Better reactors grow from better simulations

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1 NSE Nuclear Science & Engineering at MIT science : systems : society Better reactors grow from better simulations Massachusetts Institute of Technology Emilio Baglietto emiliob@mit.edu web.mit.edu/newsoffice/2012/baglietto-better-reactors.html

2 An Industrial/Research/Academic view Wearing multiple hats: Assistant Professor of Nuclear Science and Engineering, Massachusetts Institute of Technology. Massach Institute Technol Deputy Lead TH Methods Focus Area, CASL a US Department of Energy HUB. Nuclear Industry Sector Specialist CD-adapco. Member of NQA-1 Software Subcommittee. Disclaimer: the following slides are intended for general discussion. They represent the personal view of the author and not that of MIT, CASL or the ASME NQA-1 Software Subcommittee. STAR Chinese Conference 2013 Better reactors grow from better simulations

3 Nuclear Industry Competitiveness CFD for Nuclear Reactor Design Leveraging the research/academia efforts Computational Microscopes Multi-scale Applications CFD as Multi-physics platform CFD for Advanced Reactor Concepts Fast Reactors Fuel VHTRs virtual experiments Extreme Heat Removal Contents STAR Chinese Conference 2013 Better reactors grow from better simulations

4 CASL: The Consortium for Advanced Simulation of Light Water Reactors A DOE Energy Innovation Hub for Modeling & Simulation of Nuclear Reactors Task 1: Develop computer models that simulate nuclear power plant operations, forming a virtual reactor for the predictive simulation of light water reactors. Task 2: Use computer models to reduce capital and operating costs per unit of energy, STAR Chinese Conference 2013 Better reactors grow from better simulations 4

5 Emilio Baglietto - Nuclear Science & Engineering at MIT Virtual Environment for Reactor Applications VERA Baseline VABOC BOA ANC9 Chemistry MAMBA Thermo- Mechanics PEREGRINE Thermal-Hydraulics COBRA-TF Hydra-TH Drekar STAR-CCM+ Neutronics XSProc Denovo MPACT DeCART VIPRE-W Geometry / Mesh / DataTransferKit (DTK) LIME Trilinos DAKOTA MOOSE RELAP5 system Common Input front-end

6 Emilio Baglietto - Nuclear Science & Engineering at MIT What does workstation mean? VERA platform options laptops, workstations, clusters, HPC systems (current vs. future) What does workstation mean? you can get a 1.4 TF/s desk-side box with up to 512 GB, 16 CPU cores and ~900 GPU cores today Date Cost/GFLOPS $15million $30,000 $640 $48 $1.80 OAK RIDGE, Tenn., Nov. 12, 2012 The DOE Oak Ridge National Laboratory is again home to the most powerful computer in the world Titan is a Cray XK7 system that contains 18,688 nodes, capable of a theoretical peak speed of 27 petaflops

7 Emilio Baglietto - Nuclear Science & Engineering at MIT 4-Loop Westinghouse PWR Multi-Physics Model Development RPV ID 173, 193/4 Fuel Assemblies,13,944 fuel rods (fuel pellets, helium gap), 434 spacers, 148,224 mixing vanes; 1.2 billion cells Drawings CAD Model CFD Model

8 Emilio Baglietto - Nuclear Science & Engineering at MIT 4-Loop Westinghouse PWR Multi-Physics Model Development RPV ID 173, 193/4 Fuel Assemblies,13,944 fuel rods (fuel pellets, helium gap), 434 spacers, 148,224 mixing vanes; 1.2 billion cells CFD Model Mesh Results

9 Emilio Baglietto - Nuclear Science & Engineering at MIT A Typical Multi-Scale Problem Full-core performance is affected by localized phenomena Local T&H conditions such as pressure, velocity, cross flow magnitude can be used to address challenge problems: ogtrf ofad odebris flow and blockage The design TH questions under normal operating and accident conditions such as: o Lower plenum flow anomaly o Core inlet flow mal-distribution o Pressure drop o Turbulence mixing coefficients input to channel code o Lift force o Cross flow between fuel assemblies o Bypass flow The local low information can be used as boundary conditions for micro scale models. Model 1 Model 2

10 Emilio Baglietto - Nuclear Science & Engineering at MIT Thermal Hydraulics & Neutronics Coupling CFD + Neutronics full depletion cycle simulation: 14 state points, total time required for a complete depletion cycle: 44 hours on 1028 cores. ANC power Full Power 150MW*DAYS 1000MW*DAYS 2000MW*DAYS 44 hours /depletion-cycle proves that high fidelity CFD & Neutronics coupling is practical for engineering design for finalizing core design. The results will provide hot spot, boiling areas for CILC and crud simulation, fuel center line temperature, peak cladding temperature, and cross flow for GTRF.

11 Emilio Baglietto - Nuclear Science & Engineering at MIT STAR-CCM+ Platform for Multiphysics High Fidelity T-H / Neutronics / CRUD / Chemistry Modeling Petrov, V., Kendrick, B., Walter, D., Manera, A., Impact of fluid-dynamic 3D spatial effects on the prediction of crud deposition in a 4x4 PWR sub-assembly - NURETH15, 2013

12 Emilio Baglietto - Nuclear Science & Engineering at MIT STAR-CCM+ Platform for Multiphysics High Fidelity T-H / Neutronics / CRUD / Chemistry Modeling Petrov, V., Kendrick, B., Walter, D., Manera- NURETH15, 2013

13 Emilio Baglietto - Nuclear Science & Engineering at MIT boiling heat transfer void fraction DNB Multiphase CFD better physical understanding

14 Improved Spacers Design CFD Predictions of DNB CFD based CHF modeling development being performed by Westinghouse Nuclear Fuel. 5x5 test bundle PWR experiment from the ODEN CHF test facility were modeled in CFD using the latest 2-phase boiling model. Excellent trend agreement in CHF predictions. Novel understanding of fundamental physics allows improving the CHF performance. J. Yan, et al - Evaluating Spacer Grid CHF Performance by High Fidelity 2-Phase Flow Modeling TOPFUEL2013 STAR Chinese Conference 2013 Better reactors grow from better simulations 16

15 Improved Spacers Design J. Yan, et al - Evaluating Spacer Grid CHF Performance by High Fidelity 2-Phase Flow Modeling TOPFUEL2013 STAR Chinese Conference 2013 Better reactors grow from better simulations 17

16 RCIC SYSTEM 22 MO MO HO HO Turbine stop valve Control valve #2 70 HOURS RCIC TIME #3 20 HOURS RCIC TIME M. Pellegrini, M. Naitoh, E. Baglietto

17 UNITS 2 & 3: PCV PRESSURE EARTHQUAKE 3/11 14:46 U N I T 3 Primary containment vessel pressure (MPa [abs]) U N I T 2 0 3/11 12:00 3/12 0:00 3/12 12:00 Date/time 3/13 0:00 3/13 12:00 M. Pellegrini, M. Naitoh, E. Baglietto

18 SPARGER MAIN DIFFERENCES 24 U N I T 2 VERTICAL JET U N I T 3 HORIZONTAL JETS m D=0.010 m m D = m m m m 2577 mm m M. Pellegrini, M. Naitoh, E. Baglietto

19 1F3 GEOMETRY 25 Detail of holes mesh size Region A size = 1 mm Region B size = 2 mm Pool pressure boundary Region B ~ 8 m sparger M. Pellegrini, M. Naitoh, E. Baglietto Elements size in the pool = 0.1~0.2 m

20 1F3 TEMPERATURE IN THE SPARGER 26 steam flow 2 seconds real time ~ 3.0 m Region A Region B T pool = 30 C Large water head creates differences between mass flow rate between holes in the vertical direction M. Pellegrini, M. Naitoh, E. Baglietto

21 POOLEX STB-28-4 EXPERIMENT 27 facility sketch steam inlet pool detail mm Experimental results Large visible chugging phenomenon Bubble collapse time = 80 ms Bubble diameter = 380 mm Collapse speed = 3 m/s 380 mm T pool = 62 C Steam Mass Flux = 8 kg/m 2 s M. Pellegrini, M. Naitoh, E. Baglietto

22 PRELIMINARY RESULTS: CHUGGING kg/s Flow enters the pool. Large turbulence is created, increased condensation volume fraction CONDENSATION MASS TRANSFER 0.3 kg/s PIPE MOUTH M. Pellegrini, M. Naitoh, E. Baglietto

23 FIRST BUBBLE ANALYSIS GROWTH 29 STB-28-4 MEASUREMENTS STAR-CCM+ RESULTS Animation of the first bubble Chugging phenomenon can be recreated only for the first bubble Bubble collapse velocity and phenomenon stability is highly dependent on the modeling assumptions More physical investigation and sensitivity analysis is required M. Pellegrini, M. Naitoh, E. Baglietto

24 Emilio Baglietto - Nuclear Science & Engineering at MIT PVP : CFD ANALYSES OF THE TN-24P PWR SPENT FUEL STORAGE CASK R. A. Brewster, E. Baglietto, E. Volpenhein, C. Bajwa Spent Fuel Simulations

25 The overall mesh consists of about 18 million cells Of these, approximately 2 million are in the fluid domain Dominantly Polyhedral Cells Porous blocks meshed using trimmed hexa STAR Chinese Conference 2013 Better reactors grow from better simulations

26 Example of Analysis Results Cask Temperatures Basket Temperatures Total power dissipation in cask = 20,640 Watts STAR Chinese Conference 2013 Better reactors grow from better simulations

27 Example of Analysis Results Measurements on TN-24P under different conditions at Idaho National Laboratory, ca thermocouples measured temperatures in the fuel assemblies and basket surface - 14 thermocouples measured temperatures on the inner surface of the cask body - 35 thermocouples measured temperatures on the cask exterior Comparison of measured and computed temperatures in the fuel assemblies - (using thermocouple lances) Measured and computed temperatures on the basket, inner cask wall and outer cask wall - (thermocouple lances and surface thermocouples) STAR Chinese Conference 2013 Better reactors grow from better simulations

28 Modeling Full Detail of Fuel Assembly STAR Chinese Conference 2013 Better reactors grow from better simulations

29 And what about advanced concepts? ASTRID NuScale Power STAR Chinese Conference 2013 Better reactors grow from better simulations 35

30 Emilio Baglietto - Nuclear Science & Engineering at MIT

31 ORNL Geometry and Instrumentation 37 Images from Fontana et al. [6]

32 Model Geometry Modeling inlet region of the test section shown to be important 38

33 In-Bundle Comparison Compare to 36 different thermocouples for each case Plot below shows the experimental measurement for each thermocouple matches the at least one of the CFD probes Analyze the whole data set CDF of all the error of the measurement and nearest probe for all data points for all 7 cases exp a b c 100% 90% 80% 70% 60% 50% 40% 39

34 Emilio Baglietto - Nuclear Science & Engineering at MIT DNS-grade Pebble Bed Flow Modelling Challenge: Accurately predict the flow and heat transfer in random beds of pebble fuel cooled by helium. The tight geometrical configuration does not allow accurate experimental measurements Solution: Quasi-DNS simulations have been used to collect a virtual database and develop improved simulation guidelines based on RANS modeling. Impact: A DNS database for pebble bed simulations to support industrial applications Optimization of flow and temperature distribution allowing improved fuel performance and reliability Shams et al. Nuclear Engineering and Design, Vol

35 Emilio Baglietto - Nuclear Science & Engineering at MIT Challenging Extreme Heat Removal Heat flux versus excess temperature Challenge: design of water-cooled first wall hypervapotrons for ITER, which may encounter heat fluxes as high as 5 MW/m 2. Solution: An advanced transition boiling model, capable of predicting heat transfer across all regimes, include post-dryout. Validated for fluxes 1-10 MW/m 2 Impact: One-of-a-kind predictive capability for extreme heat removal Essential support to ITER critical heat flux margin evaluation q" q max q max Nucleate q" =qmax* (ΔT/DT1) k1 k1 > DT=T wall - T saturation total boiling mixture convection Transition I q" = parabolic Transition II q" =qmax* (ΔT/DT 2 ) k2 DT 1 DT 2 k2<0 Extreme Heat Removal for the Largest research project in the World D.L Youchison, et al. - Prediction Of Critical Heat Flux In Plasma Facing Components Using Computational Fluid Dynamics TOFE 2010

36 Some Conclusions Better Reactors Grow from Better Simulations I strongly believe this! 3D CFD results allow better understanding, more generality and fast prototyping. Mature Single Phase Applications A large number of validated applications for LWRs. Fundamental Design tool for Advanced and Innovative Concepts [LMFBR, VHTR, MoltenSalt ] Multiphase CFD is stepping up Already applied for design, successfully. Drastically enhanced robustness will derive from more physically based closures. STAR Chinese Conference 2013 Better reactors grow from better simulations