05000237/FIN-2013004-02
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Finding | |
|---|---|
| Title | Potential Non-ASME Code Section XI Repair on Unit 2 Containment Cooling Service Water 16 Line |
| Description | During review of the repair and replacement plan under work order (WO) 1667426-01 for the repair of a thru-wall leak identified by the licensee on a 16 Containment Cooling Service Water (CCSW) line, the inspectors identified an Unresolved Item (URI) associated with the licensees interpretation of defect removal requirements as described in ASME Code,Section XI, Paragraph IWA 4422.1. During review of the repair and replacement plan under WO 1667426-01 for the repair of a thru-wall leak identified by the licensee on a 16 CCSW line, the inspectors identified a URI associated with the licensees interpretation of defect removal requirements as described in ASME Code,Section XI, Paragraph IWA 4422.1. Specifically, the inspectors questioned the licensees interpretation of defect removal as only applying to areas around the thru-wall leak that are below design minimum wall thickness. Paragraph IWA 4422.1(a), states that A defect is considered removed when it has been reduced to an acceptable size. Paragraph IWA 4422.1 does not specifically define what is considered the defect for repairs involving thru-wall leaks. Areas around the thru-wall leak that recorded less than nominal wall thickness but still greater than design minimum wall thickness, were not excavated by the licensee during repair of the thru-wall leak. These areas of less than nominal wall thickness but greater than design minimum wall thickness, may be indicative of some amount of localized corrosion similar to the corrosion immediately around the thru-wall leak. Hence, the inspectors questioned the adequacy of defect removal performed by the licensee during the repair. Subsequent to the defect removal, the licensee welded a 4 diameter branched connection over the pipe area that was excavated including the original thru-wall leak location. The new pressure boundary was the seal weld around this 4 branched connection and some areas of this seal weld lie over base pipe material that has wall thickness below nominal but above minimum design thickness. The inspectors did not have an immediate safety concern with the repairs because the wall thickness under the seal weld was still above minimum design wall thickness. However, the inspectors questioned the adequacy of defect removal because some material under the seal weld that is below nominal wall thickness may still experience potential corrosion and potentially challenge the new seal weld boundary. Therefore, the inspectors questioned whether this repair was an acceptable ASME Code repair or a non-ASME Code repair strictly prohibited by 10 CFR 50.55a (b) (2) (xxv) that would have required prior NRC review and approval. The licensee entered this issue into their CAP as IR 01551855, NRC Questions on Unit 2 CCSW Pipe Leak Repair, in which the licensee documents the concerns raised by NRC inspectors regarding the repair of the thru-wall leak. This URI will remain open pending receipt and evaluation of additional information to ascertain the correct ASME Code interpretation. (URI 05000237/2013004-02; 05000249/2013004-02, Potential Non-ASME Code Section XI Repair on Unit 2 CCSW 16 Line) |
| Site: | Dresden  |
|---|---|
| Report | IR 05000237/2013004 Section 1R19 |
| Date counted | Sep 30, 2013 (2013Q3) |
| Type: | URI: |
| cornerstone | Mitigating Systems |
| Identified by: | NRC identified |
| Inspection Procedure: | IP 71111.19 |
| Inspectors (proximate) | A Shaikh E Sanchez-Santiago R Elliott G Roach D Melendez-Colon P Pelke T Go V Meghani D Lordsa Shaikhd Betancourt G Roach J Cameron M Jones M Porfirio R Edwards T Go |
| INPO aspect | |
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Finding - Dresden - IR 05000237/2013004 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Dresden) @ 2013Q3
Self-Identified List (Dresden)
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