05000390/FIN-2012003-01
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Finding | |
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| Title | Failure to Demonstrate Corrective Actions for Check Valve 0-CKV-040-0604 |
| Description | The inspectors identified a unresolved item (URI) related to 10 CFR 50 Appendix B, Criterion XVI, Corrective Action, for failure to take timely corrective action on CKV-040-0604, 0-PUMP-040-003B discharge check valve. During the semi-annual internal flooding inspection, inspectors were verifying the licensees capability to insure that the intake pumping station (IPS) sump pumps were capable of removing assumed leakage into the ERCW strainer rooms, A train and B train. This system relies on the capability of two 25 gpm sump pumps in each strainer room to remove leakage from ERCW strainers and fire protection strainers. Additionally, they are credited in the external flooding study to be operable to remove any leakage through the exterior of the building. The pumps discharge through individual check valves into a common pipe which dumps into the sluice trough external to the room. These piping outlets are submerged during the probable maximum flood. Therefore, the individual check valves, in addition to preventing recirculation between the pumps, also prevent flood waters from entering the room. These ERCW strainers are required for operation of the ERCW system A train and the fire protection system A train. Inspectors reviewed the maintenance history of the check valves to verify that they were being maintained in a manner that would fulfill their operability requirements. These check valves are in the Augmented Inservice Testing (AIST) Program under a two-year test frequency. Licensee records indicate that on March 8, 2008, 3A sump pump exhibited low flow below the allowable limits of TI-50.021, Intake Pumping Station Strainer Room A Sump Pump A Performance Test, and exhibited bubbling from the opposite sump pump suction 3B, indicating back leakage past check valve CKV-040-0604, 0-PUMP-040-003B discharge check valve. This resulted in problem evaluation report (PER) 139387 and work order (WO) 08-812124. This PER was closed to previously existing PER 128435 dated August 4, 2007, which also was for flow-related issues. WO 08-812124 has not been located and check valve CKV-040-0604 was not entered into the work control process at that time. PER 128435 was an all-encompassing PER for both A train sump pumps 3A and 3B. The next performance of TI-50.021 on March 1, 2009, the 3A sump pump yielded zero flow and the operator noted bubbles coming from the opposite sump pump, which again implicated the opposite train check valve 0-CKV-040-0604 as leaking backward past the seat sufficiently to prevent the 3A sump pump from removing water from the sump it shares with the 3B sump pump. WO 09-812234 was written for this check valve specifically. This WO was performed and its associated post maintenance test was signed off as satisfactory on April 15, 2010. TI 50-021 was performed the next day, April 16, 2010, at which time the 3A sump pump failed on low flow. However, there appeared to be no back leakage of CKV-040-0604. PER 225913 was written as a result of the test failure which closed to WO 110952174 for check valve 0-CKV-040-0606, 0- PUMP-040-003A discharge check valve for apparently being partially stuck shut. On October 19, 2011, in a situation of high demand due to fire pump strainer leakage, the licensee determined that check valve CKV-040-0604 was stuck open sufficiently to render sump pump 3A incapable of lowering level due to back leakage through check valve CKV-040-0604. As a result, service request (SR) 448624 was initiated and resulted in WO 112833360 which is scheduled to work December 11, 2012. On June 18, 2012, TI-50.021 was performed and failed. As such, no satisfactory testing has been shown to verify the functionality of CKV-040-0604 since April 16, 2010. Pending additional information from the licensee which can verify the adequacy of the corrective action for check valve 0-CKV-040-0606 |
| Site: | Watts Bar  |
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| Report | IR 05000390/2012003 Section 1R06 |
| Date counted | Jun 30, 2012 (2012Q2) |
| Type: | URI: |
| cornerstone | Mitigating Systems |
| Identified by: | NRC identified |
| Inspection Procedure: | IP 71111.06 |
| Inspectors (proximate) | R Monk S Shaeffer P Higgins A Vargas T Lighty K Miller T Sur Monks Shaeffer K Miller |
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Finding - Watts Bar - IR 05000390/2012003 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Watts Bar) @ 2012Q2
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