CCC-0164 NAC.

1. NAME OR DESIGNATION OF PROGRAM:  Neutron Activation Analysis and Product Isotope Inventory Code System

3. DESCRIPTION OF PROGRAM OR FUNCTION

NAC was designed to predict the neutron-induced gamma-ray radioactivity for a wide variety of composite materials. The NAC output includes the input data, a list  of all reactions for each constituent element, and the end-of-irradiation disintegration rates for each reaction. NAC also  compiles a product isotope inventory containing the isotope name, the disintegration rate, the gamma-ray source strength and the absorbed dose rate at 1 meter from an unshielded point source. The induced activity is calculated as a function of irradiation and decay times; the effect of cyclic irradiation can also be calculated.

4. METHOD OF SOLUTION

The standard neutron activation and decay equations are programmed.
A data library is supplied which contains target element names, atomic densities, reaction indices, individual reactions and reaction parameters, and product isotopes and gamma energy yields.

5. RESTRICTIONS ON THE COMPLEXITY OF THE PROBLEM

Each composite material may consist of up to 20 different elements and up to 20 different decay times may be included. Both limits may be increased  by the user by increasing the appropriate items in the DIMENSION statement.

6. TYPICAL RUNNING TIME

Execution time for 3 sample problems (a: 9 elements, 4 decay times; b: 6 elements, 1 decay time; c: 6 elements, 1 decay time) was 0.62 CPU seconds on the IBM 3033. Execution time for the same sample problems on an IBM PC/XT with a
math co-processor took about 45 seconds.

  NEA-DB executed the test case included in this package on a PC/80486 (66 MHz) in 8 seconds.

7. UNUSUAL FEATURES: UNUSUAL FEATURES OF THE PROGRAM

8. RELATED AND AUXILIARY PROGRAMS:  NDL: NAC Data Library.

- J. Jedruch:
  README.ASC
  Informal Notes, Ebasco (1990).
- Suzanne T. Weinstein:
  NAC - Neutron Activation Code
  NASA TM X-5260 (1968).
- J.T. West:
  Input Data Instructions for the CDC 7600, General Description
  Informal Notes (1973).

11. MACHINE REQUIREMENTS

The code was originally designed to run on the IBM 7094 with standard I-O equipment and it was converted to be  operable on the IBM 360/75/91, the IBM 3033 and also on the CDC 7600. The new PC version will run on most PC's with or without a math co-processor.

  NEA-DB installed the program on a DELL 466/L PC/80486 (66 MHz) with 8 MBytes of RAM.

13. OPERATING SYSTEM UNDER WHICH PROGRAM IS EXECUTED

The packaged codes are operable on the IBM OS/VS2 operating system using the VS Fortran compiler with the language level 55 option and on the CDC 7600 FORTRAN IV systems.
For the PC version, MICROSOFT FORTRAN Version 4.01 was used for compilation and linking under DOS 3.3 operating system.

NEA-DB installed and ran the program under MS-DOS Version 6.2 using the FORTRAN-77 compiler Lahey F77L-EM/32 Version 5.20.

15. NAME AND ESTABLISHMENT OF AUTHOR

Contributed by: Radiation Safety Information Computational Center
                Oak Ridge National Laboratory
                Oak Ridge, Tennessee, U. S. A.
Developed by:   National Aeronautics and Space Administration,
                Lewis Research Center, Cleveland, Ohio, USA
                Babcock and Wilcox, Lynchburg, Virginia.
                Ebasco Services Incorporated, New York, New York.

File name	File description	Records
CCC0164_02.001	Information file	152
CCC0164_02.002	NAC Fortran source	408
CCC0164_02.003	NAC executable (Lahey compiler)	0
CCC0164_02.004	Original NAC Library	757
CCC0164_02.005	Corrected Library	757
CCC0164_02.006	Test case input	316
CCC0164_02.007	Test case output	7388
CCC0164_02.008	Message errors from Lahey compiler	0
CCC0164_02.009	DOS file-names	8