ML20137P843

Forwards,For approval,A-85-11,RETRAN Computer Code Reactor Sys Transient Analysis Model Qualification, Per Generic Ltr 83-11.Model Compared W/Lasl Trac Model Developed for Resolving USI A-49.Fee Paid

ML20137P843
Person / Time
Site:	Calvert Cliffs
Issue date:	01/31/1986
From:	Tiernan J BALTIMORE GAS & ELECTRIC CO.
To:	Thadani A Office of Nuclear Reactor Regulation
Shared Package
ML20137P847	List: ML20137P843 ML20137P849
References
REF-GTECI-A-49, REF-GTECI-RV, TASK-A-49, TASK-OR GL-83-11, NUDOCS 8602050370
Download: ML20137P843 (2)

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Jr BALTIMORE GAS AND ELECTRIC CHARLES CENTER R O. BOX 1475 BALTIMORE, MARYLAND 21203 JOSEPH A.TIERNAN Vict PRESIDENT NUCLEAR ENERGY U.S. Nuclear Regulatory Commission Office of Nuclear Reactor Regulation Washington, DC 20555 Attention: Mr. Ashok C. Thadani, Director PWR Project Directorate #3 Division of PWR Licensing - B

Subject:

Calvert Cliffs Nuclear Power Plant Units I and 2; Dockets No. 50-317 and 50-313 Request for Approval of BC&E RETRAN Topical Report A-85-11 Gentlemen:

In Generic Letter 83-11, " Licensee Qualification for Performing Safety Analyses in Support of Licensing Actions", the NRC acknowledged and encouraged the efforts of utilities to develop the capability to perform their own safety analyses using large, complex thermal-hydraulic computer codes. In that letter the NRC emphasized the importance of quality assurance as it pertains to code development, maintenance, and verification, and stated that licensees should demonstrate their proficiency in using the code by performing code verification in-house and submitting a report to the NRC for review.

During the past three years, Baltimore Gas and Electric Company has been developing a system transient analysis capability for the Calvert Cliffs Nuclear Power Plant using the RETRAN thermal-hydraulic computer code. Our goal is to establish an NRC-recognized capability to perform best-estimate simulation of primary and secondary fluid system responses to normal operational transients and anticipated operational occurrences. This capability will primarily be used to support our evaluations of proposed changes and revisions to operating procedures. To document our RETRAN analysis capability, we have developed the enclosed topical report,"RETRAN Computer 3 Code Reactor System Transient Analysis Model Qualification (Topical Report No. A-85-il)", dated January 31,1936.

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Our program for development and verification of an in-house RETRAN capability began with an effort to independently simulate, for audit purposes, accident

.o n sequences that were being modeled for Calvert Cliffs by Los Alamos National Laboratory mo in connection with the NRC's program for resolving USI A-49, Pressurized Thermal c:c Shock. A comparison was thus obtained between our RETRAN model and the Los Alamos So TRAC model for several transients, including runaway main feedwater to one steam

@ generator and cooldown to RHR entry with auxiliary pressurizer spray. Further model o development and code verification was achieved and documented by comparing measured

$o: plant data obtained from five actual plant transients to simulations of those transients

& using RETRAN. Finally, the capability of RETRAN to model plant transient response was verified by com of-Fluid Test (LOFT)parison program. with experimental t data for two tests from the NRC's Loss-g honatY p%tor.1  %

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Mr. A. C. Thadani January 31,1986 In summary, the results of the code verification studies documented in Topical Report A-85-Il were derived from comparisons with another benchmarked best-estimate code, plant operational data, and experimental data. We believe Topical Report A-35-Il adequately demonstrates BG&E's capability to perform system transient analysis for Calvert Cliffs.

REQUEST FOR TOPICAL REPORT APPROVAL Baltimore Gas and Electric Company hereby requests NRC approval of Topical Report A-85-il for use in performing best-estimate transient analyses for the Calvert Cliffs Nuclear Power Plant. Twelve (12) copies of the report are herewith enclosed to facilitate your review.

FEE DETERMINATION Persuant to 10 CFR 170.21, we are including BC&E Check No. 1902929 in the amount of $20,000 to the NRC to cover the app oval fee for this request.

Very truly yours,

3. A. Tiernan Vice-President, Nuclear Energy STATE OF MARYLAND  :

TO WIT:

CITY OF BALTIMORE  :

Joseph A. Tiernan, being duly sworn states that he is Vice President of the Baltimore Gas and Electric Company, a corporation of the State of Maryland; that he submits the foregoing request for the purposes therein set forth; that the statements made are true and correct to the best of his knowledge, information, and belief; and that he was authorized to submit the request on behalf of said Corporation. .

WITNESS my Hand and Notarial Scal: N

[ NotaryfPublic My Commission Expires: [dc[e//f / b 3AT/BSM/dmk Enclosure cc: D. A. Brune, Esquire

3. E. Silberg, Esquire D. H. Jaffe, NRC T. Foley, NRC

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