Yu.Sorokin, N.Fil, N.BukinOKB “GIDROPRESS” Russia

Second Technical Meeting/Workshop for the ICSP on Integral Water Cooled Reactor Design, Vienna 21-23 March 2011

Solving of IAEA International Collaborative Standard Problem on Integral PWR “Double Blind Calculation” usingKORSAR/GP Code

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ICSP Purposes

International Collaborative Standard Problem(ICSP) on «Integral PWR» is performed by IAEA and OSU, which suggested to perform this ICSP on the basis of the experiments executed on MASLWR test facility.

The main purposes of ICSP:- Natural circulation flow stability;- Thermo-hydraulic Coupling of Containment and

Primary System during Accidents

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The Scheme of MASLWR Test Facility

MASLWR – is a small modular pressurized light water reactor based on natural circulation during both steady-state and transient operation.Oregon State University has constructed a system-level test facility to assess computer codes for reactor system design and analysis.

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KORSAR/GP Code 1/3Russian Thermal Hydraulic KORSAR/GP Code was used for MASLWR

parameters estimation during SP-1 & SP-2 experiments at Double BlindCalculation phase.

The purpose of KORSAR/GP usage for ICSP solving is the additionalcode validation on processes modelling in PWR operating on passivesystems.

KORSAR/GP is the Best Estimate Code and it is intended for analysesof LWR processes in stationary, transitive and emergency operation.

Modelling of Thermal Hydraulic processes in KORSAR/GP is carried out on the basis of completely nonequilibrium two-liquid model (on three equations of preservation for water and steam phases) in one-dimensional approach.It is possible to consider the behavior of non-condensable gases.Actual physical systems are simulated in KORSAR code usingh y d r o d y n a m i c a n d t h e r m o d y n a m i c m o d e l s .

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Main components of computer code functions:COL - collector,CH - channel,SCH – single channel, LR - local resistance,BVOL_T - assigned boundary cell,SMASS_T - assigned source of mass, BLJUN - impenetrable connection,SLVES – pressurized steam-water vessel,HCS - heat conducting structure, VAL - gate valve are used for the calculation model of an assumed thermal-hydraulic system.

KORSAR/GP Code 2/3

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Such components and models as:CPUMP - centrifugal pump, ACCUM - hydraulic accumulator, MOD - moderator,

FUEL - fuel, CORE - core, SR - compensating rods

are required for numerical simulation of specific physical processes and dynamics of individual equipment components in light-water reactors.

KORSAR/GP Code 3/3

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KORSAR Nodalization Diagram of the MASLWR Test Facility

VAL800

bljun1

VAL107 Ch107

Ch108VAL108

VAL103 Ch103

VAL106 Ch106

Ch210VAL30

Ch30

smass_t1

bvol_t3

HC

S3

Ch2-01

Ch2-02

Ch2-03

Ch2-04

Ch2-05

Ch2-06

Ch2-07

Ch2-08

Ch2-09

Ch2-10

Ch2-11

Ch2-12

Ch2-13

Ch2-14

Ch2-15

Ch2-16

Ch2-17

Ch2-18

Ch1-18

Ch1-17

Ch1-16

Ch1-15

Ch1-14

Ch1-13

Ch1-12

Ch1-11

Ch1-10

Ch1-09

Ch1-08

Ch1-07

Ch1-06

Ch1-05

Ch1-04

Ch1-03

Ch1-02

Ch1-01

HC

S1

Ch100

Ch3

Ch1

0C

h20

Col30

Sch4

0

HC

S2H

CS4

bvol_t1 bvol_t2

Ch400-18

Ch400-17

Ch400-16

Ch400-15

Ch400-14

Ch400-13

Ch400-12

Ch400-11

Ch400-10

Ch400-09

Ch400-08

Ch400-07

Ch400-06

Ch400-05

Ch400-04

Ch400-03

Ch400-02

Ch400-01

Ch300-20

Ch300-19

Ch300-18

Ch300-17

Ch300-16

Ch300-15

Ch300-14

Ch300-13

Ch300-12

Ch300-11

Ch300-10

Ch300-09

Ch300-08

Ch300-07

Ch300-06

Ch300-05

Ch300-04

Ch300-03

Ch300-02

Ch300-01

Ch200-20

Ch200-19

Ch200-18

Ch200-17

Ch200-16

Ch200-15

Ch200-14

Ch200-13

Ch200-12

Ch200-11

Ch200-10

Ch200-09

Ch200-08

Ch200-07

Ch200-06

Ch200-05

Ch200-04

Ch200-03

Ch200-02

Ch200-01

HC

S300

Ch200-21Ch300-21

Ch300-22 Ch200-22

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Input Data Preparing

KORSAR Input Data has been prepared on the base ofinformation found in Problem Specification [Ref.1 ] and it issimilar to the RELAP Data described in Ref. 2.

1 Problem Specification for the IAEA International CollaborativeStandard Problem on Integral PWR Design Natural CirculationFlow Stability and Thermo-hydraulic Coupling of Containment andPrimary System during Accidents. Draft.

2 Analysis of RELAP5-3D Modeling Techniques for NaturalCirculation Small Integral Light Water Reactors,Draft. OSU-MASLWR-08002.

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The form loss coefficients.The experimental data (Design Notebook.xls) was used to

determine the form loss coefficients. Total loss coefficient Ktotal obtained in experiment is the sum of

the friction loss coefficient and form (local) loss coefficient: Ktotal = Kfr + Kform

According to KORSAR model for single phase coolant Kfr = X*L/Dh, where:L – length, mDh – hydraulic diameter, mX – is defined by KOSAR model as X= max (XRe, Xroug), where

XRe and Xroug depend on Reinolds’ Number (Re) and surface roughness accordingly.

A surface roughness of 1.0x10-6m was used for all MASLWR components.

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SP-1 Initial and Boundary Conditions

Parameter NameParameter Value

Specification [1]

Calculation

Core Power, kW 36 36RPV Pressure, MPa 8.618 8.618PZR Level, m 0.3556 0.36Reactor Mass Flow, kg/s - 0.559Core Exit Temperature (subcooling), K (8.33) 488.4 (85)SG Pressure, MPa 1.379 1.38Feed Water Flow, m3/s - 1.21 E-5Feed Water Temperature, K - 293SG Steam Exit Temperature (superheat), K (13.9) 484 (16.5)RPV Wall Exterior Surface Temperature, K - 300CV-30 Valve position - OpenedPCS-103 (VAL103) Valve position Closed Closed

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SP-1 Time Sequence of EventsTime, s Event

from -1000 to 0.0 Steady State Initialization

0.0 Change of CV-30 Valve Position from "Opened" to "Closed”Open PCS-103 (VAL103)

from 0 to 14 PCS-103 (VAL103) is in position "Opened"RPV Water Level put down to 3.734 mRPV Pressure reduces to 5.74 MPa

from 14 to 2714 RPV Water Level is about 3.65 mPCS-103 (VAL103) is in position “Closed"RPV Pressure reduces to 2.97 MPaReactor Mass Flow is about 0.56 kg/s

from 2714 to 2723 PCS-103 (VAL103) is in position "Opened"RPV Water Level put down to 3.543 mRPV Pressure reduces to 2.48 MPa

from 2723 to 5423 RPV Water Level is about 3.52 mPCS-103 (VAL103) is in position “Closed"RPV Pressure reduces to 2.01 MPaReactor Mass Flow is about 0,63 kg/s

from 5423 to 5429 PCS-103 (VAL103) is in position "Opened"RPV Pressure reduces to 3.505 m

from 5429 to 8129 PCS-103 (VAL103) is in position “Closed"RPV Pressure reduces to 1.92 MPaReactor Mass Flow is about 0.6 kg/s

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Time, s Eventfrom 8129 to 8140 PCS-103 (VAL103) is in position "Opened"

RPV Water Level put down to 3.251 m

from 8140 to 10840 PCS-103 (VAL103) PCS-103 (VAL103) is in position "Closed"Reactor Mass Flow is about 0.12 kg/s

from 10840 to 10850 PCS-103 (VAL103) is in position "Opened"RPV Water Level put down to 2.997 m

from 10850 to 13550 PCS-103 (VAL103) is in position "Closed“Failure of natural circulation

from 13550 to 13560 PCS-103 (VAL103) is in position "Opened"; RPV Water Level put down to 2.743 m

from 13560 to 16260 PCS-103 (VAL103) is in position "Closed"

from 16260 to 16270 PCS-103 (VAL103) is in position "Opened"; RPV Water Level put down to 2.489 m

from 16270 to 18970 PCS-103 (VAL103) is in position "Closed"

from 18970 to 18987 PCS-103 (VAL103) is in position "Opened"; RPV Water Level put down to 2.235 m

from 18987 to 21687 PCS-103 (VAL103) is in position "Closed"; RPV Pressure is about 1.46 MPa

from 21687 to 21700 PCS-103 (VAL103) is in position "Opened"; RPV Water Level put down to 2.134 m

from 21700 to 24400 PCS-103 (VAL103) is in position "Closed"

from 24400 to 24440 PCS-103 (VAL103) is in position "Opened"; RPV Water Level put down to 1.778 m

from 24440 to 27140 PCS-103 (VAL103) is in position "Closed"

from 27140 to 27165 PCS-103 (VAL103) is in position "Opened"; RPV Water Level put down to 1.397 m

from 27165 to 29865 PCS-103 (VAL103) is in position "Closed"

from 29865 to 29885 PCS-103 (VAL103) is in position "Opened"; RPV Water Level put down to 1.016 m

from 29885 to 32585 PCS-103 (VAL103) is in position "Closed"

32585 End of calculation

SP-1 Time Sequence of Events(Continue)

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SP-1 Calculation Results

RPV Level RPV Mass Flow

Core Enter/Exit Temperature RPV Pressure

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Initial and Boundary Conditions SP-2

Parameter NameParameter Value

Specification Calculation

Core Power, kW 299 299

RPV Pressure, MPa 8.618 8.618PZR Level, m 35.56 35.56Reactor Mass Flow, kg/s - 1.28Core Exit Temperature (subcooling), K - (8.33) 569.7 (3.7)

SG Pressure, MPa 1.379 1.38

Feed Water Mass Flow, m3/s - 1.107E-4Feed Water Temperature , K - 293SG Steam Exit Temperature (superheat), K (8.33) 484.5 (17)

RPV Wall Exterior Surface Temperature, K - 300

High pressure containment (HPC) level , cm 279.4 280

Cooling pool vessel (CPV) level , cm 635 620CV-30 Valve position - ClosedSV-800 (VAL800) Valve position Opened OpenedPCS-108 (VAL108), PCS-107 (VAL107), PCS-106 (VAL106), PCS-103 (VAL103) Valves position

Closed Closed

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SP-2 Time sequence of events

Time, s Event

from -1000to 0.0

Steady State Initialization

0.0 Close CV-30 ValveClose CV-800 ValveStop Feed Water

33.0 PZR pressure reaches 1300 psig (8.963 MPa gage)Place the core in decay power mode

52.0 RPV pressure reaches 1350 psig (9.308 MPa gage)Open ADS vent valve PCS-106AOperating PCS-106A, PCS-108A, PCS-108B, SV-800

262.0 Difference between RPV pressure and HPC pressure is _ 5 psig (0.034 MPa gage)Open PCS-106A, PCS-106B, PCS-108A, PCS-108B

86000 End of Calculation

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SP-2 Calculation Results

RPV and HPC Level Core Enter/Exit Temperature

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SP-2 Calculation Results

HPC & CPV Pressure Core Power

HPC & RPV Pressure

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ConclusionWhile solving the International Collaborative Standard Problem at Double Blind Calculation stage :- The nodalization scheme and input deck are developed for MASLWR test facility modeling using the KORSAR/GP code; - The analysis of SP-1 and SP-2 experiments is executed.