ML19331D736

Forwards GE Comments Re Facility Reload Ser.Odyn Use for Rapid Pressurization Transient Analyses Re Future Reloads Appropriate.Transition to Odyn Should Not Unduly Perturb Reload Licensing Cycle or Penalize Plant Operation

ML19331D736
Person / Time
Site:	FitzPatrick
Issue date:	08/22/1980
From:	Sherwood G GENERAL ELECTRIC CO.
To:	Eisenhut D Office of Nuclear Reactor Regulation
References
MFN-149-80, NUDOCS 8009030505
Download: ML19331D736 (5)

Text

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GENERAL h ELECTRIC uuctExa eOwEn SYSTEMS DIVISION GENERAL ELECTRIC COMPAP!Y,175 CURTNER AVE., SAN JOSE, CALIFORNIA 95125 MFN 149-80 MC 682, (408) 925-5040 l

August 22, 1980 U.S. Nuclear Regulatory Commission Office of Nuclear Reactor Regulation Washington, DC 20555 Attention: Darrell G. Eisenhut, Director Division of Licensing Gentlemen:

SUBJECT:

GE COMMENTS ON THE FITZPATRICK RELOAD SAFETY EVALUATION REPORT

Reference:

" Safety Evaluation by th Office of Nuclear Reactor Regulation Supporting Amendment No. 49 to License No. DPR-59, Power Authority of the State of New York, James A. FitzPatrick Nuclear Power Plant," Docket No. 50-333, July 11, 1980.

The purpose of this letter is to provide General Electric's assessment of NRC statements in the referenced FitzPatrick Safety Evaluation Report (SER) regarding the REDY code and GEXL correlation. In the SER, the NRC questions the conservatism of using the REDY code and GEXL correlation in the reload transient analysis, and suggests that a reanalysis or minimum critical power ratio (MCPR) penalty may be required during the cycle. As described in Attachment A, General Electric does not believe this action is technically justifiable for FitzPatrick or any other General Electric BWR reload, and is very concerned about the possible consequences associated with its implementation. The requirement of a reanalysis will impose a severe resource burden on General Electric and will directly impact important safety programs. The application of a MCPR penalty will needlessly remove operating margin and flexibility and in some cases result in plant derates.

In summary, General Electric believes that plant operation under a REDY code /GEXL correlation basis for FitzPatrick and other near-term reloads with 8x8R fuel is safe, prudent,;and entirely consistent with the re-gulations. General Electric agrees that the NRC's use of the ODYN for rapid pressurization transient analyses on future reloads is appropriate.

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GENERAL h ELECTRIC U.S. Nuclear Regulatory Commission Page 2 However, GE urges that the transition to ODYN be smcoth, in accordance with requirements which do not unduly perturb the reload licensing cycle time or penalize plant operation.

Very truly yours, lksO[? -Q Glenn G. Sherwood, Manager Safety and Licensing Operation GGS:rf/660-1 cc: L.S. Gi fford e

Attachment A

References:

1) " Safety Evaluation by the Office of Nuclear Reactor Regulation Supporting Amendment No. 49 to License No. DPR-59, Power Authority of the State of New York, James A. FitzPatrick Nuclear Power Plant,"

Docket No. 50-333, July 11, 1980

2) General Electric letter MFN-416-77, E. D. Fuller to D. F. Ross, " Technical Bases for General Electric's Position on Transient Model Margins," October 27, 1977

3) NEDE-240ll-P-A, " Generic Reload Fuel Application,"

Appendix C, August 1978

4) NEDE-24131, " Basis for 8x8 Retrofit Fuel Thermal Analysis Application," October 5, 1978

5) " Safety Evaluation by the Office of Nuclear Reactor Regulation Supporting Asencsent No. 55 to Facility License No. DPR-46, Nebraska Public Power District Cooper Nuclear Station," Docket No. 50-298, April 27, 1979 REDY Code Section 2.2.2.2 of the FitzPatrick SER (Reference 1) indicates that the REDY code "is in some instances nonconservative for evaluation of core responses to anticipated transients" and that " recalculation of some limiting transients for Cycle 4 to avoid a CPR margin penalty," using the ODYN code, may be required. General Electric believes the following information should be considered and the addition 0 calculations or CPR penalties not be imposed.

A. REDY licensing basis WCPR calculations were shown to be com-parable to ODYN in an ODYN-REDY comparative study which was submitted to the NRC for review (Reference 2). Based on this study, the NRC staff stated "a degree of conservatism" exists when using REDY "to predict the consequences of licensing basis pressurization events, " and that REDY "overpredicts the peak transient pressure" on overpressurization events (Reference 3).

While not a first principles, best estimate code, REDY still provides a conservative basis for plant operation which has been confirmed by hundreds of reactor years of safe, successful BWR operating experience. Conversion to ODYN is not expected i to significantly change the operating limits, and hence the t

safety margins, of BWR plants.

B. Whether using ODYN or REDY, General Electric's licensing basis for abnormal transients establishes an operating limit which

, provides for an extremely large safety margin. First, it is based on a limiting event which is not expected to occur during the lifetime of the plant (turbine trip / load rejection without bypass). This event is generally much more severe than other abnormal transients. Second, it assumes, in general, worse-case equipment performance and operating conditions.

Attachment A Page 2 August 18, 1980 Third, it precludes operation below the GETAB " safety" limit, whereas experimental data have shown that operation below the

" safety" limit during the short time interval of the rapid pressurization transients would not cause any fuel failure, and thus would not effect public safety.

C. Requiring recalculations using ODYN for FitzPatrick and other near-term reloads would significantly impact General Electric safety workload, diverting resources from other, more important issues. In addition, it. is contrary to the General Electric /NRC agreement regarding implementatio:: of 00YN, in which General Electric was assured that the REDY-to-00YN transition would be orderly, with minimal perturbatiens to the analysis cycle.

The staff indicated that CDYN analyses would not be required for those reloads initiated before the NRC had officially approved ODYN (that is, before issuance of the 00YN SER and the utility implementation directives).

GEXL Correlation The second issue is related to the following statements in Section 2.2.2.2 of the SER regaraing GEXL:

"The test data base supporting the applicability of the GEXL critical power correlation to the retrofit (8x8R) fuel design has never been submitted for staff review in accordance with established procedures.

Although we have approved operation of several reactors for up to two cycles with 8x8R fuel, we now have concern regarding the safety limit MCPR predicted using GEXL for any fuel cycle with two water rod fuel included in the core. Our concern relates to a possible nonconservative bias, which has been observed in CPR test data for two water red fuel with high pin <to pin power peaking."

General Electric does not believe the statements in the SER are entirely correct for the following reasons:

A. The 8x8R GEXL correlation is a best-fit to experimental data.

It was generated using the same methodology extensively re-viewed and approved by the staff for the 7x7 and 8x8 correl-ations. Because General Electric used previously approved

( procedures to derive the 8x8R GEXL correlation: a formal submittal was not believed to be necessary. Rather, an in-l formation report describing the basis for the 8x8R GEXL correlation was provided (Reference 4) and subsequently referenced in the Reload Licensing Topical Report. Generic test data was also provided in response to NRC questions on Cooper Cycle 5. In response to these submittals, the NRC concluded that the 8x8R correlation was somewhat conservatively biased and predicted the test data with better precision than l

the 8x8 and 7x7 correlations (Reference 5).

s

8. General Electric h.as responded to all documented staff concerns j

regarding the basis for the GEXL 8x8R correlation. In addition to the Reference 4 information report, General Electric also l

l provided answers to the staff's questions for the Hanford 2, J

Susquehanna, and Grand Gulf dockets, as weli as several reload applications.

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Attachment A Page 3 August 18, 1980 Please note that the NRC has just recently defined its concerns with the 8x8R GEXL correlation. In response, General Electric will be meeting with the staf.' in August for the purpose of discussing these concerns and achieving speedy resolution.

JFS:rf/656-8 i

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