ML20137U447

Summary of 970312 Meeting W/W & Consultants in Rockville,Md Re AP600 Application of Wcobra/Trac for LTC Analyses.List of Attendees Encl

ML20137U447
Person / Time
Site:	05200003
Issue date:	04/10/1997
From:	Huffman W NRC (Affiliation Not Assigned)
To:	NRC (Affiliation Not Assigned)
References
NUDOCS 9704170003
Download: ML20137U447 (91)

Text

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UNITED STATES g

,j NUCLEAR REGULATORY COMMISSION

/g WASHINGTON, D.C. 20066 4 001 April 10, 1997 s

APPLICANT: Westinghouse Electric Corporation PROJECT:

AP600

SUMMARY

OF MEETING TO DISCUSS AP600 APPLICATION OF WCOBRA/ TRAC F LONG TERM COOLING (LTC) ANALYSES The subject meeting was held on March 12, 1997, in the Rockville, Maryland, offices of Westinghouse Electric Corporation between representatives of Westinghouse and its consultant and, the Nuclear Regulatory Commission (NRC) staff and its consultant. The purpose of the meeting was to discuss addition-al information Westinghouse had prepared to support is application of a

" windows" approach to analysis of AP600 LTC using the WCOBRA/ TRAC computer i

code.

This information was sent to the NRC via separate correspondence.

Westinghouse letter NSD-NRC-97-5016 dated March 10, 1997, provided a summary report on the AP600 LTC windows methodology (WCAP-14857). Westinghouse letter i

NSD-NRC-97-5014 dated March 10, 1997, provided some extended run time analyses of selected OSU tests to demonstrate that WCOBRA/ TRAC does not diverge in-between calculational windows.

A Highlights from the meeting include the following iterrs:

4 Westinghouse provided support for its assertion that the LTC is a quasi-steady process that is mostly driven by boundary conditions such as decay heat, sump level, and containment pressure.

The window solution is insensitive to initial conditions or perturbations of a transient.

Westinghouse has attempted to address the staff's concerns on possible sulution divergence at extended calculational times by extending the 1

lengths of several select windows from 1000 seconds to 3000 seconds. No change to a window solution was observed by extending the calculational length and no evidence of solution divergence was encountered.

Westinghouse presented information that showed the total vessel inflows and outflows predicted by the code was within the OSU data uncertainty.

Some 'AP600 LTC analyses will be performed assuming all non-flooded compartments eventually flood thereby minimizing the sump level for LTC recirculation.

I There has been no significant change to the LTC PIRT for over two years.

Westinghouse provided additional information on how the WG0THIC code is applied to support LTC analyses.

1G0039 gg HlE CENTER COPY c@

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m 9704170003 970410 PDR ADOCK 05200003 A

PDR 1

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i

April 10, 1997 l,

2 The meeting was productive and contributed to the staff's understanding of the windows approach for both WCOBRA/ TRAC code validation against OSU LTC tests and analyses of the AP600 LTC transients. The staff and its contractor made e

several observations during the meeting.

Specifically; r;xtending the nodalization of the vessel channels into the hot and cold legs appeared to be a unique application that the staff's contractor had i

not seen used before.

l The ADS 4 frictional pressure drop, as captured by the hot leg flow pattern transition and separation at ADS 4 tee, appears to be more 4

important than reflected in the current Westinghouse PIRT during sump injection.

I The conservative containment pressure calculation for a 2" break by i

Westinghouse was not substantially different that a best estimate pressure containment pressure estimate for a 1" break by the staff's i

contractor.

1 Westinghouse agreed to the following actions (which would be documented in the Open Item Tracking System) as a result of discussion during the meeting:

4 j

Westinghouse will describe the calculation of the mass and energy 1

releases out of ADS 4 due to core boiloff during long term cooling, j

including the use of WG0THIC and NOTRUMP to compute the draining of the IRWST.

Westinghouse will determine if Regulatory Guide 1.1 on net positive suction head criteria may have applicability to AP600 SSAR Chapter 15 l

design bcsis accident LTC analyses. The staff is uncertain if Westing-house can take credit for containment pressure grerter than the satura-l tion pressure of the sump water.

Westinghouse appears to be relying on the drainage of non-flooded

{

containment compartments into the normally flooded containment spaces for line breaks in the non-flooded compartments (i.e., various DVI line i

breaks). Westinghouse needs to address what credit is taken for the j

drainage and the operability of the compartment drain line check valves for the LTC analyses and whether these drain paths need to be safety i

related or covered under technical specifications? is the list of meeting attendees. Attachment 2 is a copy of the presentation handouts with material removed which Westinghouse claims is proprietary. Westinghouse committed to submit via separate correspondence an i

application for withholding, affidavit, and non-proprietary copy of the proprietary presentation material, i

i 4

+

$ April 10, 1997 4

A draft of this meeting summary was provided to Westinghouse to allow them the opportunity to ensure that the representation of comments and discussion was accurate.

original signed by:

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/atts: See next page.

^

DISTRIBUTION w/ attachment:

Docket File PDST,R/F TKenyon PUBLIC

' ~

WHuffman DJackson JSebrosky QISTRIBUTION::w/o attachment:

Sco111ns/fMirag11a,.0-12 G18-RZimmerman, 0-12'G18 AThadani, 0-12 G18 TMartin '.

/

MSlosson TQuay JMoore, 0-15 B18

• WDean,.0-17 G21 ACRS (11)

GHolahan,'0-8 E2.

FEltawila, T-10 G6 Alevin, 0-8 E23 Llois, 0-8 E23 NLauben,-:T-10 E46 JLyons, 0-8 E23 D0CtMENT NAME: A:3-12-LTC. SUM TJ sessive e copy of this shoevenent,Ismesses in the bes: 'C' = Copy without ettechment/ enclosure

• E' = Copy with attachment > enclosure

'N' = No copy 0FFICE PM: POST:DRPM l

SC.;DSSAit) FAB l D:PDST:DRPMl NAME WCHuffmak:is 6 b / Alevin /'

TRQuay -9 Q DATE 04/7 /97 04/r/97 04/40/97 0FFICIAL RECORD COPY

i 4

Westinghouse Electric Corporation Docket No.52-003 1

{

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 a

j-

' Westinghouse Electric Corporation 19901 Germantown Road P.O. Box 355 Germantown, MD 20874 Pittsburgh, PA 15230 Mr. Ronald Simard, Director-

)

i Mr. B. A. McIntyre Advanced Reactor Program I

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

1 Energy Systems Business Unit Suite 300 Box 355 Washington, DC 20006-3706 Pittsburgh, PA 15230 i

Ms. Lynn Connor 2

.Ms. Cindy L. Haag.

Doc-Search Associates Advanced Plant Safety & Licensing Post Office Box 34 Westinghouse Electric Corporation Cabin John, MD 20818 i

i Energy Systems-Business Unit Box 355 Mr. James.E.~Quinn, Projects Manager Pittsburgh, PA 15230 LMR and SBWR Programs GE Nuclear Energy

['

Hr. M. D. Beaumont 175 Curtner Avenue, M/C 165 Nuclear and Advanced Technology Divisicn San Jose, CA 95125 i

Westinghouse Electric Corporation 1

One Montrose Metro Mr. Robert H. Buchholz 11921 Rockville Pike-GE Nuclear Energy Suite 350.

175 Curtner Avenue, MC-781 i

i Rockville, MD 20852-San Jose, CA 95125 l

1 i

Mr.. Sterling Franks Barton Z. Cowan, Esq.

i I!.S. Department of Energy Eckert Seamans Cherin & Mellott j

NE-50 600 Grant Street 42nd Floor i

19901 Germantown Road Pittsburgh, PA 15219 Gereantown, MD 20874 Mr. Ed Rodwell, Manager Mr. S. M. Modro PWR Design Certification Nuclear Systems Analysis Technologies Electric Power Research Institute s

Lockheed Idaho Technologies Company.

3412 Hillview Avenue.

Post Office Box 1625 Palo Alto, CA 94303 l

Idaho Falls,10 83415 4

f.

Mr. Charles Thompson, Nuclear Engineer AP600 Certification L

NF-50 1

19901 Germantown Road Germantown, MD 20874

-l 4

i' l

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WESTINGHOUSE - NRC MEETING ON APPLICATI0H OF WCOBRA/ TRAC TO THE AP600 LONG TERM COOLING ANALYSES MARCH 12, 1997 MEETING ATTENDEES NAME ORGANIZATION Earl Novendstern Westinghouse Brian McIntyre Westinghouse Larry Hochreiter Westinghouse i

Dan Garner Westinghouse Bob Kemper Westinghouse Lambros Lois NRC l

Alan Levin NRC Norm Lauben NRC Bill Huffman NRC Cliff Davis NRC Consultant (INEEL)

Jack Wheeler DOE Attachment I l

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... - -... -. -. - - ~ _ -.

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PRESENTATION HANDOUT MATERIAL 1

FROM MARCH 12, 1997, MEETING ON APPLICATION OF WCOBRA/ TRAC TO AP600 4

i LONG TERM C0OLING ANALYSES l

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l AGENDA March 12,1997 Wednesday,12:00 pm Westinghouse Rockville Office LONG TERM COOLING NRC/W MEETING 4

1. Introduction (Novendstern)

2. Analysis Approach (Hochreiter)

3. PIRT(Hochreiter) i a

4. Summary of Westinghouse Topical Report (Garner) i

5. Recent Extended Time Calculation Results (Gamer)

6. WC/T Plant Model(Kemper)

7. Summary (NRC/W) 4

8. ACRS Agenda (Hochreiter) i d

l INTRODUCTION AP600 LONG TERM COOLING IS UNIQUE QUASI-STEADY GRAVITY INJECTION FOR LONG PERIODS (INDEFINITY UNTIL THE PLANT IS RECOVERED)

TWO INJECTION PHASES:

INITIAL INJECTION IS FROM IRWST (HIGHER HEAD WITH HIGHER FLOWS, WHEN DECAY POWER IS HIGHER RECIRCULATION INJECTION FROM SUMP WITH LOWER FLOWS WHEN DECAY POWER IS LOWER REACTOR CAVITY BECOMES FLOODED, COVERS HOT r

AND COLD LEGS l

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INTRODUCTION - CON'T LONG TERM COOLING IS COMMON END POINT FOR ANY I

TRANSIENT WHICH ACTIVITATES ADS 1-3, OR THE RCS IS l

DEPRESSURIZED (SBLOCA, LBLOCA).

l OBJECTIVES OF THE AP600 PLANT ANALYSIS IS T(> VERIFY THAT AP600 PASSIVE SAFETY SYSTEMS:

MAINTAIN CORE COOLABILITY INDEFINITY HAVE THE SAME PEDIGREE AS SIMILAR LONG TERM COOLING SYSTEMS ON CURRENT OPERATING PLANTS.

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LONG TERM ANALYSIS METHOD WCOBRA/ TRAC WAS SELECTED FOR AP600 LONG TERM COOLING ANALYSIS ACCURATE LOW PRESSURE CALCULATIONS ARE NEEDED APPENDIX K TYPE CALCULATIONS WERE AGREED UPON WITH THE NRC IT WAS DESIRABLE TO USE AN ANALYSIS METHOD WHICH THE NRC WAS FAMILIAR WITH t

WCOBRA] TRAC HAS BEEN VALIDATED FOR LOW PRESSURE GRAVITY INJECTION SITUATIONS (CCTF AND SCTF TESTS)

AND IS MOST SUITABLE FOR AP600 LTC

LONG TERM COOLING ANALYSIS METHOD - CON'T SINCE THE LONG TERM COOLING TRANSIENTS ARE LONG QUASI-STEADY FLOW SITUATIONS, A " WINDOW MODE" t

ANALYSIS METHOD HAS BEEN ADOPTED THE " WINDOWS" REPRESENT SELECTED TIME PERIODS OF THE FULL TRANSIENT TO EXAMINE TIME PERIODS WHICH ARE MOST CHALLENGING FOR LTC

" WINDOW." CALCULATIONS ARE TYPICALLY 1000 - 1500 SECONDS IN LENGTH FOR THE PLANT E

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DURING THE LTC TRANSIENT, THE PLANT PRIMARY SYSTEM IS IN A ONCE THROUGH COOLING MODE WITH INJECTION INTO THE DVI LINE AND VENTING OUT THE ADS STAGE 4 VALVES THE REACTOR SYSTEM TRANSIT TIME IS APPROXIMATELY 300 - 700 SECONDS DEPENDING ON THE TIME PERIOD SINCE THE WINDOW MODE CALCULATIONS ARE FOR LONGER TIME PERIODS, THE RESULTING QUASI-STEADY STATE FOR THE REACTOR SYSTEM IS DRIVEN BY THE IMPOSED BOUNDARY CONDITIONS, NOT THE INITIAL CONDITIONS THE INITIAL CONDITIONS SUCH AS VESSEL LEVELS OR MASS DlSTRIBUTION WILL BE SWEPT AWAY BY THE IMPOSED BOUNDARY CONDITIONS OF, DVI LINE FLOW CORE POWER SYSTEM PRESSURE

AS A RESULT, A REASONABLE SET OF INITIAL CONDITIONS WILL BE ADEQUATE TO INITIAL!7E A WINDOW MODE CALCULATION SINCE AT THE END OF 1000 - 1500 SECONDS THE RESULTS WILL REFLECT THE IMPOSED BOUNDARY CONDITIONS.

IN THIS FASHION, THE LONG TIME PERIODS OF THE LTC TRANSIENT CAN BE DIVIDED INTO SHORTER TRANSIENTS WHICH CAPTURE THE MOST IMPORTANT TIME PERIODS TO SHOW ADEQUATE CORE COOLING i

SEVERAL DIFFERENT CALCULATIONS ARE PERFORMED TO EXAMINE DIFFERENT LTC SITUATIONS TO ASSURE ADEQUATE CORE COOLING l

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AP600 LONG TERM COOLING P1RT LTC PIRT WAS DEVELOPED AND REVIEWED AT WESTINGHOUSE AND HAS BEEN SUBMITTED TO THE NRC AS PART OF THE LTC WCAP COMMENTS HAVE BEEN RECEIVED FROM THE NRC AND ITS CONSULTANTS AND HAVE BEEN INCLUDED IN THE FINAL LTC PIRT (MARCH 1996 MEETING)

SOME PHENOMENA WHICH WERE INITIALLY RANKED HIGHER ARE NOW RANKED LOWER BASED ON THE OSU TEST ANALYSIS AND OSU SIMULATIONS y

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i TABLE 11 PHENOMENA IDENTD'ICATION RANKING TABLE FOR AP600 LOCA LTC TRANSIENT (Rev.1)

Component IRWST Snap Phenomenon Injection'"

Injection"'

Break Cntical flow M

N/A Subsonic flow M

L l

ADS Stages I to 3 Criucal flow M

N/A Subsonic flow M

L Two phe.se pressure drop L

L Valve loss coefficients M/L L

Single phase pressure drop L

L Vessel / Core Deca > beat H

H Row resistance L

L Flastung N/A N/A Wall-stored energy M

M Natural ctreulation flow and heat transfer M

M Mixture level mass inventory H

H Pressunzer Pressunzer fluid level L

N/A Wall stored heat L

N/A Pressunzer Surge Line Pressure drop / flow regirne L

L Downcomer/ Lower Plenum Pressurt H

H Liquid levei H

H Condensanon M

M Upper Head Liquid level N/A N/A Flow through downcomer top noales M

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WCAP 14776 REvlsloN: O mM164= 1 wpr theim 17 November 1996

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PHENOMENA IDENTIFICATION RANKLNG TABLE FOR AP600 LOCA LTC TRANSIENT (Rev.1)

Component mm IRWST Phenomenon Sump lajecdon'"

Injection"'

L*pper Plenum t

Ligmd !cvel i

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Entraanment/deenmunment l

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Cold Legs 1

t Condensatica L

L Separation at balance line tee L

L

Steam Generator 20 naturaj circuladon N/A N/A Stearn generator brat transfer L/NN" N/A Secondary conditions

!.JNAi" N/A Hot Leg Flow pattern transition H/M H/M Separation at ADS 4 tee H/M H/M ADS 4 Cnucal flow H

N/A Subsonic flow H

H CMT Recirculation injection N/A N/A Gravity draining injection L

L Vapor condenssuon rate L

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! CMT Balance Lines Pirszure drop N/A N/A 1,

Flow composition L

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Accumulators 1

Noncondensible gas entrainment N/A N/A IRWST Gravity draining injection H

M Vapor condensation rate i

L L

i Temperature dismbution M

M WCAP 14776 Rzvtslos: 0 a\\2164w 1..pt:th l10596 18 November 1996 s

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a TABLE 11 (Cont)

PHENOMENA IDENTIFICATION RANKING TABLE FOR AP600 LOCA LTC TRANSENT (Rev.1)

Component IRWST Sump Phenomenon Injudon("

injwdon'"

DVI Line Pressure drop H

H PRER I

Liquid natural etreulauon flow and heat :ransfer N/A N/A Sump Gravary draining injecuen N/A H

j Level N/A H

Temperature N/A H

J Notel 1.

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= High M

= Medium L

= Low N/A a Not Applicable j

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tlc rankings for steam generator heat transfer and secondary condiuons are Low for IRWST injecuon after a large break and Not Applicable for IRWST injecuon after a small break.

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i WCAP.14776 REVISION: 0 m.ul6e=. wpt.sb.itos96 19 November 1996

WC/T Code Validation for AP600 Long-Term Cooling l

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- Overview of OSU Test Data i

- Summary of Westinghouse Topical Report Recent Edended Time Calculational Results March 12,1997 1

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Overview of OSU Test Data

- Test to Test Similarities i

- Significant Flow Rates

- Vessel Pressure Variations

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ADS 41 Flow (Ib/sec) 1 ADS 4 2 Flow (Ib/sec) 1 Total Vessel Outflow (Ib/sec) 1 i

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WCAP 14776 NSD/NRC 97-5014 WC/T Performance in WC/T Performance in Window Mode Calculations Window Mode Calculations 1

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1. ExtendedTime Sensitivity 2.Bounday Cond.

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Applicability AP600 Long Term for Plant J

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SB01,SB10.

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Sump Temperature (-F) 6.

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Break Separator Temp ("F) 8.

Core Makeup Tank 1 Flow (Wsec) 9.

Core Makeup Tank i Temp (*F)

10. Core Makeup Tank 2 Flow (Usec)

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i j

WC/T VALIDATION CALCULATIONS FOR LONG-TERM' COOLING ANALYSIS 1

l l

l 1 WC/T Initial Condition Convergence - WCAP 14776 Fixed boundary conditions j

Varied individually vessel initial conditions t

Vessel liquid level Downcomer temperature Tests $801 and SB10

2. WC/T Extended Time Calculation Convergence NSD/NRC 97 5014 1-Reference calc.. S801.1260 sec. to 4600 sec.

i Comparison calc., SB01, 3600 sec. to 4600 sec.

Identical vessel initial conditions

- Appropriate, time dependent boundary conditions

3. WC/T Boundary Condition Convergence - NSD/NRC-97-5014 Reference calc., SB01,8000 sec. to 9000 sec.

Comparison cale., SB01,8000 sec. to 9000 sec.

- IRWST_ level raised 2.5 ft for 200 sec. (3600 sec level)

Core Power raised 30% for 200 sec. (3600 sec value)

S.G. Temp. raised 45 F for 200 sec. (3600 sec value)

Identical vessel initial conditions (8000 sec value)

4. WC/T Comparison with OSU Test Data WCAP-14776

- SB01,2' CL Break,14,000 sec. to 15,000 sec.

SB10, CMT Balance Line Brk.,13,500 sec. to 14,500 sec.

SB12, DEG DVI Line Brk., B,500 sec. to 9,500 sec.

- SB23,1/2' CL Break,14,000 sec. to 15,000 sec.

- NSD/NRC 97 5014 SB01, 2' CL Break.1.260 sec. to 4,600 sec.

- SB01,2' CL Break. 8,000 sec. to 9,000 sec.

- SB10, CMT Balance Line Brk.,13,500 sec. to 16,500 sec.

~,,

WC/T Code Validation for AP600 Lona Term Coolina Analysis Letter Rpt.

WCAP 14776 NSD/NRC 97-5014 C2)

WC/T Performance in WC/T Performance in Window Mode Calculations Window Mode Calculations

1. ExtendedTime Sensitivity \\

1. Initial Condition Sensitivity

2. Boundary Cond.

Sensitivrty s

O Summary WC/T

\\

I WC/T LTC t

Validation

)

of WC/T l

Loop and Vessel M

for Applicability Models j

(

AP600 Long Term for Plant Calculations

( Cooling Analysis l

Letter Rpt.

WCAP 14776 NSD/NRC 97 5014 WC/T and OSU Data WC/T and OSU Data Comparisons of Comparisons of y

SB01,SB10.

5801 & SB10 B12 & SB23

1. 3000 Sec.

Windows l

1

i l

Sensitivity to initial Conditions - SB10 Initial Vessel Liquid Level Sensitivity

- Upper Plenum Collapsed Liquid Level 4

't Downcomer Collapsed Liquid Level 1

DVI-1 Injection Flow 4

ADS 4-1 Flow

.ivity e

Initial Downcomer Liquid Temperature Se e

- Upper Plenum Collapsed Liquid Level Downcomer Collapsed Liquic _evel 1

DVI-1 injection Flow l

ADS 4-1 Flow l

t

.j 5-1 i

4 i

-.-..=.

L i

The Following Figures are in the Proprietary Version of this Report Figure 3-22 Figure 3-36

{

Figure 3-41 t

Figure 3-47 Figure 3-54

[

Figure 3-52 i

Figure 3-57 Figure 3-63

s WCrr Code Validation for AP600 Lona Term Coolina Analysis i

Letter Rpt.

j WCAP 14776 NSD/NRC 97 5014 WC/T Performance in WC/T Performance in Window Mode Calculations Window Mode Calcu'ations

1. Initial Condition Sensitivity -

1. ExtendedTime Sensitivity i

2. Boundary Cond.

Sensitivrty O

p WC/T Summary Validation of W C!T WC/T LTC Loop and Vessel M

for Q

Apolicability AP600 Long Term for Plant l

Models L

Cooling Analysis Calculations Letter Rpt.

WCAP 14776 NSD/NRC 97 5014 WC/T and OSU Data WC/T and OSU Data Comparisons of Comparisons of 3

SB01,SB10.

SB01 & SB10 B12 & SB23

1. 3000 Sec.

Windows

i WC/T Extended Time Convergence - SB01 Upper Plenum Collapsed Liquid Level j

Downcomer Collapsed Liquid Level Core Collaosed Liquid Level DVI-1 Injection Flow 4

Integrated DVl-1 Flow L

ADS 4-1 Flow Integrated ADS 4-1 Flow i

i j

M-- Start of IRWST Craindown 3

4 O

?

r s

I

/

3 3

t Y

i

-(---

\\

e>

Identical Initial Vessel Conditions

]

j 1260 3600 4600 Time (sec)

i f

T The Following Figures are in the Proprietary Version of this Report Figure 2.1-4 Figure 2.1-2 Figure 2.1-3 L

Figure 2.1-7 Figure 2.1-8 l

L Figure 2.1-13 Figure 2.1-14 i

L e

..m.

m.

e

)

WC/T Boundary Condition Convergence - SB01 Upper Plenum Collapsed Liquid Level i

Downcomer Collapsed Liquid Level Core Collapsed Liquid Level DVl-1 Injection Flow l

3 Integrated DVl-1 Flow ADS 4-1 Flow Integrated ADS 4-1 Flow a.

Ref. Secondary Temp. + 45'F i

n s

u M

O 4

e m

I Ref. Decay Heat + 30%

l g 'N i

5

's

>a b

g

_ Ref. Level + 2.5'

.3 5

b bs m

E O

8000 8200 8300 9000 Time (sec)

~.

4

+

The Following Figures are in the Proprietary Version of this Report Figure 2.2-4 Figure 2.2-2 Figure 2.2-3 l

3 Figure 2.2-7 Figure 2.2-8 l

Figure 2.2-13 Figure 2.2-14 5

t 1

i I.

f v

~

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i

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i 5)

WC/T Code Validation for AP600 Lona Term Coolina Analysis 4

W Letter Rpt.

WCAP 14776 NSD/NRC 97-5014 WC/T Performance in WC/T Performance in Window Mode Calculations Window Mode Calculations

1. Initial Condition Sensitivity

1. ExtendedTime Sensitivity

2. Boundary Cond.

Sensitivity O

Summary WC/T l

-Validation of WC/T WC/T LTC Loop and Vessel 5

for A

Applicability Models AP600 Long Term for Plant Cooling Analysis Calculations 1

i Letter Rpt.

WCAP 14776 NSO/NRC 97 5014 WC/T and OSU Data WC/T and OSU Data Comparisons of Comparisons of SB01, SB10.

SB01 & SB10 O4 B12 & SB23

1. 3000 Sec.

Windows

~

k 1

i I

4 4

-i i

i 1

I Test Data Comparisons - SB01

- Upper Plenum Collapsed Liquid Level i

Downcomer Collapsed Liquid Level 4

Total DV!-1 injection Flow 3

t AOS 4-1 Flow

)

i e

5 l

l 1

5' i

4 j

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F F

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Fc;

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i

WC/T Code Validation for AP600 Lona Term Coolina Analysis l

Letter Rpt.

WCAP 14776 NSD/NRC 97 5014 WC/T Performance in WC/T Performance in Window Mode Calculations Window Mode Calculations

1. Initial Condition Sensitivity

1. ExtendedTime Sensitivity

2. Boundary Cond.

Sensitivrty O

~

WC/T Summary WC/T LTC Validation of WC/T Loop and Vessel

+

for

-p Applicability Models i

AP600 Long Term

/

for Plant Cooling Analysis calculatiens

[

Letter Rpt.

WCAP 14776 NSO/NRC 97 5014 WC/T and OSU Data WC/T and OSU Data Comparisons of Comparisons of h

j SB01,SB10.

SB01 & S810 B12 & SB23

1. 3000 Sec.

Windows e

8

4 l

i l

WC/T Extended Time Calculation -

i SB01 from 1260 sec. to 4600 sec.

i Upper Plenum Collapsed Liquid Level 4

Downcomer Collapsed Liquid Level M

"? ore Collapsed Liquid Level I

i DVI-1 Injection Flow l

4 Integrated DVI-1 Flow ADS 4-1 Flow 1

integrated ADS 4-1 Flow

~

t i

. -.-~........

The Following Figures are in the Proprietary Version of this Report Figure 2.3-23 i

Figure 2.3-24 i

t-

- Figure 2.3-22 Figure 2.3-3 Figure 2.3-8

+

Figure 2. 3-17

-t Figure 2.3-18 L

2 6

I I

f b

m m..

.-..r.- m..

m.

s.

l i

WC/T Extended Time Calculation -

SB01 from 8000 sec. to 11000 sec.

J

- Upper Plenum Collapsed Liquid Level Downcomer Collapsed Liquid Level Core Collapsed Liquid Level DVI-1 Injeciion Flow Integrated DVI-1 Flow ADS 4-1 Flow Integrated ADS 4-1 Flow 5

t The Following Figures are in the Proprietary Version of this Report Figure 2.4-23 Figure 2.4-24 Figure 2.4-22 Figure 2.4-3 Figure 2.4-$

Figure 2.4-17 Figure 2.4-18 1

D m

. m.

+=

~

WC/T Extended Time Calculation -

SB10 from 13,500 sec. to 16,500 sec.

- Upper Plenum Collapsed Liquid Level Downcomer Collapsed Liquid Level Core Collapsed Liquid Level DVI-1 Vessel inlet Temperature DVI-2 Vessel Inlet Temperature IRWST DVl-1 Injection Flow IRWST DVI-2 Injection Flow Sump Injection 1 Flow Sump Injection 2 Flow Total DVl-1 Injection Flow

=

Total Integrated DVI-1 Flow Total ADS 4-1 Flow TotalIntegrated ADS 4-1 Flow

t The Following Figures are in the Proprietary Version of'this Report Figure 2.5-23 Figure 2.5-24 6

Figure 2.5-22 Figure 2.511 Figure 2.5-12 Figure 2.5-3 Figure 2.5-4 Figure 2.5-5 i

Figure 2.5-6 Figure 2.5-7 Figure 2.5-8 Figure 2.5-19 Figure 2.5-20 t

d. ~.~

WC/T Code Validation for AP600 Lona Term Coo;ina Analysis Letter Rpt.

WCAP 14776 NSD/NRC 97 5014 WC/T Performance in WC/T Performance in Window Mode Calculations Window Mode Calculations

1. Initial Condition Sensitivity

1. ExtendedTime Sensitivity

2. Boundary Cond.

a Sensitivrty WC/T Summary WC/T LTC t

Validation of WC/T Loop and Vessel M

for Q

Applicabsfity Models i

AP600 Long Term for Plant Cooling Analysis Calculations t

Letter Rpt.

WCAP-14776 NSDMRC 97 5014 WC/T and OSU Data WC/T and OSU Data Comparisons of Comparisons of SB01.SB10.

SB01 & SB10 B12 & SB23

1. 3000 Sec.

Windows

s 1

I l

l s.

I l

4 Summary of WC/T vs. OSU Data i

1

- Upper Plenum Level Comparison j

- Downcomer Level Comparison i

- Total Vessel Inflow (DVI) Comparison i

- Total Vessel Outflow Comparison

- Vessel Pressure Comparison i

i i

J

-l l

l 1

I

+

9 1

Downcomer Liquid LeveI Comparison (s.ba

1. m W

n i

e I

f i

I 0

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l, I

i 4

5 e

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Uppar Plenum Liquid Level Comparison (a.b.c

)

I i

3

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1 1

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t

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Reactor Vessei Total Inflow Comparison ta.b.

J m

4 6

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Reactar y,ssel Total OutfIow Comporison i

$ 2.h.4' i

N l

i j

I I

1 I

I i

i m

a i

l I

/

i vessel Pressure Data Comparison i

1 Measured vessel (upper head) pressure range is 15.5 psia to 16.0 psia with '

a pressure sensor uncertainity of 2.44 psia at the 2a uncertainty level.

Calculate pressure of all tests were in the range of 15.3 psia to 15.9 psia during IRWST draindown and sump operation.

4 Calculated vessel pressures show excellant comparison with the measure values, i.e. well within the uncertainity bands.

i t

i 4

b-i j

j

t REACTOR VESSEL PRESSURES DURING IRWST DRAINING i

OSU Test sbO1. sb12, sb18, & sb23 t a.b.c )

i l

I l

j i

i 6

0 9

6 i

3 i

1 4

'I 4

O I

l r

P G

emmen musu 1

N

, =E* 6 l

4 i

Conclusions from WC/T Code Validation 1

for AP600 Application i

1. Several extended WC/T calculations show no indications of solution divergence at 3000 seconds or approximately 5 to 10 times the period l

required to reach a quasi-equlibrium solution.

l

- Extended Timo Sensitivity Solution

- Boundary Condition Sensitivity Solution 3 Dats Comparison Solutions 5

l

2. WC/T underpredicts reactor vessel collapsed liquid levels slightly in OSU tests providing a degree of conservatism.

3. WC/T predicts total vessel inflows and outflows in the'OSU tests within the 2e uncertainity of the flow sensors.

4. WC/T predicts tne reactor vessel pressures in the OSU tests within the i

2a uncertainity of the pressure sensors.

t i

e 1

i l

i j

AP600 LONG TERM COOLING SSAR CALCULATIONS WITH WCOBRA/ TRAC l

l LONG TERM COOLING OF AP600 IS UNIQUE PASSIVE SAFETY-RELATED SYSTEMS j

QUASI-STEADY-STATE CONDITIONS 1

ESTABLISH AND VERIFY A SIMPLIFIED WCOBRA/ TRAC NODALIZATION l

I VESSEL CHANNELS USED FOR HOT LEGS, COLD LEGS VALIDATE AGAINST OSU LONG TERM TEST RESULTS l

l CALCULATE AP600 PERFORMANCE AT LIMITING, DISCRETE TIMES USING WINDOW MODES l

l i

tan /451ank.wyf Paget

+

_ _ _... _ _ _ ~.. _.

METHODOLOGY TO PERFORM A WINDOW MODE ECCS PERFORMANCE ANALYSIS 1.

IDENTIFY LIMITING PORTION (S) OF THE LTC PHASE, THE MOST DEMANDING ON THE SAFETY SYSTEMS.

2.

ESTABLISH BOUNDARY CONDITIONS FOR WCOBRA/ TRAC.

3.

SELECT REPRESENTATIVE INITIAL C0NDITIONS FOR CALCUL.ATION.

4.

EXECUTE WCOBRA/ TRAC UNTIL QUAS!-STEADY STATE ACHIEVED.

l e

i V

rant 45i,-a.wid Page 2

SSAR LONG TERM COOLING ANALYSIS STRATEGY r

ANALYZE IN COMPLIANCE WITH APPENDIX K 1

APPLY CONSERVATISM IN GENERATING CONDITIONS FOR THE WINDOW CALCULATIONS: FOR START OF SUMP RECIRCUI ATION:

MAXIMIZE IRWST DRAIN RATE FOR MAXIMUM DECAY HEAT AT SUMP INITIATION MAXIMIZE ENERGY OF LIQUID EXITING ADS-4 DURING IRWST INJECTION TO MAXIMIZE SUMP TEMPERATURE AND MINIMIZE CONTAINMENT PRESSURE 1

6 ADDRESS THE SPECTRUM OF LOCA BREAK SIZES

~

i i

hr3 w ient..,t

i r

WGOTHIC COMPUTES CONTAINMENT CONDITIONS THROUGHOUT THE TRANSIENT LOW PRESSURE STIPULATED BY APPENDIX K CONSERVATIVE ASSUMPTIONS APPLIED MASS / ENERGY RELEASES GUTTERS PRESUMED INOPERATIVE MAXIMUM PCS WATER FLOW EXTERNAL TO CONTAINMENT i

MINIMlfM PCS WATER TEMPERATURE 1.05* BEST ESTIMATE FREE VOLUME NO HEAT TRANSFER MODELING PENALTIES MINIMIZE INITIAL AIR MASS PRESENT 1

MAXIMIZE EXTERNAL SURFACE WETI'ING fcm/45Ir-L =pf Page 4

Figure 4.2 Small Break LOCA LTC Calculation Containment Input U

WGOTHIC (Time NOTRUMP Short Mass & Energy Zer to Start of Term Analysis Data IRWST Drain)

U Containment Appendix K Core Boiloff During mssum for m

Decay Heat IRWST Drain IRWST Drain n

y U

n Mass &

IRWST Drain Rate Energy Data Calculation IRWST Draining l

U Sump

1. Containment Pressure Injection WGOTHIC (Time

2. Sump Levels y

Zero into Sump

3. Sump Temperatures

?

Injection) l U

Select Window Mode Times and Boundary Conditions Cuel Cue 2 Cue 3 o

o u

WCfr WC/T WC/T LTC LTC LTC

, Calc Calc Cale Cha er 15.6 SSAR (RCS & Core Condi io c:\\ftwsworkutccate pre OM497 ses

?

t 1

INITIAL CONDITIONS FOR WINDOW CALCULATION f

1 INITIAL CONDITIONS ARE ESTIMATED AND DO NOT DETERMINE THE QUASI-STEADY STATE OBTAINED PRIMARY CIRCUIT LIQUID LEVELS AND TEMPERATURE STEAM GENERATOR SECONDARY SIDE LIQUID LEVELS AND TEMPERATURE STRUCTURE TEMPERATURES WINDOW APPROACH HAS SHOWN THAT AN EQUIVALENT QUASI-STEADY STATE WILL BE REACHED FROM ANY REASONABLE VALUES l

FOR THESE INITIAL CONDITIONS, AS VALIDATED BY OSU SIMULATIONS i

t ANALYZE AP600 CASES USING INITIAL CONDITIONS ESTIMATED l

FROM EARLIER CALCULATIONS l

1 I

f

/asm/45thwyf Page 6

5 BOUNDARY CONDITIONS FOR WINDOW CALCULATION 1

BOUNDARY CONDITIONS WHICH DETERMINE THE QUASI-STEADY STATE t

CORE POWER (APPENDIX K DECAY HEAT) l IRWST LIQUID LEVEL AND TEMPERATURE CONTAINMENT PRESSURE SUMP LIQUID LEVEL AND TEMPERATURE i

1 i

1 I

t i

i f

Mid$

Page 7

CRITERIA FOR ACHIEVING A QUASI-STEADY STATE KEY VARIABLE REMAINS STEADY OVER AN EXTENDED PERIOD CORE LIQUID LEVEL DOWNCOMER LIQUID LEVEL l

UPPER PLENUM LIQUID LEVEL' UPPER PLENUM PRESSURE

[

DVI INJECTION RATE ADS STAGE 4 FLOW l

I t

4 I

4 u nr451,.t..yt rs

AP600 LONG-TERM COOLING CASES FOR FINAL SSAR i

I CONSERVATIVE ANALYSIS BASES UTILIZED CONTAINMENT CONDITIONS SINGLE FAILURE OF ONE PASSIVE SAFETY SYSTEM. COMPONENT f

APPENDIX K DECAY HEAT MAXIMUM DESIGN FLOW RESISTANCES FOR INJECTION PATHS

[

AND ADS PATHS MDDELING PER THE WC/T OSU FINAL VALIDATION REPORT CASES TO SHOW ADEQUATE CORE COOLING IN THE LONG TERM i

i p.,,

j

.._m_,

AP600 SSAR LONG-TERM COOLING WINDOW MODE CASES SET 1 - DOUBLE-ENDED DVI LINE BREAKS CASE I - DESIGN BASIS: ONLY PASSIVE SYSTEMS OPERATE WINDOW INCLUDES THE LATE IRWST INJECTION PHASE ON INTO STABLE SUMP INJEGION REPRESENTS EARLIEST SWITCHOVER TO SUMP INJECTION AND, i

THEREFORE, THE HIGHEST DECAY POWER FOR SUMP INJECTION CASE II - SYSTEMS INTERACTION: RNS OPERATION INITIALLY RNS FAILURE ASSUMED AT THE TIME OF SUMP SWITCHOVER, AFTER IRWST HAS BEEN DISCHARGED RAPIDLY BY PUMPS IN THIS WINDOW, SUMP INJECTION BEGINS EVEN EARLIER THAN IT l

DOES Ir4 CASE I CASE III - WALL-TO-WALL. FLOOD UP IN THE VERY LONG-TERM WINDOW MODELS THE LEVEL ' REACHED WHEN ALL COMPARTMENTS BELOW LIQUID SURFACE HAVE FILLED DUE TO PASSIVE LEAKAGE MINIMUM SUMP LEVEL FOR DESIGN BASIS EVENTS

, may

e. w

~

AP600 SSAR LONG-TERM COOLING WINDOW MODE CASES (CONT'D)

SET 2 - SMALL COLD LEG BREAKS CASE I - TWO-INCH COLD LEG BREAK WITH ONE ADS-4-PATH FAILED WINDOW INCLUDES THE LATE IRWST INJECTION PHASE ON INTO STABLE SUMP INJECTION REPRESENTATIVE OF SMALL BREAK LOCA SWITCHOVER TO INJECT FROM A NEAR-SATURATED SUMP CASE II - TWO-INCH COLD LEG BREAK WITH ONE DVI PATH FAILED SINGLE FAILURE SENSITIVITY CASE

/ceW411rakw/

Pegs 11

O AP600 SSAR LONG-TERM COOLING WINDOW MODEL CASES (CONT'D)

SET 3 - LARGE COLD LEG (DECLG) BREAK CASE I - CONTINUE SHORT-TERM TRANSIENT BEYOND ADS 1-3 INJECTION l

LEVEL

~

SHOWS CONTINUED COOLING AFTER ACCUMULATORS ARE EMPTY BY CMT INJECTION LESS AVAILABLE HEAD THAN EXISTS ONCE THE IRWST BECOMES AVAILABLE CASE II - WINDOW CONSIDERS IRWST INJECTION AT THE TIME AT WHICH THE SUMP LE'NL HAS RISEN TO WITHIN THE PERIMETER OF THE i

BROKEN COLD LEG FAIL ONE ADS-4 FLOW PATH CASE III - WINDOW CONSIDERS INJECTION FROM AN IRWST REFILLED WITH CONDENSATE ~ RETURN FROM THE CONTAINMENT GUTTERS SENSITIVITY TO GUTTER OPERATION (RAI RESPONSE)

Ann /451runkwyf Page il

~

t i

CONCLUSIONS:

1 THE WCOBRAfrRAC WINDOW MODE ANALYSIS METHODOLOGY IS A VALID TECHNIQUE TO CALCULATE ECCS PERFORMANCE OF AP600 i

DURING LONG-TERM COOLING INPUT IS GENERATED SO AS TO OBTAIN A CONSERVATIVE ANALYSIS RESULT WINDOWS SELECTED FOR THE SSAR LOCA ANALYSIS INVESTIGATE BOUNDING SCENARIOS 6

i l

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w h at. pt i

Simplif1_d AP600 Intevuel Mntassnent rww act,+ urn E

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DRAFT AGENDA Friday, March 28,1997 LONG TERM COOLING ACRS MEETING

1. Introduction i

a. Computer Code Selection

b. Window Mode Approach Definition j

2. PIRT I

3. WC/T Validation

a. OSU Model

b. Sensitivity Calculations

c. Comparisons with Data

4. AP600 Plant Mcdel

a. Plant Model

b. Containment Boundary Conditions

5. Conclusions t

o vissen 13 ;p91 i NR0tLTC.14 191

.