1. NAME AND TITLE

DOPEX-1D2C: A One-Dimensional, Two-Constraint Radiation Shield Optimization Code System.

DOPEX-1D2C is an extension of the CCC-63/OPEX, CCC-177/DOPEX series.

2. CONTRIBUTOR

NASA Lewis Research Center, Cleveland, Ohio.

3. CODING LANGUAGE AND COMPUTER

FORTRAN IV; IBM 360/370.

4. NATURE OF PROBLEM SOLVED

DOPEX-1D2C minimizes weight (or volume or cost) of a layered spherical radiation shield subject to two dose rate constraints. It assumes an exponential dose rate-shield thickness relationship with parameters specified by the user.

5. METHOD OF SOLUTION

The method of steepest descent is used to alter a set of initial (input) thicknesses of a spherical shield configuration to achieve a minimum weight while simultaneously satisfying two dose-rate constraints. The code will not add layers but it may delete layers.

6. RESTRICTIONS OR LIMITATIONS

DOPEX-1D2C is set up for a maximum of 25 regions and each of the two dose constraints is limited to 25 components. These limits could be increased.

7. TYPICAL RUNNING TIME

The sample packaged problem ran in 42 seconds on the IBM 360/91 computer.

8. COMPUTER HARDWARE REQUIREMENTS

DOPEX-1D2C is operable on the IBM 360/370 computers using approximately 56K core.

9. COMPUTER SOFTWARE REQUIREMENTS

A FORTRAN IV compiler is required.

10. REFERENCES

a. Included in the documentation:

G. P. Lahti, "DOPEX-1D2CA One-Dimensional, Two-Constraint Radiation Shield Optimization Code," NASA TM X-2836 (July 1973).

b. Background information:

R. L. Bernick, "Application of the Method of Steepest Descent to Laminated Shield Weight Optimization," NAA-SR-Memo-8181 (April 1963).

R. L. Bernick, "The OPEX Shield Optimization Code," NAA-SR-Memo-11516 (July 1965).

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

G. P. Lahti, "The DOPEX CodeAn Application of the Method of Steepest Descent to Laminated-Shield Weight Optimization with Several Constraints," NASA TM X-2554 (1972).

G. P. Lahti, "Application of the Method of Steepest Descent to Laminated Shield Weight Optimization with Several ConstraintsTheory," NASA TM X-2435 (1971).

11. CONTENTS OF CODE PACKAGE

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

12. DATE OF ABSTRACT

July 1973; updated July 1975.