ML101060265

Update to Generic Letter 2008-01 Commitment, Managing Gas Accumulation in Emergency Core Cooling, Decay Heat Removal, and Containment Spray Systems

ML101060265
Person / Time
Site:	Limerick
Issue date:	04/09/2010
From:	Mudrick C Exelon Generation Co, Exelon Nuclear
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
GL-08-001
Download: ML101060265 (3)

Text

Exelkn Limerick Generating Station www.exeloncorp.com Nuclear 3146 Sanatoga Road Pottstown, PA 19464 April 9, 2010 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Limerick Generating Station, Unit 1 Facility Operating License No. NPF-39 NRC Docket No. 50-352

Subject:

Update to Generic Letter 2008-01 Commitment

Reference:

1. Letter from K.R. Jury (Exelon Generation Company, LLC/AmerGen Energy Company, LLC) to U.S. NRC "Nine-Month Response to Generic Letter 2008-01," dated October 14, 2008 In the nine-month response to Generic Letter 2008-01 "Managing Gas Accumulation in Emergency Core Cooling, Decay Heat Removal, and Containment Spray Systems" (Reference 1), Limerick committed to the U.S. Nuclear Regulatory Commission (NRC) that it would install three new vents on the Unit 1 High Pressure Coolant Injection (HPCI) system during the current refueling outage (1R13) as documented in Attachment 16 of the Reference 1 letter. These vents were to be installed as a result of a review of system design basis and field walkdowns of areas determined to be susceptible to air entrainment. Installation of the three new vents has been completed in accordance with the commitment made in Reference 1. These vents have been installed on the HPCI discharge flow element, suppression pool suction, and injection to the feedwater piping.

Based on a review of the internal Technical Evaluation of the HPCI system in response to GL 2008-01, it has been determined that the installation of a fourth vent on the HPCl system is needed. This vent involves the HPCI Condensate Storage Tank (CST) suction piping; however, it could not be installed during the current outage due to valve through-leakage which could not be completely isolated. Following the unsuccessful piping isolation, a freeze seal of the line was attempted but was also unsuccessful. A "hot tap" of the piping was not possible due to proximity to other station components. Therefore, Exelon Generation Company, LLC (EGC) will install the additional vent on the HPCI system during the spring 2012 refueling outage. This schedule is acceptable based on the information below.

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The pipe at the intended vent location was ultrasonically tested during the current refueling outage (1 R13) to verify that no air exists at this location. With the exception of maintenance activities, the likelihood of introducing air to this location from other mechanisms is low. There are no planned activities to drain this portion of the piping or any portion of the HPCI suction line prior to the next refuel outage (1 R14). However, if draining of this piping is required prior to 1 R14, the current fill and vent procedure prescribes ultrasonic testing to support operability of HPCI. In addition, this location will be periodically monitored in accordance with the current program until the installation of the vent.

Regulatory commitments are contained in the attachment of this letter.

If you have any questions, please contact the Regulatory Assurance Manager at 610-718-3400.

I declare under penalty of perjury that the foregoing is true and correct. Executed on the 9 th day of April 2010.

Sincerely, Christopher H. Mudrick Vice President - Limerick Generating Station Exelon Generation Company, LLC

Attachment:

Summary of Regulatory Commitments cc:

S.J. Collins, Administrator Region I, USNRC E.M. DiPaolo, USNRC Senior Resident Inspector, LGS

• f q -

Q ATTACHMENT

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.)

Commitment Type Commitment Committed Date Or "Outage" One-Time Action Programmatic (Yes/No)

(Yes/No)

For the HPCI system, one Prior to the Yes No new vent will be installed completion of the on LGS Unit 1 prior to next refueling completion of the next outage (1 R14) for scheduled refueling LGS Unit 1 outage (1 R14).