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Invalid actuation of ECCS for boiling wate … Invalid actuation of ECCS for boiling water reactors (BWRs) including: high-pressure and low-pressure core spray systems; high pressure coolant injection system; low pressure injection function of the residual heat removal system.</br>The following information is provided as a 60 day telephone notification to NRC under 10 CFR 50.73(a)(1) in lieu of submitting a written LER to report a condition that resulted in an invalid actuation of the 10CFR50.73(a)(2)(iv)(B) system checked above. NUREG1022 Revision 2 identifies the information that needs to be reported as discussed below.</br>This report is being made under 10CFR50.73(a)(2)(iv)(A). On April 16, 2010, at 1717 EDT, Unit 1 received a false ECCS (Emergency Core Cooling System) Loss Of Cooling Accident (LOCA) signal on high drywell pressure. Based on plant data, all plant conditions were normal prior to event. Investigation identified an ATTS Slave Card failed in one of the Card File Racks. The Card File Rack contains ten (10) cards with two (2) being Master Trip Units (MTUs) that actuate on high drywell pressure. For initiation of an ECCS LOCA signal, both of the MTUs in the card file rack would have had to actuate. Cause of the event appears to be a momentary drop in supply voltage on the card file rack due to the failed slave card that lowered the set point of the MTUs to a point where they tripped. The set point is an internal voltage setting within the MTU. The failed ATTS cards have been replaced.</br>Actuations: Core Spray A and B pumps started; Residual Heat Removal A, B, C, D pumps started; Diesel Generator 1A, 1B, and 1C started; Standby Plant Service Water Pump started; Plant Service Water 1A pump started (it had been in standby); Plant Service Water Valves 1P41-F310A, B, C, D closed (These are the Turbine Building isolation valves); Turbine Building Chiller B tripped; Main Control Room Environmental Control trains A and B started; HPCI Started but was secured prior to injection; Cooling Tower fans on towers A, B, C tripped. </br>Reactor Water Level was normal at +37 inches and the highest Drywell Pressure indicated was 1.25 psig.</br>The licensee has notified the NRC Resident Inspector.e has notified the NRC Resident Inspector.
23:15:00, 16 April 2010 +
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11:03:00, 7 June 2010 +
23:15:00, 16 April 2010 +
Invalid actuation of ECCS for boiling wate … Invalid actuation of ECCS for boiling water reactors (BWRs) including: high-pressure and low-pressure core spray systems; high pressure coolant injection system; low pressure injection function of the residual heat removal system.</br>The following information is provided as a 60 day telephone notification to NRC under 10 CFR 50.73(a)(1) in lieu of submitting a written LER to report a condition that resulted in an invalid actuation of the 10CFR50.73(a)(2)(iv)(B) system checked above. NUREG1022 Revision 2 identifies the information that needs to be reported as discussed below.</br>This report is being made under 10CFR50.73(a)(2)(iv)(A). On April 16, 2010, at 1717 EDT, Unit 1 received a false ECCS (Emergency Core Cooling System) Loss Of Cooling Accident (LOCA) signal on high drywell pressure. Based on plant data, all plant conditions were normal prior to event. Investigation identified an ATTS Slave Card failed in one of the Card File Racks. The Card File Rack contains ten (10) cards with two (2) being Master Trip Units (MTUs) that actuate on high drywell pressure. For initiation of an ECCS LOCA signal, both of the MTUs in the card file rack would have had to actuate. Cause of the event appears to be a momentary drop in supply voltage on the card file rack due to the failed slave card that lowered the set point of the MTUs to a point where they tripped. The set point is an internal voltage setting within the MTU. The failed ATTS cards have been replaced.</br>Actuations: Core Spray A and B pumps started; Residual Heat Removal A, B, C, D pumps started; Diesel Generator 1A, 1B, and 1C started; Standby Plant Service Water Pump started; Plant Service Water 1A pump started (it had been in standby); Plant Service Water Valves 1P41-F310A, B, C, D closed (These are the Turbine Building isolation valves); Turbine Building Chiller B tripped; Main Control Room Environmental Control trains A and B started; HPCI Started but was secured prior to injection; Cooling Tower fans on towers A, B, C tripped. </br>Reactor Water Level was normal at +37 inches and the highest Drywell Pressure indicated was 1.25 psig.</br>The licensee has notified the NRC Resident Inspector.e has notified the NRC Resident Inspector.
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