ENS 53767: Difference between revisions

v t e ENS Event
06:00 Dec 3, 2018
Title	Actuation of Blackout Sequencers Due to Loss of One Offsite Power Source
Event Description	At 0315 [CST] on 12/3/18, the Comanche Peak Nuclear Power Plant experienced a loss of 138 KV transformer XST1. Unit 1 is currently at 100% power. Unit 2 was subjected to actuation of both blackout sequencers causing an automatic start of both motor driven Auxiliary Feedwater (AFW) pumps as well as the turbine driven AFW pump. No emergency diesel generators started as per design. Train A and B motor driven and the turbine driven AFW pumps have been returned to automatic. All other safety systems functioned per design. The loss of power to 138 KV transformer XST1 resulted in loss of power to both safeguards busses on Unit 2. The busses performed a load-shed and slow transfer to power supplied from 345 KV transformer XST2A as designed and were re-energized and loads sequenced back onto the busses. The emergency diesel generators are not required to start unless the busses are not re-energized by the alternate offsite transformer. All electrical power related actuations functioned as designed. There was no impact on Unit 1. The licensee has notified the NRC Resident Inspector.

ENS 53767 +/-
Where
Comanche Peak Texas (NRC Region 4)
Reporting

10 CFR 50.72(b)(3)(iv)(A), System Actuation
Time - Person (Reporting Time:+5.25 h0.219 days <br />0.0312 weeks <br />0.00719 months <br />)
Opened:	Brian Mitchell 11:15 Dec 3, 2018
NRC Officer:	Karen Cotton
Last Updated:	Dec 3, 2018
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v • d • e

v t e Emergency Notification System
Comanche Peak with 10 CFR 50.72(b)(3)(iv)(A), System Actuation
WEEKMONTHYEAR2024-03-17T20:15:00 [Table view]
[ENS list for Comanche Peak]

@@ Line 20: / Line 20: @@
 No emergency diesel generators started as per design.  Train A and B motor driven and the turbine driven AFW pumps have been returned to automatic.  All other safety systems functioned per design.
 The loss of power to 138 KV transformer XST1 resulted in loss of power to both safeguards busses on Unit 2.  The busses performed a load-shed and slow transfer to power supplied from 345 KV transformer XST2A as designed and were re-energized and loads sequenced back onto the busses.  The emergency diesel generators are not required to start unless the busses are not re-energized by the alternate offsite transformer. All electrical power related actuations functioned as designed. There was no impact on Unit 1.
-The licensee has notified the NRC Resident Inspector."
+The licensee has notified the NRC Resident Inspector.
 | URL = https://www.nrc.gov/reading-rm/doc-collections/event-status/event/2018/20181204en.html#en53767
 }}{{unit info

Latest revision as of 23:58, 23 February 2020