05000412/LER-2014-002
| Beaver Valley Power Station Unit Number 2 | |
| Event date: | 05-20-2014 |
|---|---|
| Report date: | 07-21-2014 |
| Reporting criterion: | 10 CFR 50.73(a)(2)(i)(C), 50.54(x) TS Deviation 10 CFR 50.73(a)(2)(iv)(A), System Actuation |
| Initial Reporting | |
| ENS 50124 | 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation |
| 4122014002R00 - NRC Website | |
Energy Industry Identification System (EIIS) codes are identified in the text as [XX].
CONDITIONS PRIOR TO OCCURRENCE:
Unit 2: Mode 1, 16% power, 558 degrees F, 2225 psig There were no systems, structures, or components (SSCs) that were inoperable at the start of the event that contributed to the event.
DESCRIPTION OF EVENT
On May 20, 2014 Beaver Valley Power Station (BVPS) Unit 2 was performing a plant startup from its seventeenth refueling outage. A manual reactor trip criterion of 85 percent narrow range water level in any steam generator [SG] was established with the operators. A single condensate [SD] pump [P] was in operation supplying the one main feedwater [SJ] pump [P] that was in operation. As reactor power was raised, feedwater flow to the steam generators increased requiring the start of a second condensate pump.
The start of the second condensate pump resulted in an oscillation of the steam generator water levels. A manual reactor trip was performed when it was recognized that the pre-determined trip criteria of 85 percent narrow range water level in the 'A' Steam Generator would be met. Due to low decay heat input the main steam line [SB] isolation valves [ISV] were shut in order to limit the reactor coolant system [AB] cool down. The plant trip response was as expected without complications, and all control rods [AA] fully inserted in the core. The operators entered E-0 (Reactor Trip or Safety Injection) then transitioned to ES- 0.1 (Reactor Trip Response) and stabilized the plant in Mode 3.
CAUSE OF EVENT
The cause of this event has been determined to be the lack of an integrated secondary startup procedure.
The lack of an integrated secondary startup procedure resulted in having only one condensate pump in service supplying the one main feedwater pump in operation. Starting the second condensate pump with the plant at 16% reactor power with the bypass feedwater regulating valves in service resulted in oscillating steam generator water levels and subsequently reaching the high steam generator water level trip criteria.
ANALYSIS OF EVENT
BVPS Unit 2 performed a manual reactor trip from approximately sixteen percent power when it was recognized that the pre-determined trip criteria of 85 percent narrow range water level in the 'A' Steam Generator would be met. Due to low decay heat input the main steam line isolation valves were manually shut in order to limit the reactor coolant system cool down.
The safety significance associated with the BVPS Unit 2 manual reactor trip that occurred on May 20, 2014, due to reaching the pre-determined steam generator narrow range water level manual reactor trip criteria is considered to be very low. This is based on the change in core damage frequency and change in the large early release frequency for this event.
This event is being reported pursuant to 10 CFR 50.73(a)(2)(iv)(A) as a condition that resulted in the valid manual or automatic actuation of any of the systems listed in (a)(2)(iv)(B) — (1) Reactor Protection System (RPS) and (2) Multiple Main Steam Isolation Valves (MSIV). A 10 CFR 50.72 notification was made at 1052 hours0.0122 days <br />0.292 hours <br />0.00174 weeks <br />4.00286e-4 months <br /> on May 20, 2014, to report the manual reactor trip and main steam line isolation (EN 50124).
CORRECTIVE ACTIONS
1. BVPS Unit 2 startup procedures will be revised to incorporate an integrated secondary plant startup procedure.
2. Additional training of the operators is being evaluated.
Completion of the above and other corrective actions are being tracked through the BVPS Corrective Action Program.
PREVIOUS SIMILAR EVENTS
A review of past Beaver Valley Power Station Licensee Event Reports over a five year period found one similar previous event involving a manual reactor trip due to changing steam generator levels at low power level.
BVPS Unit 2 LER 2011-002-00 "Auxiliary Feedwater System Vent line Crack Results in Technical Specification Required Plant Shutdown and Valid Reactor Protection System / Engineered Safety Feature Actuation System Actuations" CR 2014-09256