ENS 44837
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ENS Event | |
|---|---|
16:59 Feb 7, 2009 | |
| Title | Unusual Event Declared Due to a Fire Onsite |
| Event Description | Arkansas Nuclear One Unit 1 declared an Unusual Event per EAL 7.5 at 1059 CST based on a fire onsite. The fire occurred on the 354 foot elevation iso-phase bus deck of the turbine building. The fire was attributed to a failed bonnet on a manual valve which had unthreaded during operation releasing hydrogen in the vicinity of the hydrogen add station. The licensee extinguished the fire using water and posted a reflash watch. There were no reported personnel injuries. Offsite assistance was requested from the London Fire Department which arrived onsite after the fire had been extinguished.
The reactor was manually tripped with all control rods fully inserting. The plant is currently stable with decay heat removal via the steam dumps to the main condenser. The licensee informed state/local agencies and the NRC Resident Inspector.
The Unusual Event was terminated at 1338 CST after confirmation that the fire was extinguished and a review of the exit criteria as defined in plant procedures. The licensee is performing a damage assessment at this time. The licensee was in the process of informing state/local agencies and will inform the NRC Resident Inspector. Notified R4DO (Clark), NRR(Hiland), IRD (Grant), DHS (Banner) and FEMA (Canupp).
The subject event notification erroneously reported that all control rods fully inserted following the manual reactor trip initiated in response to a fire on site. In actuality, the rod bottom light for Rod 6 in Rod Group 7 on the CRD Position Indication Panel did not illuminate following the reactor trip and it was verified by plant computer to have inserted to 2.3 percent withdrawn. The control board operator identified this condition quickly and reported it to the Control Room Supervisor in his immediate action response. This condition did not necessitate any additional operator actions and shutdown margin requirements were maintained. The licensee has informed the NRC Resident Inspector. R4DO (Miller) notified. |
| Where | |
|---|---|
Arkansas Nuclear  Arkansas (NRC Region 4) | |
| Reporting | |
| Emergency class: | Unusual Event |
| 10 CFR 50.72(a) (1) (i), Emergency Class Declaration 10 CFR 50.72(b)(2)(iv)(B), RPS Actuation | |
| Time - Person (Reporting Time:+-4.68 h-0.195 days <br />-0.0279 weeks <br />-0.00641 months <br />) | |
| Opened: | Peter Jackson 12:18 Feb 7, 2009 |
| NRC Officer: | Vince Klco |
| Last Updated: | Feb 10, 2009 |
| 44837 - NRC Website
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Unit 1 | |
|---|---|
| Reactor critical | Critical |
| Scram | Yes, Manual Scram |
| Before | Power Operation (90 %) |
| After | Hot Standby (0 %) |
Arkansas Nuclear with 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(a)(1)(i), Emergency Class Declaration | |
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