ML18152A216

Summary of 990119 Meeting with Util to Discuss Issues Re GL 97-04, Assurance of Net Positive Suction Head for Emergency Core Cooling & Containment Heat Removal Pumps

ML18152A216
Person / Time
Site:	Beaver Valley, Surry, North Anna
Issue date:	02/23/1999
From:	Skay D NRC (Affiliation Not Assigned)
To:	NRC (Affiliation Not Assigned)
References
GL-97-04, GL-97-4, NUDOCS 9903020237
Download: ML18152A216 (43)

Text

e UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 February 23, 1999 LICENSEES:

Virginia Electric and Power Company (VEPCO),

Duquesne Light Company (DLC)

SUMMARY

OF JANUARY 19, 1999, MEETING TO DISCUSS ISSUES RELATED TO GENERIC LETTER 97-04 On January 19, 1999, the staff met with Virginia Electric and Power Company (VEPCO),

Duquesne Light Company (DLC), and Stone & Webster to exchange information regarding the licensees' responses to Generic Letter (GL) 97-04, "Assurance of Net Positive Suction Head (NPSH) for Emergency Core Cooling and Containment Heat Removal Pumps" for Beaver Valley, Unit 1, North Anna, and Surry Power stations. Specifically,_the staff needed additional information regarding the methodologies used in conducting the NPSH analyses. A list of the meeting attendees is provided as Enclosure 1. The meeting handouts are provided as.

Technical reviewers from the Containment Systems and Reactor Systems branches of NRR explained the specific information that the staff needs to continue its evaluations of the GL 97-04 responses for the Beaver Valley, Unit 1, North Anna, c1nd Surry stations. The staff

• stated that the objective of the meeting was to understand how VEPCO and DLC used containment back pressure in their analyses and whether it was credited (and to what extent) in the analyses. The licensees' presented their NPSH analysis methodology and results and discussed their licensing basis. Based on questions asked by the staff, the licensees provided the following additional information.

The analysis uses a containment pressure which yields a minimum NPSH; however, the pressure might not be a minimum. At low containment pressures, sump temperatures are also low resulting in improved NPSH to the pumps. Thus, for conservatism, the analysis uses the containment pressures which result in the minimum NPSH.

The low head safety injection pumps do not have problems with NPSH just prior to switching to recirculation. The pumps take suction from the reactor water storage tank prior to switching to recirculation which provides excess NPSH down to the point of switch-over.

The licensees agreed to provide the following information to the staff following the meeting:

Whether the pump testing that had been performed at North Anna Power Station to compare the actual pump performance to the manufacturer's name plate data was conducted with the pumps installed or removed. The licensees also agreed to provide information regarding what, if any, pump performance beyond the name plate information is being assumed in the analyses.

9903020237 990223 PDR ADOCK 05000280 P

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• Any differences in the timing aspects of the accident transient between the various codes (1975 Westinghouse, 1979 Westinghouse, and LOCTIC) used in the mass and energy models.

The staff stated that the presentation gave them a better understanding of how the analyses had been performed and that, with the answers to the above questions, they should be able to move forward with their reviews of the licensees' GL 97-04 responses.

Docket Nos. 50-334, 50-412, 50-338, 50-339, 50-280, 50-281

Enclosures:

1. List of Attendees

2. Meeting Handout cc: See next page

~7?7.~/

Donna M. $kay, Project Manag~

• Project Directorate 111-2

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Division of Reactor Projects Office of Nuclear Reactor Regulation

e February 23, 1999 Any differences in the timing aspects of-the accident transient between the various codes (1975 Westinghouse, 1979 Westinghouse, and LOCTIC) used in the mass and energy models.

The staff stated that the presentation gave them a better understanding of how the analyses had been performed and that, with the answers to the above questions, they should be able to move forward with their reviews of the licensees' GL 97-04 responses.

ORIG.

SIGNED BY Donna M. Skay, Project Manager Project Directorate 111-2 Division of Reactor Projects Office of Nuclear Reactor Regulation Docket Nos. 50-334, 50-412, 50-338, 50-339, 50-280, 50-281

Enclosures:

1. List of Attendees

2. Meeting Handout cc: See next page DISTRIBUTION: (w/encls)

{D.cJCK~JiJ£l PUBLIC D. Collins N. Kalyanam ACRS E-MAIL S. Collins/R. Zimmerman S. Richards.

K. Kavan~gh C. Berlingelr" B. Sheron C. Moore J. Kudrick PDlll-2 r/f G. Edison J. Zwolinski DSkay OGC T. Martin (SLM3)

S. Bajwa DOCUMENT NAME: G:\\PD3-2\\MTS97-04.WPD

, INDICATE IN THE BOX: "C" = COPY WITHOUT ENCLOSURES "E' - COPY WITH ENCLOSURES "N" OFFICE RXB C-SCSB D:PD3-2 NAME KKAVANAGH ~

JKU DATE 2/ t-i-

/99 2/

• 2/,,_3

/99 OFFICIAL RECORD COPY

. Duquesne Light Company cc:

Jay E. Silberg, Esquire Shaw, Pittman, Potts & Trowbridge 2300 N Street, NW Washington, DC20037 Director-Safety and Licensing Department (BV-A)

Duquesne Light Company Beaver Valley Power Station PO Box4 Shippingport, PA 15077 Commissioner Roy M. Smith West Virginia Department of Labor Building 3, Room 319 Capitol Complex Charleston.WV 25305 Director, Pennsylvania Emergency

• Management Agency PO Box 3321 Harrisburg, PA 17105-3321 Ohio EPA-DERR ATTN: Zack A. Clayton Post Office Box 1 049 Columbus, OH 43266-1049 Dr. Judith Johnsrud National Energy Committee.

Sierra Club 433 Orlando Avenue

• State College, PA 16803 Duquesne Light Company Beaver Valley Power Station PO Box4 Shippingport, PA 15077 ATTN: Kevin L. Ostrowski, Division Vice President, Nuclear Operations Group And Plant Manager (BV-SOSB-7)

Beaver Valley Power Station Bureau of Radiation Protection Pennsylvania Department of Environmental Resources ATTN: Michael P. Murphy Post Office Box 2063 Harrisburg, PA 17120 Mayor fo the Borough of Shippingport Post Office Box 3.

Shippingport, PA 15077 Regional Administrator, Region I U.S. Nuclear Regulatory Commission 475 Allendale Road King of Prussia, PA 19406 Resident Inspector U.S. Nuclear Regulatory Commission Post Office Box 298 Shippingport, PA 15077.

Duquesne Light Company Beaver Valley Power Station PO Box4 Shippingport, PA 15077 ATTN: S.C. Jain, Senior Vice President Nuclear Services (BV-A)

Mr. J. E. Cross President - Generation Group Duquesne Light Company Post Office Box 4 Shippingport, PA 15077 Mr. J. A. Hultz, Manager

. Projects & Support Services First Energy 76 South Main Street Akron, OH 44308

Virginia Electric and Power Company cc:

Mr. Donald P. Irwin, Esq.

Hunton and Williams Riverfront Plaza, East Tower 951 E. Byrd Street Richmond, Virginia 23219 Mr. E.S. Grecheck, Site Vice President Surry Power Station Virginia Electric and Power Company 5570 Hog Island Road Surry, Virginia 23883 Mr. W. R. Matthews, Site Vice President North Anna Power Station Virginia Electric and Power Company P. 0. Box402 Mineral, Virginia 23117 Senior Resident Inspector Surry Power Station U.S. Nuclear Regulatory Commission 5850 Hog Island Road Surry, Virginia 23883 Chairman Board of Supervisors of Surry County Surry CountyCourthouse Surry, Virginia 23683 Dr. W. T. Lough Virginia State Corporation Commission.

Division of Energy Regulation

• P. 0. Box 1197 Richmond, Virginia 23209 Regional Administrator, Region II U.S. Nuclear Regulatory Commission Atlanta Federal Center 61 Forsyth Street, SW, Suite 23T85 Atlanta, Georgia 30303 Robert B. Strobe, MD, MPH State Health Commissioner Office of the Commissioner Virginia Department of Health P.O. Box 2448 Richmond, Virginia 23218 e

North Anna Power Station Surry Power Station Office of the Attorney General Commonwealth of Virginia 900 East Main Street Richmond, Virginia 23219 Mr. J. H. McCarthy, Manager Nuclear Licensing & Operations Support Innsbrook Technical Center Virginia Electric and Power Company 5000 Dominion Road Glen Allen, Virginia 23060 Mr. J.P. O'Hanlon Senior Vice President - Nuclear Virginia Electric and Power Company Innsbrook Technical Center 5000 Dominion Road Glen Allen, Virginia 23060 Mr. J. Jeffrey Lunsford County Administrator Louisa County P.O. Box 160 Louisa, Virginia 23093 Old Dominion Electric Cooperative 4201 Dominion Road Glen Allen, Virginia 23060 Senior Resident Inspector North Anna Power Station U.S. Nuclear Regulatory Commission 1024 Haley Drive Mineral, Virginia 23117 Mr. R. C. Haag U.S. Nuclear Regulatory Commission Atlanta Federal Center 61 Forsyth St., SW, Suite 23T85 Atlanta, Georgia 30303

e MEETING WITH VIRGINIA POWER, DUQUESNE LIGHT, AND STONE AND WEBSTER TO DISCUSS ISSUES RELATED TO GENERIC LETTER 97-04 NAME Daniel Collins Gordon Edison Kerri Kavanagh Jack Kudrick S. Singh Bajwa Kaly Kalyanam Gary Miller Frank A. Elia Gary L. Darden Joseph 0. Erb Don Taylor Raymond A. Hruby Kenneth Frederick Mark Ackerman Lyle R. Berry Joern Cho JANUARY 19, 1999 AFFILIATION NRC NRC NRC NRC NRC NRC Virgina Power Stone & Webster Virginia Power Virginia Power Virginia Power Duquesne Light Co.

Duquesne Light Co.

Duquesne Light Co.

Duquesne Light Co.

Stone & Webster ENCLOSURE 1

Virginia Power - Duquesne Light NPSH Analysis Methodology - GL 97-04 Subatmospheric Plant NPSH Analysis Methodology Meeting NRC-One White Flint January 19, 1999

.ENCLOSURE. 2 e

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Virginia Power-Duquesne Light NPSH Analysis Methodology - GL 04 Introductory Remarks Meeting Objectives Meeting Agenda Overview G. L. Darden - Va Power 2

Virginia Power - Duquesne Light NPSH Analysis Methodology - GL 97-04

... Meeting Participants

§ G. L. Darden - Va Power Nuclear Safety Analysis

§ K. J. Frederick - Duquesne Light Nuclear Engineering

§ D. A. Sommers - Va Power Nuclear Licensing *

§ R. A. Hruby - Duquesne Light Nuclear Engineering

§ M. S. Ackerman - Duquesne Light Licensing

§ L. R. Berry - Duquesne Light Licensing

§ J. 0. Erb - Va Power Nuclear Safety Analysis

§ F. A. Elia - Stone & Webster/Safety & Risk Engineering

§ J. H. Cho - Stone & Webster/Safety & Risk Engineering 3

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Virginia Power-Duquesne Light NPSH Analysis Methodology-GL 97-04

)Jo,- Meeting Objectives

§ Present NPSH Analysis Methodology & Results

§ Present Licensing Basis for Subatmospheric Plants

§ Respond to Staff Questions Concerning the Methodology

§ Discuss Requirements for Closure of GL-97-04 4

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Virginia Power - Duquesne Light NPSH Analysis Methodology - GL 97-04

.- Meeting Agenda

§ Background Discussion Relevant to Subatmospheric Plants

§ NPSH Analysis Methodology for Subatmospheric Plants

§ Mass and Energy Release Analysis

§ Transient NPSH Analysis - RS & LHSI Pumps

. § Calculational Components to Determine NPSHavailable

§ NRC Feedback & Questions

§ Discuss Requirements for Closure of GL 97-04 5

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Virginia Power - Duquesne Light NPSH Analysis Methodology-GL 97-04

~ Definitions & Acronyms

[presented on next 2 pages]

6

e Definitions & Acronyms - Subatmospheric Plant NPSH Analyses Air Partial Pressure pressure in containment atmosphere attributed to air component (calculated as total pressure minus vapor pressure, expressed in psi)

Blowdown BVl COP IRS Key Parameter LHSI LOCTIC NAPSl NPSH NPS~vailable NPS~wrred NSSS ORS Pressure Flash QS RCS phase of LOCA transient during which RCS rapidly depressurizes and expels fluid into containment Beaver Valley Power Station Unit 1 Containment Overpressure Inside Recirculation Spray design input (plant or system physical characteristic) which has the potential to change and could result in a significant change in NPSH margin for the range of potential values Low Head Safety Injection Stone & Webster Containment Response Analysis Code North Anna Power Station Unit 1 Net Positive Suction Head (usually represented in feet of water)

NPSH calculated to exist for a given pump at a specific time NPSH required for long-term operation of a given pump under specified design conditions Nuclear Steam Supply System Outside Recirculation Spray model in which break liquid effluent is assumed to flash at the saturation temperature corresponding to the containment total pressure (deposits relatively more energy to sump fluid versus containment atmosphere) - used in NPSH analysis Quench Spray Reactor Coolant System 7

Definitions & Acronyms - Subatmospheric Plant NPSH Analyses (continued)

Reflood phase of LOCA transient during which liquid level fills the reactor vessel up to the elevation where spillage occurs through the RCS break RMT Recirculation Mode Transfer (operation in which LHSI pump suction is realigned from RWST to containment sump)

RMT Setpoint Setpoint (RWST level or time delay)

RS Recirculation Spray RWST Refueling Water Storage Tank SG Equilibration phenomenon modeled in analysis to describe SG secondary energy release to the containment following design basis LOCA (Equilibration Time is the timt: at which SG secondary side pressure equals containment pressure assumed in the mass & energy release analysis)

SER Safety Evaluation Report SPSl Surry Power Station Unit 1 Temperature Flash model in which break liquid effluent is assumed to flash at the dew point temperature of containment atmosphere (deposits relatively more energy to atmosphere versus containment sump fluid) - used in peak containment pressure/depressurization analyses Thermal measure of capability of spray droplets to absorb energy from the containment atmosphere (expressed as % of theoretical maximum)

Effectiveness 8

Virginia Power - Duquesne Light NPSH Analysis Methodology - GL 97-04

>- Background Discussion-Subatmospheric Plants

§ History of NPSH Calculations & System Modifications

- issues originated during North Anna licen~ing (1977)

- affected units: BV1, NAPS 1 &2, SPS 1 &2

- original containment pressure analysis assumptions were nonconservative for calculation of NPSH

- resolution involved pump testing, design changes & a more rigorous transient NPSH analysis based upon explicit sensitivity studies.

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Vi_rginia Power-Duquesne Light NPSH Analysis Methodology - GL 97-04

>- Background Discussion-Subatmospheric Plants

§ History of NPSH Calculations (continued)

- reanalyses employed new LOCTIC code options specifically developed to conservatively predict minimum containment pressure & maximum sump water temp.

- summary of plant modifications

• addition of cooled water to pump suction

• limit pump runout flowrates by installed flow limiting devices on pump discharge and/or change number and type of RS nozzles

- detailed NRC submittals were docketed describing analysis methodology (including sensitivity studies) &

results in support of the plant modifications IO e

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I Virginia Power-Duquesne Light NPSH Analysis Methodology - GL 97-04

~ Background Discussion-Subatmospheric Plants

§ History of NPSH Issues (continued)

- System flow diagrams & NPSH-related modifications

• Surry 1&2

• North Anna 1 &2

• Beaver Valley 1

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INIIDI U:ACTOII CONTAIN II ENT 2-310* SPRAY HEADERS 1/z" DIIAIN 11/z" DRAIN T.,. o P. s.

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Figure 6.3-1 CONTAINMENT SPRAY SUBSYSTEM OUTSIDE IIUCTOII CONTAINll[NT AC REFUELING WAT.ER STORAGE TANK NOTE:

I IIHU[LINC WI.TEii ITORAG[ TANK COOL[RS CHILL[D W&T[II 2*11ECIIICU*

LATION l'Ull,S ro11 COOL*

DOWN I* ll[CHAN I CAL 11,:,111our1011 UNITS POii Ulll'UATIIII!

WLC - WEIIIHT LOADED CHECK VALVE CONTAIIIIIENT ll'IIAY l'Ulll'S TO CH[CIC Ol'EIIATION o, Wlt CHEMICAL ADOIT ION TANK l*IIUUELINO W~Tt:11 CHEMICAL ADDITION TANK l'Ulll'S 0\\

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Figure 6.3-2 RECIRCULATION SPRAY SUBSYSTEM ours,<< 11cA&ro1t--+-----------'-"5 e-'-tJC_,,_:c_A_c_rOR;;._..,;""=:..-'A-'N_,,_c_N_r ____________ -t-- ours,oc tcAcro1t CONrAtNIICNr CONrAINll!Nr SEIIVICE WATER stRVICE WATER Tl 1

RECIRCU\\.ATION SPRAY COOLERS PIC PIC CONTAINMENT SUMP WLC I!)

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1--...--4-.l-----t RECIRCULATION COtlmii:.ENT SPRAY PUMPS SPRAY SYSTEII I

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• RINGS TO INSDt RS PUMPS CONT AINMEl'IT Lenend CAT CHEMICAL ADDmONTANK OS QUENCH SPRAY RS RECIRC SPRAY RWST REFUELING WATER STORAGE TANK S STRAINER A MOTOR OPERATED VALVE MOY

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REfRIGERA TION UNITS CASING COOLING RECIRCULA TICN PUMPS CD 0 z CASING COOLING TANK Figure 6.2-52 RECIRCULATION SPRAY SUBSYSTEM S'w' IN

, SV IN RECIRCULA TICN COOLERS FROM,..._ ________________________ _,

LHSI (UNIT 1 ONLY)'r---------------

CASING COOLING PUMPS OUTSIDE RS PUMPS S'w' OUT SV IN S'w' OUT SV IN S'w' OUT leoend REACTOR CCNTAINMENl LHSI LOW HEAD SAFETY INJECTION RS RECIRC SPRAY SW SERVICE WATER A MOTOR OPERATED VALVE MOV e

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SAFETY INJECT ION SYSTEM

---~e~-----------....... -------- COLD LEG RECIRC PHASE

Virginia Power - Duquesne Light NPSH Analysis Methodology - GL 97-04

~ Background Discussion-Subatmospheric Plants

§ History of NPSH Calculations (continued)

- key points

• existing methodology consists of a conservative integrated containment pressure & NPSH analysis with key parameter values which minimize NPSHavailable

• methodology has been employed since 1977

• NRC SERs document NRC acceptance of methodology e:

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Virginia Power-Duquesne Light NPSH Analysis Methodology - GL 97-04

,.... Background Discussion-Subatmospheric Plants

§ Existing Licensing Basis Status ti

- analysis employs basic methodology developed in 1977

- acceptance criterion: NPSHavailable > NPSHrequired is satsified

- NRC SERs accepted the methodology on the basis of staff confirmatory analysis

- NRC acceptance documents did not impose limitations upon the specific components of the NPSH equation e

(e.g., containment overpressure)

. - methodology applied to IRS, ORS & LHSI pumps 13

Virginia Power-Duquesne Light NPSH Analysis Methodology - GL 97-04

~ Background Discussion-Subatmospheric Plants

§ Existing Licensing Basis Status ( continued)

- Va Power letter 98-546 (GL 97-04 RAI) cited:

• Excerpt from Surry Order for Modification of License Dated 10/17 /77 (response to 9/12/77 analysis report)

• Excerpt from NUREG-0052, Supplement 8, Safety Evaluation Related to North Anna 1 & 2, Dated 12/14/77 (acceptance of NPSH analysis methodology)*

- Duquesne Light letter L-98-183 (GL 97-04 RAI) cited:

• Safety Evaluation related to Amend. 28 to BV1 Operating License, Dated 8/27/80 (acceptance of NPSH analysis methodology) 14 I

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. Virginia Power - Duquesne Light NPSH Analysis Methodology - GL 97-04

.. NPSH Analysis Methodology

§. Components to Determine NPSHavailable NPSHavailable= hcon - hvap + hstat - h,oss hcon = containment pressure, feet of H20 hvap = pumped fluid vapor pressure, feet of H20 hstat = static head of sump water, feet of H20 h,oss = pump suction line losses, feet of H20

§ hcon, hvap and hstat are conservatively calculated as a function of time in the NPSH analysis

§ h,oss for each pump (LHSI, IRS, ORS) is conservatively calculated assuming a constant maximum flowrate, yielding a constant h,oss value 15

Virginia Power - Duquesne Light NPSH Analysis Methodology - GL 97-04

.. NPSH Analysis Methodology

§ Key Features of Integrated Analysis Performed

- analysis is a containment analysis which accounts for dynamic transient behavior of both energy release &

removal mechanisms in containment

- key parameter values are selected to minimize NPSH for each pump analyzed

- separate cases analyzed for each pump

• low head safety injection (LHSI)

• inside recirculation spray (IRS)

• outside recirculation spray (ORS)

- results are obtained for NPSHavailable as a function of time 16

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Virginia Power - Duquesne Light NPSH Analysis Methodology - GL 97-04

>- NPSH Analysis Methodology

§ 1977 Sensitivity.Study Considerations

- limiting single failures considered

• one train engineered safety features equipment

• one Quench Spray pump

• one LHSI pump or one RS pump

• normal engineered safety features (no failure)

- break location

• pump suction

• hot leg

- break size

• full double-ended rupture

• fractional double-ended rupture

• 6 inch single-ended rupture 17 I

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Virginia Power.;. Duquesne Light NPSH Analysis Methodology - GL 97-04

> NPSH Analysis Methodology

§ Key Parameter Values

- QS, IRS, ORS Systems

• flowrate

• temperature

• thermal effectiveness

• actuation timing

- *LHSI Systems

• flowrate

• temperature

• actuation timing I

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I l Virginia Power - Duquesne Light NPSH Analysis Methodology - GL 97-04

> NPSH Analysis Methodology

§ Key Parameter Values (continued)

- RWST

• water temperature

• water volume

• RMT switchover setpoint

- Service Water System

• flowrate

• temperature

• RS heat exchanger characteristics 19 I

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I Virginia Power - Duquesne Light NPSH Analysis Methodology - GL 97-04

,.... NPSH Analysis Methodology

§ Key Parameter Values (continued)

- Containment Initial Conditions

• free volume

• temperature

• relative humidity

• air partial pressure/total pressure

• passive heat sink characteristics e

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Virginia Power-Duquesne Light NPSH Analysis Methodology - GL 97-04

,.... NPSH Analysis Methodology.

§ Key Parameter Values (continued)

- NSSS and Core Assumptions.

• RCS coolant inventory

• RCS coolant temperature & pressure

• core stored energy

• core decay heat I

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Virginia Power-Duquesne Light NP SH Analysis Methodology - GL 97-04

~ Containment Response/NPSH Analysis

§ Summary of Selected Key Parameter Treatment in Containment Integrity and ContainmenUNPSH Analyses

. -. PARAMETER

. 11MAX PRESSURE;:.

IRS NPSH

• LHSI NPSH

• ORS NPSH Containment free volume II MAX II I

MIN I'

MAX 1!

MAX

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1 Containment initial temperature MAX MAX i1 MAX

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Containment initial air partial pressure

• MAX MIN MIN MIN RWSt water voiume MIN 11 MIN MIN II MIN i

RWST water temperature

,l MAX MAX MAX MAX IRWST RMT switchover setpoint MIN NIA NIA MAX jService water flow rate MIN MIN MIN MIN

!Service water temperature MAX MAX*

MIN MAX

'RS heat exchanger U A MIN MIN MIN MIN Quench spray flow rate MIN MIN MIN MIN Quench spray thermal effectiveness MIN MAX MAX MAX Recirculation spray flow rate MIN MAX*

MAX*

MIN Recirculation spray thermal effectiveness !i MIN MAX MAX MAX LHSI flow rate I'

MAX MAX MAX MAX

,1 JI Core decay heat MAX MAX MAX MAX I I

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Virginia Power-Duquesne Light NPSH Analysis Methodology - GL 97-04

,.... Mass and Energy Release Analysis

§ Models Employed in Analysis

- transient mass & energy releases used as LOCTIC input

- LOCTIC calculates NPSHavailable as a function of time ACCIDENT PHASE PLANT BLOWDOWN REFLOOD END OF REFLOOD SG EQUILIBRATION TOSG TO END OF EQUILIBRATION ANALYSIS BVl LOCTIC LOCTIC WESTINGHOUSE LOCTIC 1975 SPSl, SPS2 WESTINGHOUSE WESTINGHOUSE WESTINGHOUSE LOCTIC 1979 1975(RS); 1979(LHSI) 1975(RS); 1979(LHSI)

NAPSl, NAPS2 WESTINGHOUSE WESTINGHOUSE WESTINGHOUSE LOCTIC 1979 1975(RS); 1979(LHSI) 1975(RS); l 979(LHSI) 23

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,j Virginia Power - Duquesne Light NPSH Analysis Methodology - GL 97-04

,... NPSH Analysis Methodology

• § LOCTIC Program Options to Minimize NPSHavailable

- options differ from those chosen for containment depressurization analysis

- pressure flash treatment of break effluent

- mixing of safety injection spillage & break effluent at break 9:

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Virginia Power-Duquesne Light NPSH Analysis Methodology - GL 97-04

,.... Transient NPSH Analysis

§ Calculated Containment Transient & NPSH Results

- calculated results obtained as functions of time

• Containment Atmosphere Pressure

• Pumped Fluid Vapor Pressure

• Sump Water Vapor Pressure

• Sump Water Level

• NPSHavailable

- results are presented in UFSAR-Surry examples are attached (next 4 pages) 25

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Ill 60 50 40 30 20 Figure 6.2-10 CONTAINMENT PRESS AND SUMP VAPOR PRESS LHSI PUMP AVAILABLE NPSH ANALYSIS PUMP SUCTION DER CONTAINMENT TOTAL PRESSURE SUMP VAPOR PRESSURE 0 ~L.Lao.--&.. __

............_a..a..a....__..._............,L£.LII....._. ___...._........ ~--.....__..__._~~~......__-............ ~

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Figure 6.3-8 CONTAINMENT PRESS ORS PUMP AVAILABLE NPSH ANALYSIS HOT LEG DER

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CONTAINMENT TOTAL PRESSURE

• ORS PUMP SUCTION VAPOR PRESSURE 0................ __.___.l,,,&.,L-'JJ.,.............._........._.._.~~-...------.o..a-,'-&.LL...&,.&,-----...._._.i....r.JL..........il-l-J....__.~...._._IJ..I.I 10-1 2 1 QO 2 l 1 QI 2 l 1 Q2 2 3 1 Q3 2 l 1 Q4 TIME (SEC)

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Virginia Power - Duquesne Light NPSH Analysis Methodology - GL 97-04

,.... Va Power/Duquesne Light Conclusions

§ existing analysis methodology ensures conservative results

§ satisfies acceptance cr_iterion: NPSHavailable > NPSHrequired _

§ conservative approach employed in analysis constitutes the existing licensing basis, as accepted by NRC 26

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Virginia Power - Duquesne Light NPSH Analysis Methodology - GL 97-04

~ Discuss Requirements for Closure of GL 97-04 27