ML14199A411

Special Report - Seismic Monitoring Instrumentation Inoperability

ML14199A411
Person / Time
Site:	Limerick
Issue date:	07/18/2014
From:	Dougherty T Exelon Generation Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
LG-14-105
Download: ML14199A411 (3)

Text

LG-14-105 TRM 3.3.7.2 July 18, 2014 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 - Seismic Monitoring Instrumentation Inoperability This Special Report is being submitted pursuant to the requirements of Limerick Generating Station (LGS), Unit 1 and Unit 2 Updated Final Safety Analysis Report (UFSAR) section 3.7.4.5, Technical Specification 6.9.2, and Technical Requirements Manual 3.3.7.2 that states With one or more of the seismic monitoring instruments inoperable for more than 30 days, a Special Report shall be prepared and submitted to the Nuclear Regulatory Commission pursuant to Specification 6.9.2 of the Technical Specifications within the next ten days outlining the cause of the malfunction and the plans for restoring the instrument(s) to operable status.

On Wednesday, June 11, 2014, Unit 1 and Unit 2 were operating at 100% power with functional testing (ST-2-036-413-0) of the spray pond pump house (SPPH) seismic monitoring instrumentation in progress. During the test, at 0910 hours0.0105 days <br />0.253 hours <br />0.0015 weeks <br />3.46255e-4 months <br />, the seismic monitor channel for the foundation of an independent seismic category 1 structure (XRSH-VA-107) did not respond as expected.

Each sensor array has three channels which measure longitudinal movement, vertical movement, and transverse movement. The signal for the longitudinal channel did not exhibit the correct waveform during the functional test. Instrumentation and Control (I&C) and Engineering personnel determined that the SPPH sensor array was degraded. Accordingly, Operations declared the degraded sensor array inoperable.

The remainder of the system is unaffected by this deficiency. The SPPH portion of the system is a self-contained system with its own sensor array. Five of six instrument sensors remain operable. The SPPH sensor is inoperable.

The SPPH seismic monitor sensor channel instrumentation has been shipped to the vendor for repair. The SPPH seismic monitor sensor channel will be returned to operable status by August 29, 2014.

LG-14-105 July 18, 2014 Page 2 If you have any questions, please contact Robert B. Dickinson at (610) 718-3400.

Sincerely, Original signed by Thomas J. Dougherty Vice President - Limerick Generating Station Exelon Generation Company, LLC

Attachment:

List of commitments cc: Administrator, Region I, NRC NRC Senior Resident Inspector, Limerick

SUMMARY

OF REGULATORY COMMITMENTS The following table identifies commitments made in this document. (Any other actions discussed in the submittal represent intended or planned actions. They are described to the NRC for the NRC's information and are not regulatory commitments.)

COMMITTED COMMITMENT TYPE COMMITMENT DATE OR "OUTAGE" ONE-TIME PROGRAMMATIC ACTION (Yes/No)

(Yes/No)

The SPPH seismic monitor August 29, Yes No sensor channel will be returned to 2014 operable status by August 29, 2014.