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Benchmarking with Monte Carlo

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Benchmarking with Monte Carlo

  1. 1. Example Benchmark Activities at the Idaho National Laboratory Using Monte Carlo Methods John D. Bess Reactor Physics Analysis and Design Dept. Nuclear Science & Engineering Division July 2009
  2. 2. Outline • What is a Benchmark? • Why Do We Need Them? • The ICSBEP and IRPhEP • The Benchmark Approach • Using Monte Carlo Methods • Recent ICSBEP/IRPhEP Activities at the Idaho National Laboratory • Student Involvement with the ICSBEP and IRPhEP • Conclusion 2
  3. 3. What is a Benchmark? • Merriam-Webster • “a point of reference from which measurements may be made” • “something that serves as a standard by which others are measured or judged” • “a standardized problem or test that serves as a basis for evaluation or comparison (as of computer system performance)” 3
  4. 4. Why Do We Have Nuclear Benchmarks? • Criticality Safety • Research and – Plant Operations Development – Transportation – New Reactor Designs – Waste Disposal – Design Validation – Experimentation • Computational Methods – Accident Analysis – Cross-Section Data – Standards – Code Verification Development • Fundamental • Materials Physics – Testing – Model Validation – Physics Validation – Interrogation 4
  5. 5. Criticality Safety Engineer Specialist • American Nuclear Society Nuclear Criticality Safety Division Education Committee Definition of a Criticality Safety Engineer – “One who applies engineering principles to the understanding of the properties of fissile materials such that they are controlled in a practicable manner in systems and processes while protecting from the consequences of a criticality accident, preferably by prevention of the accident.” 5
  6. 6. 6
  7. 7. How Does Benchmark Design Apply to You? 7
  8. 8. International Criticality Safety Benchmark Evaluation Project (ICSBEP) • Purpose: – Identify and verify comprehensive sets of critical benchmark data by reviewing documentation and talking with experimenters – Evaluate the data and quantify the overall uncertainty via sensitivity analyses – Compile the data into a standardized format – Perform calculations of each experiment with standard criticality safety codes – Formally document work into a single source • http://icsbep.inel.gov 8
  9. 9. International Handbook of Evaluated Criticality Safety Benchmark Experiments (ICSBEP) The ICSBEP was initiated in Oct. 1992 by DOE and the former INL to systematically evaluate and archive data required for validation of Criticality Safety Analyses. The Program is operated under OECD NEA sanction, managed by the INL, with US participation and leadership sponsored by DOE NNSA’s Nuclear Criticality Safety Program. September 2009 Edition • 20 Contributing Countries • Spans over 50,000 Pages • 4,295 Critical or Subcritical Configurations • Four Criticality-Alarm/ Shielding Benchmarks – 24 Configurations – numerous dose points • Five Fundamental Physics Benchmarks – 155 fission rate and transmission measurements and reaction rate ratios for 45 different key materials Slide courtesy of J. Blair Briggs, INL 9
  10. 10. International Reactor Physics Experiment Evaluation Project (IRPhEP) • Similar to the ICSBEP • Focus to collect data regarding the numerous experiments in support of nuclear energy and technology performed at research laboratories • Experiments represent significant investments of time, infrastructure, expertise, and cost that might not have received adequate documentation • Measurements also include data regarding reactivity measurements, reaction rates, buckling, burnup, etc., that are of significant worth for current and future research and development efforts • http://irphep.inl.gov/ 10
  11. 11. International Handbook of Evaluated Reactor Physics Benchmark Experiments (IRPhEP) The IRPhEP is a more recent effort that synergistically complements the ICSBEP to achieve the same goal for in-core reactor physics integral experiments. The INL manages the technical review and publication aspects of this program for the OECD NEA as well. March 2009 Edition • 15 Contributing Countries • Data from 36 Experimental Series performed at 21 Reactor Facilities Slide courtesy of J. Blair Briggs, INL 11
  12. 12. The Benchmark Approach • An ICSBEP Benchmark Report has Four Major Sections – 1.0 Detailed Description • Compilation of All Known Available Data Regarding the Experiment • Try to Provide a Clear Idea of the Experiment Purpose and Procedure • Note Any Inconsistencies in Available Data • Essentially this Section Acts as a Means of Preserving Pertinent Available Data for the Experiment 12
  13. 13. The Benchmark Approach • An ICSBEP Benchmark Report has Four Major Sections – 2.0 Evaluation of Experimental Data • Uncertainty Assessment of Experiment Parameters – Experimental Measurements • Temperature, Position – Geometrical Properties • Shape, Amount – Compositional Variations • Density, Material Abundance • Use Best Engineering Judgment and Practices to Account for Unknown Experiment Parameters • An Overall Uncertainty is Quantified 13
  14. 14. The Benchmark Approach • An ICSBEP Benchmark Report has Four Major Sections – 3.0 Benchmark Specifications • Provide Sufficient Information to Justify and Construct a Calculational Model that Best Represents the Experiment • Justify and Quantify Simplifications in the Model Compared to the Physical Experiment – Bias or Correction Factor • Provide Expected Eigenvalue for the Benchmark – Typically keff = 1.0000 • Another User Should Be Able to Model the Benchmark Completely without Any Other Section! 14
  15. 15. The Benchmark Approach • An ICSBEP Benchmark Report has Four Major Sections – 4.0 Results of Sample Calculations • Summary of Calculated Results for Different Computer Codes and Cross-Section Data using the Benchmark Model(s) – Appendices • Any Additional Information Pertinent to the Benchmark – Input Decks for Computer Codes – Calculations – Photos or Scanned Documentation 15
  16. 16. Additional Benchmark Material • The IRPhEP Benchmark Report Follows the Same General Guidelines as for the ICSBEP Handbook, but Includes Additional Material – Critical/Subcritical – Kinetics – Buckling/Extrapolation Measurements Data Length – Reaction-Rate – Spectral Distributions Characteristics – Power Distribution – Reactivity Effects Data – Reactivity Coefficient – Isotopic Measurements Data – Miscellaneous 16
  17. 17. Review and Acceptability of Results • ICSBEP and IRPhEP Benchmarks Are Subject to Extensive Review – Evaluator(s) – Primary Assessment of the Benchmark – Internal Reviewer(s) – In-House Verification of the Analysis and Adherence to Procedure – Independent Reviewer(s) – External (Often Foreign) Verification of the Analysis – Technical Workgroup Meeting – Annual International Effort to Review All Benchmarks Prior to Inclusion in the Handbook • Sometimes a Subgroup is Assigned to Assess Any Final Workgroup Comments and Revisions Prior to Publication – Benchmarks are Determined to Be Acceptable or Unacceptable for Use Depending on Uncertainty in Results • All Approved Benchmarks Are Retained in the Handbook 17
  18. 18. Summary of Benchmarking Process 18
  19. 19. Using Monte Carlo Methods • Perturbation Analysis – Variation of Parameters within Published or Assumed Range of Uncertainty • Manufacturing Tolerances • Repeated Measurements • Measurement Limit • Bounding Compositional Requirements – Sometimes the Perturbation Modeled is Larger than the Actual Uncertainty and Scaled Back • Uncertainty is On the Same Order of Magnitude as the Statistical Uncertainty in the Computation 19
  20. 20. Using Monte Carlo Methods • Bias Assessment – The Effect of Simplifying the Model is Assessed by Comparison of the Detailed Model to the Simple Model – Some Simplifications are Anti-Correlated • Their Effects Must Be Modeled Individually and As a Whole to Understand the Complete Result – Sometimes the Bias is Smaller than the Statistical Uncertainty • The Bias is Assumed Negligible • The Uncertainty is Included in the Overall Uncertainty of the Benchmark Model 20
  21. 21. Using Monte Carlo Methods • High Performance Computing 1200 – Typically MCNP and 1000 Some KENO is Used Elapsed Time (min) 800 – Parallel Processing Speeds Up 600 Computational Time While Reducing 400 Statistical Uncertainty 200 – “Speed-Up” Curves Are Generated to 0 0 50 100 150 Optimize Computing # of Processors Efficiency 21
  22. 22. Recent ICSBEP/IRPhEP Activities at the Idaho National Laboratory • ICSBEP • IRPhEP – Plutonium Hemishells in Oil – High Temperature – Annular Tanks with Engineering Test Reactor Enriched Uranyl Nitrate in – Fast Flux Test Facility Dilute Nitric Acid – Advanced Test Reactor and – Slabs of Enriched Uranium ATR-C Oxyfluoride – Nuclear Radiography – Concrete-Reflected Reactor Enriched Uranium Metal • NASA Cylinders – Advanced Fission Surface – Power Burst Facility Power System – Nickel-Reflected Plutonium Metal Sphere Subcritical Noise Measurements 22
  23. 23. Plutonium Hemishells in Oil • Series of Steel and Oil Reflected Experiments • Performed at the Rocky Flats Critical Mass Laboratory in the Late 1960’s • Unique Experiment with Bare Plutonium Metal 23
  24. 24. Simplifying the Details 24
  25. 25. Annular Tanks with HEU in Nitric Acid • Experiments at the Rocky Flats Critical Mass Laboratory in the 1980’s • Assessed Tanks Typical of Sizes Found in Nuclear Production Plants • Variations in Number of Filled Tanks and Presence of Neutron Absorbing Material Inside and Between Tanks – Borated Concrete – Borated Plaster 25
  26. 26. Empty Tanks 26
  27. 27. Additional Plugs and Slabs 27
  28. 28. Slabs of HEU-O2F2 • Critical Experiments Performed at the Oak Ridge Critical Experiments Facility in the mid-1950’s • Different Slab Thicknesses of Uranium Oxyfluoride Solution Were Performed to Determine a Minimum Thickness for An Infinite Slab 28
  29. 29. Detailed Model for Slabs of HEU-O2F2 29
  30. 30. MCNP Model of Slabs of HEU-O2F2 30
  31. 31. Simplified Model for Slabs of HEU-O2F2 31
  32. 32. Concrete-Reflected HEU-Metal Cylinders • Part of An Extensive Program at the Oak Ridge Critical Experiments Facility – Part IV in Early 1970’s • In Support of Nuclear Safety in Transportation and Storage of Subcritical Units of Fissile Material – Most Storage Vaults Have Concrete Floors and Walls Photo of the Tinkertoy Experiments 32
  33. 33. HEU Cylinders and Concrete in MCNP 33
  34. 34. HEU Cylinders and Concrete in MCNP 34
  35. 35. Power Burst Facility (PBF) • 1972-1985 at the INL • Provide Experimental Data for Postulated Accident Failure Conditions • Unique “Inert-Matrix” Fuel – U(18)O2-CaO-ZrO2 Ternary Ceramic – Of Interest for the Generation-IV Reactor Program 35
  36. 36. Power Burst Facility (PBF) E-1 D-30 D-32 D-1 D-2 D-4 D-31 D-3 D-28 C-18 CR8 C-20 C-1 CR1 C-3 D-6 C-19 C-2 C-17 C-4 B-11 B-12 TR1 B-1 B-2 D-27 D-7 CR7 CR2 A-1 D-26 B-10 A-8 A-2 B-3 D-8 C-16 C-5 Test E-31 D-25 TR4 A-7 A-3 TR2 D-9 E-11 C-15 Space C-6 D-34 B-9 A-6 A-4 B-4 D-10 A-5 CR6 CR3 D-24 D-11 B-8 B-7 TR3 B-6 B-5 C-14 C-7 D-23 C-13 CR5 C-11 C-10 CR4 C-8 D-12 C-12 C-9 D-19 D-15 D-20 D-18 D-17 D-16 D-14 E-21 09-GA50001-38 09-GA50001-27-3 Water Shim rod Fuel rod boundary Filler CaO-ZrO2 insulator SS 304 Reflector rod element Assembly Type 5454 Al Type 6061 Al Filler rod UO2-CaO-ZrO2 fuel B4C Fuel rod 36
  37. 37. Subcritical Nickel-Reflected Plutonium Spheres • Modern Experiments at the Device Assembly Facility in Nevada • Uses Californium Source- Driven Noise Analysis (CSDNA) Methods • Currently Modeled Using MCNP and MCNP-DSP • Part of a Series of Experiments: Polyethylene, Acrylic, Tungsten, Copper, Lead, Manganese 37
  38. 38. Subcritical Nickel-Reflected Plutonium Spheres – MCNP Visual Editor 38
  39. 39. High Temperature Engineering Test Reactor (HTTR) • Japanese 30 MWt, Graphite-Moderated, Helium-Cooled Reactor • Currently Operational • Research Reactor to Assess Future High Temperature Gas Reactors • High Priority Benchmark for the Next Generation Nuclear Plant (NGNP) Project 39
  40. 40. Fully-Loaded Core Description of the HTTR 40
  41. 41. Annular HTTR Core Configurations 21 27 19 24 Initial Critical 41
  42. 42. Fast Flux Test Facility (FFTF) • 400 MWt, Sodium-Cooled, Fast-Neutron Reactor • Prototypic Liquid Metal Fast Breeder Reactor • Hanford, Washington • Provided Over 10 Years of Operation – Nuclear power plant operations and maintenance protocols – Advanced nuclear fuels – Materials and components – Reactor safety design – Radioisotope production 42
  43. 43. HEX-Z Homogenized FFTF Model in MCNP 43
  44. 44. Future Work: Advanced Test Reactor and ATR-C • 250 MW “Four Leaf Clover” Thermal Reactor • Materials Irradiation • National Science User Facility • ATR-C is a Critical Experiments Facility • Full-Core Characterization is to be Performed and Benchmarked on Both Reactors – Currently a Critical Benchmark Exists for the ATR 44
  45. 45. Future Work: Nuclear Radiography Reactor (NRAD) • Collaborative Work is being Discussed to Provide a Benchmark Assessment • The NRAD is being Refueled with LEU (<20% U235) • Neutron Radiography Allows for the Non- Destructive Testing of Objects • Full-Core Benchmark is to be Developed 45
  46. 46. Comparison of N-Ray and X-Ray Imaging N-Ray X-Ray Atominstitute of the Austrian Universities, http://www.ati.ac.at/ 46
  47. 47. Lunar Fission Surface Power (FSP) System • Inter-Laboratory Collaboration • 40 kWe, Fast-Fission, NaK- Cooled, HEU, SS316-Clad Reactor • Utilized Current Benchmark Data to Evaluate Necessity for a Cold-Critical Experiment with the FSP • TSUNAMI - Tools for Sensitivity and Uncertainty Analysis Methodology Implementation in Three Dimensions (SCALE/KENO) 47
  48. 48. Opportunities for Involvement • Each Year the ICSBEP Hosts One or Two Summer Interns • INL Also Has Funded Benchmark Development via the CSNR Next Degree Program • Students Have Participated in the Program as Subcontractors through Various Universities and Laboratories • Benchmark Development Represents Excellent Work for Collaborative Senior Design Projects, Master of Engineering Project, or Master of Science Thesis Topic • Further Information Can Be Obtained By Contacting the ICSBEP Program Director – J. Blair Briggs, J.Briggs@inl.gov 48
  49. 49. Past and Present Student Involvement • Since 1995, Approximately 30 Students Have Participated in the ICSBEP and/or IRPheP • Students Have Authored or Coauthored 51 ICSBEP or IRPhEP Evaluations • They Have Also Submitted Technical Papers to Various Conferences and Journals 49
  50. 50. Conclusion • Benchmarks Represent An Important Means for Developing and Assessing a Collection of Nuclear Experimental Data – Application of Criticality Safety – Validation of Nuclear Activities • Monte Carlo Methods Represent One of the Many Tools Available to Perform a Benchmark Analysis • There Exist Many Ongoing Benchmarking Activities at the Idaho National Laboratory 50
  51. 51. Questions? 51