ENS 50404: Difference between revisions

v t e ENS Event
22:30 Aug 26, 2014
Title	Turbine Generator Neutral Overvoltage Causes a Reactor Scram
Event Description	At 1730 CDT on August 26, 2014, Browns Ferry Unit 1 experienced a turbine trip resulting in an automatic reactor scram. The cause of the turbine trip was a control valve fast closure signal that was generated by a turbine trip on generator neutral over voltage signal. The Main Steam Isolation Valves (MSIVs) remained open with the main turbine bypass valves controlling reactor pressure. The Reactor Feedwater Pumps are in service to control reactor water level. Primary Containment Isolation Systems (PCIS) Groups 2, 3, 6, and 8 isolation signals were received. Upon receipt of these signals, all required components actuated as required with the exception of Standby Gas Treatment (SBGT) train A, which is under a clearance for planned maintenance. Neither High Pressure Coolant Injection (HPCI) nor Reactor Core Isolation Cooling (RCIC) initiation signals were received. Initially, three Main Steam Relief Valves (MSRVs) opened to control the pressure surge and subsequently reclosed. This event requires a 4 hour4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> report per 10 CFR 50.72(b)(2)(iv)(B), 'Any event or condition that results in actuation of the reactor protection system (RPS) when the reactor is critical except when the actuation results from and is part of a pre-planned sequence during testing or reactor operation.' This event also requires an 8 hour9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> report per 10 CFR 50.72(b)(3)(iv)(A), 'Any event or condition that results in valid actuation of any of the systems listed in paragraph (b)(3)(iv)(B), (1) Reactor protection system (RPS) including reactor scram or reactor trip, and (2) General containment Isolation signals affecting containment isolation valves in more than one system or multiple main steam isolation valves (MSIVs).' The NRC Resident Inspector has been notified. Service Request 926468 was initiated in the Corrective Action Program. The plant is in its normal shutdown electrical lineup. The licensee is investigating the cause of the generator neutral overvoltage signal. There was no impact on units 2 and 3.

ENS 50404 +/-
Where
Browns Ferry Alabama (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:+-1.1 h-0.0458 days <br />-0.00655 weeks <br />-0.00151 months <br />)
Opened:	Neel Shukla 21:24 Aug 26, 2014
NRC Officer:	Mark Abramovitz
Last Updated:	Aug 26, 2014
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v • d • e

v t e Emergency Notification System
Browns Ferry with 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation
WEEKMONTHYEAR2024-08-30T15:51:00 [Table view]
[ENS list for Browns Ferry]

@@ Line 16: / Line 16: @@
 | event date = 08/26/2014 17:30 CDT
 | last update date = 08/26/2014
-| title = Turbine Generator Neutral Overvoltage Causes A Reactor Scram
+| title = Turbine Generator Neutral Overvoltage Causes a Reactor Scram
 | event text = At 1730 CDT on August 26, 2014, Browns Ferry Unit 1 experienced a turbine trip resulting in an automatic reactor scram.  The cause of the turbine trip was a control valve fast closure signal that was generated by a turbine trip on generator neutral over voltage signal.  The Main Steam Isolation Valves (MSIVs) remained open with the main turbine bypass valves controlling reactor pressure.  The Reactor Feedwater Pumps are in service to control reactor water level.
 Primary Containment Isolation Systems (PCIS) Groups 2, 3, 6, and 8 isolation signals were received.  Upon receipt of these signals, all required components actuated as required with the exception of Standby Gas Treatment (SBGT) train A, which is under a clearance for planned maintenance.  Neither High Pressure Coolant Injection (HPCI) nor Reactor Core Isolation Cooling (RCIC) initiation signals were received.  Initially, three Main Steam Relief Valves (MSRVs) opened to control the pressure surge and subsequently reclosed.

v t e Unit 1
GE-4
Reactor critical	Critical
Scram	A/R
Before	Power Operation (95 %)
After	Hot Shutdown (0 %)

ENS 50404: Difference between revisions

Latest revision as of 20:49, 1 March 2018

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ENS 50404: Difference between revisions

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