Attila neutronics simulations and validation 3 D ITER machine and ports modeling with preliminary results Mahmoud Z Youssef University of California Los Angeles USA The FNS TBM Meeting UCLA September 19 20 2007 Topics Deterministic versus Monte Carlo methods in nuclear analysis Pros and Cons ATTILA code Features and Capabilities Results of Benchmarking ATTILA 3 Fusion Integral Experiments comparison to experimental Data and MCNP Results ITER CAD Model Comparison to the UW DAG MCNPX CAD based Results as well as other CAD Based MCNP codes Examples of ATTILA application for diagnostics ports Capability of ATTILA for activation and dose rate calculation Summary Advantages and Disadvantages Deterministic codes Advantages Fluxes and responses are calculated everywhere No need to redo separate runs if additional responses are needed Shorter time to run a case compared to Monte Carlo methods Disadvantages Large disk space is required to store angular flux Ray effect due to angular discretization Cross section should be shielded particularly in resonance regions Monte Carlo codes Advantages Complex geometry can be modeled accurately However extensive effort is needed to generate the appropriate geometry cards This is why CAD based versions are in progress Disadvantages Fluxes and responses are calculated at pre selected locations Visualization of the responses requires generating many tallies at various planes Progress to improve this limitation is currently implemented in MCNP 5 What is Attila A finite element discrete ordinates Sn Pn neutron gamma and charged particle transport code using 3D unstructured grids tetrahedral meshes Geometry input from CAD Solid Works ProE Complete visualization of the solution field e g Flux current response function etc Supplied by Transpire Inc Gig Harbor WA USA Some New Features under testing Integrated Activation Capability Extension of current Integrated depletion module similar to ORIGEN to include decay source terms Group wise Adaptive SN Order For ITER can run 14 MeV source bin at a high Sn order to transport the primary flux Distributed Memory Parallel Linear scaling achieved on test version up to 256 processors A primary motivation is to distribute memory resources Benchmarks Experiments FNG Facility Tungsten Experiment Streaming Experiment Bulk Shielding Experiment Experiments performed at the FNG facility ENEA Frascati Italy Measurements of many reactions rates Measured Reactions Zr 90 n 2n Zr 89 Ni 58 n 2n Ni 57 Nb 93 n 2n Nb 92 Al 27 n a Na 24 Fe 56 n p Mn 56 Ni 58 n p Co 58 In115 n n Au197 n g Eth 12 MeV Eth 12 MeV Eth 9 MeV Eth 5 MeV Eth 3 MeV Eth 0 5 MeV Eth 0 2 MeV All energies The accuracy in predicting these reactions is a good measure of how well the neutron spectrum and energy dependent reactions rates are predicted Tungsten Experiment Attila s Model and Calculation Calculations Quadrature S12 XS Scattering P3 Number of Cells 14681 cells for Nb Ni Au Fe In Foils 19398 cells For Zr Al Mn foils Cells and three iso surfaces are shown Examples of Calculated Experimental C E values 1 2 Zr 90 n 2n Zr 89 Reaction Rate Al 27 n a Na 24 Reaction Rate 1 2 1 1 1 1 0 9 0 8 0 8 C E MCNP C E Attila 0 7 0 6 Nuclear Data FENDL2 1 Response Function IRDF 90 0 6 Expt Upper Limit Expt Lower Limit MCNP C E 2 1 Attila C E Nuclear Data FENDL2 1 Response Function IRDF 90 0 4 0 5 0 5 10 15 20 25 30 35 40 0 20 Tungsten Expt Foil Position from front Edge cm Tungsten Experiment FNG 40 60 80 100 Penetration Depth Along Central Axis cm Streaming Expt 1 2 Ni 58 n p Co 58 Reaction Rate Al 27 n a Na 24 Reaction Rate 1 2 1 1 1 1 0 9 0 8 C E MCNP C E Attila 0 8 0 6 0 7 0 6 0 4 0 5 0 0 5 10 15 20 Expt Upper Limit Expt Lower Limit MCNP C E 2 1 Attila C E Nuclear Data FENDL2 1 Response Function IRDF 90 Nuclear Data FENDL2 1 Response Function IRDF 90 25 30 Foil Position from front Edge cm 35 40 20 40 60 80 Penetration Depth Along Central Axis cm 100 Examples of Calculated Experimental C E values Bulk Shield Experiment Nb 93 n 2n Nb 92 Reaction Rate Fe 56 n p Mn 56 Reaction Rate 1 2 1 2 1 1 0 8 0 8 MCNP MCNP 0 6 ATTILA 0 6 Nuclear Data FENDL2 1 Response Function IRDF 90 ATTILA ATTILA MCNP Nuclear Data FENDL2 1 Response Function IRDF 90 ATTILA MCNP 0 4 0 4 0 20 40 60 80 100 0 Penetration Depth Along Central Axis cm 20 40 60 80 100 Penetration Depth Along Central Axis cm Ni 58 n p Co 58 Reaction Rate 1 2 Al 27 n alpha Na 24 Reaction Rate 1 2 1 1 0 8 0 8 MCNP 0 6 MCNP 0 6 ATTILA Nuclear Data FENDL2 1 Response Function IRDF 90 ATTILA Nuclear Data FENDL2 1 Response Function IRDF 90 ATTILA MCNP ATTILA MCNP 0 4 0 4 0 0 20 40 60 80 Penetration Depth Along Central Axis cm 20 40 60 80 100 Penetration Depth Along Central Axis cm 100 Average Estimates for the C E Values and Deviation from Experiment Reaction Zr 90 n 2n Zr 89 Ni 58 n 2n Ni 57 Nb 93 n 2n Nb 92 Al 27 n a Na 24 Fe 56 n p Mn 56 Ni 58 n p Co 58 In 115 n n In 115m Au 197 n g Au 198 Calculation Method Tungsten MCNP Attila MCNP Attila MCNP Attila MCNP Attila MCNP Attila MCNP Attila MCNP Attila MCNP Attila Largest Deviation From Expt Data ATTILA 25 MCNP 23 2 6 1 6 1 9 3 7 4 14 6 4 6 18 1 10 Experiment Streaming Channel Cavity 4 13 10 20 6 10 7 11 4 6 3 3 3 9 7 10 Bulk Shield 10 13 11 13 11 14 7 8 23 25 Largest Between ATTILA and MCNP 12 Benchmarking ATTILA with the ITER CAD Model and Comparison to MCNP Results Void Part TF PF and OH Coils VV and Bio Shield The Blanket Shield Modules BSM and divertor CAD model integrated in the 40degree CAD model BSM Void Part Divertor Diverter Model The 40 degree Solid Works CAD model of ITER BSM Model Mesh Scheme used in the calculation 500 000 mesh Layering techniques is used to reduce mesh counts Z R D T plasma Source and its Strength 10E x 1 7753E20 10E x 1 7753E20 Scalar Flux Multiply by 1 7753E20 Neutron Flux solution can be visualized at any location or at any plane Run done with 0 1111 normalization factor Source strength 0 1111 x 1 7753E20 1 9724E19 neutrons in the sector Hot spots can be identifiedModification in the design can be altered to minimizes these spots Comparison to MCNPX CGM CAD Based Results UW Neutron Wall Loading NWL at First Wall 1 8 9 10 7 0 8 11 6 ATTILA …