coupled thermal-hydraulics/neutronics code, mars/master

-1/28-KAERIKAERI-- Nuclear Hydrogen Development & Demonstration ProjectNuclear Hydrogen Development & Demonstration Project

Coupled Thermal-Hydraulics/Neutronics Code, MARS/MASTER

June 17, 2005

Presented at the 1st Workshop on PBMR Coupled Neutronics/Thermal-Hydraulics Transient Benchmark,

the PBMR-400 Core Design

Prepared by

J.-J. Jeong*, W. J. Lee, K. S. Kim, J. M. Noh, H. K. Joo(*[email protected])

Korea Atomic Energy Research Institute


Outline

The Coupled Thermal-Hydraulics/NeutronicsCode, MARS/MASTER- Thermal-Hydraulic System Code, MARS- Neutronics Code, MASTER- Coupled Code, MARS/MASTER

Improvement of MARS/MASTER for GCR Applications- Development of MARS-GCR- Improvement of MASTER for GCR Applications- MARS/MASTER-GCR


*MARS: Multi-dimensional Analysis of Reactor Safety.

The Coupled Thermal-Hydraulics/NeutronicsCode, MARS/MASTER- Thermal-Hydraulic System Code, MARS*- Neutronics Code, MASTER- Coupled Code, MARS/MASTER



Best-Estimate T/H System Code, MARS*– Developed by KAERI Since 1997

– Best-Estimate Analysis of LWR T/H System Transient– Supported by Long-term Nuclear R&D Program– Main Structures: RELAP5/MOD3 (1D Module) and

COBRA-TF (3D Module)– MARS Code Development Activities

• Improvement and Extension of T/H Modeling Capabilities• Code Couplings • Restructuring of Data Structure (Fortran90, More than 40%

Rewritten)• GUI on Windows System (QuickWin and NPA Versions)

The MARS Code Development

*J.-J. Jeong, K.S. Ha, B. D. Chung and W.J. Lee, ”Annals of Nuclear Energy, vol. 26, no. 18, pp. 1161-1642 (1999).


New component• Multi-D porous media equations• R-θ and Cartesian coordinatesMulti-D Hydrodynamics

Option in 1D/3D module• Viscous shear term in momentum eq.Viscous Shear

Option in 3D module• Liquid film dryout in annular flowMechanistic Dryout

Option in 1D module• NE/NH model for bubbly flow

derived from system Characteristics Eq.

Critical Flow

Under V&V• Interfacial area, heat transfer and

steam penetration in sonic jet flow regime

Direct Contact Condensation in Condensation Tank

Under implementation• Incorporation of droplet field in 1D module

Droplet Field in 1D Module

Option in 1D module• Stability enhancing interfacial pressure force model

Improved Numerical Method

Default in 3D moduleUnder further development

• Interfacial drag and heat transfer in inverted pool flow regimeDirect Vessel Injection

Implementation StatusMajor ImprovementsT/H Models

Improvement of the MARS T/H Models


Option in 1D module

• Horizontal flow regime map• Fuel heat-up in stratified flow• Digital sampling model• Spray flow regime model• CANDU decay heat • EM critical flow

CANDU

Option in 1D module• Helical SG heat transfer• Critical heat flux• Critical flow with non-condensable

SMART

Option in 1D module• Heat transfer packageHANARO

Option in 1D/3D moduleUnder V&V

• Thermodynamic and transport properties of He and CO2

• Heat transfer package for gas flowGas-Cooled Reactor

Option in 1D module• Heat transfer correlationsTight Lattice Core

Implementation StatusMajor ImprovementsT/H Models

Extension of the MARS T/H Models


RELAP5/MOD3 + COBRA-TF*Three-Dimensional Reactor Kinetics Code, MASTER, which contains the COBRA-III/CP Subchannel AnalysisModuleContainment Analysis Code, CONTEMPT4 andCONTAIN

*Thermal-Hydraulic Code for the Reactor vessel T/H and Subchannel Analysis

Coupled Analysis Capability of MARS


GUI: QuickWin or NPA

3D Module(COBRA-TF)

1D Module(RELAP5)

Internal, Implicit Coupling – Consolidation

External, ExplicitCoupling with DLL

CONTEMPT & CONTAIN

MASTER &COBRA-III/CP

MARS Code Structure


The MASTER Code (I)Core Neutronics Design and Analysis Code Developed by KAERI– Three-dimensional, Two-group Neutron Diffusion Equations– Core Reactivity and Pin-wise Power Distribution Calculation with T/H

Feedback– Coupled to HELIOS and CASMO Generated Cross Sections– Depletion Calculation with Microscopic Cross Sections– Xe Dynamics Calculation– Transient Calculation with COBRA-III/C T/H Module– Verified Against Critical Experiments and Plant Measured Data

• B&W Criticals• 14 Cycles including YGN1, YGN3, Palo Verde

Additional Features– Hexagonal Geometry Handling (Base = Rectangular)– Various Solutions Kernels (NEM, ANM, AFEN, TPEN)– Multigroup Calculation Possible for Block Type VHTR– QuickWin Graphics for Online Transient Plots

*Multi-purpose Analyzer for Static and Transient Effects of Reactors


The MASTER Code (II)


MARS/MASTER MARS/MASTER/COBRAMARS/MASTER MARS/MASTER/COBRA

MASTER3D KineticsModule

RELAP5:Coolant System

COBRA-TF:Reactor Vessel

COBRA IIISub-channelModule

MASTER

ρi & TFi at tj

Local powers at tj

Refined ρi & TFi at tj

tj-1

Core inlet flows &exit pressures at tj

MASTER:3D KineticsModule

1D (RELAP5)Coolant System

3D(COBRA-TF)Reactor Vessel

COBRA-III/CP:Core T/H & DNBR

i

tj-1

MARS Core inlet flows &exit pressures at t

Single Coupling Double Coupling

Refined coreT/H nodalization

Subchannel module

CONTAIN &CONTEMPT

Local powers at

MARS/MASTER Code Coupling

*H. G. Joo, J.-J. Jeong, B. O. Cho, W. J. Lee, and S. Q. Zee, “Analysis of the OECD MSLB Benchmark Problem using the Refined Core Thermal-Hydraulic Nodalization Feature of the MARS/MASTER Code,” Nuclear Technology, vol. 142, pp. 166-179 (2003).

Explicitly Coupled with Dynamic Link Library (DLL) TechniqueTwo Coupling Schemes: Single & Double Coupling Scheme*


Conceptual ProblemsConceptual Problems

The OECD/NEA MSLB Benchmark ProblemThe OECD/NEA MSLB Benchmark Problem

0 20 40 60 80 1000.0

0.2

0.4

0.6

0.8

1.0

1.2

Nor

mal

ized

cor

e po

wer

Time (s)

A B C D E F G H I KAERI

V&V of the Coupled Code

Radial Power at 67.2 s

Intact side

Broken side

Total Core Power Behavior


MARS/MASTER has been developed for LWRs.

In the PBMR, the coolant is gas, the moderator is graphite, and …


The Coupled Thermal-Hydraulics/NeutronicsCode, MARS/MASTER - Thermal-Hydraulic System Code, MARS- Neutronics Code, MASTER- Coupled Code, MARS/MASTER



Development of MARS-GCR

T/H Modeling Requirements for GCR Applications*

M3-D Kinetics/ContainmentCoupled Analysis

--AvailableRadiation Heat Transfer

HN/A, GAMMAGraphite Chemical Reaction

MN/ASystem Component Models

MN/AMulti-D Heat Conduction

HMULTI-D ComponentMulti-D Hydrodynamics

HN/AContact Heat Transfer

HSimple Model at Low ReConvection Heat Transfer

HSimple NC gas in VaporGas Flow & Properties

PriorityMARS CapabilityT/H Models

H: High, M: Medium

Developed

Modified

DevelopedDeveloped

To be develope

To be develope

To be develope

To be develope

OK

*W. J. Lee et al., “Development of MARS-GCR/V1 and its Application to Thermo-Fluid Safety Analysis of Gas-Cooled Reactors,” ICAPP 2005, Seoul, Korea, May 2005.


Gas Flow & Properties

He and CO2: One of Main System Fluids– Generation of Thermodynamic Property Tables outside the Code – New Search Routines for Thermodynamic Property Tables– State-of-the-Art Transport Properties in Functional Form

Verification and Validation

ReasonableModeling capability of complicated fluid systems (IHX Problem)

Multi-Fluid System

ReasonablePropagation of inlet flow and temperature perturbation

2-D Slab Transients

Good Agreement with ATHENA

Cooldown & heatup transients at 1-φ/2-φ/supercritical states

1-D Transients

Good Agreement with NIST

Accuracy of calculated properties at 1-φ/2-φ/supercritical states

1-D Steady States

ResultsObjectivesProblem ID


Convection Heat Transfer Model

Original MARS Heat Transfer Models– Forced Turbulent Convection Heat Transfer

• Dittus-Boelter Model – Heat Transfer at Low Reynolds Number

• Maximum of Free Convection, Laminar and Forced Turbulent

Technical Issues– Dittus-Boelter Forced Convection Model is known to Over-

predict– Wall Temperature and Geometric Effects become more

Dominant in Gas Flows– Heat Transfer Regimes during Conduction Cooling Transients

are in Free, Mixed, Laminar or Turbulent Convections


Churchill-ChuNatural

Burmeister (Gr < Re2)TransitionCriterion

ChurchillMinimum (hlam, htur)ChurchillMixed

Aicher (Ra1/3/(Re0.8Pr0.4) < 0.05 )TransitionCriterion

Olson

Interpolation between hlam and htur (2300 <

Re < 5000)

Nu = 4.364 (heating)

Nu = 3.657 (cooling)

Forced

TurbulentTransitionLaminarRegime

Gas Heat Transfer Regime Map

MIT Model based on Metais-Eckert MapHeat Transfer Regime during GFR Post-LOCA Decay Heat Removal


Assessment: Turbulent Forced Convection Model

1067.1027.1042.1048.Reynolds No. in Core28.~41.38.5~42.638.5~42.638.~40.2HTC in Core

Gniel. (’75) w/o Twall EffectGniel (‘75)Gniel.

(’75)Olson (’00)

21.~36.40.3~65.040.3~65.138.2~55.1HTC in HX

1067.01027.01026.31047.9Max. Clad. Temp.951.0935.4934.9948.7Temp. at Core Outlet440.0429.8429.7441.4Temp. at Core Inlet8.748.908.918.82Loop Flow

LOCA-COLAATHENAMARS-GCRCalculated Variables

Units in SI (bar, kg/s, K, W/m2-K)



0 5 10 15 20 25

0

10

20

30

40

50

60

LOCA-COLA MARS

Dec

ay H

eat R

emov

ed (M

W)

Pressure (bar)

Comparison of GFR Decay Heat Removal CapabilityComparison of GFR Decay Heat Removal Capability

Assessment: Whole Heat Transfer Package- GFR Decay Heat Removal Capability compared with LOCA-COLA (MIT)



Contact Heat Transfer

Contact Heat Transfer Model– Need to model the Heat Conduction by “Contact” between

Fuel Pebbles, Blocks, and Vessel Internals– Simple Model as a Short-Term Resolution

Qcon = Acon Hcon (Ti-Tj) = Ai (Acon/Ai) Hcon (Ti-Tj)= Ai Heff (Ti-Tj)

where Heff is the Effective Thermal ConductivityCurrently, Constant Input Value is provided by User.Mechanistic Model will be developed.

– Verified on Debugger Level


Multi-D Hydrodynamic Component

Geometry– Rectangular: Slab– Cylindrical: Downcomer, Core, Pipe, Tank

3-D, 2-Phase Flow Formulation– Porous Media Approach:

• Volume (γv) and Area Fraction (γs)– 3-D Momentum Equation

– 3-D Energy Equation

– 3-D Flow Regime Map• Modified Flow Regime Map based on 1-D Map

y

x

γs,x A

γs,y A

αfγv V

αgγv VV

( ) ( ) wiskv

kkkkkkksv

kkk FFgPvvvt

−−∇+=⋅∇+∇+∂∂ τγα

γρααραγ

γρα 11

( ) ( )[ ]kkUkkkvkkkv vUKV

VU

tραγραγ ⋅∇⎟

⎠⎞

⎜⎝⎛+

∂∂ 1( ) ( )[ ]kk

Ukkkvkkkv vUKV

VU

tραγραγ ⋅∇⎟

⎠⎞

⎜⎝⎛+

∂∂ 1 ( )⎥

⎦

⎤⎢⎣

⎡ ⋅∇⎟⎠⎞

⎜⎝⎛+

∂∂−= kkv

kVk vV

VtP αγαγ 1 ( )⎥

⎦

⎤⎢⎣

⎡ ⋅∇⎟⎠⎞

⎜⎝⎛+

∂∂−= kkv

kVk vV

VtP αγαγ 1 ( ) [ ]

kkvkkskvk qVV

PU '1/ αγργ ⋅∇⎟⎠⎞

⎜⎝⎛−+Γ+ ( ) [ ]

kkvkkskvk qVV

PU '1/ αγργ ⋅∇⎟⎠⎞

⎜⎝⎛−+Γ+


RPI Air-Water Test

10 20 30 40 50 60 70 800.00.10.20.30.40.50.60.70.80.91.0

10 20 30 40 50 60 70 800.00.10.20.30.40.50.60.70.80.91.0

10 20 30 40 50 60 70 800.00.10.20.30.40.50.60.70.80.91.0

Void

Fra

ctio

n

Lateral position (cm)

Lower Position

Air-Water outlet Water inlet

Air-Water outlet

Air-Water Inlet

Middle Position

Top Position

Experiment Modified MARS

1-Φ WaterInlet

2-Φ WaterAir Outlet

2-Φ WaterAir Outlet

2-Φ WaterAir Inlet

Air Velocity

Void Fraction

Calculated Void Distribution

V&V of Multi-D Hydrodynamic Component


HPCC Event Analysis using MARS-GCR

Reference Plants– NGNP 600 MWth PMR (Thot = 1000oC)– NGNP 300 MWth PBR (Thot = 1000oC)– GT-MHR Air-Cooled RCCS

MARS Modeling10

7

6

5

4

3

2

Out In

3 core ring

Centerreflector

Outerreflector

Coolant channel

Bypassregion

Outer reflecto

r

Center reflecto

r

PMR600 (1-D) PBR300 (Multi-D) GT-MHR RCCS (Multi-D)

Coolantriser

Core

ReflectorBypass112

Outlet pipe

Outlet Inlet

130 : Upper plenum

110 : Core

Cen

ter reflector

Outer reflecto

r

Vessel w

all

Coolantriser

Core

ReflectorBypass

Coolantriser

Core

ReflectorBypass112

Outlet pipe

Outlet Inlet

130 : Upper plenum

110 : Core

Cen

ter reflector

Outer reflecto

r

Vessel w

all

900 Reactor Cavity(Multi-D Component, 2-r, 1-θ, 15-z)

970

Riser

960

Down-comer

965Flow distributer

975

980

955

950

Concrete Soil

900 Reactor Cavity(Multi-D Component, 2-r, 1-θ, 15-z)

970

Riser

960

Down-comer

965Flow distributer

975

980

955

950

Concrete Soil

130(Riser

&Head)

140 (Upper plenum)

160 (Lower plenum)110(Inlet ann.)

120 (SCS & Lower head)

100(Inlet)

170(Outlet)

145

OuterReflecor

156

OuterCore

154

MiddleCore

152

InnerCore

142

InnerReflecor


Multi-Group Cross Section TreatmentCross Section Functionalization for Gas-Cooled Reactors – Burnup– Moderator Temperature– Fuel Temperature:

Radial Reflector Treatment

Axial Block Shuffling Scheme (to be developed)

Thermal-Hydraulic Feedback Model for GCR (to be developed)

Improvement of MASTER for GCR Applications

mm

ff

mfmf T∆TσT∆

Tσ),TT(Bσ),TT(Bσ

∂∂

∂∂ ++= 00,,


Code Flow Chart of MASTER

Lattice Calculation

Physics Analysis

XS Functionalization

WIMSD4 Library

DRAGON

Output

PROLOG

MASTER

XS Tableset

LIBERTE/HELIOS

Library

Output

DOPS Output ProcessingHOPE

HGC File


Result of Benchmark Calculation

0.910.95-.04

0.990.970.02

0.840.87-.03

1.191.190.00

1.021.000.02

1.101.100.00

1.081.050.03

0.940.940.00

0.970.99-.02

1.071.050.02

1.021.000.02

0.950.96-.01

1.191.180.01

0.990.970.02

0.810.85-.04

0.981.00-.02

0.960.97-.01

Keff: - MCNP : 1.39189- MASTER : 1.39366

- MCNP- HELIOS/MASTER- Difference

Prismatic NGNP (INL) Reactor Core


MARS/MASTER for GCR will be ready in a few months.

MARS/MASTER-GCR

coupled thermal-hydraulics/neutronics code, mars/master

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