1. NAME AND TITLE

QADMOD-GP: Point Kernel Gamma-Ray Shielding Code With Geometric Progression Buildup Factors.

2. CONTRIBUTOR

TU Electric, Glen Rose, Texas.

3. CODING LANGUAGE AND COMPUTER

Fortran 77; IBM PC.

4. NATURE OF PROBLEM SOLVED

QADMOD-GP is a PC version of the mainframe code CCC-396/QADMOD-G, a point-kernel integration code for calculating gamma ray fluxes and dose rates or heating rates at specific detector locations within a three-dimensional shielding geometry configuration due to radiation from a volume-distributed source.

5. METHOD OF SOLUTION

QADMOD-GP calculates gamma-ray fluxes, dose rates, or heating rates at discrete locations within a complex source-geometry configuration by representing a volume-distributed source by a number of point isotropic sources and computing the distances through all regions traversed by the line-of-sight from the source points to a desired receiver point. From these distances and the characteristics of the materials within them, energy-dependent exponential attenuation factors and energy-dependent buildup factors for gamma-rays are applied to calculate the direct gamma-ray dose and the gamma-ray dose with buildup. Like QADMOD-G, QADMOD-GP employs the FASTER geometry routines to define region boundaries with the general quadric surface equation. Additional features of the PC version are the following: 1) use of the geometric progression buildup factors; 2) addition of subroutine to allow use of updated mass attenuation coefficients (without coherent scattering); 3) addition of subroutine to compute flux-to-dose rate conversion factors for arbitrary photon energies; 4) increase of the number of allowable computed source point locations (from 500 to 3,000); 5) increase the exponential function minimum (from -180.218 to -87.0) in KERNEL to avoid underflows; 6) installation of a "card image" routine to print formatted input data at the beginning.

6. RESTRICTIONS OR LIMITATIONS

The code can treat up to 300 shielding regions, 100 material compositions, and as many detectors as desired.

7. TYPICAL RUNNING TIME

On the IBM PC/XT with a math co-processor, the sample problem took about 1 minute.

8. COMPUTER HARDWARE REQUIREMENTS

QADMOD-GP runs on the IBM PC and compatibles with a math co-processor.

9. COMPUTER SOFTWARE REQUIREMENTS

A Fortran 77 compiler is required. The IBM Professional Fortran Version 1.0 compiler was used by TU Electric to create the executable program. Alternatively, The RM/Fortran compiler version 2.42 can be used.

10. REFERENCES

J. K. Warkentin, "QADMOD-GP Notes," Informal notes (November 2, 1990).

J. K. Warkentin, "Utilization Instructions For QADMOD-GP -- A PC Version Of QADMOD-G With Geometric Progression Buildup Factors," (November 1, 1990).

J. H. Price and W. G. M. Blattner, "Utilization Instructions for QADMOD-G," RRA-N7914 (December 1979).

b. Background information:

Y. Harima, Y. Sakamoto, S. Tanaka, and M. Kawai, "Validity of the Geometrical Progression Formula in Approximating Gamma-Ray Buildup Factors," Nucl. Sci. Eng. 94, 24-35 (September 1986).

D. K. Trubey, "New Gamma-Ray Buildup Factor Data for Point Kernel Calculations: ANS-6.4.3 Standard Reference Data," ORNL/RSIC-49 (September 1988).

11. CONTENTS OF CODE PACKAGE

Included are the referenced document and one (1.2 MB) DOS diskette.

12. DATE OF ABSTRACT

November 1990.