ML052640167

Special Report, Channel #12 of the Containment Hydrogen Monitoring System Inoperable

ML052640167
Person / Time
Site:	Nine Mile Point
Issue date:	09/12/2005
From:	O'Connor T Constellation Energy Group
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
NMP1L 1984
Download: ML052640167 (2)

Text

Constellation Energy- P.O. Box 63 Lycoming. NY 13093 Nine Mile Point Nuclear Station September 12, 2005 NMP1L 1984 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D.C. 20555-0001

SUBJECT:

Nine Mile Point Unit 1 Docket No. 50-220 Facility Operating License No. DPR-63 Special Report, Channel #12 of the Containment Hydrogen Monitoring System Inoperable Gentlemen:

In accordance with Action 4.a of Nine Mile Point Unit 1 Technical Specification Table 3.6.11-2, "Accident Monitoring Instrumentation Action Statements," Nine Mile Point Nuclear Station, LLC, is submitting the following Special Report concerning inoperability of Channel #12 of the Containment Hydrogen Monitoring (CHM) System.

Descriptionof Event This Special Report is submitted for two separate and unrelated inoperability events for Channel

1. 12 of the CHM System.

On August 29, 2005, at 0437 hours0.00506 days <br />0.121 hours <br />7.225529e-4 weeks <br />1.662785e-4 months <br />, operators removed Channel #12 of the CHM System from service due to planned maintenance on another system's equipment. On August 30, 2005, at 1726 hours0.02 days <br />0.479 hours <br />0.00285 weeks <br />6.56743e-4 months <br />, Channel #12 of the CHM System was restored to operable status.

On September 1, 2005, at 0850 hours0.00984 days <br />0.236 hours <br />0.00141 weeks <br />3.23425e-4 months <br />, operators again removed Channel #12 of the CHM System from service to perform required surveillance exercise testing of the torus and drywell sample stream check valves. At 1015 hours0.0117 days <br />0.282 hours <br />0.00168 weeks <br />3.862075e-4 months <br />, the surveillance test was declared unsatisfactory for the torus sample stream. Operators subsequently removed Channel #12 of the CHM System from service by procedure due to the inability to sample both the drywell and the torus.

k Page 2 NMP1L XXXX In both cases the redundant Channel #11 of the CHM System was verified to be operable prior to removal of Channel 1112 from service.

Cause of Inoperabilitl' On August 29, 2005, Channel #12 of the CHM System was removed from service to support planned maintenance. To support the planned maintenance, a power board feeding Channel #12 of the CHM System sample line heat tracing was required to be de-energized. On August 30, 2005, Channel #12 of the CHM System was restored to operable status.

On September 1,2005, Channel #12 of the CHM System was declared inoperable by procedure due to the inability to sample both the drywell and the torus. The surveillance test indicated unacceptable performance of the torus sample stream check valves.

Actions Taken For the first event, planned maintenance was completed and Channel #12 of the CHM System was restored to operable status on August 30, 2005, at 1726 hours0.02 days <br />0.479 hours <br />0.00285 weeks <br />6.56743e-4 months <br />.

For the second event, Channel #12 of the CHM System was declared inoperable on September 1, 2005, at 1015 hours0.0117 days <br />0.282 hours <br />0.00168 weeks <br />3.862075e-4 months <br />. Operators isolated the torus sample stream to perform troubleshooting. As a result of the troubleshooting and investigation it was determined that the initial exercise testing of the torus sample stream check valves was acceptable and Channel #12 of the CHM System was restored to operable status on September 3, at 0219 ho rs.

Pi neral Manager TJO/RF/sac cc: Mr. S. J. Collins, NRC Regional Administrator, Region I Mr. G. K. Hunegs, NRC Senior Resident Inspector