ML18068A424

Summary of 980528 Meeting W/Util Re Revised Reactor Vessel Fluence Calculations for Palisades Plant.List of Attendees Encl

ML18068A424
Person / Time
Site:	Palisades
Issue date:	08/31/1998
From:	Robert Schaaf NRC (Affiliation Not Assigned)
To:	NRC (Affiliation Not Assigned)
References
NUDOCS 9809080367
Download: ML18068A424 (4)

Text

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i UNITED STATES NUCLEAR REGULATORY COMMiSSION WASHINGTON, D.C. 20565-4001 August 31~ 1998 LICENSEE:

Consumers Energy Company FACILITY:

Palisades Nuclear Plant

SUMMARY

OF THE MAY 28, 1998, MEETING REGARDING PALISADES NUCLEAR PLANT REACTOR VESSEL PTS EVALUATION A meeting was held at NRC Headquarters on May 28, 1998, between Consumers Energy Company and the NRC to discuss the. revised reactor vessel fluence calculation for the Palisades plant. A list of attendees is provided in Enclosure 1. The purpose of the meeting was to facilitate technical exchange regarding the unresolved issues identified in the staffs December 20, 1996, interim safety evaluation (SE) concerning the licensee's April 4, 1996, submittal that provided a reevaluation of reactor pressure vessel (RPV) neutron fluence exposure.

The licensee's revised fluence evaluation calculated a reduction in RPV fluence of 25-percent, resulting in the Palisades RPV reaching the 10 CFR 50.61 (PTS rule) screening criteria in late-2011. This fluence reduction consisted of: (1) an 8-percent reduction resulting from changes in physical plant parameters; and (2) a 17..:percent reduction due to a combination of

• biasing of the calculated fluence with the results of RPV and reactor cavity dosimetry measurements and adjustment of the measured and calculated fluence values using a least-squares spectral adjustment code. The staffs interim evaluation approved the 8-percent reduction due to changes in physical plant parameters, resulting in the Palisades RPV reaching the PTS rule screening criteria in mid-2003. The staff did not approve the 17-percent reduction due to biasing of the calculated RPV fluence and the least-squares spectral adjustment.

The licensee indicated that the primary focus of its presentation would be on the methodology of combining calculated and measured fluence values to obtain a best-estimate of the vessel fluence. The licensee stated its belief that the methodology is consistent with 10 CFR 50.61, Draft Regulatory Guide DG-1053, and applicable ASTM standards. The licensee stated its objectives for the meeting were to present the methodology and solicit staff feedback on what additional fnformation would be needed for the staff to complete its review.

• Westinghouse, the licensee's contractor, presented a historical review of the fluence calculation methodology, including an overview of its development, a description of its components, and a description of benchmarking performed to validate the methodology. The presentation material is provided in Enclosure 2. The licensee concluded that the combination of plant specific measurements and calculation, using a least-squares evaluation, provides the most appropriate method for determining the best-estimate vessel neutron exposure.

Following the presentation, the participants discussed areas of contention regarding application of the methodology to the. Palisades reactor vessel. These include uncertainties assigned to th.e capsule dosimetry values, the dosimeter thresholds, and energy spectrum dependence.

Tne particip-ants also-discussed the relative merits of use of bias values based on a fleet-wide 98()908036 7-980831--*IIY-::~l PDR ADOCK -05000255 : :/ I

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2 data base versus plant-specific bias values. The staff indicated that use of a well-justified fleet-wide bias could be acceptable.

. The staff indicated that its concern with the Palisades plant-specific bias determination is

. related to the uncertainties assigned to the capsule dosimetry data input to the least-squares adjustment code. The staff stated that the uncertainty values assigned to the dosimetry data have not been adequately justified. The staff acknowledged that adjustments to the measured and/or calculated fluence values could be acceptable, provided that they are made based on statistically valid and qualified data bases.

• The licensee reiterated its belief that the proposed methodology is sound and requested that the staff provide specific, detailed questions regarding additional information needed to complete the review of,the methodology. The staff indicated that it would develop questions to be forwarded to the licensee in a request for additional information (RAI). By letter dated July 31, 1998, the staff forwarded its RAI to the licensee.

Enclosures:

As stated (2)

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ORIGINkL SIGNED BY Robert G. Schaaf, Project Manager Project Directorate 111-1 Division of Reactor Projects - Ill/IV

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M.A. Mitchell (MAM4)

E. Hacket (EMH1)

B. *B*urgess (BAB2)

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DOCUMENT NAME: G:\\WPDOCS\\PALISADE\\PAL0528.MTS To receive a copy of this document, indicate in the box C=Copy w/o atta~hment/enclosure E=Copy with attachment/enclosl)re N = No copy OFFICE PM:PD31 D:PD31 NAME RSchaaf:d CA Carpente DATE

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~ l'!fO 198 FICIAL RECORD COPY

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'9 Consumers Energy Company cc:

Mr. Thomas J. Palmisano Site Vice President Palisades Plant 27780 Blue Star Memorial Highway Covert, Michigan 49043 Mr. Robert A Fenech, Sr Vice Pres Nuclear, Fossil, and Hydro Operations Consumers Energy Company 212 West Michigan Avenue Jackson, Michigan 49201 Arunas T. Udrys, Esquire Consumers Energy Company 212 West Michigan Avenue Jackson, Michigan 49201 Regional Administrator, Region Ill U.S. Nuclear Regulatory Commission 801 Warrenville Road Lisle, Illinois 60532-4351 Jerry Sarno, Supervisor Covert Township P. 0. Box 35 Covert, Michigan 49043 Office of the Governor P. 0. Box 30013 Lansing, Michigan 48909 U.S. Nuclear Regulatory Commission Resident Inspector's Office Palisades Plant 27782 Blue Star Memorial Highway Covert, Michigan 49043 Palisades Plant Drinking Water and Radiological Protection Division Michigan Department of Environmental Quality 3423 N. Martin Luther King Jr Blvd P. 0. Box 30630 CPH Mailroom

• Lansing, Michigan 48909-8130 Michigan Department of Attorney General Special Litigation Division 630 Law Building P.O. Box 30212 Lansing, Michigan 48909

• Mr. Nathan L. Haskell Director, Licensing Palisades Plant 27780 Blue Star Memorial Highway Covert, Ml 49043 August 1998

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MEETING A TIEN DANCE MEETING REGARDING PALISADES NUCLEAR PLANT REACTOR VESSEL FLU ENCE CALCULATION Name Ralph Caruso Lambros Lois Tony Ulses Robert Schaaf Barry Elliot Mathew Mitchell Santos Cayetano John Carew Nicholas Tsoulfanidis Daniel J. Malone Nathan Haskell George Goralski John Kneeland Ross Snuggerud Stan Anderson John Perock Patrick Griffin Richard Maerker Affiliation NRC/NRR/SRXB NRC/NRR/SRXB NRC/NRR/SRXB NRC/NRR/PD31 NRC/NRR/EMEB NRCNRRIEMEB NRC/RES/DET Brookhaven National Laboratory University of Missouri-Rolla Consumers Energy Consumers Energy

• Consumers Energy Consumers Energy Consumers Energy Westinghouse Westinghouse Sandia National Laboratory Oak Ridge National Laboratory (ret.)

ENCLOSURE 1