05000338/FIN-2011004-02
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Finding | |
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| Title | Licensee-Identified Violation |
| Description | 10 CFR 50, Appendix B, Criterion XVI, requires the licensee to identify and correct conditions adverse to quality involving the unacceptable presence of Microtherm and Cal-Sil insulation within the GSI 191 zone of influence (ZOIs) inside each Units containment. Contrary to this above, on September 22, 2010, the licensee identified that an inadequate methodology was used to determine the types and quantities of insulation during the GSI-191 containment walkdowns in 2003 and 2004, resulting in unacceptable insulation not being included in the containment debris inventory and subsequently removed. The issue is more than minor because it associated with the Mitigating Systems cornerstone and the related attribute of equipment availability and reliability because the presence of Microtherm and Cal-Sil insulation within the ZOI would impact the availability and reliability of the containment sump strainers in post-loss of coolant accident (LOCA)/high energy line break (HELB) conditions. A phase 1 Significance Determination Process (SDP) screening determined that the finding represented a potential loss of long term decay heat removal as the Microtherm could impact flow from both the Low Pressure Safety Injection (LHSI) containment sump strainer and the Recirculation Spray (RS) sump strainer during the recirculation phase of a LOCA. The phase 2 SDP evaluation determined that the finding was potentially greater than Green but did not account for the specific LOCA size and frequency required to release the insulation, the probability factor of the LOCA occurring at locations where the insulation was present, or the potential recovery actions, therefore a detailed phase 3 SDP risk assessment was performed by a regional Senior Reactor Analyst (SRA). The risk was mitigated by the low probability of the required initiators and the proceduralized recovery actions. The result of the phase 3 SDP evaluation was a core damage frequency increase for the PD of <1E-6 per year, a Green finding of very low safety significance. The licensee has documented in their corrective action program as CR 396377. |
| Site: | North Anna  |
|---|---|
| Report | IR 05000338/2011004 Section 4OA7 |
| Date counted | Sep 30, 2011 (2011Q3) |
| Type: | NCV: Green |
| cornerstone | Mitigating Systems |
| Identified by: | Licensee-identified |
| Inspection Procedure: | |
| Inspectors (proximate) | W Pursley A Alen A Nielsen A Sengupta C Fletcher D Mas G Kolcum G Macdonald G Mccoy J Reece M Cain M Speck M Yoo R Carrion R Clagg R Hamilton R Kellner S Sandal |
| INPO aspect | |
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Finding - North Anna - IR 05000338/2011004 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (North Anna) @ 2011Q3
Self-Identified List (North Anna)
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