ENS 49873
ENS Event | |
|---|---|
16:20 Mar 5, 2014 | |
| Title | Discovery of Individual Pathways That Could Bypass Flood Barriers |
| Event Description | During walk downs to ensure the availability of flood protection barriers, a condition was identified which had the potential to adversely impact the ability to address external flooding conditions. Several individual pathways between both unit's Turbine Building and Auxiliary Building were identified that could bypass flood barriers. In the aggregate however, the current equipment could become overwhelmed and the flooding in the Auxiliary Building could then potentially challenge equipment necessary to remove residual heat.
The identified pathways were for the most part unscheduled partially filled conduits. There were no isolation features on these pathways and no barriers to flooding were in place between the Turbine Building and Auxiliary Building thus the potential existed to bypass the existing flood barriers. Flooding of the Turbine Building conceivably could have resulted in the accumulation of water in sufficient quantities to fill the Turbine Building to the height of the external floodwaters which could enter the Auxiliary Building via one or more deficient flood barrier. These floodwaters would then potentially challenge equipment, located within the Auxiliary Building, which is required to remove residual heat. This condition has been determined to be reportable per 10CFR50.72(b)(3)(v)(B) and 10CFR50.72(b)(3)(ii)(B). This condition is a non-emergency condition. This condition has been entered into the Corrective Action Program. Barriers are being installed in these pathways as they are identified or compensatory measures implemented. The walk downs were performed in response to Fukishima lessons learned. The licensee notified the NRC Resident Inspector. |
| Where | |
|---|---|
Arkansas Nuclear  Arkansas (NRC Region 4) | |
| Reporting | |
| 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition 10 CFR 50.72(b)(3)(v)(B), Loss of Safety Function - Remove Residual Heat | |
| Time - Person (Reporting Time:+-5 h-0.208 days <br />-0.0298 weeks <br />-0.00685 months <br />) | |
| Opened: | Robert Clark 11:20 Mar 5, 2014 |
| NRC Officer: | Steve Sandin |
| Last Updated: | Mar 5, 2014 |
| 49873 - 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 %) |