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NESC0482 COMNUC/CASCADE (Abstract last modified 21-MAY-1987)


COMNUC, Gamma Emission Neutron Emission Fission and Scattering Cross-Sections Using Hauser-Feshbach
CASCADE, Intranuclear Gamma Cascade Calculation for Particle Emission Probability

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Abstract Table of Contents:

NAME | COMPUTER | PROBLEM | SOLUTION | RESTRICTIONS | CPU | FEATURES | AUXILIARIES | STATUS | REFERENCES | REQUIREMENTS | LANGUAGE | OPERATING SYSTEM | OTHER RESTRICTIONS | AUTHOR | MATERIAL | CATEGORIES |

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1. NAME OR DESIGNATION OF PROGRAM - COMNUC/CASCADE 


2. COMPUTER FOR WHICH PROGRAM IS DESIGNED AND OTHER MACHINE VERSION PACKAGES AVAILABLE -

To request or retrieve programs click on the one of the active versions below. A password and special authorization is required.

Explanation of the status codes.

Program-name         Package-ID  Status
COMNUC-CASCADE       NESC0482/01 Obsolete
COMNUC-CASCADE       NESC0482/02 Tested

Machines used:
Package-ID     Orig.Computer                       Test Computer
NESC0482/02    IBM 370 series                      DEC VAX 11/780

3. DESCRIPTION OF PROBLEM OR FUNCTION - COMNUC   calculates   neutron 
reaction cross sections using a statistical model for decay of the 
compound nucleus.  Competing reaction types permitted are elastic, 
discrete  and continuum  inelastic, gamma  ray emission,  capture, 
fission, and n,2n. 
   CASCADE solves the  intranuclear gamma ray cascade  equation to 
determine  secondary particle  emission probabilities.   Competing 
processes considered are gamma ray  emission, neutron emission and 
fission. 


4. METHOD OF SOLUTION - In COMNUC Hauser-Feshbach  theory as modified 
by Moldauer is  used to determine competition in the  decay of the 
compound nucleus.  Physical models for  the various reaction types 
permit  the user  to input  parameters for  those models.   Direct 
reaction components  may be provided  by card input.   These cross 
sections  are  combined  with calculated  compound  nucleus  cross 
sections  to provide  a complete  self-consistent  set of  neutron 
cross sections at each incident neutron energy. 
   In CASCADE a coupled set of inhomogeneous Volterra equations of 
the  second   kind  describing  the   energy  dependence   of  the 
probability for  particle termination  of a  gamma ray  cascade is 
solved  numerically.   Branching  ratios   determined  from  these 
probabilities may be used as input to the COMNUC program. 


5. RESTRICTIONS ON THE COMPLEXITY OF THE PROBLEM - 
   COMNUC - Only reaction types listed  above may be analyzed, but 
other reactions such as n,p and n,alpha may be included easily. 
   CASCADE - Only  dipole radiation is permitted in  the gamma ray 
cascades.  No  discrete channels  are permitted  - only  continuum 
particle emission. 


6. TYPICAL RUNNING TIME - For low incident-neutron energies and few open channels COMNUC running time is about 15 seconds per case on an IBM360/65. Cases of the complexity of the sample cases can take as much as 1.5 minutes. Approximately 15 minutes are required on an IBM360/65 for a CASCADE case exercising all options and incident neutrons up to 5 MeV in energy.

NESC0482/02:

NEA-DB executed the test cases included in this package on a VAX-11/780 computer. The COMNUC test problem (U-238 and Pu-239) required 24 seconds; the CASCADE test problem (U-238) required 187 seconds of CPU time.


7. UNUSUAL FEATURES OF THE PROGRAM - 


8. RELATED AND AUXILIARY PROGRAMS - CASCADE   generates   gamma   ray 
cascade branching ratios for input to COMNUC.  Output from CASCADE 
can be used  as input for COMNUC when  calculating neutron capture 
cross sections. 


9. STATUS
NESC0482/01: 21-MAY-1987 Obsolete
NESC0482/02: 21-MAY-1987 Tested at NEADB


10. REFERENCES  - 
NESC0482/02:
- C.  L.  Dunford:  A Unified  Model  for  Analysis  of Compound
  Nucleus Reactions
  AI-AEC-12931, July 1970.
- C.  L. Dunford:  Compound  Nucleus Reaction  Analysis Programs
  COMNUC and CASCADE
  AI-TI-707-130-013, March 1971.


11. MACHINE REQUIREMENTS - 150K bytes 

NESC0482/02:

On VAX-11/780, the execution of the test problems required a peak working set size of 750 pages.


12. PROGRAMMING LANGUAGE(S) USED -
NESC0482/02: FORTRAN-IV 


13. OPERATING SYSTEM UNDER WHICH PROGRAM IS EXECUTED -  OS/360. 

NESC0482/02:

 VMS V4.4 (VAX-11/780). 


14. OTHER PROGRAMMING OR OPERATING INFORMATION OR RESTRICTIONS - 


15. NAME AND ESTABLISHMENT OF AUTHOR - 
   Author        C. L. Dunford 
   Contact       Alex Nickols, Code Coordinator 
                 Atomics International 
                 P. O. Box 309 
                 Canoga Park, California  91304 


16. MATERIAL AVAILABLE -
NESC0482/02:
NESC0482_02.001   Information File                                   82 records
NESC0482_02.002   COMNUC Source Program (FORTRAN)                  2245 records
NESC0482_02.003   COMNUC Sample Problem Input (U-238, Pu-239)       219 records
NESC0482_02.004   COMNUC Sample Problem Punched Output                6 records
NESC0482_02.005   COMNUC Sample Problem Printed Output              662 records
NESC0482_02.006   CASCADE Source Program (FORTRAN)                 1111 records
NESC0482_02.007   CASCADE Sample Problem Input (U-238)               29 records
NESC0482_02.008   CASCADE Sample Problem Punched Output              59 records
NESC0482_02.009   CASCADE Sample Problem Printed Output             389 records


17. CATEGORIES  - 

- A.  Cross Section and Resonance Integral Calculations


Keywords: CAPTURE, COMPOUND NUCLEI, CROSS SECTIONS, ELASTIC SCATTERING, FISSION, INELASTIC SCATTERING

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