05000338/FIN-2009002-01
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Finding | |
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| Title | Degradation of the Containment Sump |
| Description | On September 30, 2007, while performing maintenance and cleanup in the Unit 1 sump area, the licensee discovered that the top of a containment pressure test connection plug had corroded away and was missing. This discovery was documented in condition report (CR) 021245. The original CR was assigned to a minor work request which was later canceled prior to work commencement. Later, the licensee initiated CR325382, apparent cause evaluation (ACE) 017479 and operability determination (OD) 000272 to address this issue during the spring 2009Unit 1 outage. The typical pressure test connection consists of a 3 1/2 diameter standard pipe cap with a 1/8 diameter screwed half coupling and 1/8 screwed socket head pipe plug. This setup was originally used to locally pressure test a plugged grout injection hole in an embedded 3/4 plate that is part of the containment liner. The grout injection hole below the protective cover was originally used during plant construction to backfill grout under the sump liner. It is plugged with a threaded 2 diameter hex head pipe plug and sealed with a 1/4 fillet weld. All of the above mentioned materials are carbon steel. The exposed area of the test connection was originally coated with a zinc-based paint for corrosion inhibition. The test connection was directly exposed to the boric acid containing wetted environment of the containment sump. This led to general corrosion of the test connection and socket head pipe plug and allowed borated water from the sump to directly contact the carbon steel containment liner and 2 diameter hex head pipe plug. The licensee identified several other sump areas with test connections exhibiting corrosion including four locations where the 1/8 screwed socket head pipe plugs were missing and instituted a work order to clean and redrill the test connections to accept a 1/4 stainless steel pipe plug. Subsequently, the licensee initiated corrective actions and performed successful pressure tests on the connections at 45 psig for 15minutes. Similar issues exist for the Unit 2 sump area and will be addressed under request for engineering assistance (REA) 2008-094 during the next Unit 2 outage. This issue is unresolved pending completion of NRC review of the licensees ACE, and a related corrosion analysis. It is identified as URI 05000338/2009002-01, Degradation of the Containment Sump |
| Site: | North Anna  |
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| Report | IR 05000338/2009002 Section 1R08 |
| Date counted | Mar 31, 2009 (2009Q1) |
| Type: | URI: |
| cornerstone | Mitigating Systems |
| Identified by: | NRC identified |
| Inspection Procedure: | IP 71111.08 |
| Inspectors (proximate) | R Hamilton W Loo H Gepford J Reece G Mccoy R Clagg R Williamse Michelr Hamilton R Chou J Reece G Mccoy R Clagg R Williams |
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Finding - North Anna - IR 05000338/2009002 | |||||||||||||||||||||||||||
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Finding List (North Anna) @ 2009Q1
Self-Identified List (North Anna)
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