ML20148C739

Forwards Staff Evaluation Rept of Prairie Island Nuclear Generating Plant IPE for Internal Events & Internal Floods Submitted on 940301 in Response to GL 88-20.Staff Concludes Utility Met Intent of Generic Ltr

ML20148C739
Person / Time
Site:	Prairie Island
Issue date:	05/16/1997
From:	Wetzel B NRC (Affiliation Not Assigned)
To:	Richard Anderson NORTHERN STATES POWER CO.
Shared Package
ML20148C745	List: ML20148C739 ML20148D544 ML20148D546
References
GL-88-20, TAC-M74454, TAC-M74455, NUDOCS 9705290036
Download: ML20148C739 (3)

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.\ . . . . . ,o/ May 16, 1997 1 Mr. Roger 0. Anderson, Director Licensing and Management Issues Northern States Power Company gy g 5

414 Nicollet Mall Minneapolis, Minnesota 55401

SUBJECT:

STAFF EVALUATION OF THE PRAIRIE ISLAND NUCLEAR GENERATING PLANT it INDIVIDUAL PLANT EXAMINATION (IPE) SUBMITTAL - INTERNAL EVENTS

, (TAC NOS. M74454 AND M74455)

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Dear Mr. Anderson:

i{ The purpose of this letter is to transmit our evaluation of your IPE which you j submitted on March 1, 1994, in response to~ Generic Letter 88-20, " Individual

Plant Examination for Severe Accident Vulnerabilities." In addition, Northern

States Power Company responded to the staff's requests for additional

, information by letters dated February 27, 1996, and September 5, 1996.

Enclosed is the Staff Evaluation Report (SER) of the Prairie Island Nuclear Generating Plant IPE for internal events and internal floods. The i- contractor's Technical Evaluation Report (TER) is attached as Appendix A of j the SER.

l A " Step 1" review was performed to examine the IPE results for their

. " reasonableness" considering the design and operation of the Prairie Island j Nuclear Generating Plant. The staff employed Brookhaven National Laboratory i; to review the front- and back-end analyses of the IPE submittal, and Sandia j National Laboratories to review the human reliability analysis. The TER was j reviewed by the IPE " Senior Review Board" (SRB) as part of the NRC quality

assurance process. The SRB is comprised of NRC staff and consultants at '

j Sandia National Laboratories with probabilistic risk assessment expertise.

i* The IPE estimated the core damage frequency to be SE-5/yr from internally i, initiated events, including the contribution from internal floods. Loss-of-coolant accidents contribute 24 percent, station blackout 22 percent, internal flooding 21 percent, transients (without loss of offsite power) 19 percent, l and steam generator tube ruptures 13 percent.

! Strengths of the IPE include a thorough analysis of initiating events and

!, their impact for both units of the plant, descriptions of the plant responses, lt reasonable failure data and common cause factors, and the usage of plant-

specific data whenever possible. In addition, several recommendations for

!! plant improvements were made as a result ot' insights obtained from the IPE.

!' The staff evaluation of the IPE found no fuidamental weaknesses. The f I: " leading" minor weakness is the lack of detail in the individual accident l* sequence descriptions. t i

280059 DP NRC FTE CENTER COPY

9705290036 970516 PDR l

P ADOCK 05000282

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i .- n-- -- - - - - . - - -

, o R. O. Anderson Based on a " Step 1" review, we conclude that Northern States Power Company has met the intent of Generic letter 88-20. Furthermore, the IPE provides an evaluation of all phenomena of importance to severe accident progression in accordance with Appendix ! of the generic letter. A more detailed " Step 2" review will not be conducted. If you have any questions regarding the enclosed SER, please contact me at (301) 415-1355.

Sincerely, YG 0- h Beth A. Wetzel, oject Manager Project Directorate 111-1 Division of Reactor Projects - III/IV Office of Nuclear Reactor Regulation Docket Nos. 50-282 and 50-306

! Enclosurc: Safety Evaluation w/ attachment cc w/ encl: See next page DISTRIBUTION w/ encl:

Docket File i

PUBLIC PD# 3-1 Reading J. McCormick-Barger, RIII S. Ray, SRI, RIII SEDB (TLH3) w/o encl:

J. Roe i E. Chow R. Hernan 0GC ACRS C. Munson DOCUMENT NAME: G:\WPDOCS\ PRAIRIE \PI74454.IPE To receive a copy of this document, indicate in the box C= Copy w/o attechment/ enclosure E= Copy with attachment / enclosure N =

No copy 0FFICE PM:PD31 E LA:PD31 C D:PD31[ k NW BWetZel:dthl CJamerson0h JHannon DATE 5//f/97 5/l5/97 h 5/[O/97 0FFICIAL RECORD COPY

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,  ! Mr. Roger 0. Anderson, Director Prairie Island Nuclear Generating Northern States Power Coripany Plant 4

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, i J. E. Silberg, Esquire Tribal Council

Shaw, Pittman, Potts and Trowbridge Prairie Island Indian Community l i l 2300 N Street, N. W. ATTN

Environmental Department l

'l ; Washington DC 20037 5636 Sturgeon Lake Road l 1: Welch, Minnesota 55089 I

! Plant Manager  !

- Prairie Island Nuclear Generating

• r Plant i' Northern States Power Company 1717 Wakonade Drive East ,

Welch, Ninnesota 55089 t

Adonis A. Nebiett Assistant Attorney General Office of the Attorney General 455 Minnesota Street Suite 900 i St. Paul, Minnesota 55101-2127 U.S. Nuclear Regulatory Commission Resident Inspector's Office i 1719 Wakonade Drive East Welch, Minnesota 55089-9642 l

! Regional Administrator, Region III U.S. Nuclear Regulatory Commission 801 Warrenville Road Lisle, Illinois 60532-4351 Mr. Jeff Cole, Auditor / Treasurer

~

Goodhue County Courthouse Box 408 Red Wing, Minnesota 55066-0408 Kris Sanda, Commissioner Department of Public Service 121 Seventh Place East Suite 200 St. Paul, Minnesota 55101-2145 Site Licensing i Prairie Island Nuclear Generating Plant Northern States Power Company-1717 Wakonade Drive East Welch, Minnesota 55089 November 1996

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