ENS 49495
ENS Event | |
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17:06 Nov 1, 2013 | |
Title | Both Trains Of Auxiliary Building Special Ventilation System Declared Inoperable |
Event Description | During Unit 2 refueling outage [currently defueled] preventative maintenance on CV-31117, Loop B Main Steam Isolation Valve (MSIV), an opening in the valve was discovered without direct administrative controls to ensure the opening could be closed within 6 minutes following a Loss of Coolant Accident on Unit 1. Addition of this opening to other openings created a total of greater than 10 square feet of non-closable openings and required declaring the Auxiliary Building Special Ventilation System (ABSVS) boundary inoperable. The inoperable ABSVS boundary caused both trains of ABSVS to be declared inoperable and required entry into Technical Specification (TS) 3.7.12, Condition B. This could have prevented the ability to control the release of radioactive material and is considered a potential loss of safety function per 10CFR50.72(b)(3)(v)(C).
Administrative controls in the ABSVS Boundary were re-established by installing a closure device in the opening on CV-31117 at 1246 CDT. The ABSVS boundary and both trains of ABSVS were declared operable at that time. During the time that the ventilation system was out of service, no evolutions were in progress that could have resulted in an unmonitored release.
After further evaluation, the non-closable boundary openings for the Auxiliary Building Special Ventilation Zone (ABSVZ) including CV-31117, Loop B Main Steam Isolation Valve (MSIV), at the time of discovery is calculated to be 9.48 square feet. This is below the 10 square feet required in TS 3.7.12, thus both trains of ABSVS were operable and no loss of safety function existed. The licensee has notified the NRC Resident Inspector. Notified the R3DO (Cameron). |
Where | |
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Prairie Island Minnesota (NRC Region 3) | |
Reporting | |
10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material | |
Time - Person (Reporting Time:+0.42 h0.0175 days <br />0.0025 weeks <br />5.75316e-4 months <br />) | |
Opened: | Stephen Seilhymer 17:31 Nov 1, 2013 |
NRC Officer: | Howie Crouch |
Last Updated: | Nov 14, 2013 |
49495 - NRC Website
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Unit 1 | |
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Reactor critical | Critical |
Scram | No |
Before | Power Operation (100 %) |
After | Power Operation (100 %) |
Prairie Island with 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material | |
WEEKMONTHYEARENS 508702015-03-07T17:55:0007 March 2015 17:55:00
[Table view]10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Containment Declared Inoperable Due to Containment Fan Coil Leak ENS 508082015-02-11T04:05:00011 February 2015 04:05:00 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Containment Declared Inoperable Due to Containment Fan Coil Leak ENS 506302014-11-20T16:22:00020 November 2014 16:22:00 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Containment Declared Inoperable Due to Containment Fan Coil Leak ENS 501232014-05-19T17:36:00019 May 2014 17:36:00 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Containment Declared Inoperable Due to Containment Fan Coil Leak ENS 500042014-04-07T11:00:0007 April 2014 11:00:00 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Control Room Special Vent Boundary Inoperable ENS 494952013-11-01T17:06:0001 November 2013 17:06:00 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Both Trains of Auxiliary Building Special Ventilation System Declared Inoperable ENS 492612013-08-10T01:28:00010 August 2013 01:28:00 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Inoperable Control Room Envelope ENS 488702013-03-31T04:44:00031 March 2013 04:44:00 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Both Trains of Auxiliary Building Special Ventilation System Declared Inoperable 2015-03-07T17:55:00 | |