Computational Fluid Dynamics for Reactor Design & Safety-Related Applications

Transcription

1 NSE Nuclear Science & Engineering at MIT science : systems : society Computational Fluid Dynamics for Reactor Design & Safety-Related Applications 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 Korean 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 CFD for Safety Related Applications The US-NRC example Contents STAR Korean Conference 2013 Better reactors grow from better simulations

4 Background present Assistant Professor of Nuclear Science and Engineering, MIT Director Nuclear Application, CD-adapco Research Associate, Tokyo Institute of Technology PBMR Emilio Baglietto - Nuclear Science & Engineering at MIT 2012

5 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

6 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

7 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

8 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

9 Not only Fuel Related Applications 10 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

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

11 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 Korean Conference 2013 Better reactors grow from better simulations 13

12 Improved Spacers Design 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 14

13 RCIC SYSTEM 19 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

14 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

15 SPARGER MAIN DIFFERENCES 21 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

16 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 M. Pellegrini, M. Naitoh, E. Baglietto Elements size in the pool = 0.1~0.2 m

17 1F3 TEMPERATURE IN THE SPARGER 23 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

18 POOLEX STB-28-4 EXPERIMENT 24 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

19 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

20 FIRST BUBBLE ANALYSIS GROWTH 26 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

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

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

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

24 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% 30

25 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

26 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