05000461/FIN-2011002-04
From kanterella
Jump to navigation
Jump to search
Finding | |
|---|---|
| Title | Reactor Coolant System Pressure Isolation Valve Leakage Surveillance Test Procedure Questions |
| Description | The inspectors identified that the licensee s surveillance test procedure for demonstrating operability of RCS PIVs may not correctly incorporate the required test pressure limits of TSSR 3.4.6.1. This issue is considered to be an Unresolved Item pending additional review by the inspectors to determine whether the surveillance test procedure was adequate to satisfy the surveillance testing requirement. The inspectors reviewed the licensee s performance of surveillance testing that was accomplished in accordance with CPS 9843.01, ISI Category A Valve Leak Rate Test, Revision 35. This surveillance test procedure was performed to satisfy TSSR 3.4.6.1, which required the licensee to verify the equivalent leakage of each RCS PIV is U 0.5 gpm per nominal inch of valve size up to a maximum of 5 gpm, at an RCS pressure Y 1000 pounds-per-square-inch gage (psig) and U 1025 psig. As described in the Bases for TS 3.4.6.1, the main purpose in establishing a leakage limit for the RCS PIVs is to prevent overpressure failure of the low pressure portions of connecting systems. The leakage limit is an indication of whether the PIVs between the RCS and the connecting systems are degraded or degrading. During review of CPS 9843.01 and the completed test packages for RCS PIV testing performed during the last refueling outage, the inspectors noted that much of the testing was performed at pressures greater than the TSSR 3.4.6.1 maximum test pressure of 1025 psig. The procedure had the test performers calculate a corrected test pressure to adjust for the elevation differences between the test gage and the valves undergoing testing. This appeared to be appropriate in order to account for an actual pressure difference at the valves as read from the test pressure gage to assure that the valves would be tested at the correct pressure. However, the inspectors found that the test procedure did not ensure that leakage testing was performed within the 1000-1025 psig range specified by TSSR 3.4.6.1. Instead of calculating both an upper and a lower test pressure based on the TSSR 3.4.6.1 limiting pressure range, the procedure had the test performers calculate only one test pressure based on the maximum limit of 1025 psig. Step 8.2.4 of the procedure directed the test performers to pressurize the test volume to 1025 psig (+25/-0 psig), rather than 1025 psig (-25/+0 psig). During review of the completed test packages, the inspectors noted that, not accounting for calculation errors, test performers pressurized the test volume to the calculated test pressure (+25/-0 psig). The inspectors noted that the Bases for TS 3.4.6 states that leakage testing at a lower pressure differential than between the specified maximum RCS pressure and the normal pressure of the connected system during RCS operation (the maximum pressure differential) is allowed. The observed rate may be adjusted to the maximum pressure differential by assuming leakage is directly proportional to the pressure differential to the one-half power. However, the inspectors found that the test procedure did not make any allowance by way of calculating a corrected leakage for a lower pressure differential. 25 Enclosure The inspectors found no allowance in the TS Bases or in the procedure for testing with a higher pressure differential. The inspectors discussed these observations with the licensee and questioned whether the required test pressure limits of TSSR 3.4.6.1 had been correctly incorporated into the surveillance test procedure. This issue is considered to be an Unresolved Item (URI 05000461/2011002-04, Reactor Coolant System Pressure Isolation Valve Leakage Surveillance Test Procedure Questions) pending additional review and resolution of open questions to determine whether the surveillance test procedure was adequate to satisfy the surveillance testing requirement. The licensee initiated AR 00282084 to address the inspectors questions. |
| Site: | Clinton  |
|---|---|
| Report | IR 05000461/2011002 Section 1R22 |
| Date counted | Mar 31, 2011 (2011Q1) |
| Type: | URI: |
| cornerstone | Mitigating Systems |
| Identified by: | NRC identified |
| Inspection Procedure: | IP 71111.22 |
| Inspectors (proximate) | R Orlikowski J Cassidy B Kemker C Brown S Mischke D Lords S Wests Mischkea Dunlop B Kemker C Brown D Lords J Cassidy M Jones M Ring R Winter |
| INPO aspect | |
| ' | |
Finding - Clinton - IR 05000461/2011002 | |||||||||||||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Finding List (Clinton) @ 2011Q1
Self-Identified List (Clinton)
| |||||||||||||||||||||||||||||||||||||||||||