05000327/FIN-2007006-04
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Finding | |
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| Title | Inadequate Abnormal Operating Procedure for RHR System Malfuctions During Mode 4 Conditions |
| Description | The team identified a violation of TS 6.8.1, related to the failure to establish an adequate abnormal operating procedure for RHR system malfunctions during shutdown conditions. Procedure AOP-R.03, RHR System Malfunction, Rev. 17, was not adequate in that it did not establish adequate actions to restore RHR cooling following isolation of an RHR leak during hot shutdown (Mode 4) operations. The instruction provided in the procedure could result in a total loss of RHR cooling capability during mode 4 conditions if an RHR leak occurred. Description: Procedure AOP-R.03, RHR System Malfunction, Rev. 17, provided instruction for protection of the reactor core during shutdown (non power) conditions (Modes 4,5 and 6) in the event of a loss of RHR cooling, RHR system leak, or a loss of RHR level. Section 2.4 provides instruction for mitigation of an RHR system leak. Step 2 of section 2.4 stated: if the magnitude of a leak requires rapid isolation, secure RHR pumps and close hot leg and individual RHR pump suction valves [valves 74-1, 74-2, 74-3, and 74-21]. (Note: magnitude of leak was not defined) Steps 3 through 9 involved identifying and isolating the RHR leak. Step 10 directed the operator to place the unaffected RHR loop in service using procedure 0-SO-74-1, System Operating Procedure for RHR System. Entry points into this procedure would be at section 5.5.2, Placing RHR in Service for Normal Shutdown Cooling or section 8.2, Swapping RHR Pumps with RCS in Mid-Loop Conditions. Section 5.5.2, directed the loop suction valves [74-1 and 74-2] to be opened; however, there was no direction to open or verify open the individual pump suction valves [74-3 and 74-21] before the direction to start the pumps nor did section 8.2. The team concluded the pumps could be started without a suction flow path, resulting in pump damage in a relatively short period (minutes), while running on mini flow with the pump suction valves closed due to a lack of NPSHA. Analysis: The failure to establish an adequate abnormal operating procedure for RHR system malfunctions during shutdown conditions is a performance deficiency associated with the Initiating Events Cornerstone. This finding is more than minor because it impacts the Cornerstones objective to limit the likelihood of those events that upset plant stability and challenge critical safety functions during shutdown in that the loss of RHR pumps would increase the likelihood of a loss of RHR cooling. This finding was reviewed for cross-cutting aspects and none were identified |
| Site: | Sequoyah  |
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| Report | IR 05000327/2007006 Section 1R21 |
| Date counted | Sep 30, 2007 (2007Q3) |
| Type: | NCV: |
| cornerstone | Initiating Events |
| Identified by: | NRC identified |
| Inspection Procedure: | IP 71111.21 |
| Inspectors (proximate) | J Rivera -Ortizr Taylor R Moore W Fowler S Kobylarz M Lewis T Tinkel |
| INPO aspect | |
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Finding - Sequoyah - IR 05000327/2007006 | |||||||||||||||||||||||||
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Finding List (Sequoyah) @ 2007Q3
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