92-U -234 Kawasaki Eval-Mar87 T.Watanabe
DIST-MAR02 REV4-FEB02 20020226
----JENDL-3.3 MATERIAL 9225
-----INCIDENT NEUTRON DATA
------ENDF-6 FORMAT
HISTORY
87-03 New evaluation for JENDL-3 was made by T.Watanabe (Kwasaki
Heavy Ind.)
87-06 Compilation was made by T.Nakagawa (JAERI)
93-07 JENDL-3.2.
Modified by T.Nakagawa (NDC/JAERI)
00-08 JENDL-3.3.
Modified by T.Nakagawa (NDC/JAERI)
***** Modified parts from JENDL-3.2 ********************
(2,151) Parameters of the -2.06-eV resonance
(3,2),(3,102) Direct and semi-direct capture added.
(5,16),(5,17),(5,91) Around threshold energies.
(5,455) Adopted from Brady-England.
***********************************************************
MF=1 General Information
MT=451 Descriptive data and dictionary
MT=452 Number of neutrons per fission
Sum of MT=455 and 456.
MT=455 Delayed neutrons per fission
Systematics of Tuttle/1/. Six group decay constants were
adopted from Brady et al./2/
MT=456 Prompt neutrons per fission
Based on the experimental data by Mather et al./3/ Nu-p of
Cf-252 spontaneous fission was assumed to be 3.756.
MF=2 Resonance Parameters
MT=251 Resonance Parameters ; 1.0E-5 eV - 50 keV
Resolved resonances for MLBW formula : 1.0E-5 eV - 1.5 keV
Parameters of Ref./4/ were adopted after modification of
an average radiative width to 0.026 eV/5/. A negative
level was added at -2.06 eV so as to reproduce the cross
sections at 0.0253 eV/5/.
Total = 119.1 +- 1.3 b
Elastic = 19.6 +- 1.0 b
Capture = 99.8 +- 1.3 b
and
Fission = 0.30 + - 0.02 b /6/
Unresolved resonances : 1.5 keV - 50 keV
The following parameters were given.
= 0.026 eV/2/, = 0.0 eV, D-obs = 10.6 eV/2/,
S-0 = 0.96E-4 (calculated with ECIS/7/),
S-1 = 1.197E-4 (adjusted to the total cross section
calculated with ECIS/7/),
R = 9.70 fm (adjusted to the total cross section at
50 keV).
Calculated 2200m/s cross sections and resonance integrals.
2200 m/s Resonance integral
total 119.5 b ---
elastic 19.41 b ---
fission 0.299 b 6.76 b
capture 99.75 b 631 b
MF=3 Neutron Cross Sections
Below 50 keV, resonance parameters were evaluated.
Background cross sections for the fission were given in the
unresolved resonance region.
MT=1,2,4,51-69,91,102 Total, elastic and inelastic scattering,
and capture
Calculated with coupled-channel code ECIS/7/ and spherical
optical and statistical model code CASTHY/8/.
The Deformed optical potential parameters of Lagrange/9/
were adopted for the ECIS calculation.
V = 46.42 - 0.3 * En, ro = 1.26, ao = 0.63
Ws = 3.72 + 0.4 * En, rs = 1.26, b = 0.52
En up to 10 MeV
= 7.72
En above 10 MeV
Vso = 6.2 rso= 1.12 aso= 0.47
beta2 = 0.194
beta4 = 0.071
The following spherical optical potential parameters for the
CASTHY calculation were determined so as to reproduce the
total cross section calculated with ECIS by using the above
OMP.
V = 41.49 - 0.1359 * En
Ws = 9.284 - 0.2086 * En+ 0.03225 * En**2
(derivative Woods-Saxon form)
Vso= 4.248,
r = 1.315, rs = 1.381, rso= 1.15
ao = 0.528, b = 0.372, aso= 0.597
The level scheme was taken from Ref./10/.
No. Energy(MeV) Spin-Parity Coupled lvl
g.s 0.0 0 + *
1 0.04348 2 + *
2 0.14334 4 + *
3 0.29606 6 + *
4 0.49702 8 + *
5 0.7412 10 + *
6 0.78628 1 -
7 0.80989 0 +
8 0.84930 3 -
9 0.85172 2 +
10 0.92672 2 +
11 0.94785 4 +
12 0.9626 5 -
13 0.9691 3 +
14 0.9895 2 -
15 1.0236 4 +
16 1.0238 3 -
17 1.0445 0 +
18 1.0854 2 +
19 1.0916 0 +
Continuum levels were assumed above 1.126 MeV
Level density parameters were evaluated using D-obs and
excited level data/2,6/.
a(1/MeV) T(MeV) Ex(MeV) Sig**2(0)
92-U-234 29.349 0.4058 4.769 16.872
92-U-235 31.415 0.3914 4.231 14.378
The gamma-ray strength function (=84.6E-4) was determined
by normalizing the capture cross section to 0.46535 b at 50
keV which was calculated from above-mentioned unresolved
resonance parameters.
The direct and semi-direct capture cross section was
calculated with DSD code /11/, and added to the CASTHY
calculation.
MT=16,17 (n,2n) and (n,3n)
JENDL-2 data calculated with the evaporation model were
renormalized so that they might be consistent with the
fission and compound formation cross sections calculated
with ECIS and CASTHY.
MT=18 Fission
Experimental data /12,13,14/ of fission cross section ratio
to U-235 were evaluated. Fission cross section was
obtained by multiplying the U-235 fission cross section/15/
to the ratio.
MF=4 Angular Distributions of Secondary Neutrons
MT=2,51-69,91 Calculated with ECIS and CASTHY
MT=16,17,18 Assumed to be isotropic in the lab. system.
MF=5 Energy Distributions of Secondary Neutrons
MT=16,17,91 Table type data were given
Spectra were calculated with preequilibrium and multi-
step evaporation model code PEGASUS /16/
Interpolation of 22 was adopted.
MT=18
Calculated with the formula of Madland and Nix /17/.
Constant compound nucleus formation cross section model
was adopted.
Total average FF kinetic energy = 171.09 MeV
Average energy release = 187.976 MeV
Average mass number of light FF = 95
Average mass number of heavy FF = 140
Level density parameter = A/10.0
MT=455
Taken from Brady and England /2/.
References
1) Tuttle R.J.: INDC(NDS)-107/G+Special, p.29 (1979).
2) Brady M.C. and England T.R.: Nucl. Sci. Eng., 103, 129(1989).
3) Mather D.S. et al.: Nucl. Phys., 66, 149 (1965).
4) James G.D. et al: Phy. Rev., C15, 2083 (1977).
5) Mughabghab S.F.:"Neutron cross sections, Vol 1, Part B",
Academic Press (1984).
6) Wagemans C. et al.: Nucl. Sci. Eng., 132, 308 (1999).
7) Raynal J.: IAEA SMR-9/8 (1970).
8) Igarasi S. and Fukahori T.: JAERI 1321 (1991).
9) Lagrange C.H.: NEANDC(E)-228 (1982).
10) Ellis-Akovali Y.A.: Nucl. Data Sheets, 40, 567 (1983). and
ENSDF as is 1993.
11) Kawano T.: Private communication (1999).
12) Behrens J.W. and Carlson G.W.: Nucl. Sci. Eng., 63, 2501977).
13) Meadows J.W.: Nucl. Sci. Eng., 65, 171 (1978).
14) Kanda K. et al.: 1985 Santa Fe, 1, 569 (1986).
15) Matsunobu H.: JENDL-3 U-235 evaluation (1987).
16) Nakagawa T., Iijima S. et al.: JAERI-Data/Code 99-031 (1999).
17) Madland D.G. and Nix J.R.: Nucl. Sci. Eng., 81, 213 (1982).