RA13-002, Evaluation of LaSalle County Station Unit 1 120 Capsule Surveillance Data

Evaluation of LaSalle County Station Unit 1 120 Capsule Surveillance Data

ML13011A005
Person / Time
Site:	LaSalle
Issue date:	01/10/2013
From:	Karaba P Exelon Generation Co
To:	Office of Nuclear Reactor Regulation, Document Control Desk
References
RA13-002
Download: ML13011A005 (2)

Text

RA1 3-002 10 CFR 50 App. H January 10, 2013 Document Control Desk U. S. Nuclear Regulatory Commission 11555 Rockville Pike Rockville, MD 20852 LaSalle County Station, Unit 1 Facility Operating License No. NPF-11 NRC Docket No. 50-373

Subject:

Evaluation of LaSalle County Station Unit 1 120° Capsule Surveillance Data

Reference:

BWRVIP Letter 2011-206 from David Czufin (Chairman, BWR Vessel and Internals Project) to Andrew Hon (U. S. Nuclear Regulatory Commission),

"Project No. 704-- BWRVIP-250NP: BWR Vessel and Internals Project, Testing and Evaluation of the LaSalle Unit 1 120° Surveillance Capsule,"

dated November 18, 2011 The purpose of this letter is to discuss the effects of the BWR Vessel and Internals Project's (BWRVIP) evaluation of the LaSalle County Station (LSCS) Unit 1 120° capsule surveillance data, as required by 10 CFR 50 Appendix H.W.C.

Background

In accordance with the BWRVIP Integrated Surveillance Program (ISP), the LSCS Unit 1 120° surveillance capsule was withdrawn in 2010 and tested by the BWRVIP. The capsule test report required by 10 CFR 50 Appendix H was issued by the BWRVIP to the U. S. Nuclear Regulatory Commission (NRC) in the referenced letter.

The ISP requires the BWRVIP to evaluate the irradiated data from all removed surveillance capsules and provide recommendations for the best use of data to the plants which are assigned to use it. Each BWR participating in the ISP is then responsible to review the data and determine the effects (if any) on plant operations (e.g., operating limits). If a plant's existing Pressure-Temperature (P-T) curves or leak test conditions are found to be non-conservative after consideration of the data, then the plant must notify the NRC of actions that will be taken to update limit curves within one year.

Results The surveillance capsule contained weld material 1 P3571, and this is the limiting material for the current LSCS Unit 1 P-T curves. The ISP surveillance data, including new chemistry factors, was used to revise the projected Adjusted Reference

Temperature (ART) value for the Unit I vessel weld, and concluded that the ART for this weld increased by approximately 50°F. The change in the ART due to the testing of the plate material in the surveillance capsule is bounded by the change in the ART for weld 1 P3571.

The increase in the ART associated with weld 1 P3571 requires revision of the LSCS Unit 1 P-T curves. Using the revised chemistry factor and maintaining the current conservative fluence value determines that the current P-T curves for Unit 1 remain valid for 21 EFPY. However, to more realistically calculate the fluence used to determine the current EFPY limitation on the Unit 1 curves, the fluence calculated by the ISP program for the time frame when the capsule was installed (cycles 1 through 13) was used, and then the fluence associated with the current licensed flux calculation was assumed until an anticipated power uprate, and then the higher power uprate fluence was used for the rest of the analysis. This realistic method determines that the current P-T curves for Unit 1 remain valid for 26.5 EFPY. As of January 1, 2013, LSCS Unit 1 has operated for 21.6 EFPY.

LSCS is currently performing analyses to develop new Unit 1 P-T curves that include the ISP data. LSCS will submit the new curves to the NRC for review and approval by December 31, 2013.

Should you have any questions concerning this letter, please contact Mr. Guy V. Ford, Jr.,

Regulatory Assurance Manager, at (815) 415-2800.

Respectfully, Peter J. Karaba Site Vice President LaSalle County Station cc: Regional Administrator -- NRC Region III NRC Senior Resident Inspector - LaSalle County Station