Two nukes down Friday: “lowering reactor water level was due to the trip of all three Feedwater Pumps” (Pilgrim 1 in Massachusetts) and “unidentified leakage” (Salem 1 in New Jersey). That’s the fifth downtime for Entergy’s Pilgrim 1 this year: cold, heat, leak, and now feedwater pumps. Remind me about the reliability and safety of big baseload nuclear?
REACTOR PROTECTION ACTUATION (SCRAM)
“On Thursday, August 22, 2013 at 0755 hours [EDT], with the reactor critical at approximately 98% core thermal power, and the mode switch in RUN, a manual reactor scram was inserted due to lowering reactor water level. The cause of the lowering reactor water level was due to the trip of all three Feedwater Pumps. The cause of the Feedwater Pump trip event is currently under investigation.
“Following the reactor scram, all control rods were verified to be fully inserted. All 4kV busses transferred to the Startup Transformer as designed. Following the scram the reactor water level lowered to +12 inches initiating the Primary Containment Isolation System (Group II, Reactor Building Isolation System (RBIS); and Group VI—Reactor Water Cleanup System) automatically as per design.
“Reactor water level lowered to -46 inches initiating Primary Containment Isolation System Group I—Main Steam Isolation Valves (MSIVs); Emergency Core Cooling Systems (ECCS) actuated which included automatic start and injection of the High Pressure Coolant Injection (HPCI) System and the Reactor Core Isolation Cooling (RCIC) System and an automatic start of the Emergency Diesel Generators as designed. Reactor water level was promptly restored to normal level.
“Currently a cooldown is in progress with reactor pressure is being maintained by the HPCI System operating in the pressure control mode and reactor water level is being maintained by the RCIC System. Reactor Water Clean-up System and normal reactor building ventilation have been restored. Off-site power is being supplied to the station by the Start-up Transformer (normal power supply for shutdown operations).
“This event had no impact on the health and/or safety of the public. The USNRC Senior Resident Inspector has been notified. This 4-hour notification is being made in accordance with 10 CFR 50.72 (b)(2)(iv)(A) and (B).”
The plant is transferring from decay heat removal to the torus to decay heat removal to the main condenser. Reactor pressure is 371 psig.
Initial indications are that a main feedwater power supply breaker tripped.
UNIT 1 COMMENCED A TS REQUIRED SHUTDOWN DUE TO UNIDENTIFIED RCS LEAKAGE > 1 GPM
“Salem Unit 1 has initiated a unit shutdown in accordance with TS (Technical Specification) Action Statement 18.104.22.168(b) for unidentified leakage greater than 1 gpm [gallon per minute] (Entered on 8/22/13 at 1029 EDT). TS 22.214.171.124 Action Statement (b) requires a reduction of leakage rate to within limits within 4 hrs. or be in at least Hot Standby within the following 6 hours. Initial investigation has indicated that the leakage source is from packing on Pressurizer Spray Valve 1PS1 located in the RCS [Reactor Coolant System] Pressurizer shroud area inside Containment. Unidentified leakage is currently indicating 4 gpm. NRC Resident [Inspector] has been notified. Manual isolation is in progress.
“Additionally, TS Action Statement 126.96.36.199 Primary Containment Internal Pressure was entered at 1510 [EDT] for exceeding 0.3 psig. Action requires restoration of containment pressure to within specification in 1 hour or be in hot standby within the next 6 hours. Containment pressure was restored to less than 0.3 psig at 1647 [EDT] and TS 188.8.131.52 was exited. Peak containment pressure reached [was] 0.33 psig.
“Location of leak: Unit 1 RCS (containment), Pressurizer, 1PS1 Pressurizer Spray Valve Packing “Time & date leak started: 1019 [EDT] on 08/22/2013 “Leak rate: 4 gpm, T/S leak limits: 1 gpm “Last known coolant activity: Primary (DEI [Dose Equivalent Iodine]-microCuries/cc) 5.973E-5 microCuries/cc“Secondary (gbg [Gross Beta Gamma]-microcuries/cc) < LLD [Lower Limit of Detectability]
“Was this leak a sudden or long-term development? Sudden”
The licensee is reducing power at 30%/hour and anticipates entering Mode 3 in approximately 3 hours. The 1PS1 Pressurizer Spray Valve was replaced and the air operator rebuilt during the last refueling outage in April/May of 2013.
The licensee informed the State of New Jersey and will 9inform the Lower Alloways Creek [LAC] Township.
That’s “only” the second downtime for Salem 1 this year; it was down April 15th to May 22nd, and finally got to full power June 2nd.