multi-physics simulation of fuel rod failure during accidents in sodium fast reactors
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Multi-Physics Simulation of Fuel Rod Failure during Accidents in Sodium Fast Reactors Roman Samulyak AMS Department, Stony Brook University and Computational Science Center Brookhaven National Laboratory. Collaborators: Michael Podowski, Ken Jansen (RPI), Lap Cheng (BNL) - PowerPoint PPT PresentationTRANSCRIPT
Brookhaven Science AssociatesU.S. Department of Energy 1
Multi-Physics Simulation of Fuel Rod Failure during Accidents in Sodium Fast Reactors
Roman Samulyak
AMS Department, Stony Brook Universityand
Computational Science CenterBrookhaven National Laboratory
Collaborators:Michael Podowski, Ken Jansen (RPI), Lap Cheng (BNL)
James Glimm, Xiaolin Li, Shuqiang Wang, Lingling Wu (Stony Brook)Paul Parks (General Atomics)
Brookhaven Science AssociatesU.S. Department of Energy 2
23/4/22 NERI PROJECT NO. 08-033 2
Project ObjectivesProject Objectives
NERI consortium of Rensselaer Polytechnic Institute, Stony Brook University, Columbia University, and Brookhaven National Laboratory
The overall objective is to develop a multiple computer code platform for advanced multiscale/multiphysics simulations of Generation IV reactors
Apply proposed methodology to accident analysis for Sodium Fast Reactor (SFR)
Brookhaven Science AssociatesU.S. Department of Energy 3
Fuel degradation and transport in SFR during fuel rod failure accidents
Brookhaven Science AssociatesU.S. Department of Energy 4
23/4/22 NERI PROJECT NO. 08-033 4
Project Work Scope Project Work Scope MD simulations of reactor fuel
Multicomponent material (gas, solid, melt) distribution inside fuel elements and ejection through cladding breach
Cladding heatup and failure
Gas (volatile fission products) and fuel particle injection into liquid metal coolant
Multicomponent/multiphase fluid transport inside coolant channels
Computational issues: development, implementation and testing of higher order solution algorithms
Development of multiple-code computational platform for Blue Gene
Brookhaven Science AssociatesU.S. Department of Energy 5
Project OverviewProject Overview
NPHASE-CMFD code uses Reynolds-
Averaged Navier Stokes (RANS, e.g. k-ε
model) approach to multiphase modeling
Flow of liquid sodium coolant and fission gas
around l reactor fuel
rods
PHASTA uses direct numerical simulation (DNS) with Level Set method to track the
interface between gas and liquid phases
Jet of high pressure fission
gas entering coolant channels
FronTier is a front tracking code capable
of simulating multiphase
compressible fluid dynamics
Fuel rod overheating and melting of
cladding in case of coolant-blockage
accident
Molecular Dynamics approach analyses the irradiated fuel
properties
Prediction of fuel properties evolution
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Brookhaven Science AssociatesU.S. Department of Energy 6
Interaction between component-codesInteraction between component-codesDetermines the effects on the reactor fuel due to thermal loads and provides temperature- and irradiation-dependent thermal conductivity, density, effective porosity of fragmented/fractured fuel, diffusive properties of irradiated fuel
Simulates the fuel rod heating and melting of stainless steel cladding. Computes the fission gas properties and escape velocity during the meltdown as well as the shape of the damaged cladding
Performs a two-phase direct numerical simulation of fission gas jet entering the liquid sodium coolant. The fluctuating velocity field is post-processed to provide the two-phase flow turbulence parameters downstream of fuel rod: mean velocity, turbulent kinetic energy, turbulence dissipation rate and gas volume fraction
Performs a multiphase RANS simulation of a coolant flow during the accident scenario around several fuel rods using the detailed information provided by PHASTA and FronTier
NPHASE-CMFD
NPHASE-CMFD
PHASTAPHASTA
FronTierFronTier
Molecular Dynamics
Molecular Dynamics
fuel, , ,k Dρ φ
fission gas U, shape
of melted
cladding
U,k,ε,α
CU
Lin
ear
Solv
er
Improves the ability of NPHASE, PHASTA and FronTier to solve large systems of linear equation in parallel environments
coolant
PHASTA domain(DNS)
NPHASE domain(RANS)
FronTierdomain
MD
fission gas
P
P
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Front Tracking: A hybrid of Eulerian and Lagrangian methods
Advantages of explicit interface tracking:• No numerical interfacial diffusion• Real physics models for interface propagation• Different physics / numerical approximations
in domains separated by interfaces
Two separate grids to describe the solution:1. A volume filling rectangular mesh2. An unstructured codimension-1
Lagrangian mesh to represent interface
Main Ideas of Front Tracking
Major components:1. Front propagation and redistribution2. Wave (smooth region) solution
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• FronTier is a parallel 3D multiphysics code based on front tracking• Being developed within DOE SciDAC program• Adaptive mesh refinement• Physics models include
• Compressible fluid dynamics, MHD• Flows in porous media• Phase transitions and turbulence models
The FronTier Code
Turbulent fluid mixing.Left: 2DRight: 3D (fragment of the interface)
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Role of FronTier Code in Fuel Rod SimulationsRole of FronTier Code in Fuel Rod Simulations
Using material data from MD, simulate overheating scenarios in nuclear fuel rods and predict the shape and size of cracks in the steel clad and the fission gas and melted fuel flow into the coolant reservoir. Provide input to the PHASTA code.
Research tasks of the FronTier team:1. Develop new algorithms for the phase transition (melting and
vaporization) in the nuclear fuel rod2. Develop algorithms for the crack formation and failure of solid
materials 3. Perform simulations of the fuel rod failure and provide input to
the PHASTA code
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Brookhaven Science AssociatesU.S. Department of Energy 10
Developed Embedded Boundary Elliptic Interface method for the heat transfer problem in nuclear fuel rods
Implemented and fully tested front-tracking-based solver of Stefan problem in FronTier
Applied the new solver to the phase transition problem in fuel rods (fuel and clad melting)
Developed algorithms for dynamic creation of boiling/vaporization nucleation centers in regions that exceed critical conditions
New Phase Transition Algorithms for FronTier
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Brookhaven Science AssociatesU.S. Department of Energy 11
Calculations of normal operating conditions
Coolant
Cladding
Gas gap
Fuel
€
ΔTSurface
€
ΔTFuel
€
TCenter€
ΔTGap
€
ΔTClad
• Performed calculations of normal operating conditions for metallic and oxide fuels
• Assumed empirical models for effective heat transfer coefficients in the gas gap and turbulent fuel flow
Ideal (top) and real gas gap
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Simulation of fuel rod melting
Performed calculations of the heat transfer and phase transitions (melting) in a nuclear fuel rod at
• Increased power production rate (transient overheating accident)
• Increasing coolant temperature (loss of coolant accident)
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Development of mesoscale solid failure models for FronTier
• Finite element meshes conforming to interfaces of solid structures
• The medium is represented by a network of nodes connected by bonds satisfying some stress - strain relation
• Bonds are present with the probability p. The probability of initial defect is p-1
• The process consists of the energy minimization and sequential breaking of bonds which exceed the critical stress threshold
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Fuel clad failure
• Performed simulations of the failure of cladding
• The failure was caused by the increased pressure and fuel rod deformation. Thermal changes of clad properties were ignored
• Future work will focus on the implementation of more realistic stress-strain relations for bonds that include the plastic region and thermal changes of material properties
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04/22/23 NERI PROJECT NO. XX-XXX 15
Fission Gas Flow from Plenum to Sodium Pool
At the time of clad failure, fission gas transport inside fuel pin is first modeled using flow in porous medium equations
Then, FronTier calculations are performed to simulate pressure-driven ejection through cracked cladding wall of multiphase/ multicomponent mixture of fission gasses and molten/solid fuel into reactor coolant channel
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Ejection of the gas jet into sodium poolEjection of the gas jet into sodium pool
PHASTA simulation
04/22/23 16
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FronTier simulation
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PHASTA/NPHASE LinkPHASTA/NPHASE Link
High Rek-ε model
Low Rek-ε model
Channel flow DNS at Reτ = 180, Rehd = 11,200
17NERI PROJECT NO. 08-03304/22/23
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23/4/22 18
Simulation of processes in materials at extreme conditions in other energy applications
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• ITER is a joint international research and development project that aims to demonstrate the scientific and technical feasibility of fusion power
• ITER will be constructed in Europe, at Cadarache in the South of France in ~10 years
ITER Fueling by Pellet Injection
Models and simulations of tokamak fueling through the ablation of frozen D2 pellets
Our contribution to ITER science:
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• ITAPS Front tracking was used for first systematic “microscale” MHD studies of pellet ablation physics• Simulations revealed new propertied of the ablation flow:
• Supersonic rotation of the ablation channel • Resolution of this phenomenon greatly improves the agreement with experiments
• Strong dependence of the ablation rate on plasma pedestal properties• Simulations suggested that novel pellet acceleration technique (laser or gyrotron driven) are necessary for ITER
Main results of ITER fuelling simulations
Isosurfaces of the rotational Mach number in the pellet ablation flow
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Striation instabilities: Experimental observation
(Courtesy MIT Fusion Group)
• Current work focuses on the study of striation instabilities
• Striation instabilities, observed in all experiments, are not well understood
• We believe that the key process causing striation instabilities is the supersonic channel rotation, observed in our simulations
Work in Progress
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Inertial Confinement Fusion
National Ignition Facility
•Construction started in 1997
• Official opening ceremony: May 29, 2009
• 500 Terawatt flash of light within a few picoseconds
•192 laser beams focused on the target
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New Ideas in Nuclear Fusion: MTF
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Mercury Jet Target for Neutrino Factory / Muon Collider
Jet disruptionsTop: experiment Bottom: simulationTarget schematic
• Target is a mercury jet interacting with a proton pulse in a magnetic field• Target converts protons to pions that decay to muons and neutrinos or to neutrons (accelerator based neutron sources)• Understanding of the target hydrodynamic response is critical for design
• Studies of surface instabilities, jet breakup, and cavitation • MHD forces reduce both jet expansion, instabilities, and cavitation