Computational Fluid Dynamics for Reactor Design & Safety-Related - PowerPoint PPT Presentation

NSE Nuclear Science & Engineering at MIT science : systems : society Computational Fluid Dynamics for Reactor Design & Safety-Related Applications Emilio Baglietto emiliob@mit.edu Massachusetts web.mit.edu/newsoffice/2012/baglietto-better-reactors.htm l Institute of Technology

An Industrial/Research/Academic view Wearing multiple hats: Massachusetts Assistant Professor of Nuclear Science and  Institute of Engineering, Massachusetts Institute of Technology. Technology  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 Korean Conference 2013 Better reactors grow from better simulations

Contents  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  CFD for Safety Related Applications  The US-NRC example STAR Korean Conference 2013 Better reactors grow from better simulations

Background  2011- present A ssistant Professor of Nuclear Science and Engineering, MIT  2006-2011 Director Nuclear Application, CD-adapco  2004-2006 Research Associate, Tokyo Institute of Technology PBMR 2005 2012 2009 Emilio Baglietto - Nuclear Science & Engineering at MIT

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, …… 5 STAR Korean Conference 2013 Better reactors grow from better simulations

A “Typical” Multi -Scale Problem Full-core performance is affected by localized phenomena Model 1 Model 2 • Local T&H conditions such as pressure, velocity, cross flow magnitude can be used to address challenge problems: o GTRF o FAD o Debris 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. 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 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 Emilio Baglietto - Nuclear Science & Engineering at MIT

10 Not only Fuel Related Applications Mature Applications  Fuel  Pressure Drops  Crud (CIPS/CILC)  Vibrations (GTRF)  System and BOP  Transient Mixing  Hot Leg Streaming  Thermal Striping  SG performance  Cooling Towers Interference  Fuel Cycle and Beyond Design Basis Applications  Spent fuel transportation and Storage STAR Korean Conference 2013 Better reactors grow from better simulations

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

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 13 STAR Korean Conference 2013 Better reactors grow from better simulations

Improved Spacers Design 14 J. Yan, et al - Evaluating Spacer Grid CHF Performance by High Fidelity 2-Phase Flow Modeling – TOPFUEL2013 STAR Korean Conference 2013 Better reactors grow from better simulations

RCIC SYSTEM 19 MO MO Turbine HO 70 HOURS stop valve #2 HO RCIC Control valve TIME 20 HOURS #3 RCIC TIME M. Pellegrini, M. Naitoh, E. Baglietto

UNITS 2 & 3: PCV PRESSURE 20 EARTHQUAKE U N I T 3 3/11 14:46 0.6 Primary containment vessel pressure (MPa [abs]) 0.4 0.2 U N I T 2 0 3/11 3/12 3/12 3/13 3/13 12:00 0:00 12:00 0:00 12:00 Date/time M. Pellegrini, M. Naitoh, E. Baglietto

SPARGER MAIN DIFFERENCES 21 D=0.010 m U N I T 2 U N I T 3 0.033 m VERTICAL JET HORIZONTAL 0.036 m JETS D = 0.025 m 0.065 m 0.680 m 1.275 m 2577 mm 0.283 m M. Pellegrini, M. Naitoh, E. Baglietto

1F3 GEOMETRY 22 Detail of holes mesh size Region A size = 1 mm Region B size = 2 mm Pool pressure boundary Region B ~ 8 m sparger Elements size in the pool = 0.1~0.2 m M. Pellegrini, M. Naitoh, E. Baglietto

1F3 TEMPERATURE IN THE SPARGER 23 steam flow 2 seconds real time Region A ~ 3.0 m 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

POOLEX STB-28-4 EXPERIMENT 24 steam inlet facility pool detail sketch 219.1 mm 380 mm Experimental results • Large visible chugging phenomenon • Bubble collapse time = 80 ms T pool = 62 ° C • Bubble diameter = 380 mm Steam Mass Flux = 8 kg/m 2 s • Collapse speed = 3 m/s M. Pellegrini, M. Naitoh, E. Baglietto

PRELIMINARY RESULTS: CHUGGING 25 0.3 kg/s Flow enters the pool. Large turbulence is created, increased condensation volume fraction 1.00 CONDENSATION MASS TRANSFER 0.75 0.50 0.25 0.00 0.3 kg/s PIPE MOUTH M. Pellegrini, M. Naitoh, E. Baglietto

FIRST BUBBLE ANALYSIS GROWTH 26 STB-28-4 MEASUREMENTS Animation of the first bubble STAR-CCM+ RESULTS • 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

And what about advanced concepts? ASTRID NuScale Power 27 STAR Korean Conference 2013 Better reactors grow from better simulations

ORNL Geometry and Instrumentation Images from Fontana et al. [6] 28

Model Geometry  Modeling inlet region of the test section shown to be important 29

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 2 100% 90% 1.5 exp 80% 1 70% a 0.5 60% b 50% 0 c 40% -0.5 0 5 10 15 20 25 30 35 30

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  Shams et al. Nuclear Engineering and applications Design, Vol. 242-261-263 - 2012-2013 • Optimization of flow and temperature distribution allowing improved fuel performance and reliability Emilio Baglietto - Nuclear Science & Engineering at MIT

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 Korean Conference 2013 Better reactors grow from better simulations