94-Pu-240
94-Pu-240 AITEL+ Eval-Feb00 T.Murata, T.Kawano, T.Nakagawa
DIST-MAR02 REV4-FEB02 20020214
----JENDL-3.3 MATERIAL 9440
-----INCIDENT NEUTRON DATA
------ENDF-6 FORMAT
HISTORY
87-05 Evaluation was made by
T.Murata (NAIG) : Cross sections above resonance region
and other quantities,
A.Zukeran(Hitachi): Resonance parameters.
88-06 MT's=16, 17, 37 and 102 were modified.
89-02 FP yields were taken from JNDC FP Decay File version-2.
Compilation was made by T. Nakagawa (JAERI).
90-07 FP yield data were modified.
90-10 MF=5, MT=16, 17, 91: modified at threshold energies.
93-08 JENDL-3.2.
Compiled by T.Nakagawa (NDC/JAERI)
01-12 JENDL-3.3. Evaluation was made by T. Murata (AITEL),
T.Kawano(Kyushu Univ.) and T.Nakagawa (NDC/JAERI) and
compiled by T.Nakagawa (NDC/JAERI).
***** Modified parts from JENDL-3.2 *******************
(2,151) Both of resolved and unresolved resonance params.
(3,2), (3,4), (3,16), (3,17), (3,18), (3,37), (3,51-91),
(3,102)
(4,51-53), (4,55-57)
(5,16), (5,17), (5,91), (5,455)
*******************************************************
02-01 Covariances were added by K. Shibata.
Most of the covariances were taken from JENDL-3.2 covariance
file except for MF/MT=32/151, 33/16, 33/17, 33/18, and
33/102.
MF=1 General Information
MT=451 Comments and dictionary
* The data for MT=452, 455 and 456 were adopted from JENDL-3.2.
MT=452 Number of neutrons per fission
Sum of MT=455(delayed neutrons) and MT=456(prompt neutrons).
MT=455 Delayed neutron data
Below 5 MeV, nu-d of 0.00911 measured by Benedetti et al.
/1/ was adopted. Above 6 MeV, 0.0067 was given on the
basis of Tuttle's systematics /2/. Decay constants were
taken from evaluation by Bardy and England /3/.
MT=456 Number of prompt neutrons
Linear least-squares fitting to the experimental data of
Frehaut et al. /4/ renormalized to Cf-252 Nu-p=3.756.
MF=2 Resonance Parameters
MT=151 Resolved and unresolved resonance parameters
1) Resolved resonances (1.0E-05 to 2.7keV)
Reich-Moore type resonance parameters given by Bouland et
al./5/ were adopted in the incident neutron energy of
1.0E-05 eV to 2.7 keV. Capture widths of -3 and 1.056-eV
levels were slightly modified so as to reproduce the thermal
capture cross section better.
* Bouland et al. analyzed the resonance parameters up to 5.7 keV.
However, the upper boundary of 2.7 keV was adopted for JENDL-
3.3, because the capture cross section was too small above this
energy.
2) Unresolved resonances (2.7 to 40 keV)
Energy dependent parameters up to d-wave resonance were
determined to reproduce evaluated cross sections based on
the data of Weston and Todd /6/ in the energy region of 2.7
to 40 keV. The parameters ofJENDL-3.2 were revised to
reproduce all cross sections without background cross
sections. To connect smoothly to the cross sections in the
resolved resonance region, elastic and capture cross sections
in the region below 100keV, and fission cross section in the
connection region were revised.
3) Thermal Cross Sections and Resonance Integrals
Calculated 2200-m/sec cross sections and resonance integrals
are given in the following Table.
2200-m/sec RES. INTEG.
TOTAL 291.9 b
ELASTIC 2.66 b -
FISSION 0.059 b 9.78 b
CAPTURE 289.1 b 8510 b
MF=3 Neutron Cross Sections
Above 2.7 keV: Evaluated as follows. In the energy range
from 2.7 to 40 keV, the cross sections are represented with
the unresolved resonance parameters.
MT=1 Total
Below 100keV, sum of partial cross sections.
Above 100keV, evaluated cross section of JENDL-3.2 was
adopted.
* comment of JENDL-3.3 for MT=1
Evaluated with spline fitting to the experimental data of
Smith et al./7/, Kaeppeler et al./8/ and Poenitz et
al./9/
MT=2 Elastic scattering
Below 100keV, to connect smoothly to the unresolved resonance
region cross section which were calculated using the s-wave
strength function determined consistently with the resolved
resonance parameters. Above 100keV,obtained by subtracting
the other cross sections from total cross section.
MT=4 Total inelastic scattering
Sum of partial inelastic scattering cross sections (MT=51 to
MT=91).
MT=51-77, 91 Partial inelastic scattering
The results of ECIS-88 calculation with the parameters of
Lagrange et al. /10/ and the Pu-240 level scheme/11/ given in
the following Table were modified to include the competition
with the fission, capture, (n,2n), (n,3n) and (n,4n)
reactions. The cross section shape of final continuum (n,n')
of JENDL-3.2 was also revised in the higher energy region.
LEVEL SCHEME
NO. Energy(MeV) Spin-Parity Coupling
G.S. 0.0 0 + yes
1 0.04282 2 + yes
2 0.14168 4 + yes
3 0.2943 6 + yes
4 0.4975 8 + no
5 0.5974 1 - yes
6 0.6489 3 - yes
7 0.7423 5 - yes
8 0.8607 0 + no
9 0.9003 2 + no
10 0.9381 1 - no
11 0.9589 2 - no
12 0.9922 4 + no
13 1.0019 3 - no
14 1.0305 3 + no
15 1.0375 4 - no
16 1.0762 4 + no
17 1.0895 0 + no
18 1.1156 5 - no
19 1.1320 2 + no
20 1.1370 2 + no
21 1.1615 6 - no
22 1.1775 3 + no
23 1.2325 4 + no
24 1.2408 2 - no
25 1.2820 3 - no
26 1.3087 5 - no
27 1.4108 0 - no
Levels above 1.4200 MeV were assumed to be continuum.
MT=16,17,37 (n,2n),(n,3n) and (n,4n)
Calculated from neutron emission cross section and branching
ratios of these reaction channels. The neutron emission cross
section was obtained by subtracting the fission and capture
cross sections from compound nucleus formation cross section
calculated with ECIS-88 code. The branching ratios were
obtained from the consistent calculation made by Konshin/12/.
MT=18 FISSION
Below 130 keV: Taken from JENDL-3.2
Above 130 keV: Results of recent simultaneous evaluation of
fission cross sections /13/ were adopted.
* comment of JENDL-3.2 for MT=18
Below 100 keV: Average values of fission cross section
measured by Weston and Todd /14/ were normalized to the
value at 100 keV of the simultaneous evaluation.
Above 100 keV: Simultaneous evaluation was made by taking
account of experimental data of fission ratio and absolute
cross sections of U-235, U-238, Pu-239, Pu-240 and Pu-241,
and capture cross section of Au-197 /15/.
MT=102 CAPTURE
Below 80 keV: Based on the experimental data of Weston and
Todd/6/, however, rather smaller values than that of
JENDL-3.2 was adopted considering the suggestion of Bouland et
al./5/. Above 80keV: Taken from JENDL-3.2.
* comment of JENDL-3.2 for MT=102
Below 350 keV: Based on the experimental data of Hockenbury et
al. /16/, Weston and Todd /17/ and the ratio data of
Wisshak and Kaeppeler /18/ with the capture cross section
of Au-197 /15/. As a guide line, statistical model
calculation was made with CASTHY code /19/.
Above 350 keV: The statistical model calculation was
normalized to the value at 350 keV. Direct and collective
capture was included in high energy region adopting the
value for U-238 given by Kitazawa et al. /20/.
The spherical optical potential parameters
V = 40.6 - 0.05*En, Ws = 6.5 + 0.15*En (MeV)
Vso= 7.0 (MeV)
r = rso =1.32 , rs = 1.38 (fm)
a = as = aso =0.47 (fm)
Level density parameters were determined to reproduce the
resonance level spacings and staircases of discrete levels.
MF=4 Angular Distributions of Secondary Neutrons
MT=51-53, 55-57
For the coupled levels, ECIS-88 calculation results adopted.
* For other levels, taken from JENDL-3.2.
MT=2
Taken from JENDL-1 /21/.
MT=16,17,18,37,91
Assumed to be isotropic in the laboratory system.
MT=51-78 except 51-53 and 55-57
For the 1st and 2nd levels, results of Lagrange et al. /22/
were adopted. For others, statistical and DWBA calculations
were made.
MF=5 Energy Distributions of Secondary Neutrons
MT=16,17,91
Calculated with pre-compound and multi-step evaporation
theory code EGNASH /23,24/.
MT=455 Delayed neutron spectra
Summation calculation made by Brady and England /3/ was
adopted.
* The data of JENDL-3.2 were adopted for MT's=18 and 37.
MT=37
Evaporation spectrum was given.
MT=18 Fission spectra
Calculated from Madland-Nix formula /25/.
Average energy release = 199.179 MeV
Total average FF kinetic energy = 177.53 MeV
Average mass number of light FF = 101
Average mass number of heavy FF = 140
Level density parameter = A/10.0
MF=31 Covariances of Average Number of Neutrons per Fission
MT=456
Based on experimental data. /4,26/
MF=32 Covariances of Resonance Paremeters
MT=151
Resolved resonance
Based on experimenta data./5/
Unresolved resonance
The covariances were obtained by using kalman./27/
MF=33 Covariances of Cross Sections (ref.27)
MT=1
Based on experimental data. A chi-value was 0.91.
MT=2
Constructed from MT=1, 4, 16, 17, 18, 37, and 102.
MT=4, 51-78, 91
The covariances were obtained by using kalman /27/.
A chi-value was 1.485.
MT=16
Uncertainties in model calculations./12/
MT=17
Uncertainties in model calculations./12/
MT=18
Based on simultaneous evaluation /13/.
MT=37
Systematics.
MT=102
The covariances were obtained by using kalman /27/.
A chi-value was 0.79.
MF=34 Covariances of Angular Distributions (ref.27)
MT=2
The covariances of p1 coefficients were obtained by using
kalman. A chi-value was 0.50.
MF=35 Covariances of Energy Distributions
MT=18
The covariances were obtained by using kalman./28/
Assumed to be the same as those for U-238.
References
1) Benedetti G. et al.: Nucl. Sci. Eng., 80, 379 (1982).
2) Tuttle R.J.: INDC(NDS)-107/G-special, p.29 (1979).
3) Brady M.C. and England T.R.: Nucl. Sci. Eng., 103, 129(1989).
4) Frehaut J., et al.: CEA(R) 4626 (1974).
5) Bouland O. et al.: Nucl. Sci. Eng., 127, 105 (1997).
6) Weston L.W. and Todd J.H.: Nucl. Sci. Eng., 63, 143 (1977).
7) Smith A.B. et al.: Nucl. Sci. Eng., 47, 19 (1972).
8) Kaeppler F. et al.: Proc. of Meeting on Nuclear Data of
Higher Pu and Am Isotopes for Reactor Application, held at
BNL, p.49 (1978)
9) Poenitz W.P. et al.; Nucl. Sci. Eng., 78, 333 (1981), and
ANL/NDM-80 (1983).
10) Lagrange CH. and Jary J.: NEANDC(E) 198"L" (1978).
11) Shurshikov E.N. and Timofeeva,N.V.:Nucl. Data Sheets, 59,
947 (1990).
12) Konshin V.A.: JAERI-Research 95-010 (1995).
13) Kawano T. et al.: JAERI-Research 2000-004 (2000).
14) Weston L.W. and Todd J.H.: Nucl. Sci. Eng., 88, 567 (1984).
15) Kanda Y. et al.: 1985 Santa Fe, 2, 1567 (1986).
16) Hockenbury R.W. et al.: Nucl. Sci. Eng., 49, 153 (1972).
17) Weston L.W. and Todd J.H.: Nucl. Sci. Eng.,63, 143 (1977).
18) Wisshak K. and Kaeppeler F.: Nucl. Sci. Eng., 66, 363 (1978)
and Nucl. Sci. Eng., 69, 39 (1979).
19) Igarasi S. and Fukahori T.: JAERI 1321 (1991).
20) Kitazawa H. et al.: Nucl. Phys., A307, 1 (1978).
21) Igarasi S. et al.: JAERI 1261 (1979).
22) Lagrange Ch. and Jary J.: NEANDC(E) 198"L" (1978).
23) Yamamuro N.: JAERI-M 90-006 (1990).
24) Young P.G. and Arthur E.D.: LA-6947 (1977).
25) Madland D.G. and Nix J.R.: Nucl. Sci. Eng., 81, 213 (1982).
26) Vorob'jova V.G. et al.: AE,32,83,1972
27) Shibata K. et al.: JAERI-Research 98-045 (1998).
28) Kawano T. et al.: JAERI-Research 99-009 (1999).[in Japanese]