NLS9100405, Requests Extension Until 920131 to Complete Actions in Response to Generic Ltr 88-20 Re Individual Plant Exams for Severe Accident Vulnerability (10CFR50.54(f))

Requests Extension Until 920131 to Complete Actions in Response to Generic Ltr 88-20 Re Individual Plant Exams for Severe Accident Vulnerability (10CFR50.54(f))

ML20081M514
Person / Time
Site:	Cooper
Issue date:	06/27/1991
From:	Horn G NEBRASKA PUBLIC POWER DISTRICT
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
GL-88-20, NLS9100405, NUDOCS 9107100004
Download: ML20081M514 (3)

Text

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1. GENERAL 08FICE y -

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P O DO E 4H. COLUMDUS. NEBRASKA 68602 o4W H #m]j k N ebraska Public Power District "73M'42nt"

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NLS9100405 June 27, 1991 U. S. Nuclear Regulatory Commission Attention: Document Control Desk Unshington, DC 20555

Subject:

Cenoric Letter 88-20, Individual Plant Examination for Severe Accident Vulnerabilities 10CFR50.54(f), Request for Extension Cooper Nuclear Station Docket No. 50-298, DPR 46

References:

1) Individual Plant Examination for Severe Accident Vulnerabilities - 10CFR50.54(f), Generic Letter 88 20, dated November 23, 1988

2) Letter from L. C. Kunci (NPPD) to U. S. NRC Document Control Desk dated October 31, 1989;

Subject:

Response to Generic Letter 88 20

3) letter from P. W. O'Connor (NRC NRR) to C. A. Trevors (NPPD) dated January 12, 1990;

Subject:

Review of 60-Day Responso to Generic Letter 88 20, Individual Plant Examinations (IPE)

Centlemen:

The Nuclear Regulatory Commission (NRC) requested in Reference 1, pursuant to 10 CFR 50.54(f), that licensees perform an Individual Plant Examination (IPE) to identify any plant specific vulnerabilities to severe accidents and submit the results to the NRC. In response to Reference 1, and associated supplements, the Nebraska Public Power District (District) committed (Reference 2) to perform an IPE for the Cooper Nuclear Station (CNS). The IPE would utilize a Level I Probabilistic Risk Assessment (PRA), and would include an analysis for internal floods. The District also committed to conduct a containreent performance analysis following the general guidance given in Appendix 1 to Generic Letter 88-20 (Reference 1). As documented in Reference 3, the NRC has reviewed the District's response to Reference 1 and has concluded that the District's IPE approach, methodology, and schedule are acceptable.

The District has taken a comprehensive and conservative approach in developing and documenting the IPE effort. Although the District is currently in the process of completing the Level I PRA ef fort, delays in the Level I PRA original schedule have occurred as a result of the increased magnitude of District review and involvement beyond that previously anticipated, the complexity and documentation requirements which have exceeded original estimates, and limited availability of qualified PRA personnel in the industry. The District is also determined to maintain a high level of in house engineering and operations involvement throughout the PRA process for further incorporation of this process into other programs.

As stated in Reference 2, the District committed to the completion of a containment performance analysis. The containment performance analysis would bq 9107100004 910627 $f PDR ADOCK 05000208 ,

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NLS9100405 June 27, 1991

• Page 2 of 3 accomplished via a Level II PRA performed in accordance with Appendix 1 to Generic Letter 88-20, It had been anticipated that the Level 11 PRA could begin in November 1990. The delays in completing the Level 1 PRA have extended the start date of the Level 11 PRA to November 1991.

The District believes, for the reasons previously given, that the Level 11 PRA will also take significantly longer than originally expected. This expectation is based on several lessons learned during the Level I PRA evaluation. These lessons are:

• The increased amount of time and District personnel (both corporate dnd on-site) involvement required for internal review, technical assistance, and technology transfer. The District is committed to an effective and beneficial internal review process, a high degree of operations involvement, and an ef fective transfer of technology to District personnel,

• The limited availability of industry resources. Qualified contractor expertise is limited and due to the extensive work load, difficult to sustain for long periods.

• The increased amount of PRA documentation deemed necessary over that which was originally conceived. The District is committed to structuring the PRA so it can be maintained and used as a living document.

In addition to the above lessons Icarned, recent information gained at industry meetings has indicated both the ind"stry and its contractors have significantly underestimaced the ac ual time it w ' take to successfully perform a Level II PRA.

In consideration of the above .. som i arned, the District no longer believes that an IPE completion date of ,,br- '91 (Re ference 2) is achievable. This date was based upaa information af Up y contractors and some members of the industry at the time of the mhiv .1 and the District's then limited understanding of the PRA techna q the time required to complete cert:in activities, and technology transfer tequirements. The District, for the reasons given, hereby requests that the NRC authorized completion date in Reference 2 (October 1991) be revised to Au5ust 1992. The revised completion date is consistent with the NRC's expected schedule of three years following the issuance of NUREG 1335, as delineated in Generic Letter 88-20 (Reference 1). This revised completion date request takes into consideration the District's commitment to maintain a high level of in house utility involvement ond ;;o thoroughly document the IPE process for maximum future usage. The scope of the IPE effort remains unchanged from the scope delineated in Reference 2.

As the IPE process continues, the District will continue tc closely monitor the IPE schedule. An update of our progress in sustaining the August 1992 completion date will be forwarded to the NRC prior to January 31, 1992.

If you have any questions regarding this request for extension, please contact thi 7 o f f; ice .

Si cere \y,

u. lohn" Nuc-lear Power Group Lnager

NLS9100405 June 27, 1991 CRil/drun: dis cc: U.S. Nuclear Regulatory Commission

- Region IV Arlington,-TX NRC Resident Inspector Cooper Nuclear Station l

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