Outline Proposal: FETCH Modelling of the MIPR

Matthew Eaton, Christopher Pain, Jeff Gomes, Brendan Tollit, Tony Goddard,

Gerard Gorman and Matthew PiggottApplied Modelling and Computation Group

Babcock & Wilcox 05/12/2008

Team Members

• Dr Matt Eaton (RT and Uncertainty Analysis) – Principal

Investigator

• Prof Chris Pain (Numerical Analysis and Multiphysics) – Head

of the AMCG and Co-I

• Prof Tony Goddard (RT and Reactor Physics) – Senior Adviser

and Co-I

• Dr Matt Piggott (CFD and Turbulence) – Co-I

• Dr Gerard Gorman (Parallel Mesh Adaptivity and QA) – Co-I

• Dr Jeff Gomes (Multiphysics and CMFD) – Funded PDRA

• Mr Brendan Tollit (Multiphysics and Reactor Physics) – Funded

PDRA

Tabulated Group

Constants

WIMS9

Coupled CMFD and RT Models: FETCH

MIPR

Uranium Solution

Reactor Vessel

Cooling Coils

Control Rod

Water Inlet

Water Outlet

Uranium Solution Inlet

Uranium Solution

Drain

Sweep Gas Inlet

Sweep Gas Outlet

Mist Eliminator

Reflector(Sectioned)

Goals

• Investigation of transient fault modelling of the MIPR’s under numerous prescribed conditions

•Investigating MIPR’s stability at high power densities

Challenges

• 3D Complex Geometry – heterogeneous modelling

• Phase change – Boiling and Condensation

•Large Scale Fully-Coupled RT/CMFD-TH

• Parameterisation of the radiolytic gas bubbles nucleation on the cooling coil and submerged surfaces

•Automated and Continuous QA

Work-Packages

•WP1: Neutronics modelling of MIPR and 50KW Operational reactor

• WP2: Development of 2-D RZ and 3-D non-explicit geometry coupled RT/CMFD-TH MIPR model

• WP3: Initial 50KW test cases and Accident scenarios for 2-D RZ and 3-D non-explicit geometry

Work-Packages

• WP4: Large Scale Modelling using FETCH and parallel visualization interfacing with PARAVIEW• WP5: Development of a 3-D explicit geometry coupled RT/CMFD-TH MIPR model and a 50KW fully operational test-case

• WP6: Initial 50KW test-cases and Accident scenarios for 3-D explicit geometry model of the MIPR

• WP7: Automated QA, RT/CMFD-TH Interfaces, Documentation and Deliverables

•Task 1: Development of 2-D axi-symmetric RZ model and 3-D non explicit geometry (parameterization of control rods and cooling coils) with nuclear cross-section data generated using WIMS

WP1: Neutronics Modelling of MIPR and 50KW Operational Reactor

•Task 2: Development of a 3-D explicit geometry model of the MIPR using GID and RHINO and explicit sub-group spatial/energy self-shielding phenomena in FETCH

•Task 3: Interfacing FETCH with the SCALE US NRC criticality code for generation of nuclear data for the MIPR

• Task 1: Parameterization of the heat transfer aspects of the cooling coils

WP2: Development of 2-D RZ and 3-D non-explicit geometry coupled RT/CMFD-TH MIPR model

• Task 2: Parameterization of the radiolytic gas bubble nucleation on cooling coil and control rod surfaces and within the solution volume of the MIPR

• Task 3: Parameterization of homogeneous and heterogeneous (submerged surfaces) boiling

• 1: Inadvertent withdrawal of control rods

WP3: Possible 50KW test cases and Accident scenarios for 2-D RZ and 3-D non-explicit geometry

• 2: Introduction of excess fuel into solution

• 3: Changing the fuel U/H ratio by introducing hydrogenous (excess acid, coolant tube leak etc) material into the solution core

• 4: Increased fuel solution density due to rise of dome pressure or drop of fuel temperature

WP3: Possible 50KW test cases and Accident scenarios for 2-D RZ and 3-D non-explicit geometry (cont)

• 5: Fuel solution leakage

• 6: Hydrogen deflagration and/or detonation

• 7: Overpower without scramming of control rods

• 8: Loss of pumping power

WP4: Parallel FETCH interface and parallel visualization interfacing with PARAVIEW

• Task 1: Interface module of CMFD/RT parallelisation

• Task 3: Parallel visualization

• Task 2: Distributed and multi-core processor testing on ICT facilities.

WP5: Development of a 3-D explicit geometry coupled RT/CMFD-TH MIPR model and a 50KW fully operational test-case

• Task 1: Parameterization of the nucleation on cooling coil and control rod surfaces and within the solution volume of the MIPR

• Task 2: Parameterization of homogeneous and heterogeneous (submerged surfaces) boiling

WP6: Possible 50KW test-cases and Accident scenarios for 3-D explicit geometry model of the MIPR (repeated from previous)

• 1: Inadvertent withdrawal of control rods

• 2: Introduction of excess fuel into solution

• 3: Changing the fuel U/H ratio by introducing hydrogenous (excess acid, coolant tube leak etc) material into the solution core

• 4: Increased fuel solution density due to rise of dome pressure or drop of fuel temperature

WP6: Possible 50KW test-cases and Accident scenarios for 3-D explicit geometry model of the MIPR (cont)

• 5: Fuel solution leakage

• 6: Hydrogen deflagration and/or detonation

• 7: Overpower without scramming of control rods

• 8: Loss of pumping power

WP7: Automated QA and RT/CMFD-TH Interfaces and Documentation

• Task 1: Verification and Validation Suite Procedures – Bubbly solutions initial benchmarks (TRACY, SILENE, Aparatus B, CRAC, etc)

• Task 2: Users-orientated interface for the RT and CMFD-TH Modules: Spud-Diamond and CAD-based Mesh-generator

• Task 3: Automated and Continuous QA: SVN, Buildbot

• Task 4: Complete Wiki-based documentation

Explicit Heterogeneous Modelling

Uranium Solution

Reactor Vessel

Cooling Coils

Control Rod

Water Inlet

Water Outlet

Uranium Solution Inlet

Uranium Solution

Drain

Sweep Gas Inlet

Sweep Gas Outlet

Mist Eliminator

Full Assembly

Sweep Gas Diffuser

Cooling Coils

Control Rods

Cross Section View

Similar PBR Mesh to homogeneous 3-D

model

Explicit Heterogeneous Modelling

• Spatial variation in flux and power around cooling coils (water moderator) and control/safety rods effecting spatial shielding of multi-group cross-section data – subgroup treatment in full 3-D. Also movement of control rods only approximately taken into account e.g. in rod ejection accidents.

• Spatial variation in radiolytic gas and steam. In reality this may provide significant effects on heat transfer between coils and the Uranyl Nitrate solution as well as cross-sections.

Explicit Heterogeneous Modelling

•Flow paths in homogeneous 2-D RZ and 3-D homogeneous models only approximately modelling the full heterogeneous flow paths. e.g. effects of cooling coils may provide significant distortions in flow paths within the reactor with consequent perturbations on the power. •Validation and verification: provides a more rigorousjustification for the modelling to the US NRC if an explicit model has been performed.

Deliverables and Post-Work

• FETCH use at B&W and post project

i) homogeneous (2D & 3D) and explicit FETCH models

ii) continuous regression testing iii) user friendly interface for possible B&W use iv) analysis of MIPR transients