ENS 45856
ENS Event | |
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06:58 Apr 19, 2010 | |
Title | Tsc Emergency Ventilation System Discovered Non-Functional While Placing a Clearance |
Event Description | At 0158 [CDT] on 4/19/2010, during implementation of clearance order activities, it was identified that the Technical Support Center (TSC) ventilation system would not transition to the emergency mode of operation. This condition is reportable under 10CFR50.72(b)(3)(xiii).
The TSC ventilation system consists of normal ventilation equipment, including a normal air supply unit OAF-1, and an emergency air supply unit OAF-2 which provides conditioned air with HEPA and charcoal filtration. The system is placed in the emergency mode as follows: When TSC HEPA FILTER BYPASS switch is placed to EMER UP, the Energy Management System (EMS) receives an emergency signal and the following actions occur: 1. Air Dampers AD1443 and AD1445 close and cause OAF-1 to stop. 2. Air Dampers AD1442 and AD1444 open and cause OAF-2 to start. 3. Outside air to the TSC is routed through HEPA filter unit. During the clearance order activities, the TSC HEPA FILTER BYPASS switch was placed to EMER UP, but the actions above did not occur. A second attempt was made to place the system in the emergency mode, without success. Based upon these indications, it is considered that the TSC ventilation cannot be placed in the emergency mode. This is reportable under 10CFR50.72(b)(3)(xiii) as an event that results in a major loss of emergency assessment capability due to the loss of the emergency response facility. Per Emergency Plan Implementing Procedure 5.7.7 for Activation of TSC, personnel can relocate to the Alternate TSC (control room) and Alternate Operations Support Center (OSC) where the TSC functions will be performed. Both of these alternate facilities are equipped with emergency ventilation systems and are currently fully functional. Troubleshooting of the TSC ventilation system discrepancy will commence today. This system was last tested successfully on 10/20/2008 and due for retest on 6/21/2010. The licensee will inform the NRC Resident Inspector. |
Where | |
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Cooper ![]() Nebraska (NRC Region 4) | |
Reporting | |
10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | |
Time - Person (Reporting Time:+-0.63 h-0.0263 days <br />-0.00375 weeks <br />-8.62974e-4 months <br />) | |
Opened: | John Myers 06:20 Apr 19, 2010 |
NRC Officer: | Steve Sandin |
Last Updated: | Apr 19, 2010 |
45856 - 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 %) |
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