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This telephone notification is provided in … This telephone notification is provided in accordance with 10 CFR 50.73(a)(1), to report an invalid actuation reportable under 10 CER 50.73(a)(2)(iv)(A).</br>On March 3, 2007, Unit 2 was in a refueling outage. Reactor penetration nozzles were being flushed to remove crud deposits. At 0814 CST, Low Reactor Vessel Level 1, Level 2, and Level 3 alarms were received in the Main Control Room, and the Division 1 Emergency Core Cooling System (ECCS) initiated. The Low Pressure Core Spray (LPCS) pump started on the ECCS initiation signal and injected into the Unit 2 reactor vessel. In addition, the '0' Diesel Generator auto-started, and the Low Pressure Coolant Injection valve (2E12-F042A) auto-opened.</br>Operators verified that reactor vessel and reactor cavity water levels were normal, and then stopped the ECCS injection into the vessel by placing the LPCS pump control switch in pull-to-lock. ECCS is not required to be operable in Mode 5 with the spent fuel pool storage gates removed and water level greater than or equal to 22 feet above the Reactor Pressure Vessel (RPV) flange.</br>Investigation determined that the low reactor vessel water level signal occurred when the flushing wand was inserted into instrument nozzle N14A, which is the reference leg tap for the reactor vessel level instruments. The transient in differential pressure sensed by the level instruments resulted in the invalid actuation.</br>Corrective actions included a revision to the model work order for this task to clearly identify the nozzles that shall and shall not be flushed during this evolution.</br>This event is reportable under 10 CFR 50.73(a)(2)(iv)(A) as an invalid ECCS actuation and invalid system actuation.</br>The licensee notified the NRC Resident Inspector.ensee notified the NRC Resident Inspector. +
13:14:00, 3 March 2007 +
43,333 +
13:17:00, 1 May 2007 +
13:14:00, 3 March 2007 +
This telephone notification is provided in … This telephone notification is provided in accordance with 10 CFR 50.73(a)(1), to report an invalid actuation reportable under 10 CER 50.73(a)(2)(iv)(A).</br>On March 3, 2007, Unit 2 was in a refueling outage. Reactor penetration nozzles were being flushed to remove crud deposits. At 0814 CST, Low Reactor Vessel Level 1, Level 2, and Level 3 alarms were received in the Main Control Room, and the Division 1 Emergency Core Cooling System (ECCS) initiated. The Low Pressure Core Spray (LPCS) pump started on the ECCS initiation signal and injected into the Unit 2 reactor vessel. In addition, the '0' Diesel Generator auto-started, and the Low Pressure Coolant Injection valve (2E12-F042A) auto-opened.</br>Operators verified that reactor vessel and reactor cavity water levels were normal, and then stopped the ECCS injection into the vessel by placing the LPCS pump control switch in pull-to-lock. ECCS is not required to be operable in Mode 5 with the spent fuel pool storage gates removed and water level greater than or equal to 22 feet above the Reactor Pressure Vessel (RPV) flange.</br>Investigation determined that the low reactor vessel water level signal occurred when the flushing wand was inserted into instrument nozzle N14A, which is the reference leg tap for the reactor vessel level instruments. The transient in differential pressure sensed by the level instruments resulted in the invalid actuation.</br>Corrective actions included a revision to the model work order for this task to clearly identify the nozzles that shall and shall not be flushed during this evolution.</br>This event is reportable under 10 CFR 50.73(a)(2)(iv)(A) as an invalid ECCS actuation and invalid system actuation.</br>The licensee notified the NRC Resident Inspector.ensee notified the NRC Resident Inspector. +
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00:00:00, 1 May 2007 +
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22:36:52, 24 September 2017 +
13:17:00, 1 May 2007 +
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59.044 d (1,417.05 hours, 8.435 weeks, 1.941 months) +
13:14:00, 3 March 2007 +
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