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9.223400+4 2.320300+2 1 1 2 2
0.000000+0 1.000000+0 0 0 0 6
1.000000+0 2.000000+7 0 0 10 31
0.000000+0 0.000000+0 0 0 271 1
92-U -234 MINSK+ EVAL-SEP02 V.M. Maslov et al.
DIST-MAY05 REV1-MAY05 20050504
----JEFF-31 MATERIAL 9225
-----INCIDENT NEUTRON DATA
------ENDF-6 FORMAT
***************************** JEFF-3.1 *************************
Original data taken from: New evaluation
MT=458(ENERGY RELEASE IN FISSION) evaluation from ENDF/B-V
05-01 NEA/OECD (Rugama) 8 delayed neutron groups
Jefdoc-976 (Wilson and England, Prog Nucl Eng 41,71(2002)
******************************************************************
----B-404-ISTC MATERIAL 9225
-----INCIDENT NEUTRON DATA
-----ENDF/B-VI FORMAT
*****************************************************************
UNRESOLVED RESONANCE PARAMETERS FOR 1.5-140 KEV REGION,
TOTAL, ELASTIC SCATTERING, INELASTIC SCATTERING, FISSION,
CAPTURE,(N,2N) AND (N,3N) CROSS SECTIONS AS WELL AS
ANGULAR AND ENERGY DISTRIBUTIONS OF SECONDARY AND PROMPT
FISSION NEUTRONS WERE EVALUATED BY
V.M. MASLOV, Yu.V. PORODZINSKIJ, N.A. TETEREVA,
M. BABA, A. HASEGAWA,
N.V. KORNILOV, A.B. KAGALENKO /1/.
MF=1 GENERAL INFORMATION
MT=451 DESCRIPTIVE DATA AND DICTIONARY
MT=452 NUMBER OF NEUTRONS AND DICTIONARY
SUM OF MT=455 and 456.
MT=455 DELAYED NEUTRONS PER FISSION
ARE DEFINED USING SYSTEMATICS BY TUTTLE/2/. SIX GROUP
DECAY CONSTANTS WERE ADOPTED FROM BRADY ET AL./3/
MT=456 PROMPT NEUTRONS NUMBER
ESTIMATED WITH SYSTEMATICS /4/, WHICH WAS NORMALIZED IN
THE ENERGY RANGE 2.5-4 MeV TO MEASURED DATA BY MATHER ET
AL./5/. NU-BAR OF Cf-252 SPONTANEOUS FISSION WAS ASSUMED
TO BE 3.756. FOR INCIDENT NEUTRON ENERGIES HIGHER THAN
(N,NF) REACTION THRESHOLD, NU-BAR WAS CALCULATED TAKING
INTO ACCOUNT PARTIAL CONTRIBUTIONS OF (N,XNF) REACTIONS
/1/.
MF=2 RESONANCE PARAMETERS
MT=151 RESOLVED AND UNRESOLVED RESONANCE PARAMETERS
(RESOLVED RESONANCE REGION = 1.0E-5 EV TO 1.5 KEV),
(UNRESOLVED RESONANCE REGION = 1.5 KEV TO 140 KEV)
RESOLVED MLBW RESONANCE PARAMETERS RECOMMENDED IN
JENDL-3.2 WERE ADOPTED. THESE ARE RESONANCE PARAMETERS BY
JAMES ET AL./6/, MODIFIED ASSUMING AVERAGE RADIATION
WIDTH OF 0.026 EV. FISSION WIDTH OF NEGATIVE 2.06-eV RESO-
NANCE WAS VARIED TO FIT THERMAL FISSION CROSS SECTION
VALUE BY WAGEMANS ET AL./7/
ENERGY-DEPENDENT UNRESOLVED RESONANCE PARAMETERS COVER
ENERGY RANGE FROM 1.5 TO 140 KEV. PARAMETERS WERE
OBTAINED TO REPRODUCE SMOOTH TOTAL AND CAPTURE CROSS
SECTIONS, CALCULATED WITH STATISTICAL MODEL. CAPTURE
CROSS SECTION DATA BY MURADYAN ET AL. /8/ IN THE ENERGY
RANGE OF 0.03 - 2 KeV ARE DESCRIBED.
ENDF/B PROCESSING CODES /9,10/ IGNORE DIRECT INELASTIC
SCATTERING CONTRIBUTION. TO COMPENSATE THAT DEFICIENCY WE
INCREASED AVERAGE INELASTIC SCATTERING WIDTHS, CAPTURE
WIDTHS ABOVE 50 KEV ALSO WAS SLIGHTLY INCREASED TO KEEP
CAPTURE CROSS SECTION UNDISTORTED AS COMPARED WITH
CALCULATED BY PHYSICALLY CORRECT (PC) CODES. AS A RESULT,
TOTAL,ELASTIC SCATTERING AND CAPTURE CROSS SECTIONS,
CALCULATED WITH THESE PCC CODES,ARE REPRODUCED WITH
CONVENTIONAL ENDF PROCESSING CODES USING AVERAGE RESONANCE
PARAMETERS GIVEN MF=2 MT=151.
2200-M/S CROSS SECTIONS AND CALCULATED RESONANCE INTEGRALS.
2200 M/S(B) RES. INTEG.(B)
TOTAL 119.23
ELASTIC 19.416
FISSION 67.96 6.637
CAPTURE 99.75 631.980
MF=3 NEUTRON CROSS SECTIONS
FROM 1.5 KEV UP TO 140 KEV EVALUATED CROSS SECTIONS WERE
REPRESENTED WITH THE UNRESOLVED RESONANCE PARAMETERS.
MT= 1, 2, 4, 51-86, 91 - TOTAL, ELASTIC AND INELASTIC
SCATTERING CROSS SECTIONS.
TOTAL, ELASTIC AND DIRECT INELASTIC FOR ROTATIONAL GROUND
STATE BAND LEVELS MT=51,52,53,54 (COUPLED LEVELS)
AS WELL AS OPTICAL TRANSMISSION COEFFICIENTS ARE OBTAINED
IN A RIGID ROTATOR MODEL COUPLED CHANNELS CALCULATIONS.
DIRECT EXCITATION OF GAMMA- AND BETA-VIBRATIONAL, OCTUPOLE
AND K=2+ QUADRUPOLE BAND LEVELS,MT=56-65,67-73,75,76,78,
80,83,85,86 ARE OBTAINED IN A SOFT ROTATOR MODEL COUPLED
CHANNEL CALCULATIONS, FOR NORMALIZATION PURPOSES THESE
DIRECT INELASTIC CROSS SECTIONS WERE SUBTRACTED FROM MT=2
ELASTIC SCATTERING CROSS SECTION. DIRECT INELASTIC
CONTRIBUTIONS WERE ADDED INCOHERENTLY TO HAUSER-FESHBACH
CALCULATIONS OF COMPOUND NUCLEUS INELASTIC SCATTERING
CROSS SECTIONS.
THE DEFORMED OPTICAL POTENTIAL ADOPTED WAS THAT FOR 232Th,
THEN EVALUATED VALUE OF S-WAVE STRENGTH FUBCTION
S0= 0.95x10-4(EV)-1/2 WAS FITTED:
VR=(45.722-0.334xE) MEV; RR =1.2668 FM; AR =.6468 FM;
WD=(3.145+0.455xE)MEV; E< 8 MEV RD =1.25 FM;
WD= 6.785 MEV; E>= 8 MEV AD =.5246 FM;
VSO= 6.2 MEV; RS0=1.12 FM; ASO=.47 FM;
B2= .190; B4=.072;
FISSION, CAPTURE AND COMPOUND INELASTIC SCATTERING CROSS
SECTIONS WERE CALCULATED WITH HAUSER-FESHBACH-MOLDAUER/11/
APPROACH, AT INCIDENT NEUTRON ENERGIES HIGHER THAN 1.3 MEV
(LEVEL OVERLAPPING ENERGY) TEPEL ET AL./12/ THEORY WAS
EMPLOYED.
ADOPTED LEVEL SCHEME OF U-234 FROM NUCLEAR DATA SHEETS /13/.
LEVEL SCHEME:
--------------------------------------------------------
NO. ENERGY(MEV) SPIN-PARITY K-PARITY*
--------------------------------------------------------
G.S. .000000+00 0+ 0+
.434980-01 2+ 0+
.143350-00 4+ 0+
.296070-00 6+ 0+
.497040+00 8+ 0+
.741200+00 10+ 0+
.786290+00 1- 0-
.809880+00 0+ 0+
.849300+00 3- 0-
.851700+00 2+ 0+
.926740+00 2+ 2+
.947850+00 4+ 0+
.962600+00 5- 0-
.968600+00 3+ 2+
.989450+00 2- 2-
.102370+01 4+ 2+
.102380+01 12+ 0+
.102383+01 3- 2-
.104450+01 0+ 0+
.106930+01 4- 2-
.108530+01 2+ 0+
.109090+01 5+ 2+
.109590+01 6+ 0+
.112520+01 7- 0-
.112670+01 2+
.112760+01 5- 2-
.115000+01 4+ 0+
.116520+01 3+
.117210+01 6+ 2+
.117420+01 1+
.119470+01 6- 2-
.121460+01 4+
.123720+01 1-
.126180+01 7+ 2+
.127440+01 5+
.127750+01 7- 2-
.129260+01 8+ 0+
*) K-PARITY ARE SHOWN ONLY FOR THE LEVELS,
IDENTIFIED WITHIN RIGID AND SOFT ROTATOR MODELS
OVERLAPPING LEVELS ARE ASSUMED ABOVE 1.3 MEV
MT=16,17,37. (N,2N) AND (N,3N) CROSS SECTION FROM
STATISTICAL MODEL CALCULATIONS /1/ WITH ACCOUNT OF
PRE-EQUILIBRIUM NEUTRON EMISSION (MODIFIED STAPRE CODE/14/
WAS USED). PRE-EQUILIBRIUM NEUTRON EMISSION CONTRIBUTION WAS
FIXED ACCORDING TO CONSISTENT DESCRIPTION OF(N,F) AND (N,XN)
REACTION DATA FOR 238U AND 232Th TARGET NUCLIDES.
MT=18, 19, 20, 21,38. FISSION CROSS SECTION IS CALCULATED
WITHIN STATISTICAL MODEL /1/. MEASURED FISSION DATA /15-28/
ANALYSIS WAS ACCOMPLISHED. THE CONTRIBUTION OF EMISSIVE
(N,NF) AND (N,2NF) FISSION TO THE TOTAL FISSION CROSS SECTION
WAS ESTIMATED USING FISSION BARRIER PARAMETERS OF 234-U AND
233-U, WHICH FIT 233-U(N,F) AND 232-U(N,F) CROSS SECTION
DATA.
MT=102 CAPTURE
CAPTURE CROSS SECTION IS CALCULATED WITHIN A STATISTICAL MO-
DEL. ABOVE NEUTRON ENERGY 5 MEV CAPTURE IS ASSUMED TO BE
CONSTANT. COMPETITION OF (N,GF) AND (N,GN') REACTIONS IS
TAKEN INTO ACCOUNT. ADOPTED ESTIMATE OF RADIATION CAPTURE
CROSS SECTION IS CONSISTENT WITH CAPTURE CROSS SECTION DATA
BY MURADYAN ET AL. /8/ IN THE ENERGY RANGE OF 0.03 - 2 KeV.
MF=4 ANGULAR DISTRIBUTIONS OF SECONDARY NEUTRONS
FOR MT=2,51,52,53 AND 54 FROM COUPLED CHANNEL CALCULATIONS
(RIGID ROTATOR MODEL),
FOR MT=56-65,67-73,75,76,78,80,83,85,86 FROM COUPLED CHANNEL
MODEL (SOFT ROTATOR MODEL) WITH ADDED ISOTROPIC STATISTICAL
CONTRIBUTION.
MT=16, 17, 18-21, 38, 66,74,77,79,81,82,84 AND 91 ARE ISOTROPIC
IN THE LAB SYSTEM.
MF=5 ENERGY DISTRIBUTIONS OF SECONDARY NEUTRONS
ENERGY DISTRIBUTIONS FOR MT=16,17,91 WERE CALCULATED WITH
A HAUSER-FESHBACH STATISTICAL MODEL OF CASCADE NEUTRON
EMISSION TAKING INTO ACCOUNT THE HISTORY OF THE DECAY WITH
THE ALLOWANCE OF PREEQUILIBRIUM EMISSION OF THE FIRST
NEUTRON, SIMULTANEOUSLY WITH (N,F) AND (N,XNF) REACTION CROSS
SECTIONS.
MT=18,19,20,21,38
PROMPT FISSION NEUTRON SPECTRA (PFNS)WERE CALCULATED WITH THE
SEMI-EMPIRICAL MODEL/1/, PRE-FISSION NEUTRON EMISSION IN
(N,XNF) REACTION, EITHER EQUILIBRIUM AND PRE-EQUILIBRIUM
MODES ARE INCLUDED. SPECTRA OF PRE-FISSION (N,XNF) NEUTRONS
ARE CALCULATED WITH HAUSER-FESHBACH STATISTICAL MODEL.
BASICALLY PFNS FROM FISSION FRAGMENTS (FF) WERE CALCULATED AS
A SUPERPOSITION OF TWO WATT DISTRIBUTIONS FOR LIGHT AND HEAVY
FF WITH EQUAL CONTRIBUTIONS, BUT DIFFERENT TEMPERATURE
PARAMETERS. FF KINETIC ENERGY, ONE MORE MODEL PARAMETER,
MIGHT BE LOWER THAN TKE, WHICH REFLECTS IT'S DEPENDENS ON THE
MOMENT OF NEUTRON EMISSION. THIS EFFECTIVELY REDUCES AVERAGE
ENERGY OF PFNS FOR INCIDENT NEUTRON ENERGIES ABOVE EMISSIVE
FISSION THRESHOLD.
REFERENCES
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N., Kagalenko A., Tetereva N.A. JAERI-Research 01-0XX, 2002.
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