ML20028E292

Final Deficiency Rept Re Defective Welds in Suppression Pool Clad Floor Plates.Initially Reported on 820324.All Weld Metal Redeposited,Tested to Design Requirements & Accepted. All Welds Covered W/Leakchase.No Further Work Required

ML20028E292
Person / Time
Site:	Perry
Issue date:	01/14/1983
From:	Edelman M CLEVELAND ELECTRIC ILLUMINATING CO.
To:	James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
References
10CFR-050.55E, 10CFR-50.55E, RDC-51(82), NUDOCS 8301210184
Download: ML20028E292 (2)

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P.o. BOX 5000 - CLEVELAND. oHlo 44101 - TELEPHONE (216) 622-9800 - ILLUMINATING BLDG. - 55 PUBLICSOUARE Serving The Bes' Location in the Nation MURRAY R. EDELMAN Jaruary 14, 1983 VICE PRESIDLNT NUCUAR Mr. James C. Keppler Regional Administrator, Region III Office of Inspection and Enforcement U.S. Nuclear Regulatory Commission 799 Rooseselt Road Glen Ellyn, Illinois 60137 RE: Perry Nuclear Power Plant Docket Nos. 50-440; 50-441 Final Report on Unit I Suppression Pool Floor Plate Welding Deficiencies

[RDC 51(82)]

Dear Mr. Keppler:

This letter serves as the Final Report pursuant to 10CFR50.55(e) concerning defective welds in the Unit I Suppression Pool clad floor plates. On March 24, 1982, Mr. E. Riley of The Cleveland Electric Illuminating Company notified Mr. P. Pelke of your office that this problem was being evaluated, and on April 23, 1982, an Interim Report was submitted to your office outlining the deficiency and the evaluatior:s that were underway at the time.

This report contains a description of the deficiency, analysis of the safety implications, and corrective action taken to alleviate the problem.

Description of Deficiency

" thick stainless steel clad floor plates in the The welds joining the Unit I Suppression Pool have been found to contain deficiencies such as a lack of fusion at the sidewalls, between the carbon steel / stainless steel layers, and to the embedded steel. The welding problem was under investigation by Newport News Industrial Corporation of Ohio (NNICO) and on February 17, 1982, they wrote Nonconformance Report (NCR) #17-334 which explained, in detail, their basic research and the problems encountered.

In March 1982 they presented CEI with a partial resolution copy of the NCR, at which time your of fice was notified of the problems, based on the extensive evaluation and possible rework required.

Analysis of Safety Implications The presence of indications in the floor plate welds, had the condition gone undetected, would not have resulted in the welds failing under accident condi-tions. The floor plates could possibly have buckled slightly, but no violation of the leak barrier would have resulted, hence there would be no breach of containment.

0301210184 830114 317 dad PDR ADOCK 05000440 PDR S

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Mr,. Jrmes G. Ksppler January 14, 1983 e

Corrective Action As part of the evaluation undertaken by NNICO, the top k" of weld material was removed from all welds in the Suppression Pool floor. It was shown that by removing this amount, the stainless / carbon interface was completely removed, and any sidewall lack of fusion was apparent by visual inspection. Where this sidewall lack cf fusion was observed, the weld was excavated to insure complete removal of the defect.

At the same time this ef fort was underway, Newport News (Virginia) was investi-gating the design of the floor plates to determine the amount of fusion to the embed required to insure design integrity of the floor. It was found that two (2) welds, Weld Joints 1-5 and 1-14, required 100% fusion to the embeds.

These welds were 100% longitudinally tested ultrasonically (UT), and where a lack of fusion was evident, the weld was excavated and repaired to provide adequate fusion. The remainder of the floor plate welds required a minimum of 2" of fusion every 15" to provide adequate anchorage. NNICO had the option to perform a 100% UT of the remaining welds to verify that the 2" in 15" criteria was met, or to excavate and reweld the joints to provide the required anchorage.

NNICO opted to forego the UT and excava te 2" slots every 15 where necessary, to assure compliance with the anchorsge criteria.

! Prior to the redeposition of any weld metal in this area, NNICO's welders and l quality personnel were thoroughly retrained in the procedures required for this repair. The procedure for deposition of weld metal was selected after extensive evaluation of the various techniques available to avoid recurrence of the original problems.

All weld metal has now been redeposited, tested to the design requirecents, und accepted. All welds have now been covered with leakchase and no further l work in this area is required by NNICO.

If you have any questions, please do not hesitate to call.

Sincerely,

's l

Murray R. Edelman Vice President Nuclear Group l MRE:pab l

! cc: Mr. M. L. Cildner NRC Site Office i

Director Office cf Inspection and Enforcement l

U.S. Nuclear Regulatory Commission Washington, D.C. 20555 U.S. Nuclear Regulatory Commission i c/o Document Management Branch Washington, D.C. 20555

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