ML080710391

Response to Request for Additional Information Regarding Stretch Power Uprate License Amendment Request Response to Question SCVB-07-0091

ML080710391
Person / Time
Site:	Millstone
Issue date:	03/10/2008
From:	Gerald Bichof Dominion Nuclear Connecticut
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
07-0846F
Download: ML080710391 (5)

Text

Dominion Nuclear Connecticut, Inc.

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U. S. Nuclear Regulatory Commission Attention: Document Control Desk One White Flint North 11555 Rockville Pike Rockville, MD 20852-2378 DOMINION NUCLEAR CONNECTICUT. INC.

MILLSTONE POWER STATION UNIT 3 RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING STRETCH POWER UPRATE LICENSE AMENDMENT REQUEST RESPONSE TO QUESTION SCVB-07-0091 Dominion Nuclear Connecticut, Inc. (DNC) submitted a stretch power uprate license amendment request (LAR) for Millstone Power Station Unit 3 (MPS3) in letters dated July 13, 2007 (Serial Nos. 07-0450 and 07-0450A), and supplemented the submittal by letters dated September 12, 2007 (Serial No. 07-04508), December 13, 2007 (Serial No. 07-0450C) and March 5, 2008 (Serial No. 07-0450D).

The NRC staff forwarded requests for additional information (RAls) in October 29, 2007, November 26, 2007, December 14, 2007 and December 20, 2007 letters.

DNC responded to the RAls in letters dated November 19, 2007 (Serial No. 07-0751), December 17, 2007 (Serial No.

07-0799), January 10, 2008 (Serial Nos. 07-0834, 07-0834A, 07-0834C, and 07-0834F),

January 11, 2008 (Serial Nos. 07-08348, 07-0834E, 07-0834G, and 07-0834H),

January 14, 2008 (Serial No. 07-0834D), January 18, 2008 (Serial Nos. 07-0846, 07-0846A, 07-08468, 07-0846C, and 07-0846D), January 31, 2008 (Serial No. 07-08341) and February 25,2008 (Serial Nos. 07-0799A, and 07-0834J).

In a letter dated January 18, 2008 (Serial No. 07-0846C), DNC provided a response to NRC question SCVB-07-0091.

Subsequently, in a conference call with the NRC staff on February 26, 2008, DNC informed the NRC staff of the intent to supersede the response to question SCVB-07-0091. The superseded response additionally provides the initial conditions used for stretch power uprate in the pressurizer compartment analysis.

The revised response to RAI Question SCVB-07-0091 is provided in the attachment to this letter and supersedes the previous response in its entirety.

The information provided by this letter does not affect the conclusions of the significant hazards consideration discussion in the December 13, 2007 DNC letter (Serial No. 07-0450C).

Serial No. 07-0846F Docket No. 50-423 RAI Ques. SCVB-07-0091, SPU Page 2 of 3 Should you have any questions in regard to this submittal, please contact Ms. Margaret Earle at 804-273-2768.

Sincerely, Vice President - Nuclear Engineering COMMONWEALTH OF VIRGINIA COUNTY OF HENRICO The foregoing document was acknowledged before me, in and for the County and Commonwealth aforesaid, today by Gerald T. Bischof, who is Vice President - Nuclear Engineering of Dominion Nuclear Connecticut, Inc. He has affirmed before me that he is duly authorized to execute and file the foregoing document in behalf of that Company, and that the statements in the document are true to the best of his knowledge and belief.

Acknowledged before me this It) ~day of AllrcA

,2008.

My Commission EXPires:ffiu 3~ zdJ(;.

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Notary Public Attachment Commitments made in this letter: None cc:

U.S. Nuclear Regulatory Commission Region I Regional Administrator 475 Allendale Road King of Prussia, PA 19406-1415 Mr. J. G. Lamb U.S. Nuclear Regulatory Commission One White Flint North 11555 Rockville Pike Mail Stop 0-8B1A Rockville, MD 20852-2738 VICKI L. HULL 4

Notary PubUc

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• Mr. J. D. Hughey Project Manager U.S. Nuclear Regulatory Commission One White Flint North 11555 Rockville Pike Mail Stop 0-8B3 Rockville, MD 20852-2738 NRC Senior Resident Inspector Millstone Power Station Director Bureau of Air Management Monitoring and Radiation Division Department of Environmental Protection 79 Elm Street Hartford, CT 06106-5127 Serial No. 07-0846F Docket No. 50-423 RAI Ques. SCVB-07-0091, SPU Page 3 of 3

Serial No. 07-0846F Docket No. 50-423 ATTACHMENT LICENSE AMENDMENT REQUEST STRETCH POWER UPRATE LICENSE AMENDMENT REQUEST RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION RESPONSE TO QUESTION SCVB-07-0091 MILLSTONE POWER STATION UNIT 3 DOMINION NUCLEAR CONNECTICUT, INC.

Serial No. 07-0846F Docket No. 50-423 Attachment, Page 1 of 1 Containment and Ventilation Branch NRC Question SCVB-07-0091 Millstone Power Station Unit 3 (MPS3) FSAR lists the following initial containment conditions selected for the subcompartment analyses:

Pressurizer Subcompartment: Temperature 100 0 F; Air partial pressure 8.9 pounds per square inch absolute (psia); relative humidity 10 percent.

Steam Generator and Upper Reactor Cavity Subcompartments:

Temperature 120 0

F; air partial pressure 9.0 psia; relative humidity 50 percent.

Section 2.6.2 of Attachment 5 of the licensing amendment request (LAR) does not list the initial conditions used for subcompartment analysis.

Please provide the initial conditions used for SPU subcompartment analysis. In case any of these conditions deviate from the current licensing bases, provide appropriate justification for the deviation.

DNC Response Since the Stretch Power Uprate (SPU) Mass and Energy releases for the steam generator and reactor cavity subcompartments are bounded by the Mass and Energy releases assumed in the current analyses, no new subcompartment analyses were performed for the steam generator and reactor cavity subcompartments. The assumption on initial conditions (stated in MPS3 FSAR Section 6.2.1.2.1) remains unchanged.

For the pressurizer compartment, the SPU Mass and Energy releases are not bounded by the current analyses. Thus, the pressurizer compartment analyses were re-performed.

Sensitivity studies were performed to determine the limiting conditions. Four cases were analyzed:

80°F and 9.0 psia (total pressure) 100°F and 9.0 psia (total pressure) 100°F and 10.4 psia (total pressure) 100°F and 14.2 psia (total pressure)

All cases assumed relative humidity of 10 percent.

The sensitivity studies bound the current assumed conditions. Based on the sensitivity studies and the Technical Specification lower limit on containment pressure, the initial conditions assumed for the limiting case are 100 OF and 10.4 psia (total pressure).