05000281/LER-2009-001

LER-2009-001, Manual Reactor Trip Initiated to Replace a Rod Control Data Logging Card

Docket Number
Event date:
Report date:
Reporting criterion:	10 CFR 50.73(a)(2)(iv)(A), System Actuation
2812009001R00 - NRC Website

1.0 DESCRIPTION OF THE EVENT On November 29, 2009 at 0527 hours0.0061 days <br />0.146 hours <br />8.713624e-4 weeks <br />2.005235e-4 months <br />, Unit 2 reactor achieved criticality following the Fall refueling outage. With reactor power stable, startup physics testing commenced at 0555 hours0.00642 days <br />0.154 hours <br />9.176587e-4 weeks <br />2.111775e-4 months <br />.

At 0808 hours0.00935 days <br />0.224 hours <br />0.00134 weeks <br />3.07444e-4 months <br />, while inserting Control Bank B' (CBB) in accordance with the startup physics test procedure, the operators identified a discrepancy between Group 1 and Group 2 Step Demand Counters (SDC) [E11S-AA,CTR]. CBB bank was being inserted from 230 steps when the operator noticed that when Group 1 SDC stopped at 213 steps, the Group 2 SDC continued to increment. The startup physics test was suspended with Group 1 at 213 steps and Group 2 at 210 steps.

System Engineering reviewed the indications and determined that the condition 'resulted from a probable fault on the Supervisory Data Logging Card A114 [EIIS­ AA,DAL]in the Rod Control System Logic Cabinet [EIIS-AA,CAB]. The output signals for Shutdown Bank B, Control Bank B, and Control Bank D step counters are provided by Card A114, therefore, a Technical Specification (TS) 6-hour Hot Shutdown (HSD) action statement was entered for multiple inoperable SDCs. Due to the time required to safely replace the card and perform post maintenance testing (PMT), the decision was made to manually trip the reactor.

At 1045 hours0.0121 days <br />0.29 hours <br />0.00173 weeks <br />3.976225e-4 months <br /> on November 29, 2009, Unit 2 reactor was manually tripped and procedure 2-E-0, Reactor Trip Response, was initiated. All systems functioned as required. Initiation of auxiliary or emergency systems was not required. Heat removal was maintained by steam generator blowdown [EIIS-WI], main feedwater [EIIS-SJ], and the steam generator power operated relief valve [ElIS-SB,R1/].

At 1331 hours0.0154 days <br />0.37 hours <br />0.0022 weeks <br />5.064455e-4 months <br /> on November 29, 2009, a anon-emergency, four-hour notification was made to the NRC pursuant to 10 CFR 50.72(b)(2)(iv)(B), any event or condition that results in actuation of the reactor protection system (RPS) when the reactor is critical.

This report is being submitted pursuant to 10 CFR 50.73(a)(2)(iv)(A), manual actuation of the reactor protection system (RPS).

2.0 SIGNIFICANT SAFETY CONSEQUENCES AND IMPLICATIONS This event resulted in no significant safety consequences or implications. At the time of the manual trip, the reactor was stable below the point of adding heat and reactor power was approximately 5 x 10-8 amps on the intermediate range nuclear instrumentation [EllS-IG]. The control rods promptly inserted as designed when the reactor was manually tripped. The safety injection [El1S-BC)] and auxiliary feedwater NRC Farm 366A (9-2007) _