**1. NAME AND TITLE**

APARNA-II: Integral Transport Theory Code System Based on Discrete Ordinate Representation in Space and DirectionSlab Geometry.

**2. CONTRIBUTOR**

Reactor Research Centre, Government of India, Kalpakkam, India.

**3. CODING LANGUAGE AND COMPUTER**

FORTRAN IV; IBM 360/370.

**4. NATURE OF PROBLEM SOLVED**

APARNA-II solves the one-dimensional integral transport equation for neutrons with arbitrary
anisotropic scattering in slab geometry. It is particularly suited for deep penetration problems.

**5. METHOD OF SOLUTION**

A discrete ordinates representation of spatial and angular variables is employed, and the
multigroup equations are solved using a source-iteration procedure. Scattering anisotropy is
accounted for using a truncated Legendre polynomial expansion. The Legendre components of the
scattering matrix must be provided as input. A flexible scheme of two and three parameter
interpolations for collision source is built in to enhance the stability of solution with coarse cell
structure.

**6. RESTRICTIONS OR LIMITATIONS**

The problem size is restricted only by the machine size.

**7. TYPICAL RUNNING TIME**

A problem of 28 energy groups, 100 mesh points, and 3 regions will take approximately 2
minutes to run. The sample problem took 0.7 sec on the IBM 360/91.

**8. COMPUTER HARDWARE REQUIREMENTS**

APARNA-II runs on the IBM 360/370 series and requires 96 K active memory and one tape
unit for auxiliary storage.

**9. COMPUTER SOFTWARE REQUIREMENTS**

A FORTRAN IV compiler is required.

Input-output assignments only are made.

**10. REFERENCE**

R. Vaidyanathan, "APARNA-II, Program to Solve Integral Transport Equation in Slab
Geometry," FRG-RP-123 (no date).

**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**

December 1981, updated August 1991.

**KEYWORDS: ** ONE-DIMENSION; DISCRETE ORDINATES; MULTIGROUP; NEUTRON;
SLAB; INTEGRAL BOLTZMANN EQUATION