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92-U -237 BRC,+ EVAL-NOV04 LOPEZ JIMENEZ, MORILLON, ROMAIN DIST-JAN09 20090105 ----JEFF-311 MATERIAL 9234 -----INCIDENT NEUTRON DATA ------ENDF-6 FORMAT *************************** JEFF-3.1.1 ************************* ** ** ** Original data taken from: JEFF-3.1 ** ** ** ****************************************************************** ***************************** JEFF-3.1 ************************* ** ** ** Original data taken from: New evaluation ** ** ** ****************************************************************** 05-01 NEA/OECD (Rugama) 8 delayed neutron groups Jefdoc-976 (Wilson and England, Prog Nucl Eng 41,71(2002) ***************************** JEFF-3.1 ************************* ** ** ** Original data taken from: New evaluation ** ** ** ****************************************************************** ****************************************************************** JEFF-3.1 evaluation above the unresolved resonance region based on model calculations, from 10 keV to 30 MeV. M-J. Lopez-Jimenez, B. Morillon, P. Romain, J-Ch. Sublet CEA/DAM Bruyeres-le-Chatel CEA/DEN Cadarache MF=1 General Information The prompt fission neutron multiplicity and spectra are calculated using the BRC improved Los Alamos model from Vladuca and Tudora [1]. The model parameters are slightly different from those adopted in [1]. The prompt fission neutron multiplicity is obtained from an energetic balance ratio. The available energy (the average fission energy released minus the average fission fragment kinetic energy minus the average prompt gamma ray energy) is divided by the energy carry away by the neutron (the average fission fragment neutron separation energy plus the average center-of-mass energy of the emitted neutrons). The main improvement is the dependence of the average total fission-fragment kinetic energy and the average gamma energy on neutron incident energy. MT=452 Total Nubar. Sum of MT=455 and 456 MT=455 Delayed Neutron Yields. 05-01 NEA/OECD (Rugama) 8 delayed neutron groups. MT=456 Prompt Neutron Yields. Vladuca and Tudora BRC improved Madland-Nix model MT=458 not given MF=2 Resonance Parameters MT=151 JENDL3.3 [******* JENDL3.3 1) Resolved Resonance Parameters: MLBW (1.0e-5 - 200 ev) below 45 ev, hypothetical resonances were generated from fission width of 0.004 ev, s0 of 1.0e-4 and level spacing of 3.5 ev, and adjusted to reproduce thermal cross sections. above 46 ev, parameters were estimated from fission-area data measured by MCNALLY et al.[2] 2) Unresolved Resonance Parameters: 200 ev - 30 kev obtained by fitting to capture and fission cross sections with ASREP[3]. S0 and S2 = (0.97 - 1.02)e-4, S1 = (1.95 - 2.04)e-4, Gamma-f = (0.006 - 0.070) ev, Gamma-g = 0.035 ev R = 9.668 fm calculated thermal cross sections and res. integral (barns) 0.0253 ev resonance integral (barns) (barns) Total 478.50 - Elastic 24.39 - Fission 1.70 48.7 Capture 452.40 1080.0 *******] Unresolved Resonance Range 10 keV to 30 keV : The four energy dependant widths parameters originally described in JENDL-3.3 have been removed to account for direct interaction on the first inelastuc level MF=3 Reaction Cross-sections From the energy of 1 keV up to 200 MeV, eigth states (ground- sate rotationnal band {1/2+,3/2+,5/2+,7/2+,9/2+} and octupolar band {1/2- (540.62 keV), 3/2- (554.98 keV), 5/2- (578.01 keV)}) Coupled Channel Calculations are performed using the ECIS95[4] code which also provides compound nucleus cross sections and transmission coefficients used in pre-equilibrium/evaporation emission treated in the exciton and Hauser-Feshbach models implemented in the Bruyeres-le-Chatel modified version of the GNASH code[5]. This reaction code has been modified to include width fluctuation factors, relativistic kinematics, and a more realistic treatment of the fission process. A new fission [6,7] penetrability model taking into account Triple Humped Fission Barrier (THFB) has been developed, explicitly coupling class I, II and III states while damping those of class II and III. Emission of light hadrons up to He4 are explicitly treated in the model calculations. Fission decay of associated residual nuclei is also treated. However, none of these emissions and fission cross-sections, are yet explicitly provided in this file. The Unresolved Resonance Range end at 10 KeV and the model calculations data are implemented from 10 KeV. MT=1 calculation from BRC deformed optical potential over the whole energy range 1 keV-200 MeV. MT=2 calculation from BRC deformed optical potential MT=3 calculation from BRC deformed optical potential MT=4 calculation from BRC deformed optical potential sum of mt=51-91. MT=16 (n,2n) cross section MT=17 (n,3n) cross section MT=18 (n,F) calculation with BRC modified GNASH code, with a triple humped fission barrier penetration model MT=19-21(n,f),(n,nf),(n,2nf) calculation with BRC modified GNASH code, with a triple humped fission barrier penetration model. MT=37 (n,4n) cross-section MT=38 (n,3nf)calculation with BRC modified GNASH code, with a triple humped fission barrier penetration model. In fact this cross section include more complex processes thus as : (n,4nf),(n,pf),(n,df), (n,tf),(n,He-3f),(n,He-4f),(n,pnf), ... MT=51-84(n,n') cross-section for 1st-34th excited states MT=91 (n,n') continuum cross-section MT=102 (n,g) cross-section MF=4 Angular Distributions of Secondary Particles MT=2 elastic angular distribution, given up to 30 MeV MT=18 fission given up to 30 MeV (assumed isotropic) MT=51-84 inelastic levels, 1st-34th excited states With a uniform number of angular points (91), equal values of the tabulated probability distributions may occur. MF=5 Energy Distributions of Secondary Particles MT=18 Vladuca and Tudora BRC improved Madland-Nix model MT=455 extended NEA/OECD data MF=6 Products Energy-angle Distributions MT-16 pre-ENDF/B-VII (237l) MT=17 pre-ENDF/B-VII MT=37 pre-ENDF/B-VII MT=91 pre-ENDF/B-VII MF=12 Photon Production Multiplicities MT=18 pre-ENDF/B-VII MT=102 pre-ENDF/B-VII MF=13 Photon Production Cross-section MT=3 pre-ENDF/B-VII MF=14 Photon Angular Distribution MT=3 pre-ENDF/B-VII MT=18 pre-ENDF/B-VII MT=102 pre-ENDF/B-VII MF=15 Continuous Photon Energy Spectra MT=3 pre-ENDF/B-VII MT=18 pre-ENDF/B-VII MT=102 pre-ENDF/B-VII ---------------------------------------------------------------- References [1] G. Vladuca and A. Tudora, Ann. Nuc. Energy. 28, 689 (2001). [2] J.H.Mcnally et al: phys. rev., c9, 717 (1974). [3] Y.Kikuchi: unpublished. [4] J. Raynal, "Code ECIS95" CEA report N-2772, (1994). [5] P.G. Young, E.D. Arthur and M. B. Chadwick, Workshop on Nuclear Reaction Data and Nuclear Reactors, Trieste, Italy (1996). [6] M-J. Lopez-Jimenez, B. Morillon and P. Romain "Triple humped fission barrier model for a new 238U neutron cross-section evaluation and first validation with TRIPOLI code", to be published, ANE, (2004). [7] A.J. Koning, M.C. Duijvestijn and M-J. Lopez-Jimenez, "Data Evaluation up to 200 MeV for Fe, Pb and U", NRG Report, 20567/03.56876/P, (2003).Back |