RA-08-030, Technical Specifications Section 5.6.6, Post Accident Monitoring Instrumentation Report

Technical Specifications Section 5.6.6, Post Accident Monitoring Instrumentation Report

ML081270201
Person / Time
Site:	LaSalle
Issue date:	04/29/2008
From:	Enright D Exelon Generation Co, Exelon Nuclear
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
RA-08-030
Download: ML081270201 (3)

Text

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Exelon Generation Company, LLC www.exeloncorp.com Nuclear LaSalle County Station 2601 North 21" Road Marseilles, IL 61341-9757 RA-08-030 April 29, 2008 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 LaSalle County Station Unit 2 Facility Operating License No. NPF-18 NRC Docket Nos. 50-374

Subject:

Technical Specifications Section 5.6.6, "Post Accident Monitoring Instrumentation Report" The purpose of this letter is to submit a Post Accident Monitoring Instrumentation Report as required by LaSalle County Station (LSCS) Technical Specifications (TS) Section 5.6.6, "Post Accident Monitoring (PAM) Instrumentation Report."

On March 16, 2008, during the performance of LOS-RP-Q3, "Main Steam Isolation Valve Scram Functional Test," on Unit 2, the closed indication for the 2B inboard Main Steam Isolation Valve (MSIV) (2B21 -F022B) did not illuminate as expected. The Reactor Protection System function worked as expected during the surveillance test.

This discrepancy of an inoperable indication channel for Function 6 in Table 3.3.3.1-1, "Penetration Flow Path PCIV Position," required entry into TS Section 3.3.3.1, "Post Accident Monitoring (PAM) Instrumentation," Condition A for one or more Functions with one required channel inoperable, with a Required Action to restore the channel to OPERABLE status within 30 days.

Restoration of the channel within the 30-day requirement was not feasible due to the significant power reduction and containment entry required to perform the necessary troubleshooting and repairs. If the Required Action and associated Completion Time of TS 3.3.3.1 Condition A cannot be met, Condition B must immediately entered with a Required Action to initiate action in accordance with Specification 5.6.6.

In accordance with TS Section 5.6.6, a report shall be submitted within 14 days outlining the preplanned alternate method of monitoring, the cause of the inoperability, and the plans and schedule for restoring the instrument channel to an operable status. The attached report contains the required information.

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Should you have any questions concerning this matter, please contact Mr. Terrence Simpkin at (815) 415-2800.

Respectfully, Danie .Eright6 Site Vice President LaSalle County Station Attachment cc: Regional Administrator - NRC Region III NRC Senior Resident Inspector - LaSalle County Station

Post Accident Monitoring (PAM) Instrumentation Report Inoperable Channel For Penetration Flow Path PCIV Position Preplanned Alternate Method of Monitoring An alternate method of monitoring the isolation function of the 2B inboard Main Steam Isolation Valve (MSIV) has been implemented. The alternate method is to verify that Process Computer point D449 indicates 'valve closed" for 2B21-F022B. Computer point D449 is fed from a different set of contacts on the same limit switch (Limit Switch 1) that is fully functional. These contacts operate at the same values (91% moving closed and 94% moving open) as the failed

'valve closed" indication.

The alternate method was verified to work properly during the March 16, 2008, occurrence.

Apparent Cause of the Inoperability The most likely cause is that the limit switch contacts have not made up for a closed indication.

The limit switch is located in the drywell, and there is no further troubleshooting that can be performed without a significant power reduction and a containment entry to confirm the origin of this indication discrepancy.

Plans and Schedule for Returninq Function to Operable Status LaSalle County Station (LSCS) is planning on restoring the 2B MSIV indication channel to an OPERABLE status during the next refueling outage on Unit 2 (L2R1 2), scheduled for March 2, 2009, or at the next Unit 2 forced outage that requires a drywell entry to return the Unit to service.