ML17229A072

Disucsses Aug 1995 Meeting W/Siemens Power Corp Re LBLOCA Evaluation Model.Model Approved by NRC to Meet Requirements of 10CFR50.46

ML17229A072
Person / Time
Site:	Saint Lucie
Issue date:	10/11/1996
From:	Sheron B NRC (Affiliation Not Assigned)
To:	Plunkett T FLORIDA POWER & LIGHT CO.
References
TAC-M96355, NUDOCS 9610210093
Download: ML17229A072 (6)

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UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 205584001 October 11, 1996 Hr. T. F. Plunkett President Nuclear Division Florida Power and Light Company P.O.

Box 14000 Juno Beach, Florida 33408-0424

SUBJECT:

10 CFR 50.46 LARGE BREAK LOSS-OF-COOLANT ACCIDENT EYALUATION MODEL FOR ST.

LUCIE PLANT, UNIT 1 (TAC NO. H96355)

Dear Hr. Plunkett:

During August 1995, the Nuclear Regulatory Commission (NRC) met with Siemens Power Corporation (SPC) with regard to the large break loss-of-coolant accident (LBLOCA) evaluation model.

As a result of that meeting, we sent a

letter to SPC, dated November 13,

1995, which identified problems concerning changes in the model used by SPC for pressurized water reactors.

This model.

was approved by the NRC staff to meet the requirements of 10 CFR 50.46 in the letter of July 8,

1986, from D.H. Crutchfield (NRC) to G.

Ward (Exxon).

In the staff's letter of November 13,

1995, we stated that SPC had made changes to the NRC-approved Fuel Cooling Test Facility (FCTF) reflood heat transfer coefficient correlation used in the TOODEE2 computer code and did not properly assess the significance of the code changes.

It appears that the following two major changes were made to the FCTF correlation in the TOODEE2 code:

(1) some nonphysical non-monotonic behavior of the FCTF heat transfer coefficient correlation with respect to the reflood rate were eliminated and (2) the quench time calculation used in the model, using data from Cylindrical Core Test Facility (CCTF) experiments, was modified.

By letter dated March 13, 1996, the staff requested SPC to address the changes to the TOODEE2 model and the code errors identified since July 1986.

On June 2,

1996, SPC submitted topical report XN-NF-82-20, "EXEM/PWR Large Break LOCA ECCS TOODEE2 Updates,"

Revision 1, Supplement 5, which described the updates made to the TOODEE2 computer code since 1986.

The staff has completed its review of this report and has concluded that the proposed LBLOCA-ECCS model (i.e.,

1991 model) is not acceptable and the previous approved model (i.e., the 1986 model) has an unacceptable error in the model.

The staff's letter to SPC dated October 11, 1996, which includes the summary of conference calls with SPC on October 10 and 11,

1996, on this matter, will be telecopied separately.

9b10210093 9bi011 POR AOOCY 05000335 P,

PDR

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Hr. T. F. Plunkett Because of the staff's conclusions regarding the unaccepability of the reflood heat transfer coefficient correlation used in the TOODEE2 computer code, we conducted a conference call on Thursday, October 10, 1996, with several licensees, including a representative of your plant.

Other participants were representatives from Comanche Peak Station Units I/2, Kewaunee Plant, Harris P

Hillstone Station Unit 2, Palisades Plant Robinson Plant U it 2 Sh lant Unit 1, and SPC.

The purpose of the conference call was to t

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inform each licensee that the staff had found changes in the unapproved 1991 LBLOCA evaluation model, which were intended to address problems with the approved 1986 model used by SPC for the LBLOCA and emergency core cooling system analyses, unacceptable.

In addition, the staff indicated that it will not accept LBLOCA analyses using the previously approved 1986 model unless that model adequately corrects the non-physical behavior observed in the reflood heat transfer correlation.

Therefore, in accordance with 10 CFR 50.46(a)(3)(ii), you should 'assess the impact of these model errors and changes and take whatever actions are required to assure compliance with 10 CFR 50.46.

Further, as you were informed in the conference call, the staff has scheduled a public meeting on October 16, 1996, at 1:00 pm, in 0-12811, at its Headquarters Offices.

The affected plants and SPC were requested to attend this meeting to present the

. results of their assessment of the peak cladding temperature for the LBLOCA undertaken bo and the corrective actions"and compensatory measures that h

b a

ave een CFR 50.46.

, both short-term and long-term, to assure plant compliance

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Wl If you have any. questions about this matter, please contact Leonard Niens at 301-415-1495, or Jack Donohew at 301-415-1307..

Sincerely, H]u L Brian W. Sheron, Acting Associate Director for Technical Review Office of Nuclear Reactor Regulation Docket No. 50-335 cc:

See next page

Mr. T. F. Plunkett 2

li October 11, 1996 DISTRIBUTION:

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Hr. T. F. Plunkett Florida Power and Light Company ST.

LUCIE PLANT CC:

Jack Shreve, Public Counsel Office of the Public Counsel c/o The Florida Legislature 111 West Madison Avenue, Room 812 Tallahassee, Florida 32399-1400 Senior Resident Inspector St. Lucie Plant U.S. Nuclear Regulatory Commission 7585 S.

Hwy AIA Jensen

Beach, Florida 34957 Joe Hyers, Director Division of Emergency Preparedness Department of Community Affairs 2740 Centerview Drive Tallahassee, Florida 32399-2100 J.

R.

Newman

Morgan, Lewis 5 Bockius 1800 H Street, NW.

Washington, DC 20036 John T. Butler, Esquire

Steel, Hector and Davis 4000 Southeast Financial Center Miami, Florida 33131-2398 Hr. Thomas R.L. Kindred County Administrator St. Lucie County 2300 Virginia Avenue Fort Pierce, Florida 34982 Mr. Charles Brinkman, Manager Washington Nuclear Operations ABB Combustion Engineering, Nuclear Power 12300 Twinbrook Parkway, Suite 330 Rockville, Maryland 20852 Mr. Bill Passetti Office of Radiation Control Department of Health and Rehabilitative Services 1317 Winewood Blvd.

Tallahassee, Florida 32399-0700 Regional Administrator Region II U.S. Nuclear Regulatory Commission 101 Marietta Street, NW. Suite 2900 Atlanta, Georgia 30323 H.

N. Paduano, Manager Licensing 8 Special Programs Florida

Power, and Light Company P.O.

Box 14000 Juno

Beach, Florida 33408-0420 J.

A. Stall, Site Vice President St.

Lucie Nuclear Plant P. 0.

Box 128 Ft. Pierce, Florida 34954-0128 J. Scarola Plant General Manager St. Lucie Nuclear Plant P.O.

Box 128 Ft. Pierce, Florida 34954-0128 Hr. Kerry Landis U.S. Nuclear Regulatory Commission 101 Marietta Street, N.W. Suite 2900 Atlanta, Georgia 30323-0199 E. J.

Weinkam Licensing Manager St. Lucie Nuclear Plant P.O.

Box 128 Fort Pierce, Florida 34954-0128

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