ML20197B909

Summary of 971218 Meeting W/Westinghouse in Rockville,Md Re Open Issues Remaining on Analyses of Radiological Consequences of Design Basis Accidents for AP600 Design. List of Attendees & Handouts Provided at Meeting Encl

ML20197B909
Person / Time
Site:	05200003
Issue date:	03/06/1998
From:	Kenyon T NRC (Affiliation Not Assigned)
To:	NRC (Affiliation Not Assigned)
References
NUDOCS 9803120420
Download: ML20197B909 (16)

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1 UNITEf) STATES j NUCLEAR REGULATORY COMMISSION -

WASHINGTON, D.c. ma um e@h

%,*se++ March 6, 1998 l

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APPLICANT: Westinghouse Electric Company l FACILITY: AP600 I

SUMMARY

OF MEETING WITH WESTINGHOUSE TO DISCUSS SOURCE TERM '

ISSUES ON THE AP600 The subject raeeting was hold in the Rockville, Maryland, office of the Nuclear Regulatory Commission (NRC) between representatives of Westinghouse and the NRC staff on December 18,1998. The purpose of the meeting was to discuss the open issues remaining on the analyses of the radiologice! consequences of design basis accidents for the AP600 design.

Attachment 1 is a list of meeting attendees. Attachment 2 is the handout provided during the meeting by Westinghouse.

The participants began the meeting with a discussion of the staff's questions on meteorology.

The staff requested Westinghouse to revise the Standard Safety Analysis Report (SSAR) to reflect that it used ARCON96 in its meteorological evaluations. The X/q should be specified in the SSAR, with a brief discussion of the methodology used.

The staff indiated that there was close agreement on the A values used by Westinghouse and the NRC. Westinghause then requested feedback on the source term information it provided in April 1997 to support its proposed deviation from NUREG-1465 regarding values used for low volatiles and the GAP delay time. The staff stated that the review supportir'g the development of NUREG 1465 entailed a lot olinteraction wi'h the industry, and the staff requires significant new information to be persuaded to change its position from that described in NUREG 1465. The staff stated that it did not believe that any new information was presented in Westinghouse's April 1997 submittal to persuade it to rdlow deviation from the NUREG.

Westinghouse stated its opinion that using the NUREG-1465 values in their supporting

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calculations will not cause much (if any) actual design changes in shielding design, equipment qualification, or vital area access. Radiation zone maps would likely have to be changed.

Although it agreed to use the values of NUREG 1465 in its source term analyses for offsite and

/l main control room doses, Westinghouse proposed that it be allowed to use the already calculated dose values that were based on parameters different than NUREG 1465 to determine - ,

the shielding design, squipment qualification, and vital area access. Otherwise, Westinghouse felt that a large amount of documentation would have to be changed while having a minimal i} { ?))

impact on the design. The staff stated that it was going to have to be careful about what it approved for the APG00 design because of the restrictions that design certification placed upon The staff stated that it believed that Westinghouse should redo the supporting calculations using the NUREG-1465 values, and modify the APC00 design and radiation zone maps, as necessary.

9003120420 900306 PDR ADOCK 05200003 A PDR NRC FILE CENTER COPY l.ilI.lll.l!I.llll.ll.l

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2- March 6,1998 A draft of this meeting summary was provided to Westinghouse to allow them the opportunity to comment on the summary prior to issuance.

original signed by:

Thomas J Kenyon, Project Manager Standardization Project Directorate Division of Reactor Program Management Office of Nuclear Reactor Regulation Docket No. 52 003 Attachments: As stated cc w/atts: See next page DISTRIBUTION w/ attachments:

, Docket File PDST R/F TKenyon i PUBLIC BHuffman JSebrosky DScaletti JNWilson DISTRIBUTION w/o attachments:

SCollins/FMiraglia,012 G18 BSheron,0-12 G18 BBoger,0-12 G18 JRoe DMatthews TQuay ACRS (ii) JMoore,0-15 B18 LBrown,010 D4 REmch,010 D4 CMiller,0-10 D4 MSnodderly,0-8 H7 JLee,0-10 D4 DOCUMENT NAME: A:\ST. SUM re receive a copy of this document, Indicate in the box: "C" = Copy without attachment / enclosure "E" = Copy with attachment /en .losure "N" = No copy OFFICE PM:PM;DRPM l D:PDST:DRPM [ _ l l NAME TJKer14thsg TRQuay A%Q DATE 03/ 6/96 03/ L/98 OFFICIAL RECORD COPY

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Westinghouse Electric Corporation Docket No. 5? 003

! oc: Mr. Nicholas J. Liparulo, Manager Mr. Frank A. Ross i

Nuclear Safety and Regulatory Analysis U.S. Department of Energy, NE-42 ,

Nuclear and Advanced Technology Division omco of LWR Safety and Technology !

Westinghouse Electric Corpoestion 19901 Germantown Road i P.O. Box 355 Germantown, MD 20874

Pittsburgh, PA 15230 Mr. Russ Bell .

Mr. B. A. McIntyre Senior Project Manager, Programs Advenued Plant Safety & Licensing Nuclear Energy Institute Westinghouse Electric Corporation 1776 i Street, NW ,

Energy Systems Business Unit Suite 300

Box 355 Washington, DC 20006 3706

j. Pittsburgh, PA 16230 '

1 Ms. Lynn Connor i

! Ms. Cindy L. Haag Doc Search Associates >

Advanced Plant Safety & Licensing Post Office Box 34 Westinghouse Electric Corporation Cabin John, MD 20818

• Energy Systems Business Unit Box 355 Dr. Craig D. Sawyer, Manager l

. Pittsburgh, PA 15230 Advanced Reactor Programs GE Nuclear Energy-Mr. M. D. Beaumont 175 Curtner Avenue, MC-754 Nuclear and Advanced Technology Division San Jose, CA 95125 Westinghouse Electric Corporation One Montrose Metro Mr. Robert H. Buchholz 11921 Rockville Pike GE Nuclear Energy Seite 350 175 Cudner Avenue, MC 781 Rockville, MD 20852 San Jose, CA 95125 Mr. Sterling Franks Barton Z. Cowan, Esq.

4 U.S. Department of Energy Eci. ort Seamans Cherin & Mellott l NE 50 600 Grant Street 42nd Floor -

4 19901 Germantown Road Pittsburgh, PA 15219 d --

Germantown, MD 20874

Mr. Ed Rodwell, Manager

- Mr. Charies Thompson, Nuclear Engineer PWR Design Ceriification

AP600 Certification Electric Power Research Instituto NE-50 3412 Hillview Avenue 19901 Germantown Road Palo Aho, CA 94303

Germantown, MD 20874 L

Mr. Robert Malers, P.E.

Pennsylvania Department of 4

- Environmental Protection i Bureau of Radiation Protect Rachel Carson State Omco Building

- P.O. Box 8469 .

4 Harrisburg, PA 17105-6469

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AP600 SOURCE TERM MEETING MEETING ATTENDEES DECEMBER 18,1997 N6ME ORGANIZATION THOMAS KENYON NRR/DRPM/PDST ED RODWELL EPRI BRIAN MCINTYRE WESTINGHOUSE J.L. GROVER WESTINGHOUSE JAY LEE NRR/DPRM/PERB LETA BROWN NRR/DRPM/PERB RICH EMCH NRR/DRPM/PERB CHARLES MILLER NRR/DRPM/PERB CHARLES THOMPSON DOE MICHAEL SNODDERLY NRR/DSSA/SCSB k

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1 Attachment 1

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AP600 LOCA Source Terms and Aerosol Removal Presentation to NRC i

December 18,1997 I

l Westinghouse Electric Co. '

James L. Grover

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Purpose of Meeting Present the. proposed Westinghouse approach for performing the radiolegical consequences analysis for the LOCA Reach resolution between the staff and Westinghouse on the approach to be taken to close the existing open items in this area

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Open Items i .

l There are tigge significant open items remaining relative to the AP600 LOCA

! radiological consequences analysis 1

Aerosol removal coefficients  :

l i Source term - fraction of low-volatiles released to the containment l atmosphere l

Source term - timing of onset of core damage .

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Aerosol Removal Coefficients

- The Westinghouse values reported in the SSAR range as follows:

Gap Release Phase 0.50 - 0.58 hr-I In-vessel Release Phase 0.51 - 0.72 hf I 2-hr interval after core release is complete 0.62 - 0.72 hr-3

- The recently calculated Sandia values are time-averaged as follows:

Gap Release Phase 0.82 hr-3 In-vessel Release Phase 0.74 hrI 2-hr interval after core release is complete 0.53 hr-3

- The appropriateness of the Westinghouse removal coctTeients is coiifirmed by the Sandia calculations. There are some differences but these are not significant to the calculation of removal of airborne activity from the containment atmosphere following a LOCA.

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1 l Conclusions Regarding Aerosol Removal Coefficients i -

The aerosol removal coefficients currently reported in Appendix 15B of the SSAR can continue to be used.

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The open item should be closed 4

i Source Term Model Open item on low-volatile release fractions Westinghouse Staff Sr & Ba 0.004 0.02 Cerium group 0.0001 0.0005 Lanthanide group 0.0001 0.0002 Open item on timing of the initiation of the onset of core damage The Westinghouse value is 50 minutes The staff value is 10 minutes 4

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l l Proposal on Source Term i

We belicyp that the departures from the model in NUREG-1465 are technicallyjustified and should be accepted in the AP600 LOCA radiologf: a

consequences model.

Despite the staff statements that our arguments have been reviewed and

rejected, it seems that there has not been a full review. For a proper review l to take place there would have to be discussions between staff and l Westinghouse and there have been none.

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Low-volatile Release Fractions

- In open item 470.42F it is implied that the Westinghouse arguments in support of the reduction in low-volatile release fractions are based only on the EPRI document " Passive ALWR Source Term" from February 1991.

The document provided to the staff (April 1,1996) in support of reduced volatile release fractions is from February 1995. This document was not i reviewed in the formation of NUREG-1465.

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- In open item 470.42F there is a statement that, "In its staff requirements memorandum of January 15,1997, the Commission approved the staff position to use the low-volatile fission product release fractions outlined in NUREG-1465." The SRM does not address this issue.

- We believe that the arguments supporting the lower release fractions for the low-volatile nuclide groups are both credible and conservative.

Timing of Onset of Core Damage In open item 470.43F there is a discussion defending the use of the timing of core damage as identified in NUREG-1465. This is germane to plants similar in design to the currently operating plants but not to the AP600.

- Both in the preface to NUREG-1465 and in Section 2.2 of the document, the following statement is made:

" Source terms for future reactors may differ from those presented in this report which are based upon insights derived from current generation light-water reactors. An applicant may propose changes in source term parameters (timing, release magnitude, and chemical form) from those

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contained in this report, based upon and justified by design specific features."

- The NUREG-1465 invitation to propose changes in the source term model is assumed to be intended seriously. The AP600 has design features that delay the onset of core damage. The time delay has been documented and was provided to the staffin November of 1994.

In Section 2.3 of NUREG-1465 there is specific identification of the potential for an increase in the timing of source term for " passive" plants.

While this conjecture was made relative to lower core power densities, it is just as glicable to the AP600's core reflood capability.

t Impact of the Two Source Term Features on the AP600 I Application Delay time Using a 10 minute delay instead of a 50 minute delay results in only a small increase in offsite and control room doses (on the order of a couple percent).

- Converting to a 10 minute delay from the current 50 minutes would result in changes to the source terms for shielding, equipment qualification, vital area access doses, and radiation zone maps. This would constitute a substantial impact on existing documents.

Low-volatile release fractions -

- Using the release fractions from NUREG-1465 would result in an increase in the 2 hour2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> site boundary dose of about 20%.

- Using the release fractions from NUREG-1465 would result in no significant impact on the other post-LOCA consideratie 3 (i.e., shielding, equipment qualification, vital area access, and radiation zone maps).

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