1. Outline Proposal: FETCH Modelling of the MIPR Matthew Eaton, Christopher Pain, Jeff Gomes, Brendan Tollit, Tony Goddard, Gerard Gorman and Matthew Piggott Applied Modelling and Computation Group Babcock & Wilcox 05/12/2008

2. 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

3. Tabulated Group Constants WIMS9 Coupled CMFD and RT Models: FETCH

4. 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)

5. Goals Investigation of transient fault modelling of the MIPR’s under numerous prescribed conditions Investigating MIPR’s stability at high power densities

6. 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

7. 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

8. 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

9. 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

10. 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

11. 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

12. 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

13. 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.

14. 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

15. 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

16. 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

17. 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

18. 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

19. Similar PBR Mesh to homogeneous 3-D model

20. 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.

21. 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 rigorous justification for the modelling to the US NRC if an explicit model has been performed.

22. 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