ENS 50227: Difference between revisions

From kanterella

Latest revision as of 20:50, 1 March 2018

v t e ENS Event
20:55 Jun 25, 2014
Title	Potential Loss of Ultimate Heat Sink Capacity Due to Low Level
Event Description	At approximately 1555 CDT on Wednesday, June 25, 2014, during a review of several station abnormal operating procedures for actions related to low ultimate heat sink (UHS) level, it was discovered that the procedures do not incorporate design assumptions for shutting down the non-essential service water (WS) pumps following a loss of cooling lake dike. The pumps that take suction from the UHS include the WS, circulating water (CW) and fire protection (FP) pumps. Based on current procedural guidance, the only pumps that are secured due to a low ultimate heat sink level are the circulating water (CW) pumps based on low net positive suction (NPSH) Failing to secure the non-essential pumps on a loss of cooling lake dike failure significantly reduces the 30 day design basis UHS volume to approximately 4 days. This event is being reported in accordance with 10CFR50.72(b)(3)(ii)(B) for 'any event or condition that results in the nuclear power plant being in an unanalyzed condition that significantly degrades plant safety.' Immediate actions taken included issuance of an operations standing order providing direction to secure non-essential pumps on the failure of the cooling lake dike. Proposed corrective actions include procedure revisions. The licensee has notified the NRC Resident Inspector.

ENS 50227 +/-
Where
Braidwood Illinois (NRC Region 3)
Reporting

10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition
Time - Person (Reporting Time:+2.07 h0.0863 days <br />0.0123 weeks <br />0.00284 months <br />)
Opened:	Joe Conquest 22:59 Jun 25, 2014
NRC Officer:	Jeff Rotton
Last Updated:	Jun 25, 2014
50227 - NRC Website Loading map...
v • d • e

v t e Emergency Notification System
Braidwood with 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition
WEEKMONTHYEAR2016-05-25T19:15:00 [Table view]
[ENS list for Braidwood]

@@ Line 16: / Line 16: @@
 | event date = 06/25/2014 15:55 CDT
 | last update date = 06/25/2014
-| title = Potential Loss Of Ultimate Heat Sink Capacity Due To Low Level
+| title = Potential Loss of Ultimate Heat Sink Capacity Due to Low Level
 | event text = At approximately 1555 CDT on Wednesday, June 25, 2014, during a review of several station abnormal operating procedures for actions related to low ultimate heat sink (UHS) level, it was discovered that the procedures do not incorporate design assumptions for shutting down the non-essential service water (WS) pumps following a loss of cooling lake dike. The pumps that take suction from the UHS include the WS, circulating water (CW) and fire protection (FP) pumps. Based on current procedural guidance, the only pumps that are secured due to a low ultimate heat sink level are the circulating water (CW) pumps based on low net positive suction (NPSH)
 Failing to secure the non-essential pumps on a loss of cooling lake dike failure significantly reduces the 30 day design basis UHS volume to approximately 4 days.