1. NAME AND TITLE

AKTIV: An Evaluation of Activity, Afterheat and Biological Hazard Potential of Stainless Steel Structures in Fusion Reactor Blankets.

2. CONTRIBUTOR

Max-Planck-Institute for Plasma Physics, Federal Republic of Germany.

3. CODING LANGUAGE AND COMPUTER

Fortran IV; IBM 360/370.

4. NATURE OF PROBLEM SOLVED

AKTIV calculates the activity, afterheat, and biological hazard potential of arbitrary materials in a fusion reactor blanket environment. It can be used in any case where activating fluxes (neutrons, gamma-rays, protons, etc.), corresponding cross-sections, and all initial conditions are known. The latter comprise, primarily, the initial concentrations of the chemical elements and their isotopic composition present in the blanket.

5. METHOD OF SOLUTION

The data concerning transmutations, activity, afterheat or decay power, and the biological hazard potential (BHP) are calculated by AKTIV as a function of time for each space interval and each zone comprising a certain number of intervals which are specified by the program input. In doing this, the time dependence can be treated in three different modes corresponding to the operation sequence of the reactor:

burn period: the reactor is operating, radionuclides are being produced and decay;

shutdown period: the reactor is out of operation, all neutron fluxes are zero, the radionuclides decay;

periodic operation: the reactor is periodically started and shut down, the periods being assumed to be constant.

6. RESTRICTIONS OR LIMITATIONS

The shortest half-life involved should not be less than 0.1 second. Since the program was designed to operate on the IBM 360/370 computers, a number of variables had to be defined in double precision. This assures a calculational accuracy of better than 1% if the time variation of the activity is followed up to 10¹⁰ seconds.

7. TYPICAL RUNNING TIME

If AKTIV is applied to large problems, it requires a significant amount of computer time. This is mainly dependent upon the number of intervals and the number of time phases to be calculated.

8. COMPUTER HARDWARE REQUIREMENTS

AKTIV was designed to operate on the IBM 360/370.

9. COMPUTER SOFTWARE REQUIREMENTS

A Fortran IV compiler is required.

10. REFERENCE

H.-J. Odenthal, W. Danner, and H. Gorenflo, "AKTIV, A Computer Program for Evaluating the Activity, Afterheat, and Biological Hazard Potential of Stainless Steel Structures in Fusion Reactor Blankets," IPP 4/154 (May 1977).

11. CONTENTS OF CODE PACKAGE

Included are the referenced document and one (1.2MB) DOS diskette which contains the source codes and sample problem input and output.

12. DATE OF ABSTRACT

January 1982.