ML20132A881

Summary of 961112 Meeting W/W in Rockville,Md to Discuss AP600 Scaling & Pirt Closure Rept.W/Agenda & Handouts

ML20132A881
Person / Time
Site:	05200003
Issue date:	12/11/1996
From:	Huffman W NRC (Affiliation Not Assigned)
To:	NRC (Affiliation Not Assigned)
References
NUDOCS 9612160371
Download: ML20132A881 (27)

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UNITED STATES

[- E NUCLEAR REGULATORY COMMISSION N

f WASHINGTON, D.C. 20666-0001

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.....oo! December 11, 1996 4

APPLICANT: Westinghouse Electric Corporation PROJECT: AP600

SUBJECT:

SUMARY REPORT OF MEETING TO DISCUSS THE AP600 SCALING AND PIRT CLOSURE The subject meeting was held on November 12, 1996, at the Rockville, Maryland, offices of Nuclear Regulatory Commission (NRC) between representatives of Westinghouse, the NRC staff, and NRC consultants. The purpose of the meeting was to provide the NRC staff and consultants an overview of how the AP600 scaling and PIRT closure report (WCAP-14727) provides closure to the AP600 testing program.

The NRC consultants provided Westinghouse with some general observations concerning the report, however, the NRC staff was not yet prepared to provide-any formal comments. The NRC staff stated that it was close to being finished with its initial review of all but Chapter 3 of the report and should be able to provide comments by November 22, 1996. The staff stated that it had found some errata during its review of the report and would provide that information to Westinghouse by November 15, 1996. Westinghouse would also provide the staff a list of errata it had found since the report was issued. The staff hoped to have comments to Westinghouse on the general scaling approach (Chapter 3 of the report) by early December of 1996. Westinghouse expressed a desire to have a followup meeting or a teleconference after these comments are received and prior to the Advisory Committee on Reactor Safeguards subcommit-tee on T/H Phenomena meeting on this subject scheduled for December 18 and 19, 1996.

Based on discussions during the meeting on thermal stratification of the cold legs, Westinghouse agreed to a meeting action item (to be included in the open item tracking system). The action item is to provide the staff with any insights from testing that show the effect of multi-dimensional behavior (e.g.

thermal stratification) on system response, and to identify any effects that would not be observed in the tests (e.g. effects on system response due to thermal stratification during a main steam line break or a steam generator tube rupture).

Following the meeting presentation, the open item tracking system was reviewed and updated.

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9612160371 961211 PDR ADOCK 05200003  !

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December 11, 1996 Attachment 1 is the list of meeting attendees. Attachment 2 is the meeting agenda. Attachment 3 is the Westinghouse meeting presentation material.

Attachment 4 is update to the open item tracking system.

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l original signed by:

l William C. Huffman, Project Manager Standardization Project Directorate Division of Reactor Program Management Office Of Nuclear Reactor Regulation Docket No.52-003 Attachments: As stated cc w/ attachments:

See next page DISTRIBUTION w/ attachments:

Docket File PDST R/F TMartin PUBLIC DMatthews TQuay WHuffman TKenyon JSebrosky DTJackson GHolahan, 0-8 E2 DISTRIBUTION w/o attachments:

FMiraglia/AThadani, 0-12 G18 RZimmerman, 0-12 G18 BSheron, 0-12 G18 EJordan, T-4 D18 ACRS (11) JMoore, 0-15 818 WDean, 0-17 G21 Alevin, 0-8 E23 PBoehnert, T-2 E26 FEltawila, T-10 E46 I

DOCUMENT NAME: A:PIRT-MTG. SUM n u . ...,, .e w. 4 .. wa.. . m in. w.: c . cgy nsout .n=h nu.new... r . Cgy whh .Muhm.nu.nebsw. 'N' = No egy l 0FFICE PM:PDST:DRPM SC:DSSA;j)X_B D:PDST:DRPM l l NAME WHuf fman: sis 3CA+v--Alevin/47 \ TRQuay , ,1/ _,

DATE 12/;L/96 12/ 9/96 12/it/95'/l#4s --

t 0FFICIALRECORDSOPY l

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Westinghouse Electric Corporation Docket No.52-003 cc: Mr. Nicholas J. Liparulo, Manager Mr. Frank A. Ross  !

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

Nuclear and Advanced Technology Division Office of LWR Safety and Technology Westinghouse Electric Corporation ' J

! 19901 Germantown Road I P.O. Box 355 Germantown, MD 20874 Pittsburgh, PA 15230 ,

l Mr. Ronald Simard, Director l Mr. B. A. McIntyre Advanced Reactor Program '

Advanced Plant Safety & Licensing Nuclear Energy Institute Westinghouse Electric Corporation 1776 Eye Street, N.W.

l Energy Systems Business Unit Suite 300 l Box 355 Washington, DC 20006-3706 Pittsburgh, PA 15230 Ms. Lynn Connor i Mr. John C. Butler Doc-Search Associates '

Advanced Plant Safety & Licensing Post Office Box 34 Westinghouse Electric Corporation Cabin John, MD 20818 1 Energy Systems Business Unit i Box 355 l Mr. James E. Quinn, Projects Manager Pittsburgh, PA 15230 LMR and SBWR Programs GE Nuclear Energy -

Mr. M. D. Beaumont 175 Curtner Avenue, M/C 165 Nuclear and Advanced Technology Division San Jose, CA 95125  !

Westinghouse Electric Corporation i One Montrose Metro Mr. Robert H. Buchholz  !

11921 Rockville Pike GE Nuclear Energy Suite 350 175 Curtner Avenue, MC-781 Rockville, MD 20852 San Jose, CA 95125 Mr. Sterling Franks Barton Z. Cowan, Esq. I U.S. Department of Energy Eckert Seamans Cherin & Mellott l NE-50 600 Grant Street 42nd Floor 19901 Germantown Road Pittsburgh, PA 15219 Germantown, MD 20874 Mr. Ed Rodwell, Manager l Mr. S. M. Modro PWR Design Certification l

, Nuclear Systems Analysis Technologies Electric Power Research Institute Lockheed Idaho Technologies Company 3412 Hillview Avenue Post Office Box 1625 Palo Alto, CA 94303 Idaho Falls, ID 83415 Mr. Charles Thompson, Nuclear Engineer AP600 Certification NE-50 19901 Germantown Road Germantown, MD 20874 l

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WESTINGHOUSE - NRC MEETING

ON THE AP600 SCALING AND PIRT CLOSURE REPORT NOVEMBER 12, 1996 MEETING ATTENDEES i

4 Hadf ORGANIZATION JOHN BUTLER WESTINGHOUSE LARRY HOCHREITER WESTINGHOUSE

GENE PIPLICA WESTINGHOUSE BRIAN MCINTYRE WESTINGHOUSE

' ALAN LEVIN NRC JOHN BURTT INEL GUNOL K0JASOY NRC CONSULTANT (U OF WISCONSIN)

FAR0UK ELTAWILA NRC (PART TIME)

1. PAUL B0EHNERT NRC (PART TIME) i BILL HUFFMAN NRC 4

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4 Attachment 1

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AGENDA i

i l W/NRC Neeting on AP600 Test Program 1 November 12, 1996 I

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1. Summary of PIRT/ Scaling Closure Report Results and Conclusions M high level summary of what we did and what we learned

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2. Overview of Unanticipated Phenomena (e.g., oscillations, stratification) W description of phenomena, is it test facility related or "real" for the plant {

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impact on the code validation impact on the plant design and what we are doing about it

3. Results of staff review of PIRT/ Scaling Closure Report (to date)

NRC

4. Review and discussion of remaining test program open items W/NRC confirm common understanding of remaining open items identify necessary actions to close remaining open items

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schedule for completion of remaining open items  ;

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Attachment 2

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W/XRC Meeting on AP600 FT PIRT/ Scaling Report .-e..

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November 12,1996 L. E. Hochreiter E. J. Piplica J. C. Butler I

Westinghouse Electric Corporation N

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WNRC Meeting on AP600 pru PIRT/ Scaling Report AP600 Summary .

+ PIRT/ Scaling Report Objective-s were:

i O Provide a comprehensive assessment of the important phenomena for the AP600 0 Verify that the AP600 test provided data to assess the PIRT phenomena 0 Determine any distortions in the test facilities 0 Show that the test data is adequate for code validation l

Westinghouse 2 l

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! W/NRC Meeting on AP600 pru l PIRT/ Scaling Report nesoo

+ To accomplish the objective, the PIRT/ Scaling Report addresses:

O Development of detailed PIRTs for each accident / phase (Chapter 2) 0 Top-down system scaling to determine relative importance for each system phenomena, i

scaled-up test comparisons to show scaling is proper, and to identify distortions (Chapter 3) 0 Top-down and Bottom-up scaling for each component test; and overlap between separate effect tests and integral tests (Chapter 4-8)  :

Westinghouse 3 l l

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W/NRC Meeting on AP600 ini PIRT/ Scaling Report AP600 (Continued)

O Scaling distortion for the tests (Chapters 4-8),

and discussion of the effects of distortion on the test data (Chapter 9) and to identify distortions (Chapter 3)

O Unanticipated phenomena observed in the tests (Chapters 4-8) including oscillations.

0 Application of the test data for code validation Westinghouse 4 i

W/NRC Meeting on AP600 pra PIRT/ Scaling Report AP600

+ What did we learn: l O From the systems scaling, in Chapter 3 O inertia effects are very small and are least l properly scaled 0 buoyant and resistance effects dominate for most AP600 accident scenarios O SPES/OSU were well scaled relative to AP600 0 Systems scaling in Chapter 3 supports the l

component scaling already performed 0 Systems scaling was also useful for examining distortions i Westinghouse 5 l

W5RC MEETING ON AP600 p uL PIRT/ Scaling Report yeoj

_.m o From the distortion assessment in Chapters 4-8, and 9 we learned:

There are test distortions, however, the program, taken as a whole, provides sufficiently undistorted data to assess the phenomena.

The two integral tests complement each other.

Westinghouse 6

WNRC MEETING ON AP600 p uj PIRT/ Scaling Report ,geoo (continued)

OThe phenomena observed in the separate effects tests are also seen in the integral tests, with less distortion.

OLack of scaling similitude was known for each facility and was addressed during the testing.

OSufficient data exists to validate the highly ranked PIRT phenomena in an accurate fashion.  :

Westinghouse 7

.. l W/NRC MEETING ON AP600 1 1

PIRT/ Scaling Report Overview of Unanticipated Phenomena t

t e There was no real unanticipated phenomena observed in the separate effects tests.

ORapid condensation in the CMT was anticipated and a .

diffuser was designed.

OThe lower PRHR heat transfer was a mild surprise but could be addressed with increased number of tubes.

OThe ADS test performed as expected.

l Westinghouse 8

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W/XRC MEETING ON AP600 PIRT/ Scaling Report e Systems Tests Unanticipated Phenomena SPES Integral Systems tests OPRHR Heat Transfer was primarily in the top i horizontal section - while initial surprise, 20/20 hindsight vould indicate that we should not have i been surprised.

OPressure/ Flow Oscillations are caused by the higher power compensation used in SPES for heat loss compensation.

Westinghouse 9 i

W/XRC MEETING ON AP600 iru PIRT/ Scaling Report ageoo e OSU Integral Systems Tests l

OCMT Refill in LTC is a OSU scaling distortion due to the reduced height in the test.

OLTC oscillations are due to "over filling" the test facility such that the pressure is prevented from

, venting out the hot leg. As a result, the pressure increases in the vessel and reduces the DVI flow such that additional steam is generated. Some of the steam is initially condensed at the top of the

, downcomer but as more steam is generated, it depresses the mixture level in the upper plenum Westinghouse 10

W/NRC MEETING ON AP600 t '

PIRT/ Scaling Report (continued)

The oscillations, if they occur in AP600:

- are damped

- are limited by the pressure head in ADS-4

- may not occur in AP600 Westinghouse 11

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_ _ _ -__ _- _ _ __ _ _ - _ __- _ - _ - = - - _= - - --

l l W/NRC Meeting on AP600 p,41 PIRT/ Scaling Report . . . . .

e Thermal stratification of cold legs was investigated as a i design issue for the AP600.

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Westinghouse 12 P

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W/NRC Meeting on AP600 p ,;

PIRT/ Scaling Report .geoo

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e Ansaldo performed analysis of OSU tests and the AP600.

RELAP code used to establish plant conditions during LOCA.

Determine the T/H conditions for 0.5 inch to 2 inch breaks Establish the PRHR return flow rates and temperatures Establish the draindown conditions for the SGs Westinghouse 14

W/NRC Meeting on AP600 PIRT/ Scaling Report 73 '

.geoo m

e Application of the EPRI Stratification Screening Criteria and determination of stratification profiles.

Based on Richardson's number (stratified if Rip > 4)

Conservative interpretation of Tnot, TSAT, and Tcoio and PRHR outlet temp assumed Conservative interpretation of fluid profile (insignificant mixing of hot / cold fluid interface) .

assumed ,

Establish worst case thermal profile for the cold legs Westinghouse 15

i W/NRC Meeting on AP600 -

p, PIRT/ Scaling Report ageoo e Structural evaluation performed using RELAP fluid conditions ANSYS model (3-D) used to determine pipe metal temperature distribution.

ANSYS model (3-D) used to determine pipe stress levels.

Westinghouse 16

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WNRC Meeting on AP600 p,. ,

PIRT/ Scaling Report ageo; e Conclusions LBB analysis shows stress levels below allowable Fatigue analysis show insignificant usage factors f

Westinghouse 17

l W/NRC Meeting on AP600 l pr u PIRT/ Scaling Report ageo6

- Steam condensation events in the AP600 annular downcomer were investigated.

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t Westinghouse 18

l WNRC Meeting on AP600 ,..,

PIRT/ Scaling Report me Steam condensation events were observed in OSU testing of LOCA events:

- Westinghouse report concluded condensation events occurred in the annulardowncomer.

- Changing water levels in reactor vessel caused condensation incidents.

- Normalinstruments not detecting peak pressure from condensation events (only 1.5 ms).

- Pressure differential due to condensation events detectable by DP >

measurements.

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- Water level changes detectable by level instruments (water slug motion)

- Peak pressures indications by rapid response instruments of approximately 25 psi.

- No detectable damage resulting from events in OSU.

Westinghouse 19

s WNRC Meeting on AP600 1 e .

PIRT/ Scaling Report i

v. . . .w Condition for condensation event initiation was related to accumulator injection during LOCA.

- Water level drops to or below cold leg elevation during LOCA.

- A steam volume existing in upper end of downcomer.

i - Cold fluid from accumulator injection breaks up TSAT Doundary layer in

! downcomer. ,

- Condensation event causes DP between upper plenum and annular downcomer.

- Changing water level in reactor vessel causes water slug to hit top of annulardowncomer.

Westinghouse 20  ;

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W/NRC Meeting on AP600  ;

PIRT/ Scaling Report

- ANSALDO performed analysis using RELAP5 Code of OSU and AP600.

- Full RELAP5 model could not produce condensation event due to excessive condensation rate model.

- No steam volume possible in the annular downcomer.

- Simplified RELAP models of OSU and AP600 with disconnected cold legs and one-dimensional model of annular downcomer.

- Condensation events successfully simulated, however, with excessive system DP and resulting slug velocities.

Westinghouse 21 1

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W/XRC Meeting on AP600 p ,g PIRT/ Scaling Report ,geoo

. . . _ . .-.m Observation based analysis of water hammer events.

- System DP measured in OSU during condensation events used with simplified RELAP model.

- Slug velocities calculated by RELAP compared with observations in OSU - conservative.

- RELAP slug velocities used to calculate water hammer peak pressure (Yukowski).

- Calculated peak pressure compared with measured values in OSU -

conservative.

- OSU measured DP scaled to AP600 based on OSU scaling ratio (4).

- RELAP calculated slug velocity for AP600 used to calculate peak water hammer pressure.

- Calculated peak pressure below design pressure for core barrel.

- Calculated peak pressure likely conservative by factor of 3 for AP600 Westinghouse 22

. s OITS UPDATE OITS # NRC STATUS STATUS INFORMATION UPDATE 7 Action N Related to 0ITS #3083 3083 Action N Related to 0ITS #7 25 Action N Staff to review PRHR Final Test Report 1617 Action N Staff to review PRHR Final Test Report 1619 Action W Westinghouse has not completed all RAI respon-ses 1620 Resolved Staff review of OSU test i reports complete 1 2089 Action W No information on Westinghouse actions in-dicated in status summary 2267 Action N Staff to review ITP in-formation for accep- l tability l

3104 Action N Staff to review PRHR l Final Test Report 3130 Action N Staff to review Scaling and PIRT Closure Report 3396 Action N Staff to review response to RAI 440.568 Attachment 4