05000266/FIN-2007006-02
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Finding | |
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| Title | Failure to Protect Circuits Associated with PORVs and Block Valves (Section 1R05.2b.2) |
| Description | The P&ID 541F091, Sheet 3, Reactor Coolant System, for Unit 1, showed that PORV 1RC-431C was connected in series with its associated block valve (1RC-515) and PORV 1RC-430 was connected in series with its associated block valve (1RC-516). During normal plant operation the block valves were normally open and the PORVs were normally closed. The PORVs are air operated valves and fail to the closed position upon loss of power and/or air supply. The block valves are motor operated valves and they fail as-is in their position prior to loss of power. The same design and configuration existed for Unit 2. Abnormal Operating Procedure (AOP)-10A, Safe Shutdown - Local Control, Revision 43, provided instructions and steps for safe shutdown (SSD) of the plant in the event of a severe fire in either the control room, cable spreading room or vital switchgear room that required control room evacuation. The inspectors noted during the review of Procedure AOP-10A that it included steps to close the block valves (1/2RC-515 and 1/2RC-516) and also included later steps to open the feeder breakers to the block valves. These steps were provided to mitigate the spurious operation of the PORVs in the event of fire damage to their associated cables. The inspectors also identified that cables for both the PORVs and their associated block valves were unprotected from fire damage in the cable spreading room and control room (Fire Area A30 and A31, respectively). The inspectors were concerned that operators would not be able to close the block valves from the control room if their associated cables were damaged by fire in either one of these fire areas. The inspectors were also concerned regarding the adequacy of the steps specified in Procedure AOP-10A, since the opening of the feeder breakers to the block valves would only prevent the spurious operation of these valves, but would not close them if their associated cables were damaged in the fire. Attachment C of Procedure AOP-10A included steps to isolate instrument air to Unit 1 and Unit 2 containment and to remove the pipe plugs to vent the air from all air-operated equipment located inside containment. These actions were to be taken at the primary auxiliary building (PAB), 26' elevation, and would fail the PORVs closed. However, the inspectors noted that if the PORV valves suffer a spurious actuation and the associated block valves cannot be closed, the undesirable consequences of the PRT rupture disc failing and loss of RCS inventory could occur in approximately 200 seconds. The inspectors were concerned that the steps in Attachment C could represent a challenge to the operatorss ability to perform these steps in 200 seconds, especially, if all other actions failed (i.e., closing the block valves, initiating containment isolation as a result of circuit failure concurrent with spurious actuation of the PORVs). The inspectors also noted that within the first six steps of Procedure AOP-10A, instructions were provided to the operators to close the block valves and remove power to the block valves to ensure they remain shut. The inspectors were concerned that, in the event of fire damage to any of the cables/circuits for the block valves prior to operator action in the control room concurrent with spurious actuation of its associated PORV, the licensees approach did not assure RCS inventory control, depressurization control, and SSD. Upon discovery of this condition, this issue was entered into the licensees CAP as 01101461, Post Coincident Fire Induced Failure of PORVs and Block Valves, dated July 12, 2007. The licensee initiated compensatory measures and will evaluate this finding during transition to NFPA 805. Pursuant to 10 CFR Part 50, Section 72(b)(3)(ii)(b), on July 12, 2007, the licensee made an event notification (EN 43487) to the NRC and reported the unanalyzed condition. Since the licensee is in transition to NFPA 805, this finding is considered an URI pending the licensees completion of a risk assessment evaluation to determine the risk significance in accordance with the established NRC Enforcement Discretion regarding plants in transition to NFPA 805. Subsequent NRC review of the risk evaluation will determine if this finding meets the four criteria established by Section A of the NRC's Interim Enforcement Policy Regarding Enforcement Discretion for Certain Fire Protection Issues (10 CFR 50.48). (URI 05000266/2007006-02(DRS);05000301/2007006-02(DRS)) |
| Site: | Point Beach  |
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| Report | IR 05000266/2007006 Section 1R05 |
| Date counted | Sep 30, 2007 (2007Q3) |
| Type: | URI: Severity level Enforcement Discretion |
| cornerstone | Mitigating Systems |
| Identified by: | NRC identified |
| Inspection Procedure: | IP 71111.05 |
| Inspectors (proximate) | D Mcneil R Ruiz D Szwarc J Jacobson W Slawinski R Krsek L Kozak D Betancourt K Barclayg Hausman A Dahbur D Szwarcr Daley R Langstaff A Dahbur C Moore D Passehl L Jones |
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Finding - Point Beach - IR 05000266/2007006 | |||||||||||||||||||||
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Finding List (Point Beach) @ 2007Q3
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