05000346/FIN-2011005-01
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Finding | |
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| Title | Inadequate Control of Weld Filler Metal Electrodes |
| Description | A finding of very low safety significance and an associated NCV of 10 CFR 50, Appendix B, Criterion V, Instructions, Procedures, and Drawings were identified by the inspectors for the licensees failure to control weld rod oven temperature in accordance with procedure WFMC-1 during a rebar splice weld completed for restoration of the shield building access opening. As a corrective action, the licensee removed the welders certification to weld rebar and documented this issue in CR 2011-05536. To ensure that the horizontal rebar splice weld 2H-03R was not affected by delayed hydrogen cracking, the licensees vendor examined the weld splice 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> after fabrication and did not identify cracks. The finding was determined to be more than minor because the finding was associated with the Barrier Integrity Cornerstone attribute of Configuration Control and adversely affected the cornerstone objective to provide reasonable assurance that the physical design barriers (e.g., containment) protect the public from radionuclide releases caused by accidents or events. The shield building is part of the containment system. Absent NRC identification, rebar welds would have been fabricated with electrodes exposed to ambient temperatures for excessive periods of time creating a condition that results in hydrogen-induced weld cracking. Rebar splice material with cracks returned to service would increase risk for shield building failure during design basis events such as wind-driven missile impact or earthquake-induced loads. The inspectors completed a significance determination, in accordance with IMC 0609, Significance Determination Process, Attachment 0609.04, Phase 1 - Initial Screening and Characterization of Findings, Table 4a for the Containment Barrier. Because the issue was corrected promptly, prior to introduction of weld material with hydrogen-induced cracks, the inspectors answered no to each of the four Phase 1 screening questions. Therefore, the finding screened as having very low safety significance. This finding had a cross-cutting aspect in the area of Human Performance, Work Practices because the licensee did not provide adequate supervisory and management oversight of work activities including contractors such that nuclear safety was supported. Specifically, the failure to control the weld rod oven temperature in accordance with procedure WFMC-1 was caused by inadequate licensee oversight of the contracted welder. |
| Site: | Davis Besse  |
|---|---|
| Report | IR 05000346/2011005 Section 1R08 |
| Date counted | Dec 31, 2011 (2011Q4) |
| Type: | NCV: Green |
| cornerstone | Barrier Integrity |
| Identified by: | NRC identified |
| Inspection Procedure: | IP 71111.08 |
| Inspectors (proximate) | A Wilson D Kimble J Cameron J Neurauter J Steffes L Jones M Holmberg M Mitchell P Cardona Morales P Smagacz T Briley T Go |
| CCA | H.2, Field Presence |
| INPO aspect | LA.2 |
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Finding - Davis Besse - IR 05000346/2011005 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Davis Besse) @ 2011Q4
Self-Identified List (Davis Besse)
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