficiency concerning a weld radiograph for a recirculation piping spool piece. This matter was reported via telephone to Mr. H. Kister of your staff on January 13, 1983. An interim 30 day report was submitted on February 14, 1983.
Very truly yours, D. P. Dise Vice President Quality Assurance SFM/TL:ja xc: Director of Inspection and Enforcement U.S. Nuclear Regulatory Commission Washington, DC 20555 Mr. R. D. Schulz, Resident Inspector F306280597 830613 6
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NIAGARA M0 HAWK POWER CORPORATION NINE MILE POINT NUCLEAR STATION - UNIT 2 DOCKET N0. 50-410 Final Report for a Problem
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Concerning a Weld Radiograph for a Recirculation Piping Spool Piece
' Description of the Problem Niagara Mohawk Power Corporation Quality Assurance conducted a review of weld radiographs of recirculation piping supplied to the Nine Mile Point Unit 2 site by a General Electric Company subcontractor (Associated Piping and Engineering Corporation). As a result of this review, it was discovered that 15 weld radiographs of 11 welds showed indications that were not addressed by the vendor.
The 11 welds were re-radiographed on site.
Fourteen of the re-radiographs showed no indications. One re-radiograph showed two indications (Mark Number G004-A-2 at view 2-3 location) which were still suspect.
This weld was excavated to identify the problem.
The excavation determined that one indication was not present and the other suspected indication was a discontinuity.
Analysis of Safety Implications General Electric's subcontractor has concluded that the false-indications occurring on the 14 radiographs are a result of "x-ray defraction."
General Electric has performed a fracture mechanics evaluation of the excavated discontinuity. The General Electric calculation / evaluation has concluded that, even considering fatigue crack growth, the indication would still be below the allowable flaw size to meet the minimum wall thickness required for pressure integrity.
This calculation / evaluation is contained in General Electric Design Record File.
Based on the General Electric calculation / evaluation,.if this deficiency were to have remained uncorrected, the safe operation of the plant would not have been adversely affected.
Corrective Actions 1.
The discontinuity was excavated and repaired via General Electric Field Deviation Disposition Report (FDDR) No. KGl-0108, Rev. 1.
Final Non-Destructive Examination (NDE) found the discontinuity to be removed and the weld satisfactory.
2.
Wherever radiograph indications are described as "x-ray defraction," the
-pipe supplier must re-radiograph the area and resolve the indication before General-Electric acceptance. This information was provided to General Electric Quality Assurance inspectors during a seminar held May 9, 10'and 11 in San Jose.
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