ENS 53622

v t e ENS Event
05:00 Sep 25, 2018
Title	Control Building Chillers in Unanalyzed Condition
Event Description	At 1200 CDT on September 25, 2018, while the plant was in MODE 1 at 90 percent power, it was identified that an additional condition existed which had not previously been considered in developing the compensatory measures implemented for design flaws and single point vulnerabilities associated with the Control Building Chilled Water System. Specifically, a 20 minute 'quick restart timer' on Control Building Chillers that have analog control systems (HVK-CHL1A & 1B) would prevent the chillers from starting in specific scenarios. The recommended compensatory actions to address the new condition were implemented at 1235 CDT on September 25, 2018. Currently the Chilled Water System is otherwise operating as designed. Operator actions are in place to ensure the plant meets all required design safety system functions. Work is currently underway to identify and correct all design vulnerabilities. The [NRC] Senior Resident Inspector has been notified. This was identified by engineering during an extended condition search.

ENS 53622 +/-
Where
River Bend Louisiana (NRC Region 4)
Reporting

10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident
Time - Person (Reporting Time:+15.42 h0.643 days <br />0.0918 weeks <br />0.0211 months <br />)
Opened:	Jason Bush 20:25 Sep 25, 2018
NRC Officer:	Ossy Font
Last Updated:	Sep 25, 2018
53622 - NRC Website
v • d • e

v t e Emergency Notification System
River Bend with 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident, 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition
WEEKMONTHYEAR2022-09-19T06:32:00 [Table view]
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