ML12129A200

Supplement to Response to Request for Additional Information Regarding the Cycle 21 Core Operating Limits Report

ML12129A200
Person / Time
Site:	Millstone
Issue date:	05/01/2012
From:	Hartz L Dominion Nuclear Connecticut
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
Download: ML12129A200 (2)

Text

Dominion Nuclear Connecticut, Inc.

5000 Dominion Boulevard, Glen Allen, VA 23060 DominEoN Web Address: www.dom.com May 1, 2012 U. S. Nuclear Regulatory Commission Serial No.12-271 Attention: Document Control Desk NSSL/WDC RO Washington, DC 20555 Docket No. 50-336 License No. DPR-65 DOMINION NUCLEAR CONNECTICUT, INC.

MILLSTONE POWER STATION UNIT 2 SUPPLEMENT TO RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING THE CYCLE 21 CORE OPERATING LIMITS REPORT (TAC NO.

ME6365)

Dominion Nuclear Connecticut, Inc. (DNC) submitted the Millstone Power Station Unit 2 (MPS2) Cycle 21 Core Operating Limits Report (COLR) to the Nuclear Regulatory Commission (NRC) in a letter dated May 19, 2011. The COLR included the values of cycle-specific parameter limits and was submitted to the NRC for information. In a letter dated October 24, 2011, the NRC transmitted a request for additional information (RAI) to DNC related to the MPS2 Cycle 21 COLR. In letters dated November 30, 2011 and January 18, 2012, DNC responded to the RAIs.

In the November 30, 2011 response to the RAI, DNC stated:

"For Cycle 20 operation, no change was needed to the acceptable operation regions as defined in the COLR figures (i.e., tents) and the impact on FQN (or Linear Heat Generation Rate (LHGR)) was accommodated within the known conservatism of the methodology."

In a phone call on April 4, 2012, the NRC requested DNC provide the Cycle 20 calculated FQN uncertainty, including the impact of the offset incore instrument (ICI) detector strings on the uncertainty. This letter supplements the DNC responses dated November 30, 2011 and January 18, 2012 to the NRC request for additional information dated October 24, 2011, and provides the additional requested information.

N For MPS2 Cycle 20 operation, AREVA determined that the total FQ 0 uncertainty was 1.0690. This value includes the statistical uncertainty on FQN and bias (or penalty) associated with the offset ICI detector strings. This value was less than the Cycle 20 COLR linear heat rate measurement-calculational uncertainty factor of 1.07. As a result, no additional penalty on FQN was required for Cycle 20 operation.

If you have any questions regarding this submittal, please contact Wanda Craft at (804) 273-4687.

Sincerely, L_

L. N. Hartz Vice President - Nuclear Support Services

Serial No.12-271 Docket No. 50-336 Page 2 of 2 Commitments made in this letter:

1. None cc: U.S. Nuclear Regulatory Commission Region I 475 Allendale Road King of Prussia, PA 19406-1415 J. S. Kim Project Manager - Millstone Power Station U.S. Nuclear Regulatory Commission One White Flint North 11555 Rockville Pike Mail Stop 08 C2A Rockville, MD 20852-2738 NRC Senior Resident Inspector Millstone Power Station