RSIC CODE PACKAGE CCC-084
1. NAME AND TITLE
SHADRAC: Kernel Integration Code Shield Heating and Dose Rate Calculation in Complex Geometry.
The code is a complete rewrite of machine language computer codes CCC-5/C-17 and CCC-6/L-63, now obsolete.
USAF Nuclear Aerospace Research Facility,
Air Force Weapons Laboratory, Kirtland Air
3. CODING LANGUAGE AND COMPUTER
FORTRAN IV; IBM 7090 and 7094.
4. NATURE OF PROBLEM SOLVED
SHADRAC calculates the neutron and/or gamma-ray spectra, heat generation rate, and/or dose rate at each of a group of point detectors, due to each of a group of point sources. The sources may be divided into sets, with each set having a unique source spectra. The spectrum, heating rate, and/or dose rate for each detector, summed over each source-point set and over the entire source group, may also be computed. Complex geometry may be treated.
5. METHOD OF SOLUTION
Point-to-point kernels, based upon the differential energy spectra for a point isotropic source in an infinite medium, are integrated over various sources. The data used is based on the moments-method solution of the fast-neutron or gamma-ray transport equation. The stepping-point method is used to solve for the path lengths from source to detector in each region.
The gamma-ray absorption coefficients are based on interpolations of the photoelectric and pair production cross sections so that the coefficients may be computed for all media of the system. The effective atomic number is interpolated from a table of atomic numbers versus the absorption coefficient per electron.
The mode of distributing the source points is chosen (either equal interval or according to Gaussian quadrature abscissa) which locates the coordinate planes that are perpendicular to the coordinate axes. The intersections of these planes are source point locations.
Modifications in SHADRAC resulting in improvement over earlier models are: direct computation of unscattered flux, removal of all neutron energy modes except the first, greater capabilities in the use of the source spectra, library tape storage of material data, coding of gamma-ray data into the program, and improvement of the output format.
6. RESTRICTIONS OR LIMITATIONS
Enough physical and source description capability is provided by the program so that there should be little uncertainty except that associated with the point-to-point kernels as applied to specific geometries. Inhomogeneities generally increase the error since it is necessary to use arbitrary prescriptions for combining homogeneous media data.
7. TYPICAL RUNNING TIME
No study has been made at this time to determine typical running time. Estimated running time of sample problem on the IBM 7090: 0.05 hour.
8. COMPUTER HARDWARE REQUIREMENTS
IBM 7090 and 7094 32 K computer with 7 tape units.
9. COMPUTER SOFTWARE REQUIREMENTS
The code was designed for and is operable in the IBM FORTRAN IV Operating System, using the ALTIO package, and is compatible with the CDC 6600 FORTRAN IV system. Four pool tapes, in addition to standard input, output, and systems tapes, are assigned. Allowance has been made for a library to be read in from tape. It is currently being read as standard input data.
J. A. Moore, J. B. Eggen, C. W. Austin, D. H. Huckaby, and R. A. Miller, "Shield Heating and Dose Rate Attenuation Calculation (SHADRAC)," NARF-DC-MEMO 1.097 (March 1966).
11. CONTENTS OF CODE PACKAGE
Included are the referenced document and one (1.2MB) DOS diskette which contains the source code, a library of cross sections and input and output for a sample problem.
12. DATE OF ABSTRACT
January 1968; updated July 1981, February 1985.
KEYWORDS: KERNEL; HEATING; ENVIRONMENTAL DOSE; COMPLEX GEOMETRY