**1. NAME AND TITLE**

PALLAS-1D(VII): Multigroup Time-Independent Neutron Transport Code System for Plane or Spherical Geometry.

**2. CONTRIBUTOR**

Ship Research Institute, Tokyo, Japan.

**3. CODING LANGUAGE AND COMPUTER**

Fortran IV (C00380FM38000).

**4. NATURE OF PROBLEM SOLVED**

PALLAS-PL/SP solves multigroup time-independent one-dimensional neutron transport problems in plane or spherical geometry. The problems solved are subject to a variety of boundary conditions or a distributed source. General anisotropic scattering problems are treated for solving deep-penetration problems in which angle-dependent neutron spectra are calculated in detail.

**5. METHOD OF SOLUTION**

Energy dependence is treated by the multigroup approximation and angular dependence by a discrete ordinates approximation. A system of coupled one-group integral transport equations is calculated by performing a line integration along the neutron path in the direction of motion at each discrete ordinate direction. Scattering integral including anisotropic scattering is treated by a numerical integration. No iteration scheme is applied in the calculation. The resulting solutions are always physically reasonable and have no oscillating flux distributions sometimes found in discrete ordinates solutions.

**6. RESTRICTIONS OR LIMITATIONS**

The PALLAS-PL/SP program cannot treat thermal neutron transport problems. This code is also not appropriate for a mono-energy neutron transport problem.

**7. TYPICAL RUNNING TIME**

No study has been made by RSIC.

**8. COMPUTER HARDWARE REQUIREMENTS**

The code is operable on the FACOM computers. It requires 55 Kw core memories and a maximum of 1.041 Kw disk or drum memories in the case of a maximum of 120 energy groups, 300 spatial mesh points, 20 angular mesh points and 18 nuclei.

**9. COMPUTER SOFTWARE REQUIREMENTS**

A Fortran IV compiler is required.

**10. REFERENCE**

Kiyoshi Takeuchi and Shun-ichi Tanaka, "PALLAS-1D(VII) A Code for Direct Integration of Transport Equation in One-Dimensional Plane and Spherical Geometries," JAERI-M 84-214 (October 1984).

**11. CONTENTS OF CODE PACKAGE**

Included are the referenced document and one DS/HD 3.5-in. (1.44 MB) diskette in self-extracting compressed DOS files which contains the source codes and sample problem input and output.

**12. DATE OF ABSTRACT**

February 1982, December 1986.

**KEYWORDS: ** ONE-DIMENSION; NEUTRON; CYLINDRICAL GEOMETRY;
SPHERICAL GEOMETRY; MULTIGROUP; SLAB; ENDF/B
FORMAT; INTEGRAL BOLTZMANN EQUATION