ENS 50227
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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. |
| 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 | |
Unit 1 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (100 %) |
| After | Power Operation (100 %) |
Unit 2 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (100 %) |
| After | Power Operation (100 %) |
WEEKMONTHYEARENS 519592016-05-25T19:15:00025 May 2016 19:15:00
[Table view]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 Discovery of Non-Conforming Conditions During Tornado Hazards Analysis ENS 517712016-03-07T02:00:0007 March 2016 02:00:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Unanalyzed Condition Involving Diesel Driven Auxiliary Feedwater Pump Air Intakes ENS 513342015-08-20T22:10:00020 August 2015 22:10:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Condition That Could Prevent Pressurizer Porv Block Valves from Operating ENS 502822014-07-15T14:42:00015 July 2014 14:42:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Unanalyzed Condition - Low Containment Spray Flow Rate ENS 502272014-06-25T20:55:00025 June 2014 20:55:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Potential Loss of Ultimate Heat Sink Capacity Due to Low Level ENS 501892014-06-11T19:34:00011 June 2014 19:34:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition One Containment Spray Train Chemical Additive Flow Out of Specifications ENS 493712013-09-09T22:00:0009 September 2013 22:00:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Unanalyzed Leakage of Containment System Isolation Valve Controlled Leakage Devices ENS 468682011-05-20T23:00:00020 May 2011 23:00:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Unanalyzed Condition Marine Life Inside Afw Piping ENS 467072011-03-30T01:00:00030 March 2011 01:00:00 10 CFR 50.72(b)(3)(v)(B), Loss of Safety Function - Remove Residual Heat, 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Potential Voiding in Auxiliary Feedwater Alternate Suction Line ENS 464152010-11-12T19:00:00012 November 2010 19:00:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Inaccurate Information Provided in License Amendment Request ENS 462032010-08-24T16:40:00024 August 2010 16:40:00 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 Essential Service Water Placed in a Line-Up That May Have Prevented Its Safety Function ENS 460212010-06-17T10:19:00017 June 2010 10:19:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Unanalyzed Condition Due to Containment Spray Recirc Sump Isolation Valve Failure to Stroke Closed 2016-05-25T19:15:00 | |
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