ENS 52195
ENS Event | |
|---|---|
13:41 Aug 24, 2016 | |
| Title | Unanalyzed Condition Associated with Damaging Effects of Tornados |
| Event Description | During performance of an extent of condition evaluation of protection for Technical Specification (TS) equipment from the damaging effects of tornados, Arkansas Nuclear One, Unit 1, identified non-conforming conditions in the plant design such that specific TS equipment on Unit 1 is considered to not be adequately protected from tornado missiles. The reportable condition is postulated by tornado missiles entering the Unit 1 Cable Spreading Room through penetrating the hollow metal door or potentially from spalling of the block wall separating Room 96 and 97. A tornado could generate multiple missiles capable of striking the Unit 1 Cable Spreading Room and rendering both safety related electrical trains inoperable.
This condition is reportable per 10 CFR 50.72(b)(3)(ii)(B) for any event or condition that results in the nuclear power plant being in an unanalyzed condition that significantly degrades plant safety, and per 10 CFR 50.72(b)(3)(v) for any event or condition that at the time of discovery could have prevented the fulfillment of the safety function of structures or systems that are needed to (A) Shut down the reactor and maintain it in a safe shutdown condition, (B) Remove residual heat, or (D) Mitigate the consequences of an accident. This condition was identified as part of an on-going extent of condition review of potential tornado missile related site impacts. Licensee Event Report (LER) 50-313/2016-002-00 was recently submitted addressing previously identified tornado missile vulnerabilities at the Unit 1 plant. Enforcement discretion per Enforcement Guidance Memorandum EGM 15-002 has been implemented and required actions taken. Corrective actions will be documented in a follow-on licensee event report. The licensee has 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)(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 | |
| Time - Person (Reporting Time:+-1.43 h-0.0596 days <br />-0.00851 weeks <br />-0.00196 months <br />) | |
| Opened: | Steven Kirshberger 12:15 Aug 24, 2016 |
| NRC Officer: | Jeff Herrera |
| Last Updated: | Aug 24, 2016 |
| 52195 - NRC Website
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Unit 1 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (100 %) |
| After | Power Operation (100 %) |