NEA-0294 CODAC.

1. NAME OR DESIGNATION OF PROGRAM:  CODAC.

3. NATURE OF PHYSICAL PROBLEM SOLVED

CODAC-2 is a nuclear data processing program. It converts ENDF/B version 2 data into group averaged cross sections in the form needed by Monte Carlo codes. CODAC generates the mean values of sigma-c,sigma-el,sigma-inel, sigma-f and nu for any group structure by using specified weighting  spectra. In the case of anisotropic elastic scattering either the average cosine or the angular derivation of cross section is calculated for each energy group. The inelastic scattering is described by a transfer matrix which can also include (n,2n) reactions.

4. METHOD OF SOLUTION

Averaging is done by using a weighting spectrum  given by an input. Group averaged cross sections are calculated by summing up the smooth contributions and the contributions of the resolved and unresolved resonances, using the method of the ETOG-ETOM program and of MC2 at zero temperature. Anisotropic elastic secondary angular distribution is calculated optionally as mu-average in laboratory system, Legendre expansion, or point by point along the mu-axis. The inelastic secondary energy distribution is computed as transfer matrix.

5. RESTRICTIONS ON THE COMPLEXITY OF THE PROBLEM

The programme handles any number of ENDF/B materials during one run. The number of energy  groups is limited to 50. The output formats of CODAC-2 correspond to the input formats of TIMOC.

6. TYPICAL RUNNING TIME

The running time is very sensitive to the input options and items and to the materials chosen.
For instance, an unweighted calculation will decrease the computation time by about a factor 1/2 to 3/4.
Running time increases with increasing number of groups and with the number of data given for the material. A material with many resonances or many different types of reactions and many energy points for each reaction will need much more time than one without resonances or with only few possible reactions and few energy points. So computation times for one material lie between 1 min and  about 15 min on the IBM 360/65.

7. UNUSUAL FEATURES OF THE PROGRAM

Anisotropic elastic scattering secondary angle distribution can optionally be calculated in 3 different ways: as Legendre expansion in the c.m. system, point by point along the nu-axis in the c.m. system, as averaged cosine in the lab. system. In calculating, nearly isotropic scattering is assumed in and below the resonant region.

8. RELATED AND AUXILIARY PROGRAMS

CODAC uses the ENDF/B retrieval subroutines by H.C. Honeck, and parts of the MC2 programme and the ETOG-ETOM programme of Westinghouse.

- H. Krainer:
  CODAC - A FORTRAV IV Programme to Process a TIMOC Library from the
  ENDF/B File
  EUR 4521e (1970).
- F. Beonio-Brocchieri and C. Daolio:
  CODAC 2 - A New Version of the CODAC Code which Accepts ENDF/B
  Version II Data for the Production of a few Group Library for
  TIMOC
  FBB/10 (March 30, 1972).
- H. Krainer:
  CODAC - A FORTRAV IV Programme to Process a TIMOC Library from the
  ENDF/B File
  EUR 4521e (1970).
- F. Beonio-Brocchieri and C. Daolio:
  CODAC 2 - A New Version of the CODAC Code which Accepts ENDF/B
  Version II Data for the Production of a few Group Library for
  TIMOC
  FBB/10 (March 30, 1972).
- H. Krainer:
  CODAC - A FORTRAV IV Programme to Process a TIMOC Library from the
  ENDF/B File
  EUR 4521e (1970).
- F. Beonio-Brocchieri and C. Daolio:
  CODAC 2 - A New Version of the CODAC Code which Accepts ENDF/B
  Version II Data for the Production of a few Group Library for
  TIMOC
  FBB/10 (March 30, 1972).

11. MACHINE REQUIREMENTS

The Programme is built in an overlay structure where it requires 155,600 bytes (38,900 words) on the 360/65. Without overlay 221,400 bytes (55,350 words) are necessary. CODAC-2  requires 2 I/O devices for reading and printing, one I/O device for  the ENDF/B library tape and one on which the TIMOC library is written or punched. One additional I/O device is necessary if the program is loaded from tape.

13. SOFTWARE REQUIREMENTS: OPERATING SYSTEM OR MONITOR UNDER WHICH PROGRAM IS EXECUTED

14. OTHER PROGRAMMING OR OPERATING INFORMATION OR RESTRICTIONS

ANY OTHER PROGRAMMING OR OPERATING INFORMATION OR RESTRICTIONS

15. NAME AND ESTABLISHMENT OF AUTHOR

          H. Krainer
          EURATOM CCR
          I-21020 Ispra (Varese), Italy
Present address:
          AEG-Telefunken, Kostanz (Germany)
The UNIVAC 1106 version was received from:
          Junta de Energia Nuclear
          Madrid, Spain.

File name	File description	Records
NEA0294_01.001	SOURCE PROGRAM + SAMPLE PROBLEM DATA	7176
NEA0294_01.002	SAMPLE PROBLEM PRINTED OUTPUT	754

File name	File description	Records
NEA0294_02.001	INFORMATION	2
NEA0294_02.002	SOURCE PROGRAM (F4)	7151
NEA0294_02.003	OVERLAY,DD CARDS+SAMPLE INPUT	45
NEA0294_02.004	OUTPUT LIST OF SAMPLE PROBLEM	1218

File name	File description	Records
NEA0294_03.001	INFORMATION	1
NEA0294_03.002	SOURCE PROGRAM-F4-EBCDIC	7191
NEA0294_03.003	OVERLAY CARDS	17
NEA0294_03.004	JCL	10
NEA0294_03.005	SAMPLE PROBLEM INPUT DATA	23
NEA0294_03.006	SAMPLE PROBLEM PUNCHED OUTPUT	73
NEA0294_03.007	SAMPLE PROBLEM PRINTED OUTPUT	675