9.223600+4 2.340178+2 1 1 2 0
0.000000+0 0.000000+0 0 0 0 6
1.000000+0 3.000000+7 0 0 10 31
0.000000+0 0.000000+0 0 0 206 1
92-U -236 BRC,+ EVAL-NOV04 LOPEZ JIMENEZ, MORILLON, ROMAIN
DIST-MAY05 REV1-MAY05 20050504
----JEFF-31 MATERIAL 9231
-----INCIDENT NEUTRON DATA
------ENDF-6 FORMAT
***************************** JEFF-3.1 *************************
** **
** Original data taken from: New evaluation **
** **
******************************************************************
05-01 NEA/OECD (Rugama) 8 delayed neutron groups
Jefdoc-976(Spriggs,Campbel and Piksaikin,Prg Nucl Eng 41,223(2002)
***************************** JEFF-3.1 *************************
** **
** Original data taken from: New evaluation **
** **
******************************************************************
******************************************************************
JEFF-3.1 evaluation above the unresolved resonance region
based on model calculations, from 1.5 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 Energy Release. BRC modified JEFF3.0
MF=2 Resonance Parameters
MT-151 JEFF3.0
[******* JEFF3.0
Resolved Resonances for MLBW formula : 1.0e-5 ev to 1.5 kev
res. energies and gam-n(for gam-n greater than 0.1*gam-g)
: Carraro [2]
gam-n (for gam-n smaller than 0.1*gam-g) : Mewissen [3]
gam-g : Mewissen [3], when not given, mean value was taken.
gam-f : Theobald [4].
average gam-g = 23.0 milli-ev
average gam-f = 0.354 milli-ev
a negative resonance was introduced to reproduce the 2200-
m/s capture cross section of (5.11+-0.21) barns recommended
in bnl-325 4th edition.
calculated 2200-m/s cross sections and res. integrals
2200m/s values resonance integral
(barns) (barns)
Total 13.69 -
Elastic 8.337 -
Fission 0.0613 7.77
Capture 5.295 346.
*******]
MF=3 Reaction Cross-sections
From the energy of 1 keV up to 200 MeV, six states (ground-
sate rotationnal band {0+,2+,4+} and octupolar band {1-,3-,5-})
Coupled Channel Calculations are performed using the ECIS95[5]
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[6]. 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 [7,8]
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 Resolved Resonance Range, ending now at 1.5 KeV, the
model calculations data are implemented from this energy.
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=51-81(n,n') cross-section for 1st-31th 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=51-81 inelastic levels, 1st-31th 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 (U236l)
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] G. Carraro, et al.: nucl. phys., a275 (1976) 333.
[3] L. Mewissen, et al.: 1975 Washington, 729 (1975).
[4] J.P. Theobald: nucl. phys.,181 (1972) 637.
[5] J. Raynal, "Code ECIS95" CEA report N-2772, (1994).
[6] P.G. Young, E.D. Arthur and M. B. Chadwick, Workshop on
Nuclear Reaction Data and Nuclear Reactors, Trieste,
Italy (1996).
[7] 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).
[8] 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).
************************ C O N T E N T S ***********************
1 451 211
Back