ML032970390

Environmental Assessment, Revise the Calculation of Long-Term Containment

ML032970390
Person / Time
Site:	Monticello
Issue date:	01/06/2004
From:	Padovan L NRC/NRR/DLPM/LPD3
To:	Thomas J. Palmisano Nuclear Management Co
References
TAC MB7185
Download: ML032970390 (7)

Text

January 6, 2004 Mr. Thomas J. Palmisano Site Vice President Monticello Nuclear Generating Plant Nuclear Management Company, LLC 2807 West County Road 75 Monticello, MN 55362-9637

SUBJECT:

MONTICELLO NUCLEAR GENERATING PLANT - ENVIRONMENTAL ASSESSMENT RE: PROPOSED LICENSE AMENDMENT TO REVISE THE CALCULATION OF LONG-TERM CONTAINMENT RESPONSE TO A LOCA AND THE CALCULATION OF OVERPRESSURE REQUIRED FOR ADEQUATE NPSH OF THE LOW-PRESSURE ECCS PUMPS (TAC NO. MB7185)

Dear Mr. Palmisano:

Enclosed is a copy of the Environmental Assessment and Finding of No Significant Impact related to your application for amendment dated December 6, 2002, as supplemented September 24, 2003. The proposed amendment revises the Monticello operating license to change the Monticello design bases and the Updated Safety Analysis Report.

The proposed amendment would revise the existing analyses for the following:

• long-term containment response to the design-basis loss-of-coolant accident (LOCA).

• containment overpressure (the pressure above the initial containment pressure) required for adequate available net positive suction head for the low-pressure emergency core cooling system pumps following a LOCA.

The assessment is being forwarded to the Office of the Federal Register for publication.

Sincerely,

/RA/

L. Mark Padovan, Project Manager, Section 1 Project Directorate III Division of Licensing Project Management Office of Nuclear Reactor Regulation Docket No. 50-263

Enclosure:

Environmental Assessment cc w/encls: See next page

ML032970390 Monticello Nuclear Generating Plant cc:

Jonathan Rogoff, Esquire Commissioner Vice President, Counsel & Secretary Minnesota Department of Commerce Nuclear Management Company, LLC 121 Seventh Place East 700 First Street Suite 200 Hudson, WI 54016 St. Paul, MN 55101-2145 U.S. Nuclear Regulatory Commission Manager - Environmental Protection Division Resident Inspectors Office Minnesota Attorney Generals Office 2807 W. County Road 75 445 Minnesota St., Suite 900 Monticello, MN 55362 St. Paul, MN 55101-2127 Manager, Regulatory Affairs John Paul Cowan Monticello Nuclear Generating Plant Executive Vice President & Chief Nuclear Nuclear Management Company, LLC Officer 2807 West County Road 75 Nuclear Management Company, LLC Monticello, MN 55362-9637 700 First Street Hudson, WI 54016 Robert Nelson, President Minnesota Environmental Control Nuclear Asset Manager Citizens Association (MECCA) Xcel Energy, Inc.

1051 South McKnight Road 414 Nicollet Mall, R.S. 8 St. Paul, MN 55119 Minneapolis, MN 55401 Commissioner Minnesota Pollution Control Agency 520 Lafayette Road St. Paul, MN 55155-4194 Regional Administrator, Region III U.S. Nuclear Regulatory Commission 801 Warrenville Road Lisle, IL 60532-4351 Commissioner Minnesota Department of Health 717 Delaware Street, S. E.

Minneapolis, MN 55440 Douglas M. Gruber, Auditor/Treasurer Wright County Government Center 10 NW Second Street Buffalo, MN 55313 October 2003

7590-01-P UNITED STATES NUCLEAR REGULATORY COMMISSION NUCLEAR MANAGEMENT COMPANY, LLC DOCKET NO. 50-263 MONTICELLO NUCLEAR GENERATING PLANT ENVIRONMENTAL ASSESSMENT AND FINDING OF NO SIGNIFICANT IMPACT The U.S. Nuclear Regulatory Commission (NRC) is considering issuance of an amendment to Facility Operating License No. DPR-22, issued to Nuclear Management Company, LLC (NMC), for operation of the Monticello Nuclear Generating Plant (Monticello),

located in Wright County, Minnesota. Therefore, as required by 10 CFR 51.21, the NRC is issuing this environmental assessment and finding of no significant impact.

ENVIRONMENTAL ASSESSMENT Identification of the Proposed Action:

The proposed action would revise the Monticello operating license to change the Monticello design bases and the Updated Safety Analysis Report (USAR). The proposed action would revise the existing analyses for the following:

• long-term containment response to the design-basis loss-of-coolant accident (LOCA).

• containment overpressure (the pressure above the initial containment pressure) required for adequate available net positive suction head (NPSH) for the low-pressure emergency core cooling system (ECCS) pumps following a LOCA.

NMC intends to use these analyses to justify restoring the service water temperature to its licensing-basis value of 90 degrees F. NMC administratively limits the service water temperature to 85 degrees F because the results of previous analyses of a scenario (reactor

vessel isolation with high-pressure coolant injection being unavailable) showed that the design temperature for the piping attached to the wetwell would be exceeded. NMCs revised analyses shows the design temperature is not exceeded.

The proposed action is in accordance with NMCs application of December 6, 2002, as supplemented September 24, 2003.

The Need for the Proposed Action:

NMC needs this license amendment because it has determined, in accordance with 10 CFR 50.59(c)(2)(viii), that the updated containment analyses involve different evaluation methods from those currently described in Monticellos USAR and previously approved by the NRC.

Environmental Impacts of the Proposed Action:

The NRC staff reviewed NMCs amendment request and will issue a safety evaluation documenting its review. The NRC staff has reviewed NMCs calculation of the mass and energy releases that are used to determine containment pressure response, including the methods and key underlying input assumptions (e.g., decay heat generation).

NMC used conservative assumptions in its reanalyses which underestimate the containment pressure and overestimate the suppression pool water temperature. Some overpressure is necessary to ensure sufficient available NPSH. The conservative assumptions used in NMCs calculations and the cautions in Monticellos emergency operating procedures are intended to ensure that this pressure will be available.

The NRC has completed its evaluation of the proposed action and concludes, as set forth below, that there are no significant environmental impacts associated with the proposed changes to the Monticello design basis and USAR. The details of the NRC staffs review of the amendment request will be provided in the related safety evaluation when it is issued by the NRC.

The proposed action will not significantly increase the probability or consequences of accidents, no changes are being made in the types or amounts of effluents that may be released off site, and there is no significant increase in occupational or public radiation exposure. Therefore, there are no significant radiological environmental impacts associated with the proposed action.

With regard to potential nonradiological impacts, the proposed action does not have a potential to affect any historic sites. It does not affect nonradiological plant effluents and has no other environmental impact. Therefore, there are no significant nonradiological environmental impacts associated with the proposed action.

Accordingly, the NRC concludes that there are no significant environmental impacts associated with the proposed action.

Environmental Impacts of the Alternatives to the Proposed Action:

As an alternative to the proposed action, the staff considered denial of the proposed action (i.e., the no-action alternative). Denial of the application would result in no change in current environmental impacts. The environmental impacts of the proposed action and the alternative action are similar.

Alternative Use of Resources:

The action does not involve the use of any different resource than those previously considered in the Final Environmental Statement for Monticello dated November 1972.

Agencies and Persons Consulted:

On January 6, 2004, the staff consulted with the Minnesota State official, Nancy Campbell of the Department of Commerce, regarding the environmental impact of the proposed action. The State official had no comments.

FINDING OF NO SIGNIFICANT IMPACT On the basis of the environmental assessment, the NRC concludes that the proposed action will not have a significant effect on the quality of the human environment. Accordingly, the NRC has determined not to prepare an environmental impact statement for the proposed action.

For further details with respect to the proposed action, see NMCs letter of December 6, 2002, as supplemented September 24, 2003. Documents may be examined, and/or copied for a fee, at the NRCs Public Document Room (PDR), located at One White Flint North, Public File Area O1 F21, 11555 Rockville Pike (first floor), Rockville, Maryland. Publicly available records will be accessible electronically from the Agencywide Documents Access and Management System (ADAMS) Public Electronic Reading Room on the Internet at the NRC Web site, http://www.nrc.gov/reading-rm/adams.html. Persons who do not have access to ADAMS or who encounter problems in accessing the documents located in ADAMS, should contact the NRC PDR Reference staff by telephone at 1-800-397-4209 or 301-415-4737, or by e-mail to pdr@nrc.gov.

Dated at Rockville, Maryland, this 6th day of January 2003.

FOR THE NUCLEAR REGULATORY COMMISSION

/RA/

L. Raghavan, Chief, Section 1 Project Directorate III Division of Licensing Project Management Office of Nuclear Reactor Regulation