ENS 46597
ENS Event | |
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15:18 Feb 7, 2011 | |
Title | High Energy Line Break Analysis for Aux Steam to the Auxiliary Building |
Event Description | On December 15, 2009, Callaway Plant reported a condition in which valve FBV0146, an isolation valve on an auxiliary steam line in the Auxiliary Building, was found to be kept normally open. With FBV0146 open, the auxiliary steam line downstream of FBV0146 must be considered a high energy line. This configuration was not consistent with the analysis of record for High Energy Line Break (HELB) events. Valve FBV0146 was closed upon discovery of the condition.
This condition was reported under EN # 45571 as an unanalyzed condition that significantly degrades plant safety. EN #45571 was then retracted on January 21, 2010 when analysis showed that no safety-related components would be rendered inoperable in a postulated HELB event due to the condition. Based on this analysis, FBV0146 was reopened. Subsequent review of this condition now shows that, with FCV0146 open, a harsh environment from a postulated HELB downstream of FBV0146 could be transmitted to other areas of the Auxiliary Building. This would occur via a flow path through door gaps and an Auxiliary Building elevator shaft. This flow path had not been considered by the previous analysis. The areas that could be affected by a postulated line break contain safe shutdown equipment (such as equipment for the Component Cooling Water system) that is not assumed to experience harsh conditions. Because of the potential impact on this equipment, this condition is considered to have met the criteria for reporting under 10 CFR 50.72(b)(3)(ii)(B). FBV0146 is now closed. This review was performed as part of the ongoing evaluation of HELB Program deficiencies described in Callaway Plant License Event Report (LER) 2010-009-00. The NRC Resident Inspector has been notified. The auxiliary steam line in the Auxiliary Building feeds non-safety related components.
The licensee is retracting this report based on the following: On 02/07/2011, EN #46597 documented that a harsh environment from a postulated High Energy Line Break (HELB) could be transmitted to areas of the Auxiliary Building not qualified for harsh environments. This break was postulated to occur on an Auxiliary Steam line downstream of valve FBV0146 when FBV0146 is open. This condition was initially reported as an unanalyzed condition that significantly degraded plant safety. When EN #46597 was reported, the analysis of the Auxiliary Steam line included postulated break locations at any intermediate fitting, welded attachment, or valve. Subsequent analysis shows that this section of Auxiliary Steam piping is able to withstand safe shutdown earthquake (SSE) loadings and rupture loadings. For piping of this qualification, line breaks are only assumed to occur at terminal ends and at the locations specified for ASME Class 2 and 3 piping. Breaks at intermediate fittings, welded attachments, and valves are not required to be assumed. Postulated breaks of this Auxiliary Steam line at the locations described above have been analyzed. This analysis demonstrates reasonable assurance that safety-related equipment would have performed their safety functions following a postulated break of this Auxiliary Steam line. Therefore, this condition is not an unanalyzed condition that significantly degrades plant safety and does not meet the reporting requirements of 10 CFR 50.72(b)(3)(ii)(B). Event notification #46597, made on 02/07/2011, is hereby retracted. The NRC Resident Inspectors have been notified. Notified R4DO (O'Keefe). |
Where | |
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Callaway Missouri (NRC Region 4) | |
Reporting | |
10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition | |
Time - Person (Reporting Time:+2 h0.0833 days <br />0.0119 weeks <br />0.00274 months <br />) | |
Opened: | Kieth Duncan 17:18 Feb 7, 2011 |
NRC Officer: | Mark Abramovitz |
Last Updated: | Apr 8, 2011 |
46597 - NRC Website | |
Unit 1 | |
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Reactor critical | Critical |
Scram | No |
Before | Power Operation (100 %) |
After | Power Operation (100 %) |
WEEKMONTHYEARENS 548062020-07-30T13:15:00030 July 2020 13:15:00
[Table view]10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition ENS 534852018-07-03T05:00:0003 July 2018 05:00:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition En Revision Imported Date 8/1/2018 ENS 532232018-02-20T18:25:00020 February 2018 18:25:00 10 CFR 50.72(b)(3)(v)(A), Loss of Safety Function - Shutdown the Reactor, 10 CFR 50.72(b)(3)(v)(B), Loss of Safety Function - Remove Residual Heat, 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 All Three Auxiliary Feedwater Pumps Inoperable Due to Helb Door Being Open ENS 529052017-08-15T16:46:00015 August 2017 16:46:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Discovery of Non-Conforming Conditions During Tornado Hazards Analysis ENS 526072017-03-13T18:58:00013 March 2017 18:58:00 10 CFR 50.72(b)(3)(v)(A), Loss of Safety Function - Shutdown the Reactor, 10 CFR 50.72(b)(3)(v)(B), Loss of Safety Function - Remove Residual Heat, 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 518742016-04-20T19:05:00020 April 2016 19:05:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Unanalyzed Condition Due to Essential Service Water Pressure Transient ENS 506252014-11-19T01:00:00019 November 2014 01:00:00 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 Unanalyzed Condition Due to All Four Safety Injection Accumulators Inoperable ENS 504742014-09-19T16:34:00019 September 2014 16:34:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Unanalyzed Condition Due to a Postulated Hot-Short Fire Event That Could Adversely Impact Safe Shutdown Equipment ENS 494222013-10-09T20:00:0009 October 2013 20:00:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Postulated Fire Event Could Result in a Hot Short That Could Adversely Impact Safe Shutdown Equipment ENS 478852012-05-01T18:00:0001 May 2012 18:00:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Floor Drain Blockage Adversely Affects Asumptions of Pipe Break Analysis for Electrical Switghear Rooms ENS 477832012-03-28T20:00:00028 March 2012 20:00:00 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 Degraded Condition Identified in the B Train Containment Cooler Units ENS 474262011-11-09T23:50:0009 November 2011 23:50:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Potential Failure of High Density Polyethylene Piping in Esw System ENS 470842011-07-21T16:00:00021 July 2011 16:00:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Potential Adverse Effect on Esw Train During a Postulated Control Room Fire ENS 467152011-03-31T19:32:00031 March 2011 19:32:00 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 Unanalyzed Condition Identified for Inoperable Rwst Level ENS 466932011-03-24T04:54:00024 March 2011 04:54:00 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 Pressure Transmitters Needed for Auxiliary Feedwater Suction Path Not Analyzed for Potential High Energy Line Break ENS 465972011-02-07T15:18:0007 February 2011 15:18:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition High Energy Line Break Analysis for Aux Steam to the Auxiliary Building ENS 457472010-03-05T19:25:0005 March 2010 19:25:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Unanalyzed Condition - Steam Supply Valve Credited as Closed in Fsar Analysis Is Normally Open During Operations ENS 455712009-12-15T20:30:00015 December 2009 20:30:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Helb Configuration Calculations Not Consistent with Previous Helb Analysis ENS 422422006-01-04T19:45:0004 January 2006 19:45:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Unanalyzed Condition Related to Emergency Diesel Fuel Oil Tank Vortex Formation ENS 413262005-01-12T19:30:00012 January 2005 19:30:00 Other Unspec Reqmnt, 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition 24 Hour Condition of License Report Regarding Halon System Actuator Port Connection Error ENS 403732003-12-03T18:30:0003 December 2003 18:30:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Emergency Procedure Deficiency Causes Unanalyzed Condition 2020-07-30T13:15:00 | |