ML20079D624
| ML20079D624 | |
| Person / Time | |
|---|---|
| Site: | Comanche Peak  |
| Issue date: | 07/15/1991 |
| From: | William Cahill TEXAS UTILITIES ELECTRIC CO. (TU ELECTRIC) |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| TXX-91241, NUDOCS 9107190158 | |
| Download: ML20079D624 (4) | |
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- TXX-91241 Filt: # 10010 915.9 TUELECTRIC July 15, 1991 Williara J. Cahm, Jr.
Eucutsw Vice Pressdent U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, D.C. 20555
SUBJECT:
COMANCHE PEAK STEAM ELECTRIC STA110N (CPaES)-UtilT 2 DOCKET NO. 50-446 UTillZAT10fl 0F WESTINGHOUSE OPTIMlZED FUEL ASSLMBLIES IN UNIT 2 Gentlemen: The utilization of Westinghouse supplied Optimized Fuel Assemblies (OFA) in Unit 2 of Comanche Peak Steam Electric Stati'an (CPSES) was discussed with the NRC Staff on June 19, 1991, As a follow-up to that discussion, additional information regardirig the fuel assembly design and associated safety i'ialyses is provided herein. Note that Westinghouse retains responsibility for performing all safety analyses on behalf of TU Electric except the analysis of the Steam Generator Tube Ruptore Event (SGTR). A list of the codes and references used in support of Unit 2 safety and transient antlysis is previded in an attachment to this letter. 1. Mechanical Desion and Analysis The principal dif f erences between the fuel assembly mechm.ica' a !ans of 0FA and standard fuel, such as that employed in U i' 1, re shten below. ti d anical Dosion Comparison OFA S t a nd g_rd Clad OD, inches 0.360 0.3/4 Fuel Mass. KaU 424 461 Spacor Grid f taterial Inc intenel .. : r Active toel region oniv. 9107190158 910715 g pr< -cxosoogg6- ,,,s,,,,01,,,s,,,,, u,.,, o,,,,,,,,,,,,,,, \\o
3 'y. TXX;91241 Page.2 of:-3 The mechanical' analysis of the tinit 2 fuel employs items 1 and 2 of the attachment-in addition to those~ utilized in the analysis of the Unit 1 __ core. A very similar 0FA design has previously been used in Catawba Unit 1. The initial core for CPSES Unit 2 will incorporate-Wet Annular Burnable - . Absorber (WABA) rods. These burnable absorbers are discussed in item-3 of=the attachment. Cycle 2 of CPSES Unit 1. seneduled for startup in late 1991,.will also utilize WABA rods. 2. Nuclear Design. The nuclear design analyses have been performed with standard . Westinghouse methodology. - In addition to thel computer codes utilized for CPSES Unit.1.. Cycle: 1, :the ~ PALAD0N computer code, items 4 and 5 of the. attachment, was employed for the analyses of Unit 2. -3. - Loss of Coolant Accident Analysis The large Break -Loss of Coolant Accident (LOCA) Analysis employs the 1981 Westinghotse ECCS Evaluation model, item 6 of the attachment. This-methodology has inn approved f or application to CPSES Unit-2 in items -7 ' and,8 of the atta;hment. The 5nall Break LOCA Analysis uses the 1975 Westinghouse ECCS Evaluation model 1 1 tem 9 of.the attachment. The same methodology was previously - applied to CPSES Unit 1. 4. - Thermal Hydraulle Analysis-The core pressure drop f or the OFA design.is slightly dif ferent from that of standard fuel dtie to the-fuel rod diameter and spacer grid, differences. The verification testing performed.on the. Westinghouse 17 x 17 0FA is described in item 1 of the attachment. The report in item 1 . of the attachment also.contains the results of-the Critical Heat Flux - ( CilE) tests. Westinghouse further documents, in item 10 of the attachment, that the WRB-1 correlation, the-Improved Thermal: Design Procedure-(ITDP), and the THINC-IV code (items 11, 12, and 13 of the - attachment. respectively). are applicable and approved. f or 0FA design purposes. L l w w- .wme ~,.,,r_. s -,,w vc-- m M+--o- -ass ~.,- e v w ver w y--w- ~r ,e -x y s
's .TXX 91241 .Page 3-of 3 5. Non-LOCA~ Accident Ant YSiS l .Ali-computer programs'(principally LOFTRAN, item 14 of the attachment). - utilized by.. Westinghouse in-the analyses of the-Chapter 15 non'LOCA . events, are cither. identical to those used for the standard 17 x 17 f uel or have been modified and approved for use with the-optimized 17.x 17-fuel..A-description ~of the methodology is contained in item 2 of the attachment, Til Electric is. responsible for the analysis of -the.SGTR event. The Tl! Electric-methodology has been reviewed and. approved by the NRC in item 15 of the attachment. TV Electric intends to submit the OFA related FSAR amendments, in support of -Unit 2 licensing, in February, 1992. Sincerely, W. J. Cahill, Jr. By: .\\ D. R. Woodlan i Manager, Docket Licensing WJCikh ' Attachment c: 'Mr. R. D. Martin,c_ Region.IV Resident inspectors, CPSES-(2) Mr. M.,-B. F hlds. NRR r
m._ _ m._ _. ^< Attachment to 1XX-91241- 'Page 1 of.1, 1. " Verification Testing and Analyses of the 17 x 17. Optimized fuel Assembly,"-WCAP-9401 P A and WCAP-9402-A, March 1979. .2; " Reference. Core Report
- 17 7 17 Optimized fuel Assembly," WCAP 9500-A, May, 1982.
3, ' Westinghouse Wet Annular Burnable. Absorber Evaluation Report," WCAP 10021-P-a, Revision 1, and WCAP-10377 A, October, 1983. 4. "PALADOH-Westinghouse Nodal Computer Code,"-_WCAP-9485-P-A, December, 1978, 5. ."PALAD0ll Westinghouse Hodal Computer Code,"- WCAP-9485-P A, Supplement 1. September, 1981, '6. " Westinghouse ECCS Evaluation Model, 1981 Version," WCAP-9220 P A,. WCAP-9221 A, Revision 1;-1981, 7. " Safety Evaluat10n Report Related to Operation of Comanche Peak Steam Electric Station, Units 1 and 2," flVREG-0797 Supplement 21. April, 1989, 6. " Safety Evaluat1on Report Rela: ad to Operation of Comanche Peak Steam ' Electric Statlon.,-Units 1 and 1 " NUREG 0797, Supplement 24, April, 1991. 9. " Westinghouse Emergency Core Cooling System Small Break October 1975 Model," WCAP-8971-A, Ap ri l, 197 7, 10,' _"NRC' Safety Evaluation Reports and Westinghouse Summaries for WCAP-l 9401/9402-and WCAP 9500," June, 1981, 111. "New Westinghouse Correlation WRB-l_for Predicting Critical lleat Flux in L ad-Bundles with Mixing Vane Grids," WCAP-8762-P-A anu WCAP 8/63-A, .i.ly, 19 76, .12. " Improved Thermal ' Des ign Procedure," WCAP-8567-A, July, 1975. o L 13. "THINC-IV' An' Impioved Frrgric for Thermal-Hydraulic Analysis of Rod Bundle Cores," WCAP-7956-A, June, 1973. 14. "LOFTRAN Description " WCAP-790/-P A, April, 1984. L15. " Safety Evaluation Report Related to the Operation of Comanche Peat j' Steam Electric Station, Units-1 and 2
- flVREG-0797, Suppi cment flo. 23, February. 1993.
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