ENS 42869
ENS Event | |
|---|---|
12:35 Oct 1, 2006 | |
| Title | Temporary Scaffolding for Upcoming Outage Renders 'A' and 'B' Msiv Inoperable |
| Event Description | Scaffold that was built for upcoming refueling outage work at Beaver Valley Power Station Unit 2 may have prevented two Main Steam Isolation Valves (MSIV) from reaching the full closed position.
Scaffold was built on 9/29/06 and 9/30/06 for refueling outage work on the 'A' and 'B' MSIV's. The 'C' MSIV was not impacted. Some of the seismic bracing for these scaffolds were in the area of travel when closing the MSIV's. There is reasonable assurance these braces would have prevented the 'A' and ' B' MSIV's from reaching the full closed position. During a Steam Generator Tube Rupture accident, this MSIV interference may have prevented accident mitigation by not allowing the MSIV to properly close and cause additional release of radioactive material to the environment beyond that already analyzed in the Updated Final Safety Analysis Report. On 10/1/06 at 0835 the MSIV inoperability was discovered and Technical Specification 3.7.1.5 (MSIV Operability) and 3.0.3 were entered. The scaffold bracing was moved out of the valve closure path of the 'B' MSIV and at 0915 Technical Specification 3.0.3 was exited. At 0945 the 'A' MSIV was free to close and Technical Specification 3.7.1.5 was exited. This is being reported as a loss of a safety function for a Main Steam Line Isolation Valve which is required to control the release of radioactive material, and which is required to mitigate the consequences of an accident, pursuant to 10 CFR 50.72(b)(3)(v)(C) and 50.72(b)(3)(v)(D). Unit power remained constant throughout the event and no other safety systems have been compromised. The licensee is currently lowering power for the Unit 2 refueling outage. The licensee notified the NRC Resident Inspector. |
| Where | |
|---|---|
| Beaver Valley Pennsylvania (NRC Region 1) | |
| Reporting | |
| 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | |
| Time - Person (Reporting Time:+2.82 h0.118 days <br />0.0168 weeks <br />0.00386 months <br />) | |
| Opened: | Ken Tiefenthal 15:24 Oct 1, 2006 |
| NRC Officer: | Jason Kozal |
| Last Updated: | Oct 1, 2006 |
| 42869 - NRC Website
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Unit 2 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (60 %) |
| After | Power Operation (60 %) |