ENS 52646
ENS Event | |
|---|---|
00:57 Mar 29, 2017 | |
| Title | Unanalyzed Condition For A Postulated Moderate Energy Line Break |
| Event Description | On March 28, 2017 at approximately 1957 CDT, a condition was discovered whereby a postulated moderate-energy line break (MELB) involving three fire protection (FP) pipe segments in the Safeguards Building did not contain MELB shielding. It was subsequently determined a postulated crack in one of the affected FP piping sections could adversely affect circuitry associated with the cooling support system for the train A RHR [Residual Heat Removal] pump room, potentially causing the ventilation system to be unavailable to support operation of the train A RHR pump. This condition is not consistent with the CPNPP licensing basis for the protection of essential safe shutdown RHR equipment.
At approximately 1957 CDT train A RHR was declared inoperable but available and the unit entered a seventy-two hour LCO [Limiting Condition for Operation] Action Statement per Technical Specification 3.5.2 B pending completion of mitigative actions. Since Unit 1 train B RHR system components and related supporting equipment have been periodically declared inoperable at various times in the last three years for surveillance testing or maintenance, given the MELB condition, both trains of RHR and or support equipment could have been inoperable and this represents an unanalyzed condition per 10 CFR 50.72(b)(3)(ii)(B). At the time of discovery, train B RHR and support equipment were operable. Therefore, the identified condition is not reportable as a loss of safety function per 10 CFR 50.72(b)(3)(v). The Senior NRC Resident Inspector has been notified. Compensatory actions will include installing a spray shield on the affected cable trays.
On 03/29/2017 Comanche Peak reported an ENS Report (no. 52646) related to the identification of potential moderate-energy line break (MELB) considerations in the Safeguards Building and the potential for adverse interaction with specified Unit 1 electrical equipment. The specific interactions of concern were related to ventilation equipment which would support operation of the Unit 1 A RHR train and several segments of fire protection piping. Subsequent investigations by Engineering have determined: (1) all but one of the suspected potential interactions were determined to not be credible, i.e., the potential MELB would not result in an adverse interaction with the 'target' equipment, and (2) for the remaining potential interaction, an assessment of piping stresses determined there was not a credible MELB source in the affected piping segment and therefore there was not a potential for adverse interaction with the ventilation support equipment. Based on the above, the condition described in ENS report no. 52646 is not considered to be an un-analyzed condition as described in 10 CFR 50.72(b)(3)(ii)(B). The licensee informed the NRC Resident Inspector. Notified the R4DO (Groom). |
| Where | |
|---|---|
Comanche Peak  Texas (NRC Region 4) | |
| Reporting | |
| 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition | |
| Time - Person (Reporting Time:+2.52 h0.105 days <br />0.015 weeks <br />0.00345 months <br />) | |
| Opened: | Raul Martinez 03:28 Mar 29, 2017 |
| NRC Officer: | Mark Abramovitz |
| Last Updated: | May 23, 2017 |
| 52646 - NRC Website
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Unit 1 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (100 %) |
| After | Power Operation (100 %) |
WEEKMONTHYEARENS 528172017-06-21T15:00:00021 June 2017 15:00:00
[Table view]10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Postulated Fire Event Could Adversely Impact Safe Shutdown Equipment ENS 526462017-03-29T00:57:00029 March 2017 00:57:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Unanalyzed Condition for a Postulated Moderate Energy Line Break ENS 524842017-01-11T21:00:00011 January 2017 21:00:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Teflon Found in Containment Spray Pump Components ENS 522442016-09-15T20:40:00015 September 2016 20:40:00 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, 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Potential Degradation of Eccs Pump Pressure Indicators ENS 522392016-09-13T22:30:00013 September 2016 22:30:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Unanalyzed Condition Involving Station Service Water Trains ENS 522172016-09-01T15:25:0001 September 2016 15:25:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Unanalyzed Condition on Turbine Driven Auxiliary Feedwater Pump ENS 517512016-02-23T23:00:00023 February 2016 23:00:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Unanalyzed Condition Involving Normally Open Battery Room Doors ENS 508352015-02-19T22:00:00019 February 2015 22:00:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Unanalyzed Condition Involving Normally Closed Watertight Doors ENS 500432014-04-18T17:52:00018 April 2014 17:52:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Cable Routing Unanalyzed for Fire Safe Shutdown Barrier ENS 494192013-10-08T17:40:0008 October 2013 17:40:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Postulated Hot Short Fire Event That Could Adversely Impact Safe Shutdown Equipment ENS 477132012-03-01T23:05:0001 March 2012 23:05:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Battery Room Ventilation System Degraded ENS 473572011-10-20T01:02:00020 October 2011 01:02:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Unanalyzed Condition Due to Pressure Instruments Containing Aluminum Material ENS 473522011-10-18T20:45:00018 October 2011 20:45:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Aluminum Valve Discovered Installed in Containment ENS 470862011-07-21T16:53:00021 July 2011 16:53:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Vulnerability from a Potential Control Room Fire on "a" Safeguards Bus ENS 435622007-08-13T14:00:00013 August 2007 14:00:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Inadequate Fire Protection on Safety Chilled Water System Electrical Cables 2017-06-21T15:00:00 | |