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The following event description is based oThe following event description is based on information currently available. If through subsequent reviews of this event, additional information is identified that is pertinent to this event or alters the information being provided at this time, a follow-up notification will be made via the ENS or under the reporting requirements of 10CFR50.73.</br>On January 19, 2011, at approximately 1840 Mountain Standard Time (MST), Palo Verde Unit 3 received a Reactor Power Cutback (RPCB) due to the 'B' Main Feedwater Pump (MFP) tripping on low suction pressure in response to the 'A' MFP mini-flow valve failing open. Reactor power lowered to approximately 60% in response to the RPCB. Steam Generator levels continued to decrease and a Reactor Trip occurred on Low Steam Generator #1 level at 18:41. Unit 3 was at normal operating temperature and pressure prior to the trip. Following the automatic reactor trip all CEAs (Control Element Assemblies) inserted fully into the reactor core. No emergency classification was required per the Emergency Plan. An AFAS-2 (Auxiliary Feedwater Actuation Signal) occurred at 1844 on low Steam Generator #2 level. Safety related busses remained energized during and following the reactor trip. The Emergency Diesel Generators started in response to the AFAS-2 actuation but did not energize the class 4.16kV buses as they remained energized from off-site power. The offsite power grid is stable. No major equipment was inoperable prior to the event that contributed to the event.</br>Unit 3 is stable at normal operating temperature and pressure in Mode 3 feeding the steam generators with Auxiliary Feedwater pump 'B'. The event did not result in any challenges to fission product barriers and there were no adverse safety consequences as a result of this event. The event did not adversely affect the safe operation of the plant or the health and safety of the public.</br>The (NRC) Senior Resident Inspector was informed of the Unit 3 reactor trip.</br>Unit 3 is in a normal post-trip electrical lineup. Decay heat is being removed via the turbine bypass valves to the main condenser. No safety valves on the secondary or primary side opened.s on the secondary or primary side opened.  
01:41:00, 20 January 2011  +
46,556  +
00:08:00, 20 January 2011  +
01:41:00, 20 January 2011  +
The following event description is based oThe following event description is based on information currently available. If through subsequent reviews of this event, additional information is identified that is pertinent to this event or alters the information being provided at this time, a follow-up notification will be made via the ENS or under the reporting requirements of 10CFR50.73.</br>On January 19, 2011, at approximately 1840 Mountain Standard Time (MST), Palo Verde Unit 3 received a Reactor Power Cutback (RPCB) due to the 'B' Main Feedwater Pump (MFP) tripping on low suction pressure in response to the 'A' MFP mini-flow valve failing open. Reactor power lowered to approximately 60% in response to the RPCB. Steam Generator levels continued to decrease and a Reactor Trip occurred on Low Steam Generator #1 level at 18:41. Unit 3 was at normal operating temperature and pressure prior to the trip. Following the automatic reactor trip all CEAs (Control Element Assemblies) inserted fully into the reactor core. No emergency classification was required per the Emergency Plan. An AFAS-2 (Auxiliary Feedwater Actuation Signal) occurred at 1844 on low Steam Generator #2 level. Safety related busses remained energized during and following the reactor trip. The Emergency Diesel Generators started in response to the AFAS-2 actuation but did not energize the class 4.16kV buses as they remained energized from off-site power. The offsite power grid is stable. No major equipment was inoperable prior to the event that contributed to the event.</br>Unit 3 is stable at normal operating temperature and pressure in Mode 3 feeding the steam generators with Auxiliary Feedwater pump 'B'. The event did not result in any challenges to fission product barriers and there were no adverse safety consequences as a result of this event. The event did not adversely affect the safe operation of the plant or the health and safety of the public.</br>The (NRC) Senior Resident Inspector was informed of the Unit 3 reactor trip.</br>Unit 3 is in a normal post-trip electrical lineup. Decay heat is being removed via the turbine bypass valves to the main condenser. No safety valves on the secondary or primary side opened.s on the secondary or primary side opened.  
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02:08:01, 2 March 2018  +
00:08:00, 20 January 2011  +
-0.0646 d (-1.55 hours, -0.00923 weeks, -0.00212 months)  +
01:41:00, 20 January 2011  +
Reactor Trip Due to Main Feedwater Pump Trip  +
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