ENS 48246
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ENS Event | |
|---|---|
00:00 Aug 29, 2012 | |
| Title | Mitigating Actions Implemented for Inoperable Control Room Envelope |
| Event Description | On August 28, 2012, 17:00 PDT, Pacific Gas and Electric Company (PG&E) identified additional release pathways that could affect the control room (CR) operator dose following a Large-Break Loss-of-Coolant Accident (LBLOCA). Consequently, PG&E declared the control room envelope (CRE) inoperable and is establishing mitigative actions in accordance with TS 3.7.10, Action B.1, 'Initiate action to implement mitigating actions' immediately, and Action B.2, 'Verify mitigating actions ensure CRE occupant exposures to radiological hazards will not exceed limits, and CRE occupants are protected from smoke and chemical hazards' within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.
PG&E is establishing mitigative actions in accordance with TS 3.7.10 and RG 1.196. These mitigative actions are for operations control room personnel to administer potassium iodide and don self-contained breathing apparatus equipment in a timely fashion should a LBLOCA occur. They will be communicated and controlled by a standing order to the control room staff. PG&E previously established controls on other release pathways that offset the potential increases to the maximum predicted offsite dose due to the new release pathways. No increase in maximum predicted offsite dose is expected from the new release pathways. Diablo Canyon (DCPP) is making this 8-hour, non-emergency notification under 10 CFR 50.72(b)(3)(ii)(B) and 10 CFR 50.72(b)(3)(v)(D). Plant personnel notified the NRC Resident Inspector.
PG&E is retracting EN 48246, based on the results from a new dose analysis coupled with compensatory measures implemented to ensure that the analysis input parameters and assumption will not be inadvertently exceeded. The analysis concluded that the CRE was operable and that CR doses remained below regulatory limits. Plant personnel notified the NRC resident inspector. Notified R4DO (Gaddy). |
| Where | |
|---|---|
Diablo Canyon  California (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:+0.27 h0.0113 days <br />0.00161 weeks <br />3.69846e-4 months <br />) | |
| Opened: | Dan Stermer 00:16 Aug 29, 2012 |
| NRC Officer: | John Knoke |
| Last Updated: | Sep 8, 2012 |
| 48246 - NRC Website
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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 %) |
Diablo Canyon 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 | |
WEEKMONTHYEARENS 544172019-11-30T19:00:00030 November 2019 19:00:00
[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 Both Trains of Containment Spray Removed from Service ENS 522602016-09-21T03:47:00021 September 2016 03:47:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Steam Line Pipe Whip Restraint Coupling Sleeve Found Not Engaged ENS 507112014-12-31T18:05:00031 December 2014 18:05:00 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 Through Wall Seepage Affecting Rhr System ENS 503342014-08-01T00:29:0001 August 2014 00:29:00 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)(ii)(B), Unanalyzed Condition, 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Unanalyzed Condition ENS 498792014-03-06T17:06:0006 March 2014 17:06:00 10 CFR 50.72(b)(3)(v)(A), Loss of Safety Function - Shutdown the Reactor, 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Unanalyzed Condition Regarding Potential Tornado Missile Damage to Emergency Diesel Exhaust Plenum ENS 496632013-12-19T15:52:00019 December 2013 15:52:00 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 Two of Three Emergencey Diesel Generators Inoperable at the Same Time ENS 496342013-12-14T23:03:00014 December 2013 23:03:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Unanalyzed Condition Affecting Unit 1 Emergency Diesel Generator ENS 491482013-06-26T04:58:00026 June 2013 04:58:00 10 CFR 50.72(b)(2)(xi), Notification to Government Agency or News Release, 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)(2)(i), Tech Spec Required Shutdown Plant Shutdown Required Due to Rhr System Socket Weld Leak ENS 491472013-06-24T23:15:00024 June 2013 23:15:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Emergency Diesel Generators Unavailable for Auto-Start ENS 487262013-02-06T23:24:0006 February 2013 23:24:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Unanalyzed Condition for Control Room Ventilation ENS 485412012-11-28T04:38:00028 November 2012 04:38:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident Control Room Ventilation System Will Not Automatically Start in Pressurization Mode ENS 483952012-10-04T01:15:0004 October 2012 01:15:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Unanalyzed Fire Protection Deficiencies ENS 482462012-08-29T00:00:00029 August 2012 00:00:00 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 Mitigating Actions Implemented for Inoperable Control Room Envelope ENS 480022012-06-07T08:29:0007 June 2012 08:29:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident Both Trains of Low Temperature Overpressure System Inoperable ENS 475642011-12-31T10:00:00031 December 2011 10:00:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Fire Barrier Rating of Vital Swtichgear Walls May Not Meet Standards ENS 474142011-11-03T22:50:0003 November 2011 22:50:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Unanalyzed Condition - Control Room Ventilation Single Point Vulnerability ENS 472582011-09-13T00:45:00013 September 2011 00:45:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Control Room Envelope Declared Inoperable ENS 472232011-08-30T00:24:00030 August 2011 00:24:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Maintenance Inadvertently Renders Control Room Ventilation System Inoperable ENS 465312011-01-10T21:21:00010 January 2011 21:21:00 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 Both Trains of Auxiliary Building Ventilation Became Inoperable ENS 457542010-03-10T03:16:00010 March 2010 03:16:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Potential Loss of 1E Pumps Due to Degraded Voltage During Postulated Accidents ENS 454612009-10-23T15:00:00023 October 2009 15:00:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Post Loca Recirculation Valve Position Interlocks ENS 449272009-03-22T20:34:00022 March 2009 20:34:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Unit 1 Steam Generator Found in an Unanalyzed Condition Related to Gaps on Seismic Washer Plates ENS 442872008-06-11T21:05:00011 June 2008 21:05:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident Identification of a Potential Issue with Accumulator Drain Valves 2019-11-30T19:00:00 | |
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