ML20058L271

Safety Evaluation Finding Overlay Repair of Weld 02C-F7 Acceptable & in Conformance W/Gl 88-01.Plant May Be Returned to Safe Operation

ML20058L271
Person / Time
Site:	Quad Cities
Issue date:	12/08/1993
From:	Office of Nuclear Reactor Regulation
To:
Shared Package
ML20058L269	List: ML20058L268 ML20058L271
References
GL-88-01, GL-88-1, NUDOCS 9312160240
Download: ML20058L271 (1)

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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO WELD OVERLAY REPAIR OF A RECIRCULATION PIPING WELD COMMONWEALTH EDISON COMPANY AND IOWA-ILLINDIS GAS AND ELECTRIC COMPANY OVAD CITIES NUCLEAR POWER STATION. UNIT 2 DOCKET NO. 50-265 1.0 INTRODUCT!0N During the Q2R12 Unit 2 outage, Commonwealth Edison Company (Ceco, the licensee)(inspected cracking IGSCC welds susceptible to intergranular stress88-01 corrosion and NUREG-0313,Rev}sion2.per i its commitments to Generic The inspection identified crack-liLetter (GL)ke indications in the heat affected zone of weld 02C-F7. This weld is in a 12-inch riser in the recirculation system. Supplemental examinations of this area confirmed the presence of three cracks. The deepest crack was an axial crack extending s about 75% through wall. The licensee expanded the sample to include additional welds of similar susceptibility. It did not find any additional indications. By letter dated April 30, 1993, as supplemented by letter dated August 27, 1993, CECO requested NRC approval to implement the non-Code repair.

2.0 DISCUSSION The weld is classified as a Category C weld per the GL. A Category C weld is a weld of non-resistant materials that has been stress improved af ter two years of operation. The licensee stress improved the weld with the induction method. The licensee repaired the weld with heating stress improvement a full structural weld overlay(IHSI)d an requested NRC approval for the repair.The repair was desioned per the requirements of NUREG-0313, Revisier. 2, and Section XI of tfie American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code (Code).

After the repair the licensee submitted an analysis by Pacific Nuclear. It reported the effect of shrinkage on the piping system, the increase of deadweight and stiffness from the overlay and the as-built dimensions and measured delta ferrite content. The results were all acceptable.

3.0 CONCLUSION

The staff finds the overlay repair of weld 02C-F7 acceptable and in conformance with Generic Letter 88-01 and that Quad Cities, Unit 2, may be returned to safe operation.

Principal Contributor: L. Banic Date: December 8, 1993 9312160240 931200' PDR ADDCK 05000265 P PDQ