Computational Fluid Dynamics for Reactor Design and Safety-related Applications

Transcription

1 NSE Nuclear Science & Engineering at MIT science : systems : society Computational Fluid Dynamics for Reactor Design and 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 Japanese Conference 2013 CFD for Reactor Design and Safety-related Applications

3 Nuclear Industry Competitiveness CFD for Nuclear Reactor Design Leveraging the research/academia efforts Review - State of the art and current challenges Where and why CFD Multiscale Applications CFD as Multi-physics platform CFD for Safety Related Applications The US-NRC example Commercial Grade Dedication of Software Experience and Challenges Contents STAR Japanese Conference 2013 CFD for Reactor Design and Safety-related Applications

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 Nuclear Industry Competitiveness (since ICONE )

6 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 Japanese Conference 2013 CFD for Reactor Design and Safety-related Applications 6

7 Licensing Time / O&M Cost 1 Core and core components 2 Upper Internals 3 Steam Generator Internals 4 Steam Lines 5 PRZ components 6 Pumps and seals 7 Flow mixing, fatigue, shedding 8 Stratification, hydrogen accumulation STAR Japanese Conference 2013 CFD for Reactor Design and Safety-related Applications 7

8 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

9 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

10 STAR-CCM+ Platform for Multiphysics High Fidelity T-H / Neutronics / CRUD / Chemistry Modeling Petrov, V., Kendrick, B., Walter, D., Manera- NURETH15, 2013

11 Not only Fuel Related Applications 11 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 Japanese Conference 2013 CFD for Reactor Design and Safety-related Applications

12 boiling heat transfer void fraction DNB Multiphase CFD better physical understanding

13 CFD for Safety-Related Design and Analysis CFD is undoubtedly becoming a fundamental instrument in the Safety Analyst Toolbox. CFD offers a unique opportunity for improved physical understanding Leads to more general applicability Reduced need for empirical calibration, which means lower costs! Challenge: Provide a path for application of CFD in Safety Analysis. Assure that the process will capture all critical characteristics of the application. Make the process Applicable. 13 Emilio Baglietto - Nuclear Science & Engineering at MIT

14 Can we apply CFD to Safety-Related Design and Analysis? Let s try to reformulate the question: Is there a process that is robust, flexible, and cost effective allowing application of CFD to Safety-Related Design and Analysis. Does the process guarantee confidence in the application of CFD. Corollary: Is the application of CFD completely different from that of system codes.. Is it more challenging. Is it more costly. 14

15 Commercial Off-The-Shelf (COTS) CFD is apt to rely on COTS General Purpose CFD reasons It has been heavily used by other industries with success. Requires very large investment for development. Inherits experience and verification practices. Allows leveraging a very large base of users for testing. What are the requirements for use of COTS? 15

16 The fear of change Changes from NQA to NQA-1a-2009 Part II, Subpart 2.7 Section 302 require application of: Part I, Requirement 7, Control of Purchased Items and Services and Part II Subpart 2.14, Quality Assurance Requirements for Commercial Grade Items and Services For acquisition of software that has not been previously approved under a program consistent with NQA-1 for use in its intended application. Is it really that bad? Is it going to make it too costly to adopt COTS? Is adoption of COTS more challenging or more costly? 16 STAR Japanese Conference 2013 CFD for Reactor Design and Safety-related Applications

17 A realistic challenge Subpart 2.14 had not really been written for software, therefore not a straightforward interpretation for an applicant. There was a need to provide a guidance for CGD of software which would for example include. 17 NQA Non-Mandatory Appendix (NMA) Focused on dedication of Design and Analysis Computer Programs Aligns with each of the Sections of SP 2.14 and provides information where the SP cannot be clearly interpreted as it applies to computer programs Unique Definitions that apply to computer programs Limits application of Like-for-Like Omits Equivalency unless complete evaluation is possible STAR Japanese Conference 2013 CFD for Reactor Design and Safety-related Applications

18 The process: Commercial Grade Dedication U.S. NRC Regulatory Guide 1.28 Rev. 4, June 2010 NQA with NQA- 1a-2009 addendum NQA Non-Mandatory Appendix (NMA) 18 Emilio Baglietto - Nuclear Science & Engineering at MIT EPRI CGD Guidance for Safety- Related Design and Analysis

19 NQA Non-Mandatory Appendix (NMA) CC Description Acceptance Criteria Method of Verification Host computer The manufacture and model number of the host assembly Host computer operating environment criteria must match the purchase Verified through one or more of the following: operating or computer hardware specification. This should include the o Inspection of receipt inspection environment computer program is manufacturer name and model from a documentation (Method 1) intended to reside. This supplier s catalog. (e.g., Dell PowerEdge o Inspection of test system operating critical characteristic is T110 Tower Server, IBM AIX & System, system identifiers. (Method 1) applicable to all computer and Dell Precision T3500 Workstation, programs. Siemens Simatic S7-400) Host computer operating system identifier Software Name Software Version Identifier Vendor name, operating system version, service packs or patch identifiers that are needed for the computer to be executed. This critical characteristic is applicable to all computer programs. The full name of the software. It should be the same identifier as used for during the procurement/acquisition process. This critical characteristic is applicable to all computer programs. The complete version identifier including any patches. This critical characteristic is applicable to all computer programs. Host computer operating system identifier must match the identifier in the vendor product list (e.g., Microsoft Windows 7, UNIX Operating System Version 5.1, B-5, and Yokogawa Pro- Safe-RS R ) Software name must match the product name from vendor catalog. (e.g., CFAST, Wolfram Mathematica 8, Monte Carlo N-Particle Transport Code System (MCNP5), Emerson valve Link, and Organic Concatenater) Software version identifier must match the product identifier from the vendor catalog that includes software namemajor functional version, minor functional version. corrective revision (e.g., CFAST , Hotspot , Emerson valve Link , and Organic Concatenater-3.1b) STAR Japanese Conference 2013 CFD for Reactor Design and Safety-related Applications Verified through one or more of the following: o Inspection of receipt inspection documentation (Method 1) o Inspection of test system operating system identifiers. (Method 1) Verified through one or more of the following: o Inspection of receipt inspection documentation (Method 1) o Inspection of test system operating system identifiers. (Method 1) Verified through one or more of the following: o Inspection of receipt inspection documentation (Method 1) o Inspection of test system operating system identifiers. (Method 1)

20 How does it apply to CFD 4 Categories of Critical Characteristics Identification i.e., version, build date, release name, or part or catalog number Physical physical media (e.g., CD, tapes, downloads, or remote access) Performance/Functional required functionality of the computer program to perform its safety function and the accuracy of its results Dependability (unique to computer programs) Evaluation to develop judgment regarding built-in quality Includes attributes related to the supplier s software development process such as review of the computer program s lifecycle processes and output documentation, review of configuration management activities, testing and V&V activities, and other activities. STAR Japanese Conference 2013 CFD for Reactor Design and Safety-related Applications

21 Performance/Functional CCs COTS CFD Critical Characteristics for Performance/Functional Critical Characteristics for Performance/Functional Item characteristics Item characteristics

22 Striking a good balance It is fundamental to balance the application of the Process and the Analysis Methodology. Failures in applying CFD to Safety-Related Design and Analysis are related to incorrect use of the process. Method Failures are not unique to CFD, but it is a common failure mode. Adoption of CFD for Safety-Related Design and Analysis requires the active contribution from CFD experts*. Let s look at 2 representative examples of Incorrect CGD of CFD Software for Safety-Related Design and Analysis

23 Faith in the box failure Solving Navier-Stokes is just like solving another problem (e.g. structural analysis). V&V Support Routine Very personal view: the CGD guidelines are a very natural approach to support CFD. The process will quickly become lighter and faster as the number of CFD applications grows.

24 A more challenging example Nuclear Powered DeLorean DMC-12 CFD model of Flux Capacitor The Flux Capacitor would most likely be considered a safety grade component. SAR would need to include predictions of HTCs during all normal and off-normal operational conditions. CFD provides an excellent method to support Safety-Related Design and Analysis. STAR Japanese Conference 2013 CFD for Reactor Design and Safety-related Applications

25 Example of SAR Validation of CFD applicability based on separate effects analysis: Flow in a Y junction 2D Cavity Buoyant flow Air tests for single tube from literature, HTC data available at representative Re. Literature recommends K-w SST Model for better HTC prediction due to superior performance in modeling the near wall region. Is this sufficient / adequate?

26 Validation example Data of Easby (1978) Data of Parlatan et al (1996) 1.4 Nu/Nu K-e model K-w SST model Bo CFD results are well within the uncertainty bounds. Good prediction of Buoyancy effect. K-w SST results are conservative. Sensitivity shows acceptable influence of turbulence models. Is this sufficient / adequate?

27 DBA conditions, flow reversal 1.5 k-omega-sst Model (ACME CFD) 1.3 k-omega-sst Model (BCME CFD) 1.1 Nu/Nu Bo CFD Model predict 2x higher HTCs at Bo=0.2 Did CFD fail? Was the Process Correct? This is not looking good

28 CFD Results failure mode analysis Turbulent Kinetic Energy Velocity Low-Re k-e K-w SST

29 How did we fail? Performance/Functional required functionality of the computer program to perform its safety function and the accuracy of its results Must account for effect of buoyancy on heat transfer... CFD Code Manual G b?? Missing a fundamental critical characteristic. The model equations do not have a buoyancy term for TKE and dissipation.

30 Conclusions Can we apply CFD to Safety-Related Design and Analysis? Yes, it can be done and it has been done. The CGD process provides a robust and flexible framework to adopt CFD for Safety Analysis. The CGD process requires rigorous assessment of the functionality of the computer program to perform its safety function and the accuracy of its results. For CFD this means understanding of the physical models and VUQ of the models on the intended application. The CGD formalizes a process that is applied to all Safety-Related Design and Analysis.