ML20116A136

Forwards Proprietary & Nonproprietary Upper Plenum Injection LOCA Program Using SECY-83-472 Methodology, to Address NRC 840315 & 850313 Concerns.Proprietary Rept Withheld (Ref 10CFR2.790)

ML20116A136
Person / Time
Site:	Point Beach
Issue date:	04/19/1985
From:	Newton R WISCONSIN ELECTRIC POWER CO.
To:	Harold Denton, John Miller Office of Nuclear Reactor Regulation
Shared Package
ML19269B430	List: ML20116A136 ML20116A148 ML20116A164
References
NUDOCS 8504240372
Download: ML20116A136 (3)

Text

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lMsconsin Electnc mecwar 231 W. MICHIGAN, P.O. BOX 2046, MILWAUKEE, WI 53201 April 19, 1985 Mr. H. R. Denton, Director Office of Nuclear Reactor Regulation U. S. NUCLEAR REGULATORY COMMISSION Washington, D. C. 20555 Attention: Mr. J. R. Miller, Chief Operating Reactors Branch 3 Gentlemen:

DOCKET NOS. 50-266 AND 50-301 ANALYSIS OF EMERGENCY CORF COOLING SYSTEM WITH UPPER PLENUM INJECTION USING SECY 83-472 METHODOLOGY '

POINT BEACH NUCLEAR PLANT, UNITS 1 AND 2 A revised emergency core cooling system (ECCS) evaluation model and loss-of-coolant accident (LOCA) analysis results were submitted to the NRC on the above dockets in letters dated December 10, 1982 and February 22, 1983, respectively, to specifically account for the effects of upper plenum injection (UPI) at Point Beach Nuclear Plant. The NRC staff responded to these submittals in Mr. Miller's letters dated March 15, 1984 and February 13, 1985. This latest letter identified specific concerns with the proposed evaluation model and requested our response within sixty days of receipt. The concerns identified by the Staff included the following:

1. Inadequate documentation.

2. Absence of sensitivity studies.

3. Absence of physically meaningful models addressing upper plenum phenomena.

4. Inadequate treatment of the effects of UPI on refill, reflood, and heat and mass transfer.

5. Absence of comparison of evaluation model predictions with experiments.

6.

Lack of consideration and non-UPI plants. of the differences between UPI hoc l P94.  ;

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Mr. H. R. Denton April 19, 1985 Wisconsin Electric is participating with Northern States Power Company in an UPI LOCA program which will address each of the Staff's concerns. Westinghouse Electric Corporation will perform the technical tasks of this program and provide licensing support.

The proposed program will use a best-estimate computer progrmm augmented with the required features of Appendix K, as described in NRC Information Report SECY-83-472, " Emergency.

Core Cooling System Analysis Methods". A best-estimate model is more capable of predicting the thermal.and hydraulic phenomena associated with UPI than the current evaluation model. Compliance in each of the areas of concern will be assured as follows:

1. The computer program to be used is documented in NRC and Westinghouse reports. A report will be submitted documenting the distribution of flow injected into the upper plenum and the code validation efforts of the program.

2. Sensitivity studies with varying plant and model parameters are to be performed to determine the effect on peak cladding temperature.

3. The best-estimate programs are based on physically meaningful models to preduct thermal and hydraulic phenomena. A finite-difference numerical technique is used to calculate the thermal and hydraulic phenomena from first principles of heat, mass, and momentum transport.

4. UPI is included as an integral part of the best-estimate model. All parts of the transient (blowdown, refill, and reflood) are predicted by a single thermal-hydraulic transient calculation. The calcu-lation includes mechanistic models for important phenomena, such as top and bottom reflood, entrainment, condensation, and counter-current flow limiting.

5. Best-estimate calculations will be compared to measured data from integral test facilities, such as the cylindrical core test facility (CCTF) and the loss-of-fluid test (LOFT) facility. Comparison will also be made with single effects tests.

6. Accounting for the difference between UPI and non-UPI plants is inherent in a best-estimate model. No assumption is made as to the direction or condition of emergency core coolant flow. UPI is simply specified as a boundary condition where its effect is determined by the solution of continuity, momentum, and energy equations.

I Mr. H. R. Denton April 19, 1985 A detailed description of the program, including a schedule for completion and meetings, is enclosed. The enclosure contains information claimed to be proprietary to the Westinghouse Electric Corporation. This claim is supported by an affidavit signed by Mr. Robert A. Wiesemann representing Westinghouse Electric Corporation, the owner of the information. The affidavit sets forth the basis on which the information may be withheld from public disclosure by the Commission and addresses with specificity the considerations listed in paragraph (b) (4) of 10 CFR 2.790 of the Commission's regulations. A non-proprietary version of the program description and an authorization letter from Westinghouse are also enclosed.

Accordingly, it is respectfully requested that the information which is proprietary to Westinghouse be withheld from public disclosure in accordance with 10 CFR 2.790 of the Commission's regulations. Correspondence with respect to the proprietary aspects of the Application of Withholding or the supporting Westinghouse affidavit should reference CAW-85-032 and should be addressed to R. A. Wiesemann, Manager, Regulatory and Legislative Affairs, Westinghouse Electric Corporation, Post Office Box 355, Pittsburgh, Pennsylvania, 15230.

During this program, several meetings are proposed with the NRC staff to demonstrate compliance with 10 CFR 50.46 and Appendix K. A report on the best-estimate methodology is scheduled for submittal in 1986. Completion of plant-specific analysis for the Point Beach Nuclear Plant is anticipated approximately six months af ter receipt of a NRC Safety Evaluation Report on the best-estimate methodology report.

Please contact us if there are any questions concerning this information.

Very truly yours, s

Vice President-Nuclear Power C. W. Fay Enclosures Copy to NRC Resident Inspector