ENS 40804
ENS Event | |
|---|---|
17:13 Jun 10, 2004 | |
| Title | Automatic Reactor Trip While Performing Scheduled Solid State Protection Testing |
| Event Description | A Unit 2 automatic reactor trip occurred while the licensee was performing planned periodic testing on train "A" solid state protection. All control rods fully inserted into the reactor core. The Auxiliary Feedwater Pumps automatically started as expected immediately following the reactor trip due to low-low level in the steam generators. The unit is being maintained stable in mode 3 and heat sink is being performed via steam dump to the condensers. All other systems functioned as required. The cause of the reactor trip is under investigation.
The licensee notified the NRC Resident Inspector.
This is an update to event notification 40804. At 1313 hours0.0152 days <br />0.365 hours <br />0.00217 weeks <br />4.995965e-4 months <br /> on June 10, 2004, North Anna Unit 2 experienced an automatic trip from 100 percent during the performance of 2-PT-36.1A (Train 'A' Reactor Protection and ESF Logic Actuation Logic Test). The cause of the reactor trip, was determined to be an incorrect configuration of the cell switch (52h contract) on 'A' Reactor Bypass Breaker, 2-EP-BKR-BYA. The incorrect cell switch configuration resulted in a turbine trip signal being generated during testing which resulted in a reactor trip signal being generated in the 'B' train Reactor Protection System. The Auxiliary Feedwater System actuated in response to the event. Control room personnel responded to the event in accordance with emergency procedure E-0, Reactor Trip or Safety Injection. The control room team stabilized the plant using ES-0.1 Reactor Trip recovery. The lowest Reactor Coolant System (RCS) pressure during the event was 1988 psig and the lowest RCS temperature was 549 degrees. No human performance issues were identified during this event. A non-emergency four-hour report was made to the NRC operations center at 1611 hours0.0186 days <br />0.448 hours <br />0.00266 weeks <br />6.129855e-4 months <br /> pursuant to 10CFR50.72(b)(2)(iv)(B) for an actuation of the Reactor Protection System while critical. An eight-hour report was also made to the NRC in accordance with 10CFR 50.72(b)(3)(iv)(A) due to the Auxiliary Feedwater Pump starts (Engineering Safety Features Actuation). The Reactor Protection System, AMSAC [ATWAS Mitigating System Actuation Circuit], and the Auxiliary Feedwater System operated properly in response to the event. During the Unit 2 reactor trip, a blown output fuse on a logic card (that feeds the permissive for arming the Steam Dumps from loss of load) prevented the Main Steam Dump Valves from opening in Tavg Mode as expected. The Steam Generator Power Operated Relief Valves (PORVs) lifted and operated to control RCS temperature until transferring Steam Dump control to the Steam Pressure Mode. The fuse was replaced. A post trip review was conducted at 1500 hours0.0174 days <br />0.417 hours <br />0.00248 weeks <br />5.7075e-4 months <br /> on June 10, 2004. The cell switches on the Reactor Trip Bypass breakers have been repaired and post maintenance testing has been completed. Management approval was granted to start-up Unit 2. North Anna Unit 2 is currently in Mode 1 and is preparing to be placed on-line. The licensee notified the NRC Resident Inspector. Notified R2DO (Lesser) and NRR EO (Bateman). |
| Where | |
|---|---|
North Anna  Virginia (NRC Region 2) | |
| Reporting | |
| 10 CFR 50.72(b)(2)(iv)(B), RPS Actuation 10 CFR 50.72(b)(3)(iv)(A), System Actuation | |
| Time - Person (Reporting Time:+-1.03 h-0.0429 days <br />-0.00613 weeks <br />-0.00141 months <br />) | |
| Opened: | Brad Brown 16:11 Jun 10, 2004 |
| NRC Officer: | Arlon Costa |
| Last Updated: | Jun 11, 2004 |
| 40804 - NRC Website
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Unit 2 | |
|---|---|
| Reactor critical | Critical |
| Scram | A/R |
| Before | Power Operation (100 %) |
| After | Hot Standby (0 %) |
North Anna with 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation | |
WEEKMONTHYEARENS 571482024-05-29T10:24:00029 May 2024 10:24:00
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ECCS Discharge Reactor Trip and Spurious Safety Injection ENS 432172007-03-07T08:05:0007 March 2007 08:05:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Emergency Diesel Generator Autostart on Loss of "B" Reserve Station Service Transformer ENS 430722007-01-03T23:03:0003 January 2007 23:03:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Reactor Trip Due to a Card Failure ENS 429962006-11-16T07:26:00016 November 2006 07:26:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Reactor Trip ENS 424832006-04-08T02:31:0008 April 2006 02:31:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Group Step Counter Failure During Reactor Startup ENS 418982005-08-06T02:28:0006 August 2005 02:28:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Reactor Trip Apparently Due to Lightning Strike ENS 408042004-06-10T17:13:00010 June 2004 17:13:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Reactor Trip While Performing Scheduled Solid State Protection Testing ENS 407842004-05-29T06:02:00029 May 2004 06:02:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Control Rod Position Indication Failure During Hot Rod Drop Test 2024-05-29T10:24:00 | |