05000250/FIN-2005010-01
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Finding | |
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| Title | Unprotected Post-Fire Safe Shutdown Cables and Related Non-feasible Local Manual Operator Actions |
| Description | An apparent violation (AV) of 10 CFR 50, Appendix R requirements was identified for failure to: 1) protect the control circuit of motor operated valve (MOV) MOV-4-626, Reactor Coolant Pump (RCP) Thermal Barrier Component Cooling Water (CCW) Return Isolation Valve and to prevent its spurious operation during a fire in fire zone (FZ) 67; 2) ensure that local manual operator actions used to verify correct alignment of MOV-3-716A and MOV-4-716A, RCP Thermal Barrier CCW Supply Isolation Valves and MOV-3-626 were completed in a timely manner for fires in either FZ 63 or FZ 67; and 3) ensure local manual operator actions to verify correct alignment of valves MOV-3-716A and MOV-4-716A were completed in a timely manner for a fire in FZ 106. These conditions could result in an RCP seal loss of coolant accident (LOCA). Pursuant the safe shutdown analysis report (SSAR), thermal barrier cooling is the assured method for protecting the RCP seals during a severe fire in FZ 67 because charging pump seal injection flow may be terminated by operator action or lost due to the fire. Valve MOV-4-626 is a motor operated valve in the thermal barrier CCW header returning from all three Unit 4 RCPs. The valve can be controlled from either the main control room (MCR) (FZ 106) or the alternate safe shutdown panel (ASP) [which is located in the 4B 4160V switchgear room (FZ 67)]. Because the control cable for this valve terminates at the ASP and the cable is unprotected, thermal insult to the control circuit for the valve could cause it to spuriously close. Closure of the valve would stop thermal barrier cooling return flow from all three Unit 4 RCPs. Guidance in 0-ONOP- 016.10, Pre-fire Plan Fire Zone 67, directs local manual operator actions to prevent, or recover from, spurious closure of MOVs that could interrupt thermal barrier cooling. For FZ 67, thermal barrier cooling valves MOV-4-716B and MOV-4-626 could be subject to spurious operation but the inspectors found that MOV-4-626 was not included in the procedure. On September 9, 2003, the licensee identified an error in the safe shutdown analysis (SSA) Essential Equipment List. They found that valve MOV-4-626 was not properly classified as being required to assure safe shutdown (SSD). As a result, the fire response procedure failed to include MOV-4-626 as part of the mitigation strategy against spurious valve operation. The issue was entered into the licensees corrective action program (CAP) as condition report (CR) 03-1330-1. The need to review and update 0-ONOP-016.10 was entered into the CAP as CR 04-0292; but this deficiency was not resolved prior to the inspection. During the inspection, the licensee resolved this concern by issuing an on-the-spot-change to 0-ONOP-016.10 which specified manual actions to de-energize and verify open MOV-4-626. The licensee documented this action in its CAP as CR 04-0610. Thermal barrier cooling is also the assured method for protecting the RCP seals during a severe fire in FZ 63 because charging pump seal injection flow may be terminated by operator action or lost due to the fire. In lieu of protecting the control circuits and cables for the RCP thermal barrier cooling valves (MOV-3-716B and MOV-3-626 in FZ 63; and MOV-4-716B in FZ 67), guidance in 0-ONOP-016.10 directed local manual operator actions to prevent, or recover from, spurious closure of the MOVs. When evaluating the feasibility of the manual actions using the guidance in NRC inspection procedure (IP) 71111.05T, Fire Protection [Triennial], the inspectors identified that procedure 0-ONOP- 016.10 allowed 20 minutes to complete the operator actions for verification of thermal barrier cooling valve alignment. However, industry analyses [Westinghouse Direct Work No. DW-94-011; Westinghouse WCAP-10541, Revision 2; and Westinghouse WCAP- 15603, Revision 1-A] have determined that seal package damage could occur within 13 minutes of loss of all seal package cooling. Thus, the operator guidance provided in procedure 0-ONOP-016.10 does not provide timely action and could result in an RCP seal LOCA. Loss of reactor coolant system (RCS) inventory due to an RCP seal LOCA could be beyond the capacity of equipment dedicated to achieve and maintain post-fire safe shutdown. The licensee entered the finding into its CAP as CR 04-0688 and resolved this concern by revising procedure 0-ONOP-016.10. Fire Area (FA) MM includes the MCR, the MCR roof, and the Unit 3 and 4 mechanical equipment room. Per the SSAR, thermal barrier cooling is the assured method for protecting the RCP seals during a severe fire in FA MM because charging pump seal injection flow may be terminated by operator action or lost due to the fire. Guidance in procedure 0-ONOP-105 directs local manual operator actions to prevent, or recover from, spurious closure of MOVs that could interrupt thermal barrier cooling. The inspectors identified that 0-ONOP-105, Attachment 7 (Unit 3) and Attachment 8 (Unit 4) allowed 20 minutes to complete the operator actions for verifying that MOV-3-716A and MOV-4-716A were open. However, industry analyses [Westinghouse Direct Work No. DW-94-011; Westinghouse WCAP-10541, Revision 2; and Westinghouse WCAP- 15603, Revision 1-A] have determined that seal package damage could occur within 13 minutes of loss of all seal package cooling. Thus, the operator guidance provided in procedure 0-ONOP-105 does not provide timely action and could result in an RCP seal LOCA. Loss of RCS inventory due to an RCP seal LOCA could be beyond the capacity of equipment dedicated to achieve and maintain post-fire safe shutdown. The licensee entered the finding into its CAP as CR 04-0688 and resolved this concern by revising procedure 0-ONOP-105. |
| Site: | Turkey Point  |
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| Report | IR 05000250/2005010 Section 4OA5 |
| Date counted | Dec 31, 2005 (2005Q4) |
| Type: | AV: Severity level Enforcement Discretion |
| cornerstone | Mitigating Systems |
| Identified by: | NRC identified |
| Inspection Procedure: | |
| Inspectors (proximate) | D Payne R Rodriguez S Ninh W Rogersk Millern Merriweather N Staples R Nease R Rodriguez |
| INPO aspect | |
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Finding - Turkey Point - IR 05000250/2005010 | |||||||||
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Finding List (Turkey Point) @ 2005Q4
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