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Activation Calculations-Present and Future

Activation Calculations-Present and Future. SATIF-10 June 2-4, 2010 Franz Gallmeier. TN-RAM cask. target modulee. liner. The first SNS Spent Target leaving the SNS Site. Moderators. protons. Target. Inner Reflector. Outer Reflector. Target Activation(1).

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Activation Calculations-Present and Future

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  1. Activation Calculations-Present and Future SATIF-10 June 2-4, 2010 Franz Gallmeier

  2. TN-RAM cask target modulee liner The first SNS Spent Target leaving the SNS Site

  3. Moderators protons Target Inner Reflector Outer Reflector Target Activation(1) Thomas/Stevenson: Asat≈E(GeV) Bq per proton/second  ASNS= 6e15 Bq

  4. Target Activation (2) • Detailed listing of radionuclide inventory by required for realistic beam conditions. • We are close to the activity limit of the transport cask and of the disposal site.  We need good tools to predict activation related quantities.

  5. What do we calculate? Flux Decay constants Material composition Isotope production/destruction from event generators Activation cross sections

  6. Tools for Activation Analyses • Transport codes • Activation codes

  7. Modular Approach Particle Tracking Inelastic Reactions Transport code by Event Generator by Cross Sections Fluxes n,p,d,t,He-3,α,γ Residual Production Materials Particle emission n,β-,β+,γ,α Irradiation History Decay database Activation Analysis Decay Spectra:n,β-,β+,γ,α Radionuclide Inventory by time Activation Cross Sections

  8. All-In-One-Code Approach Particle Tracking Inelastic Reactions by Event Generator by Cross Sections Residual Nucleus Transport code Unstable Stable Particle emission n,β-,β+,γ,α Decay

  9. Comparison of Approaches

  10. FLUKA-2008 (Ferrari, Fasso, Sala …) • Reaction models: Gribov-Glauber, GINC, PE, evaporation, … • Multigroup low-energy neutron transport • Radionuclide formation: • For many materials, but not for all, group-dependent information on the residual nuclei produced by low-energy neutron interactions is available in the FLUKA libraries. This information can be used to score residual nuclei, but it is important that the user check its availability before requesting scoring. • Fission fragments are sampled separately, using evaluated data extracted from European, American and Japanese databases. • Scoring of decay radiation, and residual nuclei • for requested decay time step • semi-analog

  11. MCNPX_2.6.0 (McKinney, Hendricks …) • Reaction models: CEM-03, LAQGSM, INCL,Isabel, Bertini, MPM, ABLA, EVAP … • Continuous energy cross section based low-energy neutron and proton transport • The depletion/burnup capability for reactor applications is implemented based on CINDER90, and MONTEBURNS. • Charged ions from neutron capture:“neutron capture ion algorithm”: He-3, Li-6, B-10 • MCNPX enables the automated calculation of delayed-gamma signatures emitted due to • the decay of radioactive fission products created by neutron fission or photofission, • residual nuclides created by simple multi-particle interactions (SMRs). The delayed-gamma capability uses CINDER90. Execution of the delayed gamma capability is limited to fixed sources (SDEF) and surface sources (SSW, SSR). • Residual nuclei (from event generators only) are tallied: • By region thru history tape and post-processing with HTAPE3 utility • Overall thru tally f8:n +ft res • With heavy-ion transport with f4:# +ft4 res zzaaa1 zzaaa2 …

  12. The MCNPX Approach to more detailed Information • A multitude of tasks of preparing and performing activation analyses • Activation script does a complete activation calculation (multi-cell) with one user supplied input file minimizing the information needed • Gamma Source Script prepares MCNPX source deck from decay gamma sources

  13. GEANT4 Reaction models: Parton-String, G4Bertini, G4BinaryCascade, Abration-Ablation, INCL4.2+ABLA3, PC, Evaproation … Continuous-energy low-E neutron transport Radioactive Decay - The radioactive decay module G4RadioactiveDecay and associated classes are used to simulate the decay of radioactive nuclei by α, β+, and β¡ emission and by electron capture (EC). The simulation model is empirical and data-driven, and uses the Evaluated Nuclear Structure Data File (ENSDF) for information on: nuclear half-lives, nuclear level structure for the parent or daughter nuclide, decay branching ratios, andthe energy of the decay process. If the daughter of a nuclear decay is an excited isomer, its prompt nuclear de-excitation is treated using the G4PhotoEvaporation class. Sampling: Sampling of the β-spectrum, which includes the coordinated energies and momenta of the β, ν,and residual nucleus, is performed either from histogrammed data, or through a three-body decay algorithm. The manual did not tell me, if GEANT4 considers radionuclide production in high-precision low-energy neutron processes.

  14. MARS15 (Mokhov, Rakhno, James …) Reaction model: Inclusive phenomenological model, DPMJET3, CEM03, LAQGSM MCNP low-E neutron transport Besides the straight forward approach of following the radionuclide production in the spallation and neutron-induced activation, MARS offers an approximate solution to activation problems -the ω-factor approach – to arrive at residual dose rates. ω-factors correlate residual dose-rates to star-densities (reaction rates above 20 MeV). This does not work for calculating radionuclide information. Curtesy: M. Huhtinen, CERN/TIS-RP/IR/98-28 (1998).

  15. PHITS (Niita, Iwase …) JAM, JQMD, Bertini

  16. CINDER (Holloway, Wilson …) CINDER90 released version: • Solves coupled buildup- and decay equations • Considers material destruction in balance equations • Database contains decay data and activation cross sections, decay gamma spectra for 3400 isotopes • Neutron activation cross sections in 63 energy groups up to 20 MeV • Decay gamma structure fixed to 25 groups • Tabulating of CINDER90 results with TABCODE • Merging of results of different CINDER90 calculations by ALLCODE Towards CINDER-2008 package: • Improvement of mathematical algorithms • Update neutron activation cross sections (ENDF/B-VII, JEFF-3x, JENDL) in 65 group structure • Update of decay database to 4113 nuclides (ENDF/B-VII.0, EAF-2007, JEFF-3.11) • Photonuclear library in preparation

  17. DCHAIN-SP 2001 (Kai, Maekawa, Kosako, Kasugai, Takada, Ikeda) Present Version: • Developed from DCHAIN-2 code at JAEA • Decay library with 3139 nuclides, EAF-3.1, FENDL/D-2, ENSDF • Neutron activation cross sections in 175 groups from FENDL/A-2, JENDL-AC96, JENDL-3.3 • Decay Gamma lines from ENSDF, one line per nuclide (averaged gamma energy) • Revised 65 partial activation cross sections to match better experimental data Updates underway: • Improved neutron activation cross sections from JEFF-3.1A in 1968 groups improves contributions from resonance region

  18. EASY-2007 (Forrest, Kopecky, Sublet) EASY-2007 is the activation package of the fusion community. • Includes FISPACT-2007 activation code, • Uses EAF-2007 decay data (2233 nuclides) and cross sections(n,p,d) for 800+ nuclides to 60 MeV • Package provides multi-group cross section libraries in various group structures (69-351)and collapsed with flat, fission, and fusion spectra • FISPACT-2007 can give uncertainties due to cross sections and decay constants (not yet due to input flux statistical errors) • Contains the SAFEPAQ-II tool for processing and evaluating activation cross sections Updates: • EAF-2010 libraries on the way • Heard rumors that FISPACT-2010 may be able to handle user-provided radionuclide production rates extension to spallation products.

  19. ORIHET3 (Atchison, Schaal - no longer developed) • Decay databases: • NUBASEX built from NUBASE 3738 nuclides and uses more than 40 decay modes • Original ORIHET data for 2456 nuclides and recognises 7 decay modes • Gamma library: Darmstadt Gamma-ray atlas: 30752 gamma lines and intensities for 1275 nuclides • No beta library • Requires radionuclide production rates as input

  20. Other Activation Tools • ALARA (Paul Wilson, U. Wisconsin) • DeTra (Aarnio, CERN) • …

  21. Activation Data • Decay databases • Activation cross section libraries

  22. Decay Databases

  23. High-energy Neutron Induced Activation Cross Section Databases

  24. High-energy Proton Induced Activation Cross Section Databases

  25. High-energy Activation Cross Section Databases

  26. Benchmarking • Microscopic benchmarking • of Spallation Models (CEM, INCL, JAM, CASCADE, QMD, DPMJET, …) • Precompound nuclear reaction models • Macroscopic benchmarking • through application type quanitities (decay heat, residual dose rates, foil activation) • Measured integral production cross sections

  27. IAEA Spallation Physics Benchmark – Radionuclide Production Mass and Charge distributions by inverse kinematic experiments Isotope distributions by inverse kinematic experiments

  28. Examples: Mass Production

  29. Uncertainty in activation cross-section calculations –A. Yu. Konobeyev et al., Kerntechnik 73, 2008 (p,x) E=0-150MeV

  30. Benchmarking of isotope production in mixed energy and mixed particle fields • Typically libraries like EAF and TENDL are validated to a collection of experimental integral production cross sections • J. Kopecky, VALIDATION OF TENDL2009 USING INTEGRAL MEASUREMENTS,JUKO Research, EAFDoc54, Feb 2010 • RA Forrest et al., Validation of EASY-2007 using integral measurements, UKAEA FUS 547, EURATOM/UKAEA Fusion, April 2008 • Many other examples in proceedings of SATIF-x, ARIA2008, AccApp’xx, ICRS-xx, …

  31. How to improve Activation Analyses? • Continue improving reaction models and benchmarking • make use of cross section data bases extended to intermediate-energy • multi-group formalism and its limitations need to be addressed • Waiting for gamma-activation cross section library • Uncertainty analysis is in development in FISPACT, can it be adopted in other activation codes? Correct formalism needs bulky covariance matrices.

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