ATIKA-multigroup two-dimensional computer code for shielding calculations

Two-dimensional removal-diffusion computer code ATIKA is described that is designed for multivariant calculations of reactor biological shields. The code has a module structure and file data base organization. The code is written in ALGOL- 60 for the BESM-6 computer. The removal-diffusion equations were solved in orthogonal geometries in the finite-difference representation using the integrointerpolation method. The resulting sets of linear equations were determined by the iterative method. A 21-group constant system was chosen to calculate the diffusion component. A removal 20-group constant system was specially constructed for the ATIKA code. Comparison of the calculations with experimental data for an iron-water composition and fast neutrons testifies to the applicability of the ATIKA code