ENS 47777
ENS Event | |
|---|---|
01:20 Mar 28, 2012 | |
| Title | Spent Fuel Handling Machine Not Fully Qualified for a Seismic Event |
| Event Description | The following condition is being reported by Arkansas Nuclear One, Unit 2 (ANO-2) in accordance with 10CFR 50.72(b)(3)(ii)(B), 'Unanalyzed Condition.' Conservative engineering analysis has determined that the Spent Fuel Handling Machine (2H-3) is not qualified in a design basis earthquake event. Current seismic analysis is indicating a lack of margin for several structural parts of the machine.
The Spent Fuel Handling Machine (2H-3) is currently parked and de-energized in a safe position and administratively prohibited from being moved over any irradiated fuel assemblies in the spent fuel pool. Until further engineering evaluation or modifications can occur the Spent Fuel Handling Machine (2H-3) will remain in its current position and de-energized. The licensee has notified the NRC Resident Inspector.
The purpose of this notification is to retract the previous Event Notification#47777 made by Arkansas Nuclear One, Unit 2 on 03/27/2012. The initial report indicated that the Spent Fuel Handling Machine (2H-3) may not have been qualified during a design basis earthquake event due to seismic analysis indicating a lack of margin for several structural parts of the machine. 2H3 was parked and de-energized in a safe position, and the condition was reported in accordance with 10 CFR 50.72(b)(3)(ii)(B), 'Unanalyzed Condition.' Since the initial report, Engineering has completed a new seismic analysis which demonstrates that the discovered conditions of the Spent Fuel Handling Machine structural parts were adequate to preclude structural failure of the machine in the area of the Spent Fuel Pool. References to the calculations that formulate the basis for this conclusion are documented in the Licensee's corrective action program. Based on the new seismic analysis, the condition initially reported in EN#47777 did not result in 'an unanalyzed condition that significantly degrades plant safety' and is therefore retracted. The NRC Resident Inspector has been briefed on the seismic analysis results and informed of this retraction. Notified R4DO (Spitzberg). |
| Where | |
|---|---|
Arkansas Nuclear  Arkansas (NRC Region 4) | |
| Reporting | |
| 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition | |
| Time - Person (Reporting Time:+-2.15 h-0.0896 days <br />-0.0128 weeks <br />-0.00295 months <br />) | |
| Opened: | Brent Efird 23:11 Mar 27, 2012 |
| NRC Officer: | Bill Huffman |
| Last Updated: | May 23, 2012 |
| 47777 - NRC Website
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Unit 2 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (100 %) |
| After | Power Operation (100 %) |