ML20235P063

Forwards Technical Evaluation of Bg&E Topical Rept:Retran Computer Code Reactor Transient Analysis Model Qualification

ML20235P063
Person / Time
Site:	Calvert Cliffs
Issue date:	07/08/1987
From:	Abramson P, Komoriya H INTERNATIONAL TECHNICAL SERVICES, INC.
To:	Liang C Office of Nuclear Reactor Regulation
Shared Package
ML20235P067	List: ML20235P063 ML20235P082
References
CON-FIN-D-1350 D1350-II-04, D1350-II-4, NUDOCS 8707200324
Download: ML20235P063 (3)

Text

- _ _ _ _ _ _ _ _ _ _ _

er

. . , O Qn/\

-m ,

.nnamanu International Technical Services,Inc. (212)949-4288 !

w w war 420 Lexington Avenue, New York, New York 10170 nw 1

July 8, 1987  ;

D1350-II-04  !

I Mr. Chu-Yu Liarg I Reactor Systems Branca  ;

Division of Engineering Safety Technology j Office of Nuclear Reactor Regulation  !

U.S. Nuclear Regulatory M naion l Washington, D.C. 20555 )

Subject:

Completion of Task II of FIN - D1350 Review of RETRAN Analysis for Calvert Cliffs Plant:

References:

1. BG&E Topical Report A-85-11, "REIRAN Camputer Code Reactor System Transient Analysis Model Qualification," January 31, 1986.

2. Ietter fram J.A. Tiernan (BG&E) to NRC, dated February 24, 1987, "REIRAN Review - Submittal of Additional Information".

3. Letter from J.A. Tiernan (BG&E) to NRC, dated June 9,1987, I "REIRAN Review - Submittal of Additional Information".

Dear Mr. I.iang:

Enclosed is the Technical Evaluation Report (TER) in respect of our review of the Baltimore Gas and Electric (BG&E) Co. topical report entitlal "RETRAN Camputer Code Reactor System Transient Analysis Model Qualification", dated January 31, 1986, BG&E's response to our request for additional information dated August 22, 1986 and to a tele-conference held i on April 7, 1987 as referenced above. 'Ihis is being submitted in fulfillment of Task II of FIN #D1350. j BG&E's objective in submitting the subject topical report was to <

demonstrate the capability of B3&E analysts to properly develop REIRAN models of Calvert Cliffs, perform calculations with these models to simulate realistic plant transient responso ard to perform analysis. In addition, BG&E attempted to conduct an acceptable code verification in accordance with NRC Generic letter No.83-11. Finally, BG&E requested that the review establish the degree to which the submittal could be referenced in future submittals.

1 8707200324 87070s CF Y ADOCK o50003f7 CF

4 i

l' Our standard for makirq a determination regarding demonstration of analytical capability was that the submittal contain (i) a a h ' m ion, explanation and justification for the plant r4dalicatica and ;.cdcl i selection, (ii) at least one thorough analysis of a relatively complicated f transient, in which the analysts indicate their understanding of both the i plant behavior and the code computation by explanation of the behavior of various plant parameters by inter-camparison during the transient and  ;

inclusion of parametric studies to identify uncertainties and/or explain j anomalous behavior, aid (iii) a discussion of the limitations of the models used in the code during the transients studied. Our standard for making a determination of the code verification is in large A an issun of model l qualification, which is measured by the accuracy with which the REIRAN results predict plant data or scale tests and the applicant's discussion and 3 justification of their nodalization, internal code model selection and demonstration that such internal models are used within their rarge of l q

applicability and within the approval granted for use of REIRAN to trJRA, We note that B3&E's request for approval did not include any licensing applications, and therefore model qualification was not an important part of either their application or our review, except as it goes toward meeting the l requir2ments of the subject Generic letter. Nevertheless, B3&E used the I code in a best-estimate mode, and was therefore in a few instances able to campare their output to actual plant data. l l

We believe that B3&E has adequately demonsiaated their technical campetence, meetiry this requirement by their analysis of the Multiple Secordary Side Malfunction ("MSSM") event and their dimmions of the nasalization ard model limitations. We further feel that B3&E staff has shown their understanding of the models used. In addition, B3&E has qualified scxne of the REIRAN models for use for their plant in a best- 4 estimate sense. )

1 The report, together with the BG&E responses to our questians, contains sufficient material to serve as a document which can be used as a reference l to support future B3&E subnittals with respect to the B3&E's ability to perform transient analysis and to the application of models within the ranges studied in this report. This, however, does not mean that the all REIRAN models are qualified over the full spectrum of transient applications either for the Calvert Cliffs Nuclear Power plant or for specific licensing applications. In future submittals, B3&E should be encouraged to maintain and provide the level of thorotshness ard technical campetence exhibited in these dmments, particularly in the MSSM event analysis, by their staff.

Finally, in future licensing analyses, all BG&E submittals must be reviewed

on a transient-by-transient basis.

1 In addition, we point out that BG&E used REIRAN02/ MOD 03 which was developed as a result of making corrections necessitated after the NRC staff review of the REIRAN02/M3D02 camputer code. This " corrected" version of the code has not yet been officially approved for use in licensing analysis.

Nevertheless, we believe that there is reasonable assurcnce that this version of the code was adequate for use in this topical report ard that unless the NRC's review of that version establishes grounds for concern in l

2 i

9 the future, le W its use here in the best-estimate sense.

. . If you have any q*im regan11rq this swi., please do rot hesitate to call us.

Yours sincerely, --

ddN l s a2.-

P. B. Abramson Enclosure

oc/ enc.

W. Hodgm, NRC/NRR/ DEST /RSB l R. Jcmas, NRC/NRR/ DEST /RSB l S. Bajwa, NkT/NRR/HGMS/ PRES l c. Poslumny, HPC/NRR/HGMS/ PRE

( J. Bazin, NRC/DC i

l l

1 1 3 l

l

. _ - _ _ _ _ _ _