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Both U-1 and U-2 automatically tripped due … Both U-1 and U-2 automatically tripped due to valid actuation of the Reactor Protection Systems (RPS). U-1 due to loss of 12B Reactor Coolant Pump (RCP) which resulted in a RCS Low Flow RPS Trip. Cause for loss of 12B RCP is currently not known but is suspected to be related to the electrical transient that occurred on U-2. U-2 tripped due to Loss of Load RPS Trip when the main turbine tripped due to an electrical malfunction and partial loss of offsite power. The electrical malfunction resulted in loss of power to all 4 Kv buses on U-2 with the exception of 21 4Kv bus (ZA train power) (Lost 22-26 4Kv buses) and the loss of 14 Kv bus (ZB train power) on U-1. All the buses lost are powered from the same in house service transformer, P-13000-2, which was lost due to the electrical transient. Cause of the electrical transient is being pursued but is unknown at this time. Loss of the 14 4Kv bus on U-1 and the 24 4Kv bus on U-2 resulted in an Engineered Safeguards Actuation System (ESFAS) valid actuations on both units due to Under Voltage (UV) conditions on those buses. The 1B (Diesel Generator) DG started automatically due to the 14 bus UV and is carrying that bus. The 2B DG received an automatic start signal due to the 24 bus UV but failed to start as expected. No other system actuations occurred. Both units are currently stable in Mode 3 at normal operating temperature (532 degrees) and pressure (2250 PSIA) with no other significant equipment malfunctions. Due to the loss of P-13000-2 (transformer), U-2 sustained a loss of normal heat removal due to loss of the main condenser cooling and the loss of secondary pumps. U-2 is removing heat with auxiliary feedwater pumps and (Steam Generator) SG atmospheric dump valves without issues. Current plans are to cool U-2 down to 445 degrees to maintain RCP seals cool until RCP's can be restarted. A decision on U-1 cool down has not yet been made.</br>There is no primary to secondary leakage. U-2 is currently in a 12 hour LCO due to the partial loss of offsite power and 2B DG failing to start. </br>The licensee has notified the NRC Resident Inspector.e has notified the NRC Resident Inspector.
13:24:00, 18 February 2010 +
45,709 +
11:47:00, 18 February 2010 +
13:24:00, 18 February 2010 +
Both U-1 and U-2 automatically tripped due … Both U-1 and U-2 automatically tripped due to valid actuation of the Reactor Protection Systems (RPS). U-1 due to loss of 12B Reactor Coolant Pump (RCP) which resulted in a RCS Low Flow RPS Trip. Cause for loss of 12B RCP is currently not known but is suspected to be related to the electrical transient that occurred on U-2. U-2 tripped due to Loss of Load RPS Trip when the main turbine tripped due to an electrical malfunction and partial loss of offsite power. The electrical malfunction resulted in loss of power to all 4 Kv buses on U-2 with the exception of 21 4Kv bus (ZA train power) (Lost 22-26 4Kv buses) and the loss of 14 Kv bus (ZB train power) on U-1. All the buses lost are powered from the same in house service transformer, P-13000-2, which was lost due to the electrical transient. Cause of the electrical transient is being pursued but is unknown at this time. Loss of the 14 4Kv bus on U-1 and the 24 4Kv bus on U-2 resulted in an Engineered Safeguards Actuation System (ESFAS) valid actuations on both units due to Under Voltage (UV) conditions on those buses. The 1B (Diesel Generator) DG started automatically due to the 14 bus UV and is carrying that bus. The 2B DG received an automatic start signal due to the 24 bus UV but failed to start as expected. No other system actuations occurred. Both units are currently stable in Mode 3 at normal operating temperature (532 degrees) and pressure (2250 PSIA) with no other significant equipment malfunctions. Due to the loss of P-13000-2 (transformer), U-2 sustained a loss of normal heat removal due to loss of the main condenser cooling and the loss of secondary pumps. U-2 is removing heat with auxiliary feedwater pumps and (Steam Generator) SG atmospheric dump valves without issues. Current plans are to cool U-2 down to 445 degrees to maintain RCP seals cool until RCP's can be restarted. A decision on U-1 cool down has not yet been made.</br>There is no primary to secondary leakage. U-2 is currently in a 12 hour LCO due to the partial loss of offsite power and 2B DG failing to start. </br>The licensee has notified the NRC Resident Inspector.e has notified the NRC Resident Inspector.
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Regarding Reactor Trip Due to Water Intrusion Into Switchgear Protective Circuitry +, 05000318/LER-2010-001, Regarding Reactor Trip Due to Partial Loss of Offsite Power +, 05000317/LER-2010-001, Regarding Reactor Trip Due to Water Intrusion Into Switchgear Protective Circuitry + and Regarding Reactor Trip Due to Partial Loss of Offsite Power +
00:00:00, 18 February 2010 +
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02:10:17, 2 March 2018 +
11:47:00, 18 February 2010 +
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-0.0675 d (-1.62 hours, -0.00964 weeks, -0.00222 months) +
13:24:00, 18 February 2010 +
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