92-U -236

 92-U -236 NAIG       EVAL-MAR88 T.YOSHIDA                        
                      DIST-SEP89 REV2-DEC93                       
----JENDL-3.2         MATERIAL 9231                               
-----INCIDENT NEUTRON DATA                                        
------ENDF-6 FORMAT                                               
HISTORY                                                           
79-03 NEW EVALUATION FOR JENDL-2 WAS MADE BY T.YOSHIDA(NAIG).     
86-12 JENDL-2 DATA WERE CRITICALLY REVIEWED.                      
88-03 JENDL-2 DATA WERE REVISED TO MAKE JENDL-3 ON THE BASIS      
      OF THE 86-12 REVIEW.  NEW RUSSIAN MEASUREMENTS (1982- 1986) 
      WERE FULLY ADOPTED, RESULTANTLY LEADING TO A NEARLY 30      
      PER-CENT REDUCTION OF CAPTURE CROSS-SECTION ABOVE 1.5 KEV.  
      SUB-THRESHOLD FISSION CURVE WAS INTRODUCED BETWEEN 1.5 KEV  
      AND 700 KEV.  UNKNOWN GAMMA-F WAS ASSUMED TO BE 0.354       
      MILLI-EV.                                                   
  DATA WERE COMPILED BY T.NAKAGAWA (JAERI).                       
90-07 FP YIELD DATA WERE MODIFIED.                                
90-10 MF=5, MT=16,17,91: SPECTRA AT THRESHOLD ENERGIES WERE       
      MODIFIED.                                                   
93-12 JENDL-3.2.                                                  
      MODIFIED BY T.NAKAGAWA (NDC/JAERI)                          
                                                                  
     *****   MODIFIED PARTS FOR JENDL-3.2   ********************  
      (1,452), (1,455), (1,456)                                   
     ***********************************************************  
                                                                  
                                                                  
MF=1  GENERAL INFORMATION                                         
  MT=451  DESCRIPTIVE DATA AND DICTIONARY                         
  MT=452  NUMBER OF NEUTRONS PER FISSION                          
     SUM OF MT'S 455 AND 456.                                     
  MT=455  DELAYED NEUTRONS PER FISSION                            
     SIX GROUP DECAY CONSTANTS WERE ADOPTED FROM BRADY ET AL./1/  
     NU-D BELOW 6 MEV WAS ADOPTED FROM GUDKOV ET AL./2/, AND THAT 
     ABOVE 7 MEV FROM BOBKOV ET AL./3/, RESPECTIVELY.             
  MT=456  PROMPT NEUTRONS PER FISSION                             
     TAKEN FROM MALINOVSKII'S PAPER /4/.  ABOVE 5.9 MEV, THEIR    
     RECOMMENDATION WAS EXTRAPOLATED.                             
                                                                  
MF=2 MT=151 RESONANCE PARAMETERS                                  
  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 /5/       
     GAM-N (FOR GAM-N SMALLER THAN 0.1*GAM-G) : MEWISSEN /6/      
     GAM-G : MEWISSEN /6/, WHEN NOT GIVEN, MEAN VALUE WAS TAKEN.  
     GAM-F : THEOBALD /7/.                                        
        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.                                      
  UNRESOLVED RESONANCES : 1.5 KEV TO 40 KEV                       
     PARAMETERS WERE DETERMINED TO REPRODUCE TOTAL AND CAPTURE    
     CROSS SECTIONS CALCULATED WITH CASTHY AND EVALUATED FISSION  
     CROSS SECTION. OBTAINED PARAMETERS ARE:                      
        S0 = 0.906E-4, S1 = ENERGY DEPENDENT (1.8E-4 - 2.7E-4)    
        GAM-G = 0.023 EV, GAM-F = ENERGY DEPENDENT                
        R = 9.36 FM, D-OBS = ENERGY DEPENDENT (14.66 - 13.57 EV)  
                                                                  
     CALCULATED 2200-M/S CROSS SECTIONS AND RES. INTEGRALS        
                     2200-M/SEC      RES. INTEG.                  
         TOTAL       13.69   B          -                         
         ELASTIC      8.337  B          -                         
         FISSION      0.0613 B         7.77 B                     
         CAPTURE      5.295  B       346.   B                     
                                                                  
MF=3  NEUTRON CROSS SECTIONS                                      
  BELOW 1.5 KEV, ALL BACKGROUND CROSS SECTIONS ARE ZERO.          
  ABOVE 1.5 KEV, DATA WERE EVALUATED AS FOLLOWS. IN THE ENERGY    
  RANGE FROM 1.5 TO 40 KEV, UNRESOLVED RESONANCE PARAMETERS WERE  
  EVALUATED AND BACKGROUND CROSS SECTION WAS GIVEN TO ELASTIC     
  SCATTERING.                                                     
                                                                  
  MT=1,2,4,51-79,91,102,251  SIG-T,SIG-EL,SIG-IN,SIG-C,MU-BAR     
     COUPLED CHANNEL AND STATISTICAL MODEL CALCULATIONS WERE MADE 
     WITH ECIS /8/ AND CASTHY CODES /9/, RESPECTIVELY.            
     THE DEFORMED OPTICAL POTENTIAL PARAMETERS AFTER HAOUAT AND   
     LAGRANGE /10/:                                               
        VR =49.8 - 16*SY - 0.3*EN                   (MEV),        
        WS = 5.3 -  8*SY + 0.4*EN  (EN .LT. 10 MEV) (MEV),        
           = 9.3 -  8*SY           (EN .GE. 10 MEV) (MEV),        
        VSO= 6.2                                    (MEV),        
             WHERE SY=(N-Z)/A                                     
        R=1.26, RS=1.26, RSO=1.12                   (FM),         
        A=0.63, AS=0.52, ASO=0.47                   (FM).         
     THE SPHERICAL OPTICAL POTENTIAL PARAMETERS FOR THE STATISTI- 
     CAL MODEL CALCULATION WITH CASTHY:                           
        VR =40.8 - 0.05*EN,                       (MEV),          
        WS = 6.5 + 0.15*EN                        (MEV),          
        VSO= 7.0                                  (MEV),          
        R=1.32, RS=1.38, RSO=1.32                  (FM),          
        A=0.47, AS=0.47, ASO=0.47                  (FM).          
     COMPETING PROCESSES : FISSION, (N,2N) AND (N,3N)             
     LEVEL FLUCTUATION WAS CONSIDERED. THE GAMMA-RAY STRENGTH     
     FUNCTION WAS DETERMINED SO THAT THE CALCULATED CAPTURE CROSS 
     SECTION REPRODUCED THE MEASURED VALUE OF 0.85 BARNS /11/     
     AROUND 10 KEV.                                               
     THE LEVEL SCHEME TAKEN FROM REF. /12/.                       
        NO. ENERGY(MEV)  J-PARITY   NO. ENERGY(MEV)  J-PARITY     
        GS   0.0          0 +        1   0.04524      2 +         
         2   0.14948      4 +        3   0.30979      6 +         
         4   0.52225      8 +        5   0.68757      1 -         
         6   0.7442       3 -        7   0.7828      10 +         
         8   0.8476       5 -        9   0.91916      0 +         
        10   0.9581       2 +       11   0.9604       2 +         
        12   0.9670       1 -       13   0.9880       2 -         
        14   1.0014       3 +       15   1.0020       7 -         
        16   1.0356       3 -       17   1.0512       4 +         
        18   1.0529       4 -       19   1.0587       4 +         
        20   1.0661       3 +       21   1.0700       4 -         
        22   1.0862      12 +       23   1.0938       2 +         
        24   1.1044       5 -       25   1.1110       2 -         
        26   1.1267       5 +       27   1.1470       3 +         
        28   1.1494       3 -       29   1.1640       6 -         
        CONTINUUM LEVELS ASSUMED ABOVE 1.17 MEV.                  
     THE GROUND STATE, 1-ST AND 2-ND EXCITED LEVELS WERE COUPLED  
     IN THE ECIS CALCULATION.                                     
                                                                  
  MT=16,17  (N,2N) AND (N,3N)                                     
     CALCULATED WITH THE PEGASUS CODE /13/.                       
  MT=18   FISSION                                                 
     EVALUATED ON THE BASIS OF MEASURED DATA OF U-236/U-235       
     /14,15/.  TO GET ABSOLUTE VALUE MATSUNOBU'S EVALUATION /16/  
     FOR U-235(N,F) WAS EMPLOYED.                                 
                                                                  
MF=4  ANGULAR DISTRIBUTIONS OF SECONDARY NEUTRONS                 
  MT=2,51,52    CALCULATED WITH ECIS AND CASTHY                   
  MT=53-79,91   CALCULATED WITH CASTHY.                           
  MT=16,17,18   ISOTROPIC DISTRIBUTION IN THE LAB. SYSTEM.        
                                                                  
MF=5  ENERGY DISTRIBUTIONS OF SECONDARY NEUTRONS                  
  MT=16,17,91   CALCULATED WITH PEGASUS.                          
  MT=18         MAXWELLIAN FISSION SPECTRUM.  TEMPERATURE WAS     
                ESTIMATED FROM Z**2/A VALUES /17/.                
                                                                  
REFERENCES                                                        
 1) M.C. BRADY AND T.R. ENGLAND: NUCL. SCI. ENG., 103 (1989) 129. 
 2) A.N. GUDKOV ET AL.: ATOMNAYA ENERGIYA, 66 (1989) 100.         
 3) E.YU. BOBKOV ET AL.: ATOMNAYA ENERGIYA, 67 (1989) 408.        
 4) V.V. MALINOVSKII ET AL.: ATOMNAYA ENERGIYA, 53 (1982) 83.     
 5) G. CARRARO, ET AL.: NUCL. PHYS., A275 (1976) 333.             
 6) L. MEWISSEN, ET AL.: 1975 WASHINGTON, 729 (1975).             
 7) J.P. THEOBALD: NUCL. PHYS.,181 (1972) 637.                    
 8) J. RAYNAL: IAEA SMR-9/8 (1970).                               
 9) S. IGARASI AND T. FUKAHORI: JAERI 1321(1991).                 
10) CITED BY P.G. YOUNG IN PROC. SPECIALISTS' MTG ON USE OF       
    OPTICAL MODEL, PARIS, NEANDC - 222 U (1986)                   
11) A.A. BERGMAN: ATOMNAYA ENERGIYA, 52 (1982) 409.               
    O.T. GRUDZEVICH ET AL.: IAEA INDC(CCP)-220/L (1984)           
    A.N. GUDKOV:  ATOMNAYA ENERGIYA, 61 (1986) 379                
12) M.R. SCHMORAK: NUCL. DATA SHEETS, 20 (1977) 192.              
13) S. IIJIMA ET AL.: JAERI-M 87-025, 337 (1987).                 
14) J.W. BEHRENS AND C.W. CARLSON: NUCL. SCI. ENG., 63 (1977) 250.
15) J.W. MEADOWS: NUCL. SCI. ENG., 65 (1978) 171.                 
16) H. MATSUNOBU: EVALUATION FOR JENDL-3 (MAT=3924).              
17) A.B. SMITH ET AL.: ANL/NDM-50 (1979).