NUREG-0565, Forwards Topical Rept Evaluation of BAW-10092P,Rev 3 & BAW-10154 B&W Owners Group Small Break LOCA Evaluation model,CRAFT2 (Rev 3).Two Confirmatory Issues Identified. Response Requested within 45 Days of Ltr Receipt

Forwards Topical Rept Evaluation of BAW-10092P,Rev 3 & BAW-10154 B&W Owners Group Small Break LOCA Evaluation model,CRAFT2 (Rev 3).Two Confirmatory Issues Identified. Response Requested within 45 Days of Ltr Receipt

ML20133E259
Person / Time
Site:	Arkansas Nuclear
Issue date:	07/03/1985
From:	Stolz J Office of Nuclear Reactor Regulation
To:	Jeffery Griffin ARKANSAS POWER & LIGHT CO.
Shared Package
ML20133E263	List: ML20133E265 NUREG-0565, Forwards Topical Rept Evaluation of BAW-10092P,Rev 3 & BAW-10154 B&W Owners Group Small Break LOCA Evaluation model,CRAFT2 (Rev 3).Two Confirmatory Issues Identified. Response Requested within 45 Days of Ltr Receipt
References
RTR-NUREG-0565, RTR-NUREG-0737, RTR-NUREG-565, RTR-NUREG-737, TASK-2.K.3.30, TASK-2.K.3.31, TASK-TM GL-83-35, NUDOCS 8507220438
Download: ML20133E259 (2)

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UUL 0 31985 Docket No. 50-313 DISTRIBUTION Docket File > JPartlow NRC PDR ACRS-10 L PDR RIngram Mr. John Griffin ORB #4 Rdg GVissing Senior Vice President HThompson Gray File of Energy Supply 0 ELD EBrach Arkansas Power and Light Company EJordan H0rnstein P. O. Box 551 BGrimes DWigginton Little Rock, Arkansas 72203 BSheron EThrom

SUBJECT:

NUREG-0737 ITEM II.K.3.30, SMALL BREAK LOCA METHODS On June 27, 1985 the NRC approved the Babcock and Wilcox (88W) small break LOCA model, CRAFT 2, for use in satisfying the NUREG-0737 Item II.K.3.30.

The B&W model was documented in the two Topical Reports BAW-10092P, Rev. 3 and BAW-10154 The B&W Owners Group (BWOG) references these reports and CRAFT 2 as their new licensing small break LOCA model to satisfy the requirements of II.K.3.30.

Our Safety Evaluation of II.K.3.30 for the members of BWOG is enclosed.

However, we have identified two confirmatory issues related to the CRAFT 2 computer program.

B&W endorses the conclusion in NUREG-0565 concerning the amount of noncondensable gases which could accumulate in the primary system. This evaluation conservatively estimated the maximum volume of noncondensable gases from all potential sources, with the exception of the radiolytic decomposition of the safety injection water. The result of this evaluation was that the amount of noncondensable gases is not sufficient to block natural circulation in the hot leg U-bend if all the noncondensable gases were conservatively assumed to accumulate at that location. In addition, the B&W position regarding the radiolytical decomposition of the injected water is that this additional source of noncondensable gas does not alter the conclusion in NUREG-0565. We assume that the B&W and the B&WOG position is indeed your position on this matter. However, we request that you confirm this in writing within 45 days from receipt of this letter.

The second confirmatory issue concerns the verification benchmark program for CRAFT 2 against experimental, scaled test data for a B&W prototypical design facility. The B&W Integral System Test (IST) program is oriented at obtaining the necessary data. These data will be available in 1986. It is B&W's conclusion that the benchmark program will demonstrate that CRAFT 2-Evaluation Model (EM) is conservative to licensing calculations.

B&W also concludes that the models currently available in CRAFT 2-EM are capable of adequately representing the expected SBLOCA phenomena in a B&W PWR, and that the IST tests will not identify any new phenomena for concern.

g72204388'50703 p ADOCK 05000313 PDR.

c Mr. Griffin We concur with B&W's conclusions and consider the benchmark program to be confirmatory with respect to CRAFT 2-EM.

B&W has made a long standing comitment to continually review experimental data and code predictions of these data by both B&W and other or as they apply to the CRAFT 2 evaluation model or portions ofsee it (ganizations, Section 7 of BAW-10154). The MIST program (MIST) is one such source of new information.

We assume that as a member or the B&WOG you endorse the B&WOG comitment as your comitment with other members of the B&WOG to perform a suitable comparison to the MIST data, as identified in Section III.S.g of our SER, to demonstrate that CRAFT 2 does provide a conservative representation of the SBLOCA behavior in a B&W PWR. We request within 45 days from receipt of this letter, that you provide, in writing, your comitment to the B&WOG program to perform such comparison.

It is our understanding that as a member of the B&WOG you will use the CRAFT 2 in the small break LOCA analysis for Arkansas Nuclear One, Unit 1.

Please confirm in writing within 45 days from receipt of this letter that you endorse this position. Upon receipt of your confirming letter, we will consider NUREG-0737 ITEM II.K.3.30 complete for your plant. In accordance with NUREG-0737 ITEM II.K.3.31, your plant specific analysis is due within one year from receipt of this letter.

On November 2, 1983 in Generic Letter No. 83-35, the NRC provided clarification and proposed a generic resolution of TMI Action Item II.K.3.31. That is, resolution of II.K.3.31 may be accomplished by generic analysis to demonstrate that the previous analyses performed with SBLOCA-EM were conservative. Future plant specific analysis performed for your plant by Babock and Wilcox for reloads or Technical Specification amendments (those beyond 90 days of the date of this letter) should be calculated with the new code, CRAFT 2.

The reporting and/or recordkeeping requirements of this letter affect fewer than ten respondents; therefore, OMB clearance is not required under P.L.96-511.

Sincerely,

%w .m a Jun y, sm.

John F. Stolz, Chief Operating Reactors Branch #4 Division of Licensing

Enclosure:

As Stated ,

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