ML023250519

Westinghouse, RAI, Topical Report on Modular Accident Analysis Program Version 5 (MAAP5) Pressurized Water Reactor (PWR) Large Dry Containment Model, WCAP-15844

ML023250519
Person / Time
Site:	Beaver Valley, PROJ0700
Issue date:	11/22/2002
From:	Dan Collins NRC/NRR/DLPM/LPD1
To:	Sepp H Westinghouse
Collins D S, NRR/DLPM, 415-1427
References
TAC MB4716, WCAP-15844
Download: ML023250519 (7)

Text

November 22, 2002 Mr. H. A. Sepp ATTN: Mr. John DeBlazio Manager, Regulatory and Licensing Engineering Westinghouse Electric Company, LLC P. O. Box 355 Pittsburgh, PA 15230-0355

SUBJECT:

REQUEST FOR ADDITIONAL INFORMATION (RAI) REGARDING TOPICAL REPORT ON MODULAR ACCIDENT ANALYSIS PROGRAM VERSION 5 (MAAP5) PRESSURIZED WATER REACTOR (PWR) LARGE DRY CONTAINMENT MODEL, WCAP-15844 (TAC NO. MB4716)

Dear Mr. Sepp:

By letter dated April 1, 2002, Westinghouse Electric Company (W) submitted WCAP-15844, Topical Report on Modular Accident Analysis Program Version 5 (MAAP5) Pressurized Water Reactor (PWR) Large Dry Containment Model, for Nuclear Regulatory Commission (NRC) staff review and approval. The NRC staffs review of WCAP-15844 is being conducted in parallel with the NRC staffs review of an associated amendment request from FirstEnergy Nuclear Operating Company (FENOC) dated June 5, 2002, to allow plant operation of the Beaver Valley Power Station, Unit Nos. 1 and 2 (Beaver Valley), with containments at atmospheric pressure.

The NRC staff has conducted an initial review of your submittal and we have determined that additional information is required in order for the NRC staff to complete its review. Enclosed is the NRC staffs RAI associated with your topical report. These questions were discussed in a joint conference call with representatives from FENOC and W on November 6, 2002. A separate RAI is also being sent to FENOC regarding their plant-specific application to convert the Beaver Valley containments to operation at atmospheric pressure.

H. Sepp The staff of Beaver Valley has proposed that a joint meeting with the NRC and W be held at NRC headquarters on December 10, 2002, to discuss the NRC staffs questions. That date is tentative and is contingent upon the NRC staff receiving docketed responses to this RAI, and the RAI being sent to FENOC, at least 7 days prior to the meeting. If you have any questions, please contact me at 301-415-1427.

Sincerely,

/RA/

Daniel S. Collins, Project Manager, Section 1 Project Directorate I Division of Licensing Project Management Office of Nuclear Reactor Regulation Project No. 700 Docket Nos. 50-334 and 50-412

Enclosure:

RAI cc w/encl: See next page

H. Sepp The staff of Beaver Valley has proposed that a joint meeting with the NRC and W be held at NRC headquarters on December 10, 2002, to discuss the NRC staffs questions. That date is tentative and is contingent upon the NRC staff receiving docketed responses to this RAI, and the RAI being sent to FENOC, at least 7 days prior to the meeting. If you have any questions, please contact me at 301-415-1427.

Sincerely,

/RA/

Daniel S. Collins, Project Manager, Section 1 Project Directorate I Division of Licensing Project Management Office of Nuclear Reactor Regulation Project No. 700 Docket Nos. 50-334 and 50-412

Enclosure:

RAI cc w/encl: See next page DISTRIBUTION:

PUBLIC MOBrien EThrom BPLatchek, RGN-1 Rlobel SRichards ACRS PDI-1 Reading DCollins SDembek ANotafrancesco RLaufer GShukla OGC SWeerakkody RGuzman DOCUMENT NAME: C:\ORPCheckout\FileNET\ML023250519.wpd ACCESSION NO. ML23250519

• see previous concurrence OFFICE PDI-1/LA PDI-1/PM PDI-1/PM SPLB RES/DSARE PDI-1/SC NAME MOBrien RGuzman DCollins SWeerakkody* ANotafrancesco* RLaufer DATE 11/21/02 11/21/02 11/21/02 11/21/2002 11/21/2002 11/21/02 OFFICIAL RECORD COPY

REQUEST FOR ADDITIONAL INFORMATION (RAI)

WESTINGHOUSE ELECTRIC COMPANY BEAVER VALLEY POWER STATION, UNIT NOS. 1 AND 2 REQUEST TO ALLOW PLANT OPERATION WITH ASSOCIATED CONTAINMENT AT ATMOSPHERIC PRESSURE The U.S. Nuclear Regulatory Commission (NRC) staff, with support from its contractor, is reviewing WCAP-15844, Topical Report on Modular Accident Analysis Program Version 5 (MAAP5)

Pressurized Water Reactor (PWR) Large Dry Containment Model, which was submitted for NRC review by letter dated April 1, 2002. The NRCs review of WCAP-15844 is being conducted in parallel with the NRC staffs review of an associated amendment request from FirstEnergy Nuclear Operating Company (FENOC) dated June 5, 2002, to allow plant operation of the Beaver Valley Power Station, Unit Nos. 1 and 2 (BVPS-1 and 2), with containments at atmospheric pressure.

The following questions and concerns regarding WCAP-15844 require clarification or additional information in order for the NRC staff to complete its review. The discussion items here do not represent an exhaustive list since the review of the associated BVPS-1 and 2 calculations and MAAP5 code is currently in progress. For the purpose of organization, the items are listed under general and clarification headings.

1.0 MAAP5 Topical Report 1.1 General Items

1. Have the new MAAP5 general containment models (GCMs) and validation of those models been independently reviewed? What is the technical review process for new modeling in the MAAP code?

2. Have descriptions of the new MAAP5 general containment models and validation been published in any Journals or Conference papers? Has there been a peer review of these models?

3. How will documentation of the new MAAP5 GCM be presented in the Modular Accident Analysis Program (MAAP) manuals? Will the topical report be absorbed into the manual set?

4. What uncertainties (modeling or input parameters) associated with a) mixed and forced convection condensation, b) momentum-driven velocity, and c) water entrainment have been identified through separate effects tests?

5. Does the term momentum-driven velocity, as calculated in the MAAP code, have a definition that would allow measurement and/or validation of the momentum velocity model equations? In other words, is the momentum-driven velocity a physical quantity or an abstraction?

1.2 Clarification Items Enclosure

1. How does an empirical calibration of the natural convection condensation model (improved MAAP5 condensation) apply to other modes of condensation, such as mixed or forced convection condensation?

2. Why were no forced convection condensation separate effects tests used in the validation of the improved MAAP condensation modeling?

3. What is the source of the apparent modeling error in the Modular Accident Analysis Program Version 4 condensation model as indicated in the Dehbi tests? Discuss usage of a sensible heat transfer Grashof number (using temperature differences) vs. a composition Grashof number using density differences. Why is a sensible heat transfer Grashof number used for steam condensation in the presence of noncondensible gases?

4. What is the justification for using the Dittus-Boelter equation (duct internal flow) for turbulent convection within confined enclosures?

5. What is the justification for using the Dittus-Boelter or any other one-dimensional heat transfer correlation with the momentum-driven velocity derived as having a property value with no directional dependence? Same question for entrainment correlations?

6. What is the technical basis for a momentum balance constructed using scalar forces and non-directional momentum influx terms? Isnt the classical momentum balance equation a vector equation? Where in the technical literature does one find a similar equation or momentum defined as a fluid property that can be transported as such? Can one transport momentum with an inter-compartment velocity that is significantly different in value than the momentum-driven velocity?

7. Are the FFMULT and FCOND pessimistic, realistic, and optimistic values used for the Carolinas and Virginia Test Reactor (CVTR) calculations those values defined on page 8-6 and 7 of the Topical?

8. To what degree does water entrainment enter into the CVTR calculation? Provide a water entrainment time history profile in compartments for test 3.

9. It appears that Fauske & Associates, Inc. is using the CVTR test 3 measured velocity as a partial validation of the momentum-driven velocity model. However, measurements (both direct and indirect), as well as published CFD calculations for test 3, all indicate that the peak wall velocity is 5-6 times lower than calculated using MAAP. Further, the annular gap velocity calculated by MAAP is approximately twice the value reported in the CVTR final report. Please comment. What additional, direct validation of calculated momentum-driven velocity has been obtained (other than CVTR) through the 5SSTAR process?

10. Provide a comparison of CVTR heat plug 2 heat transfer coefficients calculated for the MAAP uncertainty parameters.

Beaver Valley Power Station, Units 1 and 2 Mary OReilly, Attorney Rich Janati, Chief FirstEnergy Nuclear Operating Company Division of Nuclear Safety FirstEnergy Corporation Bureau of Radiation Protection 76 South Main Street Deparment of Environmental Protection Akron, OH 44308 Rachel Carson State Office Building P.O. Box 8469 FirstEnergy Nuclear Operating Company Harrisburg, PA 17105-8469 Regulatory Affairs/Performance Improvement Larry R. Freeland, Manager Mayor of the Borough of Beaver Valley Power Station Shippingport Post Office Box 4, BV-A P O Box 3 Shippingport, PA 15077 Shippingport, PA 15077 Commissioner James R. Lewis Regional Administrator, Region I West Virginia Division of Labor U.S. Nuclear Regulatory Commission 749-B, Building No. 6 475 Allendale Road Capitol Complex King of Prussia, PA 19406 Charleston, WV 25305 Resident Inspector Director, Utilities Department U.S. Nuclear Regulatory Commission Public Utilities Commission Post Office Box 298 180 East Broad Street Shippingport, PA 15077 Columbus, OH 43266-0573 FirstEnergy Nuclear Operating Company Director, Pennsylvania Emergency Beaver Valley Power Station Management Agency ATTN: M. P. Pearson, Director 2605 Interstate Dr. Services and Projects (BV-IPAB)

Harrisburg, PA 17110-9364 Post Office Box 4 Shippingport, PA 15077 Ohio EPA-DERR ATTN: Zack A. Clayton FirstEnergy Nuclear Operating Company Post Office Box 1049 Beaver Valley Power Station Columbus, OH 43266-0149 Mr. B. F. Sepelak Post Office Box 4, BV-A Dr. Judith Johnsrud Shippingport, PA 15077 National Energy Committee Sierra Club Mr. Mark B. Bezilla 433 Orlando Avenue Vice President State College, PA 16803 FirstEnergy Nuclear Operating Company Beaver Valley Power Station J. H. Lash, Plant Manager (BV-IPAB) Post Office Box 4 FirstEnergy Nuclear Operating Company Shippingport, PA 15077 Beaver Valley Power Station Post Office Box 4 Shippingport, PA 15077

Westinghouse Electric Company Project No. 700 cc:

Mr. Gordon Bischoff, Project Manager Westinghouse Owners Group Westinghouse Electric Company Mail Stop ECE 5-16 P.O. Box 355 Pittsburgh, PA 15230-0355