05000456/FIN-2013002-07
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Finding | |
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| Title | Current Licensing Basis Requirements for the Unit 1 and Unit 2 Containment Sump Isolation Valves |
| Description | The normally closed 1/2SI8811A/B valves are located several feet outside the primary containment wall and isolate the open-ended ECCS containment sump suction pipes from the ECCS system. The ECCS containment sump suction pipe is double-walled and each valve body and bonnet is contained in an enclosure with normally closed vent and drain valves. This configuration is prescribed in American National Standard (ANS) 56.2/American Nuclear Standards Institute (ANSI) N271-1976, Containment Isolation Provisions for Fluid Systems. The licensee generated IR 1463476, RH01SA/B Enclosure Classification Appears Overly Conservative, on January 15, 2013, to document a similar question regarding the classification of the valve enclosure. The question was raised due to upcoming planned work to install inspection ports to allow for inspection inside the enclosures. The inspectors noted that one of the valve enclosures had inspection ports previously installed. The licensee also generated IR 1480240, 1/2RH01SA/SB Leak Tightness Not Challenged for NUREG 0737, on February 26, 2013, documenting that their NUREG-0737 program had inappropriately excluded the 1/2SI8811A/B valve enclosures from pressure testing to potential accident conditions. Through a Work Group Evaluation in IR 1480240, the licensee concluded that pressure testing was required in accordance with NUREG-0737 since the potential existed for pressurizing the valve enclosures under accident conditions. Separately, the licensee identified that there had been leakage inside the enclosure of valve 1SI8811A. The source of the leakage was suspected by the licensee to be body- to-bonnet leakage, but that could not be confirmed without a visual inspection. The licensee had been opening the enclosure vent and drain valves weekly to drain existing water or validate that no water was present. Identification of this leakage source was the impetus for the planned installation of inspection ports, which had since been deferred. At the end of the inspection period, the inspectors were continuing to review the licensees determination of the testing requirements for the valve enclosure, whether an adequate post-maintenance test was performed following installation of inspection ports, and what requirements applied to the valve enclosures and associated vent and drain valves. |
| Site: | Braidwood  |
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| Report | IR 05000456/2013002 Section 1R18 |
| Date counted | Mar 31, 2013 (2013Q1) |
| Type: | URI: |
| cornerstone | Mitigating Systems |
| Identified by: | NRC identified |
| Inspection Procedure: | IP 71111.18 |
| Inspectors (proximate) | A Garmoe E Duncan F Ramirez J Benjamin J Coroju _Sandin M Perry T Goa Garmoe E Duncan J Benjamin M Holmberg M Perry R Jickling R Ng T Daun |
| INPO aspect | |
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Finding - Braidwood - IR 05000456/2013002 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Braidwood) @ 2013Q1
Self-Identified List (Braidwood)
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