ML19250F425
| ML19250F425 | |
| Person / Time | |
|---|---|
| Site: | Comanche Peak  |
| Issue date: | 04/02/1981 |
| From: | Tedesco R Office of Nuclear Reactor Regulation |
| To: | Anderson T WESTINGHOUSE ELECTRIC COMPANY, DIV OF CBS CORP. |
| Shared Package | |
| ML18023A006 | List: |
| References | |
| NUDOCS 8104220273 | |
| Download: ML19250F425 (6) | |
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2 EB1 Vestinnhouse Electric Corporation ATTH:
?'r. T. M. Anderson, "anacer fluclear Safety Departrent P. O. Ecx 355 Pittsburgh, Pennsylvania 15230
Dear "r. Anderson:
SUBJECT:
ACCEPTANCE FCR CEFEPENCING OF LICENSING TCPICAL EEPORT VCAP-??7P/UC AP 0270 The Muclear Tapulatory Coe-issien has co~pleted its review of the vestinghouse Electric Corporation Licensirg Tooical Report WC AP-??70 end WCAP-P279 (its nonproprieta re version), both entitled "Pydraulic Flos Test of the 17x17 fuel Assembly"<. Tht review encompassed the basic reports ir,cluding appendices A throuch D dated FebrJary 1076, Appendix E antitled "Recuest for Additional Information ( AEC-Core Perfernence Eranch - Directorate of Licenting)' subritted October 22,107L; "9 Grid 17xl? Fuel Assembly Vibration in a D-Loop Test" dated May Ic7c; " responses tn ?'PC Letter of January 23, 1975" subnitted 'tay 20, 1075; and "Surry Unit 1 End o' Cycle 3 Onsite Fuel Exa ination of 17x17 De onstration Asse-blies Af ter Two Cycles of Expnsure" suh,itted January lo,1070 (L
EPC letter from J. P. Yassallo to Mr. C. Eicheldinner dated Octcher 22, 1975 transnitted FPC's Interin Evaluation of WCAP-P27Pr<! CAP 0270 At that sta.ne ~ ~~-
of the review, we found:
i la) WC AD-??7o provided an acceptable basis for denonstratinc fuel assa-bly of l? foot length to be adequate to withstand the effects of flow induced vibration, however, ^!sults of a post irradiation survaillance prograr was necessary for a final conclusion ir. this reaard.
(b) VCAD-R27P is not acceptable as a 5 asis for de crstrating the adecuacy, in general, of the Vestinchouse analytical desien methods; and (c) VEID 0270 is an acceptable ron-proprietery version of VCAD 027.
The surveillanca rroaram at Surry and the operating experience accurulated in new Vestinchouse plants provides the Sesis for nur final conclusions with recard to item (e) above as documented in the Safety Evaluation cf WCAP 827P attacked.
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wr. T. M. Anderson :^r 9 01 As a result of our reviews, we find the Licensino Topical Report WCAP-8278 and its non-proprietary version, WCAP-8279 as aucranted by the data subnitted in the refereoces listed in the Safety Evaluation f.eport te be acrantable for referencino in license applications to the extent specified and under the linitations stipulated in the subritte' documents and the topical report evaluation.
We do not intend to rereat the review of the safety features described in the topical report and the auxiliary data and f3und acceptable in the attachment and the prior Interim Evaluation. Our acceptance applies only to the features iescribed in the topical report and the auxiliary documents and under the onditions discussed in the attachment and the prior Interin Evaluation.
In accordance with established procedure, it is requested that Vestinghouse Electric Corporation publish an appraed version of these reports, proprietary and non-proprietn. y, within three ronths of receipt of this htter. The revisions are to incc.Torate this letter, the attached topical report evaluation, the interir evaluation and its transmittal letter dated October
??,107? following the title page and thus just in front of the abstract.
The revised report nust incorporate the supporting infor ation subritted in the referenca; listed in the evaluation. The report identifications of the approved raports are to have a -A suffir.
Should Nuclear Regulatory Connission criteria or regulations change such that our conclusions as to the ecceptaMlity of the report are invalidated, Westin@ouse Electric Corporation and/or the applicants referencing the topical report will be expected to revise and resubmit their respective Namentation or submit justification for the continued effective applica-bility of the topical report without revision of their respective dccumen tation.
Sincerely, Origind signw by Rot 4rt L Tedesco Pobert L. Tedesco, Assistent Director for Licensing Division o' Licensinc N ' / [/
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Mr. T. M. Anderson, Manager Nuclear Safety Department P. O. Box 355 Pittsburgh, Pennsylvania 15230
Dear Mr. Anderson:
SUBJECT:
ACCEPTANCE FOR REFERENCING OF LICENS!NG TCPICAL RCPORT WCAP-8278/iCAP-8279 The Nuclear Regulatory Cort: mission has completed its review of the Westinghousr.
Electric Corporation Licensing Topical Report WCAP-3278 and WCAP-8279 (its nonproprietary versicn), both entitled " Hydraulic Flow Test of +he 17x17 Fuel Assembly". This review encompassed the basic reports including appendices A througn D dated February 1974, Appendix E entitled " Request for Additional Information ( AEL-Core Performance Branch - Directorate of Licensing)" submitted October 22,197a; "B Grid 17x17 Fuel Assembly Vibration in a D-Loop Test" dated w y 1975; " Responses to NRC Letter of January 23, 1975" sub,nitted May 20, '975; a
anc "Surry Unit 1 End of Cycle 3 Onsite Fuel Examination of 17x17 Demonstration Assemolies Af ter Two Cycles of Exposure" submitted January 18, 1979.
NRC letter from J. S. Vassallo to Mr. C. Eicheldinger dated October 22, 1975 transmitted NRC's Interim Evaluation of WCAP-E278/WCAP-8279. At that stage of the review, we found:
(a) WCAP-8278 provided an acceptable basis for demonstrating fuel assembly of 12 foot length to be adeouate to withstand the effects of flow induced vibration, however, results of a post irradiation surveillance program was necessary for a final conclusion in this regard.
(b) WCAD-8278 is nnt acceptable as a basis for demonstrating the adequacy, in Yderal, of the Westinghouse analytical design methods; and (c) WCAP-8279 is an acceptable non-proprietary version of WCAP-2278.
The surveillance program at Surry and the operating experience accumulated il new Westinghouse plants provides the basis for our final conclusions witn egard to item (a) above as documented in the Safety Evaluation of WCAP-3273 attached.
Mr. T. M. Anderson 209 2 951 As a result of our reviews, we find the Licensing Topical Report WCAP-8278 and its non-proprietary version, WCAP-8279 as aufnented by the data submitted in the references listed in the Safety Evaluation Report to be acceptable for referencing in license applications to ' he extent specified and under t
the limitations stipulated in the submitted documents and the topical report evaluation.
We do not intend to repeat the review of the safety featuras described in the topical report and the auxiliary data and found acceptable in the attachment and the prior Interim Evaluation. Our acceptance applies only to the features described in the topical report and the auxiliary documents and under the conditions discussed in the attachment and the prior Interim Evaluation.
In accordance with established procedure, it is requested that Westinghouse Electric Corporation publish an approved version of these reports, proprietary and non-proprietary, within three months of receipt of this letter. The rev;3;ans are to incorporate this letter, the attached topical report evaluation, the interim evaluation and its transmittal letter dated October 22, 1972 following the title page and thus just in front of the abstract.
The revised report must incorporate the supporting information submitted in the references listed in the evaluation. The report identifications of the approved reports are to have a -A suffix.
Should Nuclear Regulatory Commission criteria or regulations change such that our conclusions as to the acceptability of the report are invalidated, Westinebeu;s Electric Corporation and/or the applicants referencing the topical report will be expected to revise and resubmit their respective documentation or submit justification for the continued effective applica-bility of the topical report without revision of their respective documen-tation.
Sincerely.
0Y r
-fm y: t -E.M Robert L. Tedesco, Assistant Director for Licensing Division of Licensing
ENCLOSURE MAR 19133I SAFETY EVALUATION OF WCAP-8278 Introduction When Westinghouse introduced the 17 x 17 fuel assembly design, the licensing topical report WCAP-8278, " Hydraulic Flew Test of the 17 x 17 Fuel Assembly" (Ref.1), was submitted in support of the design. Af ter reviewing the report, NRC issued a cualified approval (Ref. 2).
Final approval of WCAP-8278 was determined to be possible only af ter Westinghouse had achieved in-pile experience with the new fuel assembly design.
Subsequently, Westinghouse, with the cooperation of Virginia Electric Power Company and the Electric Power Research Institute, placed two prototype 17 x 17 fuel assemblies in Surry, Unit 1.
Tnese assemblies (designated as RD-1 and ND-1) were irradiated for two cycles and subsequently removed, examined, and analyzed.
These results were submitted (Ref. ?) for NRC review, and the following is our evaluation of that demonstration program as it relates to WCAP-8278.
Summary of Demonstration Program The objective of placing the two prototype 17 x 17 fuel assemblies in Surry, Unit 1, was to demonstrate the adequacy and overall integrity of the new design under actual operating conditions.
The fuel rod design for the prototype fuel assemblies was identical to that of the standard 17 x 17 design except for 88 removaole rods in assembly RD-1 which had a modified end plug to f acilitate removal. The 15 x 15 fuel assemblies comorising the Sur y core each have 7 spacer grids; therefore
2 for compatibility, the two prototype 17 x 17 fuel assemblies employed 7 grids rather then the intended 8-grid design. Otherwise, the prototype 17 x 17 fuel assembly design wat identical to the standard 17 x 17 fuel assembly design except for minor modifications in the adaptor plate, thimble tubes, and thimble plugging devices of the partially reconstitutable assembly RD-1.
The two prototype assemblies were discharged a1.er two cycles of operation.
The average cumulative burnup achieved was 16,125 mwd /MtU for each assembly.
Coolant activity (I '" and I" ) levels were found to be normal during both the final and subsequent cycles of irradiation, thus demonstrating (a) acceptable core-wide fuel integrity and (b) that the two prototype assemblies did not contribute significantly to the overall coolant activity.
Following irradiation underwater television examinations of the two prototype assemblies revealed no significant anomalies of the fuel assembly structures, grids, peripheral rods, or hold-down springs. Also, the grid regions of the removable rods from assembly RD-1 had no indications of cladding fretting or unusual corrosion, aside from slight scratches and burnishes at grid contact points.
Veasurements were taken on assembly RD-1 to reveal the degree of grid relaxation.
Specific measurements determined fuel rod breakaway, fuel rod withdrawal, and grid-cell friction forces. The breakaway force (that force recuired to free and initiate upward movement) and withdrawal force through the bottom grid were measured on 16 rods. The calculated relaxations were found to be 58 and 77% for one and two ':ycles of irradiation, respectively.
These relaxations were comparable to those determined by the grid-cell friction force measurements on 12 cells from each of four grids. For these intermediate level grids, the relaxations for one and two cycles of irradia-tion were found to be 63 and 73%, respectively.
It was concluded that, based on preirradiation friction forces, the rate of grid-spring relaxation decreases with increasing exposure, and that there was no signifivant cladding fretting despite operation with only a fraction of the initial grid-spring force remaining.
Summary of Staff Evaluation The qualification groundwork for the 17 x 17 fuel assembly design primarily consist of satisf actory results from (a) a 1,000 hour0 days <br />0 hours <br />0 weeks <br />0 months <br />, out-of-pile, hot-loop flow test and (b) post-irradiation inspection of lead prototype assemblies.
This satisf actory performance provides sufficient bases to conclude that the standard 17 x 17 fuel assembly design will perform adequately. More specifically, the qualification effort demonstrated that the mechanical design is adecuately resistant to flow hydraulics such that (a) fuel assendly lif t-off will not occur during normal operation, and (b) fuel rod fretting at grid-spring locations will not significantly degrade the cladding integrity. These results are further substantiated by apparently f avorable in-pile operating experience accumulated with the 17 x 17 fuel assembly design in several new Westinghouse-NSSS plants.
Regulatory Position Based on (a) an out-of-pile flow test, (b) a demonstration program involving two prototype fuel assemblies, (c} substantial operating experience accumulated in new Westinghouse-NSSS plants, and (d) analyses presented in WCAP-8278 and supporting submittals (Refs. 4 - 5), we conclude that the mechanical-hydraulic performance of the 17 x 17 fuel assembly is satisfactory. That is, that fuel assembly lift-off will not occur during normal operation and that flow-induced fretting wear degradation to ine fuel cladding is adequately accommodated in the structural design of the 17 x 17 fuel assembly.
Further stipulations of our approval are as follows:
1.
We conclude that WCAP-8278 may be referenced as a supporting document to applicable plant safety analysis reports.
2.
Our approval of WCAP-8278 does not address to the ability of the 17 x 17 fuel assembly to resist guide thimble tube wear in the location of the top nozzle where fully withdrawn control rods reside. This issue is currently being pursued generically with Westinghouse and an owners' group.
3.
Our prior review of WCAP-8278 concluded (a) that WCAP-8278 is not acceptable as a basis for demonstrating the adecuacy, in general, of the Westinghouse analytical dcsign methods and (b) that WCAP-8279 is an acceptable non-proprietary version of WCAP-8278. Those conclusions remain valid.
References 1.
" Hydraulic Flow Test of the 17 x 17 Fuel Assembly," Westinghouse report WCAP-8278 (non-proprietary version WCAP-8279), dated February 1974, attached to letter from R. Salvatori (Westinghouse) to D. B. Yassallo (USNRC) NS-RS-157, dated February 28, 1974.
2.
Letter from D. B. Vassallo (USNRC) to C. Eiche1dinger (Westinghouse) dated October 22, 1975.
3.
"Surry Unit 1 End of Cycle 3 On-Site Fuel Examination of 17 x 17 Demonstration Asserblies After Two Cycles of Exposure," attached to letter from T. M. Anderson (Westinghouse) to D. B. Vassallo (USNRC),
NS-TMA-2018, dated January 18, 1979.
4.
" Appendix E," attached to letter from R. Salvatori (Westinghouse) to D. B. Yassallo (USNRC), NS-RS-?07, dated October 22, 1974.
5.
"8-Grid 17 x 17 Fuel Assembly Vibration in a D-Loop Test," attached to letter from C. Eicheldinger (Westinghouse) to V. Stello (USNRC),
NS-CE-6?O, dated May 15, 1975.
6.
" Responses to NRC," attached to letter from C. Eiche1dinger (Westinghouse) to D. B. Yassallo (USNRC), NS-CE-649, dated May 20, 1975.