05000280/FIN-2011003-01
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Finding | |
|---|---|
| Title | Unplanned Dilution of Unit 2 RCS |
| Description | On May 28, 2011, while Unit 2 was operating in Intermediate Shutdown (>200 F, 310 psi), a control room operator noticed a decreasing level trend in the primary grade water tank over the past 2.5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br />. Additionally, it was noted that volume control tank and pressurizer level trends were increasing and charging seal injection flow was 101 gpm with letdown flow of 85 gpm. The licensee entered their abnormal procedure for emergency boration and conducted two emergency borations of the RCS while sampling RCS boron concentration and monitoring shutdown margin. Subsequently, it was identified that the cation demineralizer primary grade header isolation valve, 2-CH-19, indicated closed but was allowing primary grade water to leak by. This caused reverse flow through the cation demineralizer and introduced primary grade water into the RCS via the VCT. The licensee estimated that up to 30,000 gallons of PG water could have entered the RCS. Just prior to this event maintenance was conducted on 2-CH-19 and the valve was returned to service in a condition that allowed the primary grade water leakage flow path described above. The licensee entered this issue into their CAP as CR428947, and initiated Root Cause Evaluation (RCE) 001054. The inspectors require additional information, including the licensees completed investigation in RCE001054, to determine if there is a performance deficiency which is more than minor. This issue is identified as URI 05000281/2011003-01, Unplanned Dilution of Unit 2 RCS. |
| Site: | Surry  |
|---|---|
| Report | IR 05000280/2011003 Section 1R19 |
| Date counted | Jun 30, 2011 (2011Q2) |
| Type: | URI: Green |
| cornerstone | Mitigating Systems |
| Identified by: | NRC identified |
| Inspection Procedure: | IP 71111.19 |
| Inspectors (proximate) | M Endress R Rodriguez T Morrissey J Nadel L Lake R Carrion G Mccoy R Clagg M Coursey C Fletcher B Collins J Montgomery C Jones G Sandel |
| INPO aspect | |
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Finding - Surry - IR 05000280/2011003 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Surry) @ 2011Q2
Self-Identified List (Surry)
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