ML102160389
| ML102160389 | |
| Person / Time | |
|---|---|
| Site: | Limerick  |
| Issue date: | 07/26/2010 |
| From: | Maguire W Exelon Generation Co, Exelon Nuclear |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| Download: ML102160389 (2) | |
Text
U Nuclear TS 3.3.7.5 July 26, 2010 U.S. Nuclear Regulatory Commission Attn.: Document Control Desk Washington, DC 20555-0001 Limerick Generating Station, Units 1 and 2 Facility Operating License Nos. NPF-39 and NPF-85 NRC Docket Nos. 50-352 and 50-353
Subject:
Special Report - Accident Monitoring Instrumentation Inoperability This Special Report is being submitted pursuant to the requirements of Limerick Generating Station (LGS), Unit 1 and Unit 2 Technical Specification 6.9.2, and Technical Specification 3.3.7.5, Table 3.3.7.5-1, Action 81. Action 81 states the following:
ACTION 81 -
With the number of OPERABLE accident monitoring instrumentation channels less than required by the Minimum Channels OPERABLE requirement, initiate the preplanned alternate method of monitoring the appropriate parameters within 72,hours, and
- a.
Either restore the inoperable channel(s) to OPERABLE status within
.7 days oflthe event, or
- b.
Prepare and submit a Special Report to the Commission pursuant to Specification 6.9.2 within 14 days following the event outlining the action taken, the cause of the inoperability and the plans and schedule for restoring the system to OPERABLE status.
On Monday July 12, 2010, at 1,151 hours0.00175 days <br />0.0419 hours <br />2.496693e-4 weeks <br />5.74555e-5 months <br />, the Wide Range Accident Monitor (WRAM) was declared inoperable when it spiked upscale then failed downscale. On Thursday July 15, 2010, at 1648 hours0.0191 days <br />0.458 hours <br />0.00272 weeks <br />6.27064e-4 months <br />, the instrument high voltage power supply was replaced and the instrument was returned to service. On Friday July 16, 2010, at 2253 hours0.0261 days <br />0.626 hours <br />0.00373 weeks <br />8.572665e-4 months <br />, the WRAM was returned to inoperable status. due to an upscale spike followed by a downscale indication. Trouble shooting determined that the detector photomultiplier tube was degraded.
Action taken:
Operations verified that the affected system isolation valves were closed as required by TS 3.3.2 Isolation Actuation Instrumentation, Table 3.3.2-1, Action 23. Operations also initiated the preplanned;alternate&methbd'of rnnitoringrequiredbYTS 3.3.7.5 Accident Monitoring Instrumentation, Table 3.3.7.5-1 Action 81.
Cause of the inoperability:
A degraded detector photomultiplier tube resulted in erratic operation of the WRAM.
Plans and schedule for restoring the system to operable:
A photomultiplier tube has been ordered and will be installed following receipt. The WRAM is currently scheduled to be returned to operable status by July 30, 2010.
There are no regulatory commitments contained in this letter.
If you have any questions, please contact John Hunter III at (610) 718-3400.
Respectfully, William F. Maguire Vice President - Limerick Exelon Generation Company, LLC cc: M. L. Dapas, Acting Administrator, Region I, NRC E. M. DiPaolo, NRC Resident Inspector, Limerick