1. NAME AND TITLE

OPEX-II: Radiation Shield Optimization Code.

2. CONTRIBUTOR

National Aeronautics and Space Administration, Lewis Research Center, Cleveland, Ohio.

3. CODING LANGUAGE AND COMPUTER

FORTRAN IV; IBM 7090/7094.

4. NATURE OF PROBLEM SOLVED

OPEX-II will determine the minimum weight configuration for spherical laminated shields subject to the constraint of a constant total dose rate at a selected detector point. Once an optimized base case is obtained, effects of nominal changes in reactor size, power level, and dose constraint on shield weight may be estimated. Cost optimization may also be performed by specifying cost per unit volume rather than density for each region.

5. METHOD OF SOLUTION

The code is an extension of CCC-63/OPEX, which it replaces. The method of steepest descent has been maintained but the code has been completely rewritten to simplify data input, incorporate spherical geometry, expand the output, alter the dose-thickness relation, and effect other improvements. The dose rate is approximated by a sum of exponentials representing each dose component obtained from experiments or analytical calculations.

6. RESTRICTIONS OR LIMITATIONS

Number of regions: 25

7. TYPICAL RUNNING TIME

Estimated running time of the packaged sample problem on the IBM-7090: approximately 1 minute.

8. COMPUTER HARDWARE REQUIREMENTS

The code was designed for the IBM 7094 and uses standard I-O.

9. COMPUTER SOFTWARE REQUIREMENTS

The code is operable on the IBM 7090/7094 IBSYS Operating System using IBJOB Processor.

10. REFERENCE

G. P. Lahti, "OPEX-II, A Radiation Shield Optimization Code," NASA TM X-1769 (March 1969).

11. CONTENTS OF CODE PACKAGE

Included are the referenced documents and one (1.2MB) DOS diskette which contains the source code and input and output for a sample problem.

12. DATE OF ABSTRACT

May 1969; updated July 1981, February 1985.