**1. NAME AND TITLE:**

SCAP: Single Scatter, Albedo Scatter, or Point Kernel Analysis Code System in Complex
Geometry.

**2. CONTRIBUTOR**

Westinghouse Advanced Reactors Division, Madison, Pennsylvania.

**3. CODING LANGUAGE AND COMPUTER:**

Fortran IV; CDC-7600.

**4. NATURE OF PROBLEM SOLVED:**

SCAP solves for radiation transport in complex geometries using the single or albedo scatter point
kernel method. The program is designed to calculate the neutron or gamma-ray radiation level at
detector points located within or outside a complex radiation scatter source geometry or a user
specified discrete scattering volume. Geometry is describable by zones bounded by intersecting
quadratic surfaces with an arbitrary maximum number of boundary surfaces per zone. Anisotropic
point sources are describable as point wise energy dependent distributions of polar angles on a
meridian; isotropic point sources may also be specified. The attenuation function for gamma-rays is
an exponential function on the primary source leg and the scatter leg with a buildup factor
approximation to account for multiple scatter on the scatter leg. The neutron attenuation function is
an exponential function using neutron removal cross sections on the primary source leg and scatter leg.
Line or volumetric sources can be represented as a distribution of isotropic point sources, with
uncollided line-of-sight attenuation and buildup calculated between each source point and the detector
point.

**5. METHOD OF SOLUTION**

A point kernel method using an anisotropic or isotropic point source representation is used, line-of-sight material attenuation and inverse square spatial attenuation between the source point and scatter
points and the scatter points and detector point is employed. A direct summation of individual point
source results is obtained.

**6. RESTRICTIONS OR LIMITATIONS**

SCAP is written in complete flexible dimensioning so that no restrictions are imposed on the
number of energy groups or geometric zones. The geometric zone description is restricted to zones
defined by boundary surfaces defined by the general quadratic equation or one of its degenerate forms.
The only restriction in the program is that the total program length plus the total data array dimension
for small core memory must be less than 150 K (octal).

**7. TYPICAL RUNNING TIME**

SCAP computes approximately 200 source point-to scatter point-to detector point calculations per
second on the CDC-7600. This running time is essentially independent of the number of energy groups
and is only dependent upon the calculation of geometry dependent data.

**8. COMPUTER HARDWARE REQUIREMENTS**

SCAP is operable on the CDC-7600 computer.

**9. COMPUTER SOFTWARE REQUIREMENTS**

SCAP is operational on the Westinghouse Power Systems under SCOPE 2.1 monitor system
control. A Fortran IV compiler is required.

**10. REFERENCE**

R. K. Disney, A. R. McIlvaine, S. E. Bevan, "SCAP Computer Program Description Single
Scatter, Albedo Scatter, or Point Kernel Analysis Program in Complex Geometry," Draft (April 1980).

**11. CONTENTS OF CODE PACKAGE**

Included are the referenced document and one (1.2MB) DOS diskette which contains the source
program, sample problem input, a photon cross section library and a program to convert the library
to binary format.

**12. DATE OF ABSTRACT**

March 1982.

**KEYWORDS: ** NEUTRON; GAMMA-RAY; KERNEL; COMPLEX GEOMETRY; SINGLE
SCATTERING