ML20217K771

Refers to 960726 License Amend Request Submitted by NSP to Increase MNGP Operating License Max Power Level.Requests That NSP Submit Responses to RAIs & 0306 by 980529

ML20217K771
Person / Time
Site:	Monticello
Issue date:	04/24/1998
From:	Kim T NRC (Affiliation Not Assigned)
To:	Richard Anderson NORTHERN STATES POWER CO.
References
TAC-M96238, NUDOCS 9805040111
Download: ML20217K771 (3)

Text

,.

APdl 24,1998 Mr. Rog:r O. And:rson, Dir:ctor Licensing and Management issues Northern States Power Company 414 Nicolet Mall Minneapolis, Minneapolis 55401

SUBJECT:

MONTICELLO NUCLEAR GENERATING PLANT - REQUEST FOR ADDITIONAL INFORMATION ON LICENSE AMENDMENT REQUEST ENTITLED " SUPPORTING THE MONTICELLO NUCLEAR GENERATING PLANT (MNGP) POWER RERATE PROGRAM" (TAC NO. M96238)

Dear Mr. Anderson:

)

By letter dated July 26,1996, Northern States Power Company (NSP) submitted a license j amendment request to increase the MNGP operating license maximum power level to j 1775 megawatts thermal and revise supporting MNGP Technical Specifications. This change I reflects an increase of 6.3 percent above the currently licensed power level of 1670 megawatts I thermal.

On April 14,1997, the staff issued its request for additional information (RAI) based on .s I preliminary review of the July 26,1996, submittal. NSP responded to the staff's RAI in a Tier I dated September 5,1997. Subsequently, by a letter dated December 4,1997, NSP submitted l Revision 1 to the original submittal dated July 26,1996. '

By letters dated February 11 and March 6,1998, the staff issued RAls based on a review of the submittals dated September 5 and December 4,1997. The staff has identified additional 1 information required to complete its review. The staff discussed the information in the enclosed i RAI with your staff during a telephone conference on April 24,1998. Because your staff I indicated that its efforts to respond to this RAI will impact its schedule for responding to NRC's RAI on NSP's IPEEE [ Individual Plant Examination of External Events) for Monticellt (originally scheduled for April 30,1998), we request that NSP submit its responses to both RAls by May 29,1998.

Sincerely, ORIGINAL SIGNED BY  ;

Tae Kim, Senior Project Manager )

Project Directorate 111-1 l Division of Reactor Projects -lil/IV l Office of Nuclear Reactor Regulation Q,

Docket No: 50-263

Enclosure:

As stated phgp

/

cc w/ encl: See next page I M O Np h h k y2 f f? G TJ DISTRIBUTION:

% Docket Filei OGC PUBLIC ACRS PD31 RF EAdensam (EGA1) JMcCormick-Barger, Rill MRubin AEl-Bassioni Slee DOCUMENT NAME: G:\WPDOCS\MONTICEL\ MON 96238.RA3 To RECEtVE A COPY OF THIS DOCUMENT, INDICATE IN THE Box: "C" = COPY WITHouT ENCLOSURES "E" = COPY WITH ENCLOSURES "N" OFFICE PD31:PM PD31:LA PD31:PD NAME TJKim:db%k CJamerson @)// irr CACarpenter @

DATE 4/ 2 p /I8 4/ M /98 4/ M /98 OFFICIAL RECORD COPY 9805040111 980424 PDR ADOCK 05000263 l P PDR

i l

)

Mr. Roger O. Anderson, Director Monticello Nuclear Generating Plant Northem States Power Company l

cc:

J. E. Silberg, Esquire Kris Sanda, Commissioner Shaw, Pittman, Potts and Trowbridge Department of Public Service 2300 N Street, N. W. 121 Seventh Place East

Washington DC 20037 Suite 200 l St. Paul, Minnesota 55101-2145 U.S. Nuclear Regulatory Commission Rasident inspector's Office Adonis A. Nebiett

! 2807 W. County Road 75 Assistant Attomey General

! Monticello, Minnesota 55362 Office of the Attomey General I 445 Minnesota Street l Plant Manager Suite 900 l Monticello Nuclear Generating Plant St. Paul, Minnesota 55101-2127 l ATTN: Site Licensing Northem States Power Company 2807 West County Road 75 Monticello, Minnesota 55362-9637 Robert Nelson, President l

Minnesota Environmental Control Citizens Association (MECCA) 1051 South McKnight Road St. Paul, Minnesota 55119 Commissioner i Minnesota Pollution Control Agency 520 Lafayette Road St. Paul, Minnesota 55119 Regional Administrator, Region ill U.S. Nuclear Regulatory Commission .

1 801 Warrenville Road

( Lisle, Illinois 60532-4351 i

Commissioner of Health i Minnesota Department of Health j 717 Delaware Street, S. E.

Minneapolis, Minnesota 55440  ;

i Darla Groshens, Auditor / Treasurer Wright County Govemment Center 10 NW Second Street Buffalo, Minnesota 55313 Jariuery 1995 1

]

l 1

e REQUEST FOR ADDITIONAL INFORMATION RELATING TO LICENSE AMENDMENT REQUEST DATED JULY 26.1996 SUPPORTING THE MONTICELLO NUCLEAR GENERATING PLANT POWER RERATE PROGRAM (DOCKET NO. 50-263)

1. NSP concluded that based on its review of scram trip setpoints (and their changes) power rerate showed no significant effect on trip (initiating event) frequency. Provide a basis / discussion for this conclusion.

2. NSP indicated that the likelihood of all eight SRVs [ safety relief valves) failing is not significantly different from the likelihood of at least seven out of eight SRVs failing.

Provide a basis / discussion for tMe conclusion.

3. NSP concluded that the failure rates of equipment / components will not change due to power rerate. Provide a basis / discussion for this conclusion, j

4. On page 37 of the September 5,1997, submittal, NSP reported that from the baseline Level 2 PRA (probabilistic risk assessment), the potential for a large early release is on the order of 3% of the total CDF [ core damage frequency) and that this frequency remains at about 3% for the rerate CDF. The large early release frequency reported in the Monticello IPE (individual plant evaluation) was 4.15E-6/Yr, which represented about 16% of its estimated CDF (2.6E-5/Yr). Provide a basis / discussion for the difference between LERF [large early release frequency] estimated for IPE and LERF estimated i for baseline and rerate analysis.

5. Page 10-16 of the December 4,1997, submittal stated in part: "a sensitivity study was i performed for tornado missiles which resulted in a negligible increase in risk." Provide a discussion on what this study entails and the basis for concluding that .its effect on risk is negligible.  !

l i

l ENCLOSURE