ML20134H671

Summarizes 961025 Meeting W/W to Discuss Review Areas for AP600 Advanced Reactor Design.List of Comments Provided at Meeting Submitted

ML20134H671
Person / Time
Site:	05200003
Issue date:	11/12/1996
From:	Diane Jackson NRC (Affiliation Not Assigned)
To:	Liparulo N WESTINGHOUSE ELECTRIC COMPANY, DIV OF CBS CORP.
References
NUDOCS 9611140221
Download: ML20134H671 (7)

Text

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• am4 9 hb pe 4 UNITED STATES g NUCLEAR REGULATORY COMMISSION 2 WASHINGTON, D.C. 20555-0001

,,,,,# November 12, 1996 l

l Mr. Nicholas J. Liparulo, Manager Nuclear Safety and Regulatory Activities Nuclear and Advanced Technology Division Westinghouse Electric Corporation P.O. Box 355 Pittsburgh, Pennsylvania 15230

SUBJECT:

CONTAINMENT SYSTEMS AND SEVERE ACCIDENT

• BRANCH (SCSB) COMMENTS ON WESTINGHOUSE-PROPOSED SCHEDULE

Dear Mr. Liparulo:

The Nuclear Regulatory Commission (NRC) SCSB met with Westinghouse on October 25, 1996, to d'scuss its review areas for the AP600 advanced reactor design. Additionally, SCSB has reviewed the Westinghouse letter dated October 15, 1996, whica outlined the current Westinghouse-proposed schedule.

In response to this vecent meeting and submittal, the following comments are provided.

General -

A meeting for each review area should be included in the schedule. This should be a reasonable amount of time following a key submittal or the final Westinghouse submittal.

Chapter 19 - Level 2/3 Probabilistic Risk Assessment (PRA)

Milestone 566: July 23, 1996 - Submit DOE Complementary Report (In-Vessel Steam Explosions)

This report states that it is technically supported by two verification reports, for the analytical tools utilized, ESPROSE.m and PM-Alpha. The staff does not consider this submittal complete without the companion documents which the staff has not received to date.

Milestone 565 (External Reactor Vessel Cooling (ERVC))/

Milestone 567 (Level 2/3 - Request for additional information (RAI)

Completion)

Both organizations agreed on a path to resolution on ERVC involving the reliance on ERVC com exvessel phenomena plimented with limited deterministic analyses of Staff review comments on the DOE report on ERVC were forwarded to Westinghouse in May 1996, but Westinghouse was unable to support gob O discussions until late October 1996.

140054 9611140221 961112 HRCmECBHM PDR ADOCK 05200003 A PDR

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Mr. Nicholas J. Liparulo November 12, 1996 i .

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• The telecon that was held on October 25, 1996, degenerated rapidly and l i was unproductive. As a result, Westinghouse is being requested to  !

provide formal response to comments.  !

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The following items are not reflected in the Westinghouse schedule and can shift the completion date for review of ERVC and Level 2/3 PRA:

1. The response to May 1996 comments /RAls on ERVC. .

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2. The assessment of the impact of fuel-coolant interactions (FCIs) during late reflood on ERVC (This was to be part of In-Vessel FCI report but missing).

3. The resolution of is:ues related to the reactor pressure vessel (RPV) insulation system design impact on ERVC (These were identified in August 17, 1995, meeting, but no further actions have been taken).

Chapter 21 - Review of the WG0THIC Computer Program Milestone 739: July _1,1996 - Scaling Report Revision The original submittal was missing approximately 20 random pages. The report was resubmitted on August 8, 1996, with the missing pages.

Westinghouse did provide the missing pages in advance of the formal re-submittal.

Staff has provided, via weekly telephone calls (July 22,. July 25, August 1, August 9), comments on the revised scaling report. Three broad areas of concern were also identified. Westinghouse has provided some responses (faxed but not formal) on the comments. However, it is noted that some of the comments identified areas of omissions and errors and Westinghouse has only indicated that these would be corrected in a future submittal. The three broad areas of concern remain open as to what Westinghouse will provide in the scheduled final scaling report.

However, the staff is concerned with the tentative position on two of these areas.

First, in an earlier version of the scaling work (WCAP-14190, October 1994), Westinghouse included an integration of the pressure change equations. The staff believes that integration of the scaling equations to obtain the pressure response for the design basis analysis (D8A) provides an essential confirmation _ of the reasonableness, completeness and accuracy of the scaling approach. While Westinghouse may have other' convincing evidence to establish validity of the scaling methodology,- there is a risk of delaying the review process should the staff determine that the scaling approach lacks such sufficient validation. In view of the new bounding approach being taken, the role of scaling in'the AP600 design certification review remains unclear.

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Mr. Nicholas J. Liparulo November 12, 1996 Second, the large-scale test (LST) data, an important component of the scaling approach, is essentially steady-state. One important aspect of the scaling analysis is the determination of the characteristic time rations for the various processes. In the final scaling report, Westinghouse should address how time dependent, i.e., rates for the '

various physical processes, is validated in the scaling analysis. l Milestone 740: January 31, 1996 - Noding Convergence Report (Draft)

This was rejected by the staff in a letter dated March 1,1996. It has been re-sunmitted as Section 13 of WCAP-14407, "WG0THIC Application to AP600." Only one of the major staff comments in the letter was incorporated - the mass and energy inputs were provided for the sensitivities. The staff will be issuing RAIs on Section 13 to obtain the information identified in the rejection letter. as well as additional information determined to be necessary from the detailed review.

Milestone 741: July 1, 1996 - Mixing and Stratification Report (Draft)

The staff has discussed this early draft during a weekly call on August 9, 1996. Westinghouse has acknowledged receipt of comments through August 8,1996, in the cover letter submitting WCAP-14407. A future revision of Section 9 is planned but no schedule has been provided. The review of Section 9 will be placed on hold until the revised writeup is submitted.

Milestone 742: May 21, 1996 - Water Coverage (Draft)

Water coverage was discussed during weekly calls in June and July. The submittal was based on the old 220 gpm flow rate. The flow rate was revised to 440 gpm. There was a meeting at Monroeville, June 5 and 6, 1996, to discuss this issue. Water coverage is Section 7 in WCAP-14407, and in its cover letter Westinghouse acknowledges that staff consents on previous versions are incorporated. However, comments on the use of the Zuber-Staub model provided by Westinghouse's consultant Dr. Bankoff, as noted during the June meeting, do not seem to appear in WCAP-14407. The staff believes Dr. Bankoff's comments clearly put in proper perspective the usefulness of Zuber-Staub for the issue of water coverage.

Milestone 743: November 30, 1996 - MG0THIC RAI/open item (01) Responses There are still 45 of 139 RAIr issued through March 1996, unanswered -

26 of these date back to June of 1995. The April 1996, supplemental draft safety evaluation report (SDSER) OIs have yet to be responded to.

Note also that recent responses to RAIs are based on documents that are under revision or known to contain errors. Additionally, there is no provision provided'in the schedule to address possible RAls on WCAP-14407, the scaling report, or the phenomena identification and ranking table (PIRT) report.

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Mr. Nicholas J. Liparulo November 12, 1996 l i

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, Milestone'744: September 10, 1996 - MG0THIC Application Report {

j The submittal is not complete. In its cover letter, Westinghouse l

acknowledges that one section is missing and one is under revision to '

1 incorporate staff comments. No schedule for when these are to be

, submitted was provided. At the staff's last held weekly telephone call on September 24, 1996, it was left to Westinghouse to get back to the 1

staff with the schedules for these as well as scaling, PIRT and final standard safety analysis report (SSAR) analyses, and a proposal for j continued weekly calls.

The role of scaling, PIRT and the LST are not well documented in l WCAP-14407. PIRT and scaling are only given a brief comment in i Section 2. It is noted that these reports are not yet available for l review. The role of the LST, other than as a separate effects test for

mass and heat transfer correlations for the passive containment cooling

system (PCS) performance, is not well documented.

Section 13, as noted under. milestone 740, has not incorporated most of i the comments provided in the staff's March 1996 rejection letter of the I

< original submittal. I Sections 5 and 10 provided.the results of sensitivity analyses but do

not provide any information on the models used to perform the analyses.  !

2 They do not even appear to use the same reference case. The model described in Section 4 includes features not previously identified or l

included in any of the nodal studied performed, nor in any of the

! reference calcuir.tions.

Milestone 745: December 16, 1996 - PIRT Report Revision l The reference report wa:, submitted February 12, 1996, after being presented to the staff in a December 1995 meeting. The staff has i provided feedback to Westinghouse on the referenced report structure, as

well as other editorial and clarification issues, and Westinghouse is revising this report. In the reference report, Westinghouse used materials (for example, steel, concrete, PCS cooling water), structures (for example, shell, baffle, and baffle' supports), and regions (for

example, external atmosphere, in-containment refueling water storage i tank (IRWST), and break pool) to evaluate the AP600. The revised report is now based on spacial regions, a more common approach. A preliminary j version of the revised structure was provided to the Advisory Committee

on Reactor Safeguards (ACRS) at the May 1996, meeting. The formal

submittal is expected to include the staff's comments and be developed

consistent with the format provided to the ACRS.

4 Milestone 746: January 6,1997 - Scaling WCAP Revision (without steady state

energy partitioning).

Milestone 747: February 15, 1997 - Scaling WCAP Revision addendum.

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Mr. Nicholas J. Liparulo November 12, 1996 The. staff has provided feedback as noted under milestone 739. It is not clear why two submittals are proposed. There remains uncertainty in the role and completeness of the scaling work as noted under milestone 739.

Milestone 748: February 15, 1997 - WCAP-14386 Revision.

The staff provided comments on the verification and validation report in the form of 12 RAls in March 1996. No responses have yet been received.

Milestone 749: January 30, 1997 - MG0THIC Application Report (WCAP-14407)

Revision

. This date is overly optimistic in that there still sections to be 1

provided for staff review. The staff needs a schedule for the rewrite of Section 9 and for submittal of Section 12. Until the complete report is provided and the role of scaling, PIRT, and the LST are clarified, Section 14, " Summary," will be given a preliminary review for its content.

The staff is nearing completion of its acceptability review of WCAP-14407 (60 days after September 10, 1996, target is November 10, 1996) as provided. Pending acceptability, the staff will issue its RAIs no later than 60 addition days, target is January 10, 1997, on all but Sections 9, 12 and 14. At Westinghouse's request, RAIs will, for the most part, be issued by WCAP-14407 sections.

, The remainder of the scheduled milestones are uncertain since portions of the material are yet to be provided.

4 Milestone 753: January 24, 1997 - Staff Completes Review The staff can not complete its review prior to receiving new information (see for example milestone 747).

If you have any questions regarding this matter, you can contact me at (301) 415-8548.

Sincerely, original signed by:

Diane T. Jackson, Project Manager Standardization Project Directorate Division of Reactor Program Management Office of Nuclear Reactor Regulation Docket No.52-003 cc: See next page /

g 7 DISTRIBUTION: See next page h DOCUMENT NAME: A:SCSB 10.96 ( f f 00 b SK) k n sh,....,,.vihi.4 .t.i.s .i. h.hom(O c- i;,4y whhout attachmenUenclosure 'E' = Copy with attachment / enclosure "N" = No copy 0FFICE PM:PDST:DRPM _ < BC:SCSB:DSSA D:PDST:DRPM l NAME DTJackson:sg 1/// CBerlinger TRQuay T A DATE 11/(,/95 '/ l 11/'//96 Pg) ll//t/96

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4 Mr. Nicholas J. Liparulo Docket No.52-003

Westinghouse Electric Corporation AP600 __

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j cc: Mr. B. A. McIntyre Mr. Ronald Simard, Director Advanced Plant Safety & Licensing Advanced Reactor Programs 4

Westinghouse Electric Corporation Nuclear Energy Institute Energy Systems Business Unit 1776 Eye Street, N.W.

{ P.O. Box 355 Suite 300

Pittsburgh, PA 15230 Washington, DC 20006-3706 l Mr. John C. Butler Ms. Lynn Connor

! Advanced Plant Safety & Licensing Doc-Search Associates Westinghouse Electric Corporation Post Office Box 34 i Energy Systems Business Unit Cabin. John,-MD 20818 i Box 355 Pittsburgh, PA 15230 Mr. James E. Quinn, Projects Manager

! LMR and SBWR Programs

,i Mr. M. D. Beaumont GE Nuclear Energy i Nuclear and Advanced Technology Division 175 Curtner Avenue, M/C 165 Westinghouse Electric Corporation San Jose, CA 95125

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! U.S. Department of Energy Barton Z. Cowan, Esq.

I NE-50 .

Eckert Seamans Cherin & Mellott

19901 Germantown Road 600 Grant Street 42nd Floor Germantown, MD 20874 Pittsburgh, PA 15219 l

i Mr. S. M. Modro Mr. Ed Rodwell, Manager i Nuclear Systems Analysis Technologies PWR Design Certification "

! Lockheed Idaho Technologies Company Electric Power Research Institute Post Office Box 1625 3412 Hillview Avenue Idaho Falls, ID 83415 Palo Alto, CA 94303 l

! Mr. Frank A. Ross Mr. Charles Thompson, Nuclear Engineer

! U.S. Department of Energy, NE-42 AP600 Certification 4

Office of LWR Safety and Technology NE-50 19901 Germantown Road 19901 Germantown Road

Germantown, MD 20874 Germantown, MD 20874 .

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