ML20101N631
| ML20101N631 | |
| Person / Time | |
|---|---|
| Site: | Perry  |
| Issue date: | 12/13/1984 |
| From: | Edelman M CLEVELAND ELECTRIC ILLUMINATING CO. |
| To: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| References | |
| (RDC-105(84)), NUDOCS 8501040118 | |
| Download: ML20101N631 (3) | |
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THE CLEVELAND ELECTRIC ILLUMIN ATING COMPANY r
P.o. Box 5000 - CLEVELANo. OHIO 44101 - TELEPHONE (216) 622-9800 - lLLUMINATING BLDG. - 55 PUBLICSQUARE Serving The Best Location in the Nation MURRAY R. EDELMAN VICE PRESIDENT NUCLEAR December 13, 1984 Mr. James G. Keppler Regional Administrator, Region III Office of Inspection and Enforcement U.S. Nuclear Regulatory Commission 799 Roosevelt Road Glen Ellyn, Illinois 60137 RE: Perry Nuclear Power Plant Docket Nos. 50-440; 50-441 Drywell Equipment Hatch Covers
[RDC 105(84)]
Dear Mr. Keppler:
This letter serves as our final report pursuant to 10CFR50.55(e) concerning the Units I and II Drywell Equipment Hatch Covers which contained potentially rejectable indications in both welds and base metal, as supplied by Newport News Industrial Corporation, Newport News, Virginia (NNIV).
Mr. J. W.
McCormick-Barger of your office was first notified on May 4, 1984, by Mr. P. P.
Martin of The Clevelaad Electric Illuminating Company that this problem was being evaluated. Subsequent interim reports were filed with your office on May 31, 1984 and August 29, 1984.
This report contains a description of the deficiency, an analysis of safety implications, and information concerning corrective action taken.
Description of tha Deficiency During a review of the vendor (NNIV) documentation package for the Unit I Drywell Equipment Hatch Cover, it was noted that approximately 100 welds attaching stiffeners to the cover plate received only a 10% random magnetic particle examination (MT) although fabrication drawings required a 100% MT of these welds. Nonconformance Report (NR) CQC-3259 was written identifying the condition. Review of the documentation for the Unit If assembly also reflected a 10% random MT in lieu of the required 100%. N)nconformance Report TAS-082 was written to document this condition for Unit II.
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".,f'S Mr.~J:mes'G. K:pplar D2csubar 13, 1984 Further investigation also revealed that the full penetration butt velds of the stiffeners had not received 100% radiographic examination (RT) as required by
.the ASME Code.
Analysis of Safety Innlications Had this condition gone undetected, the potential for weld failure may have existed under Drywell pressurization. During the Drywell Structural Integrity Test (SIT) and Integrated Leak Rate Test (ILRT) the structure is pressurised to 30 psig., which is the Design Basis Accident (DBA) pressure. Failure of welds would have been evident at this time, possibly causing deformation of the Drywell Equipment Hatch Cover. This deformation may have resulted in some loss of sealing, allowing bypass leakage fron the Drywell into the Containment, possibly in excess of allowables.
Corrective Action As stated in our previous reports, the designer / fabricator, NNIV, evaluated the conditions identified on the above referenced NRs to determine if the 10% MT, as performed, was adest.te to ensure the structural integrity of the assemblies. It was determined that the 10% MT would not be sufficient.
In preparation for the required 100% MT, it was necessary to perform a 100%
visual examination (VT) of all welds, record all rejectable defects, and remove them entirely regardless of their depth. Where this excavation resulted in removal of material which exceeded design allowables, the excavation was VT and MT inspected to ensure complete removal of the defect and the area repaired by welding. After all welds were visually acceptable, all welds were then 100% MT inspected and repaired as necessary.
With respect to the required RT inspection of the full penetration butt welds, it was determined that the welds were not RT acceptable and would have to be repaired or replaced.
In lieu of completely excavating all of the full penetration welds, rewelding, and performing the required RT examination, NNIV redesigned the stiffener configuration and eliminated the full penetration welds. This redesign resulted in the complete physical removal of all of the full penetration butt welds and the installation of doubler plates across the faces of the stiffener flanges. These plates were attached to the stiffeners using fille't welds which received 100% VT and MT' examination.
1 Mr. James G. K:ppl:r Dsc;mbar 13, 1984 The work described above, and all related documentation, has been completed for the Unit I Equipment Hatch Cover. The Unit II work will be completed consistent with the Unit II construction schedule.
Please call if there are any questions.
Sincerely, 1
A j
Murra R. Edelman Vice President Nuclear Group MRE:pab cc:
Mr. J. A. Grobe USNRC, Site Office Mr. D. E. Keating USNRC, Site Office Director Office of Inspection and Enforcement U.S. Nuclear Regulatory Commission Washington, D.C.
20555 U.S. Nuclear Regulatory Commission c/o Document Management Branch Washington, D.C.
20555 Records Center, SEE-IN Institute of Nuclear Power Operations 1100 Circle 75 Parkway, Suite 1500 Atlanta, Georgia 30339