THREETRAN (hex, z) users' manual. [3-D, multigroup, discrete-ordinates code]

THREETRAN (hex,z) is a three-dimensional, multigroup, discrete-ordinates neutral-particle transport code for use in solving problems in hexagonal, z geometries. An efficient and flexible data management strategy is incorporated and uses three hierarchies of storage: fast core (or small core memory), extended core (or large core memory), and random access disk. Both isotropic (P/sub 0/) and linearly anisotropic (P/sub 1/) scattering can be treated. This manual is intended to be a guide for the users of THREETRAN (hex,z) in setting up problem input and in interpreting the output. It is not intended to provide a description of code theory or architecture. 5 figures, 4 tables.