ENS 50878: Difference between revisions

v t e ENS Event
10:21 Mar 11, 2015
Title	Automatic Reactor Trip Due to a Nuclear Instrumentation Signal
Event Description	At [0621 EDT] on 3/11/2015, Sequoyah Unit 1 reactor/turbine automatically tripped. Following the reactor trip, all safety-related equipment operated as designed. Auxiliary Feedwater automatically initiated as expected from the Feedwater Isolation Signal. Unit 1 is currently being maintained in Mode 3 at NOT/NOP, approximately 547 F and 2235 psig, with auxiliary feedwater supplying decay heat removal via the steam generators and condenser steam dumps. The immediate cause of the trip was a Power Range Nuclear Instrumentation negative rate signal, caused by a malfunction in the rod control system. There was no associated work in progress related to this and all systems were normally aligned. Current Temperature and Pressure - temperature is 547 degrees F and stable, pressure is 2235 psig and stable. There is no indication of any primary/secondary leakage. All rods are inserted. Electrical alignment is normal, supplied from Off-Site power. There is no operational impact to Unit 2. Unit 2 continues to operate in Mode 1 at 100%. There was no impact on public health and safety. Post-trip investigation is in progress and planned restart timeline has not yet been determined. The licensee notified the NRC Resident Inspector.

ENS 50878 +/-
Where
Sequoyah Tennessee (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:+-0.85 h-0.0354 days <br />-0.00506 weeks <br />-0.00116 months <br />)
Opened:	Matt Jungels 09:30 Mar 11, 2015
NRC Officer:	Vince Klco
Last Updated:	Mar 11, 2015
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v • d • e

v t e Emergency Notification System
Sequoyah with 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation
WEEKMONTHYEAR2021-05-24T13:16:00 [Table view]
[ENS list for Sequoyah]

@@ Line 16: / Line 16: @@
 | event date = 03/11/2015 06:21 EDT
 | last update date = 03/11/2015
-| title = Automatic Reactor Trip Due To A Nuclear Instrumentation Signal
+| title = Automatic Reactor Trip Due to a Nuclear Instrumentation Signal
 | event text = At [0621 EDT] on 3/11/2015,  Sequoyah Unit 1 reactor/turbine automatically tripped.
 Following the reactor trip, all safety-related equipment operated as designed.  Auxiliary Feedwater automatically initiated as expected from the Feedwater Isolation Signal.

Latest revision as of 21:48, 1 March 2018