NRC-95-4448, Provides Response Based on NRC & RAIs on Wcobra/ Trac Code & best-estimate LOCA Analysis Methodology & Code Applicability Document for AP600

Provides Response Based on NRC & RAIs on Wcobra/ Trac Code & best-estimate LOCA Analysis Methodology & Code Applicability Document for AP600

ML20083A974
Person / Time
Site:	05200003
Issue date:	04/28/1995
From:	Liparulo N WESTINGHOUSE ELECTRIC COMPANY, DIV OF CBS CORP.
To:	Crutchfield D NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM), Office of Nuclear Reactor Regulation
References
NTD-NRC-95-4448, NUDOCS 9505110217
Download: ML20083A974 (5)

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DCP/NRC0311 Docket No: STN-52-003 Westinghouse Energy Systems g3$e m mo.am Electric Corporation NTD-NRC-95-4448 Docu' ment Control Desk .

April 28,1995 United States Nuclear Regulatory Commission Washington, DC 20555-0001 Attention: Dennis M. Crutchfield Associate Director for Advanced Reactors and License Renewal Office of Nuclear Reactor Regulation

SUBJECT:

Reviews of ECOBRA/ TRAC Best-Estimate LOCA Analysis Methodology and AP600

Dear Mr. Crutchfield:

Thank you for your letter dated March 21,1995 on the subject of the staffs review of the Westinghouse ECOBRA/ TRAC code and Best-Estimate Large Break LOCA methodology (BELOCA) for operating plants and the AP600 program. This letter provides our response based on thorough consideration of both your letter and the RAls on the E COBRAfrRAC (EC/T) Code Applicability Document (CAD) for AP600.

'Ihese RAls were just received informally on April 10, 1995. Our ability to work with you to resolve the CAD RAls by May 31,1995 was an important condition associated with the target schedule identified in your

-March 21' letter.

Westinghouse believes that the target schedule identified in your March 21" letter is not achievable based on your condition (c) that " Westinghouse must resolte all remaining ECOBRA/ TRAC open items by the end of i May 1995" and that "This would include resolution of AP600 ECOBRA/ TRAC applicability items in the same time frame". The recently received CAD RAls are significant and resolution is not achievable in that time frame. However, we believe that the intent of condition (c) can be met to ensure that BELOCA licensing is consistent with operating plant and AP600 program needs. For example, some of the CAD RAls are related to the AP600 SSAR plant model and to long term core cooling. Westinghouse believes these can be scheduled in a more appropriate time frame. The March 21" letter requirement to resolve all AP600 EC/T applicability items by May 1995 is not consistent with the existing AP600 schedule for review and approval of other AP600 accident analyses codes. The NRC's review of EC/T is well ahead of the AP600 l schedule. Furthermore, Westinghouse believes that the remaining CAD RAls can also be scheduled in a j more appropriate time frame.

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Also, timely licensing of WC/T and the BELOCA methodology for operating plants has significant technical, operational, and financial impacts on the operating plant licensees. These impacts were delineated with the staff in detail during a joint licensee / Westinghouse meeting with the NRC on January 27,1994 and again during a Westinghouse meeting with the NRC on January 26,1995.

Therefore, in consideration of operating plant licensee needs, AP600 program needs, and the position expressed above, Westinghouse proposes the revised target schedule shown in Attachment A. Westinghouse realizes that there are elements of the proposed schedule that may likely require adjustment based on NRC review and we look forward to working together to establish a mutually acceptable schedule. We have already received NRC feedback on a draft version of this letter and anticipate further schedule discussions in May 1995. Key dates from the proposed schedule in Attachment A include:

5/95 -

W issue responses to Round 2 RAls on CQD Vols.1 - 3 6/95 -

E issue responses to all AP600 EC/T CAD RAls except those related to the AP600 SSAR plant model and to long term core cooling 7/95 -

W issue responses to Round 2 RAls on CQD Vols. 4 - 5 NRC provide f'mal RAls covering all issues for conventional plant applicability (The NRC must provide this information as it becomes available in advance of this date to ensure resolution by 8/95. It is our current understanding that these RAls will only address the results of the ongoing INEL assessment of the Westinghouse methodology versus the CSAU methodology and should be informally available in early May 1995.)

8/95 -

W/NRC complete resolution of conventional plant WC/T and BELOCA issues 9/95 -

Final ACRS meeting on BELOCA (1st week of 9/95)

NRC issue SER on WC/T and BELOCA applicability for conventional plants E/NRC complete resolution of AP600 EC/T CAD issues 10/95 - NRC issue SER on initial conventional plant licensing application with BELOCA W finalize AP600 LBLOCA SSAR analysis 2/96 NRC complete reviews of NOTRUMP, LOFTRAN, WC/T for applicability to AP600 and l prepare DSER input for these codes and analyses  !

Please note that this schedule is consistent with coaditions (a), (b), and (d) in your March 21" letter and, we believe, consistent with the intent of condition (c).

Westinghouse believes that we can meet operating plant and AP600 program needs if we work together using the revised target schedule shown in Attachment A to establish a mutually acceptable program schedule as a matter of urgency, nrtdme.ltr Page 2 of 5 April 28.1995 l

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Regarding our discussions with the ACRS Thermal / Hydraulic Subcommittee on compliance with Regulatory Guide 1.157, Westinghouse agrees that this represents a potentially significant issue that could affect EC/T q and its application. Westinghouse believes that oor BELOCA approach does comply with the requirements of j Regulatory Guide 1.157, and that the RAls from the staff's consultant are the appropriate vehicle for resolving technical issues. To support this position, Westinghouse has prepared a " Regulatory Guide j Compliance Document" demonstrating compliance of WC/T and our BELOCA methodology as described in  !

WCAP-12945-P with NRC positions outlined in Regulatory Guide 1.157. Furthermore, it has been brought to our attention that the NRC's consultant has prepared a detailed report that reaches the same basic conclusion. Also, the NRC's consultant has started another independent review to specifically compare the l Westinghouse methodology with the CSAU methodology. These results are expected by the end of April i 1995. 'Ihe NRC has planned a meeting on this subject with the ACRS T&H Subcommittee on May 2,1995, {

and we will continue to work with the NRC staff to successfully resolve these issues.

Towards this end, Westinghouse and the NRC staff have instituted regular BELOCA licensing progress  !

telephone calls to help ensure that successful completion of our licensing efforts. As part of these calls, we l i

will jointly consider the effectiveness of our efforts. If significant issues or schedule problems arise, they will be brought to the attention of Mr. Ashok Thadani of the NRC and Mr. Nicholas Liparuto of Westinghouse to  !

ensure timely resolution. Westinghouse will continue to interact regularly with the NRC to review progress

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and will work with the NRC as soon as possible in May 1995 to establish mutually acceptable means for these interactions (written reports, phone calls, meetings) and the frequency by which they should occur.

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Sincerely, i Nicholas J. Liparulo '

Manager, Nuclear Safety Regulatory and Licensing Activities {

cc: T. Quay T. Kenyon  !

J. Moore  ;

A. Thadani j R. Architzel i K. Shembarger '

W. Dean j W. Russell  !

F. Miraglia l P. Shea  !

E. Jordan  ;

R. Jones l

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Attachment A REVISED TARGET SCHEDULE FOR BELOCA LICENSING Date Conventional Plant Actions AP600 Actions UPI Plant Actions 4/95 NRC issue RAls on the AP600 WCOBRA/ TRAC (WC/T) Code Applicability Document (CAD) (E informally receiwd these RAls on 4/10/95 and is working to resolw them) 5/95 E issue responses to Round 2 W issue preliminary AP600 SSAR RAls on Code Qualification and preliminary WCfr V&V Document (CQD) Vols.1 - 3 reports I

6/95 2dconventional plant BELOCA E issue responses to all AP600 license amendment request issued WC/T CAD RAls except those related to the AP600 SSAR plant model and SSAR calculations, and to long term core cooling (which will be issued 9/95) 7/95 E issues responses to Round 2 W issue CQD Addendum for UPI RAls on CQD Vols. 4 - 5 (RAls Plants pertinent to UPIapplication willbe defk rred to generic addendum raiew)

NRC issue final RAls covering all issues for conventional plant (3 and 4 loop) applicability. 7his requires I provision of these RAls in admnce of this to enable resolution by 8/95 8/95 W/NRC complete resolution of conventional plant WC/T and BELOCA issues 3d conventional plant BELOCA license amendment request issued nredmc.hr Page 4 of 5 April 28,1995 I

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Date Conventional Plant Actions AP600 Actions UPI Plant Actions 9/95 Final ACRS meeting on BELOCA W/NRC complete resolution of AP600 WC/T CAD issues NRC issue SER on WC/T and BEIDCA applicability for W issue the final AP600 WC/T conventional plants V&V report 10/95 NRC issue SER on la NRC issue supplemental AP600 la UPI plant BELOCA license conventional plant licensing DSER amendment request issued application with BELOCA (l*

conventional plant license '

amendment request docketed 10/93) 4* conventional plant BELOCA license amendment request issued 11/95 12/95 NRC issue SER on 2"' conventional W respond to supplemental DSER plant licensing application with open items BELOCA 1/96 d

2/96 NRC issue SER on 3 conventional NRC complete reviews of AP600 NRC review and approve CQD plant licensing application with LOFTRAN, NOTRUMP Addendum for UPI plants BELOCA applicability and prepare final AP600 SER input for WCOBRA/ TRAC, IDFTRAN, and NOTRUMP 3/96 4/96 NRC issue SER on 4* conventional AP600 FSER to Commission /

plant licensing application with ACRS BEIDCA 5/96 6/96 7/96 8/96 NRC issue SER on 1" UPI plant licensing application with BELOCA nredme ltr Page 5 of 5 April 28,1995

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• [ I UNffED STATES NUCLEAR REQULATORY COMMIS810N i WAGNINGToN. S.o. asses 4ee,

• • "* March 21,1995 1

Mr. Nichojia s J. Liparelo 1 i

Nuclear 5tfety and Regulatory Activities j

Westin holse Electric Corporation i P.O. x h55 Pitts rg 1. Pennsylvania 15230 <

SUBJECT:

REVIEWS OF WC00RA/ TRAC BEST ESTIMATE (BE) LOSS-0F-COOLANT ACCID; 9ETH000 LOGY AND AP600 Dear Mr. L iparules Recently,l lestinghouse has requested the Division of Systems safety and Analysis, MR, to explore means of expediting the review of the appitcability '

of the WCW RA/ TRAC BE nothodology to its conventional three and four loop plants. N date the priority of our review has been for application to AP600, wiW i only,evpriapping considerations for the conventional plants.

Based on pr assessment, our amended target schedule is:

6/95 - Review completion for WC08AA/ TRAC and AP500 applicability.  !

• 8/951 -

Final meeting with Advisory Consittee on Reactor Safeguards i i AP600)*applicabilitysupplement).(ACRS , and issuance of safety 1

9/95 ! - Resume reviews of L0FTRAN and NOTALMP applicability for AP600.

9/95 -

WC08R4/TRACconventionalplantapplicabilitySER.

10/95 -

Initial conventional plant WC06RA/ TRAC licensing appilcation

$ER, 2/96! - SER input for APSCO Chapter 18 (WCOBRA/ TRAC).

2/98 -

AP400 LOFTRAN and N01MP reviews complete (final SER input drafted). ,

since the 10 TRUMP and LOFTRAN validation reports are not scheduled for submittal mtti September 1995 and April 1995 respectively, it is mcognized that the A P 500 LOFTRAN and NOTE DSER supplem,ent inputs would be incomplete.

Thus, we p F spose to issue initial requests for additional information (RA! )

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in -March l itl, and discontinue the LOFTRAN and NOTRlW mytows untti septes-ber 1995, l conventien t a order t's devote those resources to the review of WC08AA/ TRAC for (February i 5 i plants.

and 15, 1995), AdditionallyIficant a sten issue was raised affectingat the latest WCotRA/TRA: and its ~ application to any design. Th's resolution of this issue will diver; the Nuclear Regulatory Commission and contractor resourtes. We have consul ted with eer contractor regarding schedular impacts of the above and estieau that the following impacts would result: .

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F8014 MRC *108' 03.24 1999 11886 3 Mr. Miche I ns J. Lip'arsle March ti, 199$

a. The ra riews of AP600 LOFTRAN and NOTNF will be delay 9JLty AlH!st 3 sonuts. The total impact would be about 3 months for tis codes (Deces>

ber IM ment.' A)suming s high quality and timely submittals provided by Westing-5 , and t >

house, this would not affect the FSER input schedule.  !

b. Westilohouse must submit complete and comprehensive NOTRUNP and LOFTRAN  !

RAI rmponses by August 1995, and major issues would be identified and j resolmd by the end of October 1995.

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c. Westisohouse must resolve all remaining WCOBRA/ TRAC open itses by the end ,

of M '

1995. This would include resolution of AP600 WCOBRA/ TRAC applica-  :

bili itses in the same time frame.  !

d. A fini 1 RAI coverine all issues for conventional plant (3 and 4 loop) applit obility will 6e issued by July 1995. Westinghouse must resolve all i conver tional plant WC08RA/ TRAC issues by August 1995.  :

At your rd quest, we. intend to pursue thi:: change in utilisatten of resources, i while moni toring Westinghouse responsiveness, effectiveness of the >regras,  !

and accepi' ability od the impacts. Should'our assessment indicate ttat the revised re ource allocation is not sufficiently effective, we will reschedule l our resonnes based on a reevaluation of the relative priorities of these ~

reviews. : .

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$1ncerely. - ~~5

$NY {

Dennis N. Crutchfield, Associate Director for Advanced Reactors and License Renewal Office of Nuclear Reactor Regulation  ;

Docket No.62-003 l cc: See next page l

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-.- 1 ACRS THERMAL HYDRAULIC PHENOMENA SUBCOMMITTEE MEETING

'J NRC-NRR REVIEW BASIS FOR BEST-ESTIMATE ECCS THERMAL HYORAULIC-CODES.

MAY 2. 1995 '

ROCKVILLE. MARYLAND  ;

PRESENTATION SCHEDULE Presentation hA 1 Time .T g j I. Introduction 5 min 8:30 am.

• I.-Catton. Subcommittee .

Chairman II. NRC NPR Presentations A. NRC-NRR Review Method for Use  ;

of Best-Estimate ECCS Codes  !

1. Introduction and History 30 min. 8:45 am e R. Jones. NRR

2. "Walkthrough" of Provisions of 45 min. 9:25 am Regulatory Guide 1.157 i eF Orr NRR '

BREAK 15 min. 10:15 am

3. Westinghouse Compliance With 120 min. 10:30 am  :

ProvisionsofRegulatoryGuide1.157 ,

o C Fineman. Intl  !

t LUNCH 60 min 12:45 pm i

4. INEL Findings on Westinghouse 45 min. 1:45 pm ,

Overall Best-Estimate Philosophy e G. Wilson, INEL Compariscil with CSAU

5. Sumary and Comments 30 min. 2: 45 pm oF Orr l BREAK 15 min. 3:00 pm .;

III. 01scussion 60 min 3:15 pm e All

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IV. Subcommittee Caucus 15 min. 4: 15 pm

- Follow-up Items from This Meeting 3

- Decision to Bring Matter to ACRS i

V. Adjourn 4:30 pm l

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