Modern nuclear data evaluation: straight from nuclear physics to applications

Modern nuclear data evaluation: straight from nuclear physics to applications Arjan Koning and Dimitri Rochman NRG Petten, the Netherlands ND-2010 April 26-30 2010, Jeju, Korea

Contents • Introduction: A new way of nuclear data evaluation • Essence of software development and reproducibility • Example: TALYS code system • Implications and possibilities: • Large scale nuclear data library production (TENDL) • “Total” Monte Carlo uncertainty propagation • Validation with integral measurements • Conclusions

Objective • There are limits in our knowledge of nuclear physics: • Experimental possibilities and precision • Theoretical nuclear structure and reaction models • which requires and deserves everlasting support • Mantra: let’s at least provide all nuclear physics knowledge we know up to now in a form ready for applications, • while maximizing • Completeness: no unnecessary omissions • Quality: • no unnecessary approximations • with a quantitative measure about our knowledge (uncertainty information) • Satisfactory from differential and integral point of view

Nuclear data libraries: up to now • During one nuclear data career: • Evaluators make mistakes • Evaluators improve their methods (less mistakes, more complete ENDF-6 files, covariance data, etc.) • New experimental data and better nuclear model codes emerge • Up to now, such progress has not been consistently implemented in isotopic data libraries. E.g. : • 96-Cm-247 JAERI-ORNL EVAL-OCT05 R.Q. Wright, T.Nakagawa, T.Liu • 96-Cm-248 HEDL,SRL,+ EVAL-APR78 Mann,Benjamin,Howerton, + • 96-Cm-249 JAERI EVAL-OCT95 T.Nakagawa and T.Liu • 96-Cm-250 JAERI EVAL-OCT95 T.Nakagawa and T.Liu • 27-Co- 58 NEA RCOM-JUN83 Scientific Co-ordinating Group • 27-Co- 58MNEA RCOM-JUN82 Scientific Co-ordination Group • 27-Co- 59 ANL,ORNL EVAL-JUL89 A.Smith+,G.Desaussure+ • 24-Cr- 50 LANL,ORNL EVAL-OCT97 S.Chiba,M.Chadwick,D.Hetrick and these data libraries are not reproducible

Nuclear data libraries: another way • Nuclear data knowledge should no longer be assembled in an ENDF-6 nuclear data library, but one level deeper: • Resonance parameters + uncertainties • An error-free EXFOR database + selection of good data • Nuclear models: • A robust, validated, multipurpose nuclear model code • A Reference Input Parameter Library (RIPL) • For important/measured nuclides: A set of adjusted model parameters + uncertainties • If needed: per nuclide a script with other actions (copying parts of other libraries, direct inclusion of experiment, etc.) • Store the above, and make sure that ENDF formatting, processing and integral validation become robust • This yields entirely new possibilities

Nuclear data scheme + covariances +Uncertainties Determ. code Resonance Parameters . TARES +Covariances +Covariances Output ENDF Gen. purpose file NJOY MCNP • K-eff • Neutron flux • Etc. TEFAL +Covariances Experimental data (EXFOR) Output ENDF/EAF Activ. file PROC. CODE FIS- PACT -activation - transmutation +(Co)variances +Covariances +Covariances Nucl. model parameters TALYS Other (ORIGEN) +Uncertainties Monte Carlo: 1000 TALYS runs TASMAN

TALYS code scheme COMPOUND DIRECT REACTION OPTICAL MODEL Hauser-Feshbach Spherical / DWBA (ECIS) Fluctuations Deformed / Coupled channel Fission Rotational Phenomenologic  Emission Vibrational Local or global Level densities Giant Resonances GC +Ignatyuk Pickup, stripping, exchange OUTPUT Semi-Microscopic Tabulated Tabulated Cross sections Superfluid Model INPUT Spectra projectile n DDX element Fe Fission yields mass 56 energy 1.2 Ang. Distr. Astro rates Etc. PRE-EQUILIBRIUM STRUCTURE MULTIPLE EMISSION Loop over energies Exciton model Abundances Exciton model and isotopes Discrete levels Partial densities Hauser-Feshbach Deformations Fission Kalbach systematic  cascade Masses Angular distributions Cluster emissions Level densities Exclusive channels  emission Resonances Recoils Fission parameters Radial matter dens. Approx DSD

TALYS-1.2 • Released December 21, 2009, see www.talys.eu • Use of TALYS increasing • Estimated 400-500 users, 160-200 publications • Some recent improvements for TALYS-1.2: • Better fission + level density model (CEA Bruyeres-le-Chatel) • The option to easily/safely store the best input parameter set per nucleus (“best y”) • More flexibility for covariance development and adjustment to experimental data • TALYS can be used for • In-depth nuclide/reaction analyses • Global multi-nuclide calculations • These two are now being merged

Uncertainties with Monte Carlo • Standard procedure (Don Smith): • Determine uncertainty range for each nuclear model parameter • Perform K(=1000) TALYS calculations with all parameters randomly sampled around their central values • Covariance matrix for cross sections i and j: • Various refinements possible: • Reject outlying results (leads to parameter correlations) • More precise inclusion of experimental data (Unified MC, D. Smith, H. Leeb), backward-forward MC (E. Bauge), etc.

Uncertainties for Cu isotopes

Application 1: TENDL • TALYS Evaluated Nuclear Data Library, www.talys.eu/tendl2009 • n, p, d, t ,h, a and g libraries in ENDF-6 format • 2400 nuclides (all with lifetime > 1 sec.) up to 200 MeV • Neutrons: complete covariance data (MF31-MF35) • MCNP-libraries (n,p and d) and multi-group covariances (n only) • Production time: 2 months (40 processors) • Strategy: • Always ensure completeness, global improvement in 2010, 2011.. • Extra effort for important nuclides, especially when high precision is required (e.g. actinides): adjusted parameters (data fitting). These input files per nuclide are stored for future use. • All libraries are always reproducible from scratch • The ENDF-6 libraries are created, not manually touched • Zeroing in on the truth for the whole nuclide chart at once

TENDL users • European Activation File (EAF): > 95% TALYS/TENDL based • Fusion Evaluated Nuclear Data Library (FENDL) • Missing nuclides, high energies, covariances, protons and deuterons • Joint Evaluated Fission and Fusion file (JEFF) • Missing nuclides (JEFF-3.2), protons and deuterons • NEA Data Bank: Janis (E. Dupont, N. Soppera) • IAEA: visualisation system (V. Zerkin) • Fusion/IFMIF research (Sanz, Sauvan): protons and deuterons • Many downloads from www.talys.eu/tendl2009 • So far, TENDL is adopted “when nothing else exists”, but a lot of effort has been devoted to nuclide-by-nuclide neutron evaluations. We can, and will, be more ambitious!

TENDL: Complete ENDF-6 data libraries • MF1: description and average fission quantities • MF2: resonance data • MF3: cross sections • MF4: angular distributions • MF5: energy spectra • MF6: double-differential spectra, particle yields and residual products • MF8-10: isomeric cross sections and ratios • MF12-15: gamma yields, spectra and angular distributions • MF31: covariances of average fission quantities(TENDL-2010) • MF32: covariances of resonance parameters • MF33: covariances of cross sections • MF34: covariances of angular distributions • MF35: covariances of fission neutron spectra(TENDL-2010) and particle spectra (TENDL-2011) • MF40: covariances of isomeric data (TENDL-2011)

IAEA covariance visualisation system (V. Zerkin)

Quality of proton data (EXFOR vs MCNPX, A. Konobeyev, KIT) (Chi-2) (< C/E >) (H x F) ENDF/B-VII-p (LA-150): 30-40 nuclides TENDL-2009: 1170 nuclides

Other TENDL(-related) results • Astrophysical reaction rates for 4000 nuclides (Stephane Goriely) • Human-readable tables for normal nuclear physicists. Some possibilities: • Validation of the entire EXFOR • Complete table of all medical isotope production routes for all nuclides (“inverse search”) • Comparison with specific measurements • Etc.

Application 2: “Total” Monte Carlo • Propagating covariance data is an approximation of true uncertainty propagation (especially regarding ENDF-6 format limitations) • Covariance data requires extra processing and “satellite software” for application codes • Alternative: Create an ENDF-6 file for each random sample and finish the entire physics-to-application loop. (Koning and Rochman, Ann Nuc En 35, 2024 (2008)

Nuclear data scheme: Total Monte Carlo +Uncertainties Determ. code Resonance Parameters . TARES Output ENDF Gen. purpose file NJOY MCNP • K-eff • Neutron flux • Etc. TEFAL +Covariances Experimental data (EXFOR) Output ENDF/EAF Activ. file PROC. CODE FIS- PACT - activation - transmutation +Covariances Nucl. model parameters TALYS Other codes +Uncertainties TASMAN Monte Carlo: 1000 runs of all codes

Covariance versus Total Monte Carlo • Advantages: Advantages: • - Relatively quick - Exact • - Use in sensitivity study - Requires only “main” software • - Easier release (TENDL) • Disadvantages: Disadvantages: • - Approximative (cross-correlations) - (Computer) time consuming • - No covariance for gamma production, - Backward (sensitivity) route • DDX (MF36), etc. not obvious • - Requires special processing • - Requires covariance software for application codes

Application: criticality benchmarks Total of 60000 random ENDF-6 files Sometimes deviation from Gaussian shape Rochman, Koning, van der Marck Ann Nuc En 36, 810 (2009) Yields uncertainties on benchmarks

Modern nuclear data evaluation: straight from nuclear physics to applications