ENS 40910
ENS Event | |
|---|---|
17:00 Jul 30, 2004 | |
| Title | Alert Declared at Columbia Generating Station |
| Event Description | The following information was obtained by the licensee via facsimile:
Reactor SCRAM received at 0924 [hrs] PDT. Initial indications are the scram signal was caused by RPS [Reactor Protection System] High Pressure. Following the scram, 2 [two] control rods did not immediately indicate [fully inserted]. Control room staff entered [procedure] PPM5.1.2 and took the required actions. All control rods subsequently indicated [fully inserted]. An ALERT Classification was declared at 1000 [hrs] based on PPM 13.1.1 Criteria 2.2.A.1, 'RPS Setpoint exceeded and automatic actions failed to result in a rod pattern which alone assures reactor shutdown'. Manual actions resulted in all rods [fully inserted] and reactor power [less than or equal to] 5 percent. All other plant systems responded as expected with the exception of a wetwell-to-drywell vacuum breaker which indicates open. Investigation into the cause of the scram and actual control rod position is ongoing. Further details will be provided when available. The licensee also reports that no relief valves lifted during the transient. Decay heat removal is via the main condenser. Reactor level is steady at 36 inches. Reactor temperature and pressure are 507 degrees and 710 psig respectively. Offsite power is available. All emergency systems are available in standby. The licensee has notified the NRC Resident Inspector of the incidents. The NRC entered Monitoring mode at 1327 hrs EDT with Region IV leading. The NRC exited Monitoring at 1530 hrs. EDT and returned to Normal mode. Notified HHS (Ayles) as well as others noted in notification block.
At 1358 [hrs.] EDT on 7/30/04, NRC was notified of an Alert at Columbia Generating Station (EN #40910). This is a follow-up to inform NRC that the event was terminated at 1457 [hrs] (EDT) (1157 PDT). All control rods are inserted. Reactor is shutdown and water level is normal. All required emergency systems are operable. All offsite and onsite power sources are operable. Reactor pressure is normal. The licensee has notified the NRC Resident Inspector, State of Washington and local authorities of the termination. The NRC Operations Center notified R4DO(Bywater), DHS, FEMA, DOE(NRC), USDA, EPA and CDC(HHS).
At 1358 EDT on July 30, 2004, NRC was notified of an Alert at Columbia Generating Station (EN #40910). A subsequent notification was made to inform the NRC that the event was terminated at 1157 PDT (1457 EDT) on July 30, 2004. This is a follow-up to inform the NRC that Columbia Generating Station is retracting its Alert Emergency Declaration due to the following reason. Following the RPS actuation, control rod position indication for two control rods was indeterminate for approximately two minutes to the control room staff. A subsequent review of control rod position indication from the Plant Data Information System (PDIS), Rod Worth Minimizer (RWM) logs, and Auto Scram Timer (AST) data by Columbia Generating Station personnel shows that all rods were successfully inserted to the 'Full-in' position following the initial RPS actuation, assuring that the reactor was shutdown under all conditions. The Emergency Action Level for this Alert classification requires that the following three conditions be met: Any RPS set point (including manual) has been exceeded per T.S. 3.3.1.1 AND RPS actuation failed to result in a control rod pattern which alone always assures reactor shutdown under all conditions AND Manual actions (mode switch in shutdown, manual push buttons, and ARI) result in reactor power LE 5%. Since all rods were successfully inserted without the assistance of any manual actions and within the Technical Specification required time, Columbia Generating Station staff now believes that no emergency classification should have been made, and we are retracting the Alert emergency classification from this event notification. The problem with control rod position indication following the scram is being addressed through our corrective action program. The licensee notified the NRC Resident Inspector and will notify local, State, and other Government Agencies of this update. Notified R4 DO (Runyan). |
| Where | |
|---|---|
Columbia Generating Station  Washington (NRC Region 4) | |
| Reporting | |
| Emergency class: | Alert |
| 10 CFR 50.72(a) (1) (i), Emergency Class Declaration 10 CFR 50.72(b)(2)(iv)(B), RPS Actuation | |
| Time - Person (Reporting Time:+-3.03 h-0.126 days <br />-0.018 weeks <br />-0.00415 months <br />) | |
| Opened: | Arthur Moore 13:58 Jul 30, 2004 |
| NRC Officer: | Howie Crouch |
| Last Updated: | Aug 3, 2004 |
| 40910 - NRC Website | |
Unit 2 | |
|---|---|
| Reactor critical | Critical |
| Scram | A/R |
| Before | Power Operation (100 %) |
| After | Hot Shutdown (0 %) |
Columbia with 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(a)(1)(i), Emergency Class Declaration | |
WEEKMONTHYEARENS 534102018-05-18T13:51:00018 May 2018 13:51:00
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