DIMAC (A DIspersion Metallic fuel performance Analysis Code) is a computer program for simulating the behavior of dispersion fuel rods under normal operating conditions of HYPER. It computes the one-dimensional temperature distribution and the thermo-mechanical characteristics of fuel rod under the steady state operation condition, including the swelling and rod deformation. DIMAC was developed based on the experience of research reactor fuel. DIMAC consists of the temperature calculation module, the mechanical swelling calculation module, and the fuel deformation calculation module in order to predict the deformation of a dispersion fuel as a function of power history. Because there are a little of available U-TRU-Zr or TRU-Zr characteristics, the material data of U-Pu-Zr or Pu-Zr are used for those of U-TRU-Zr or TRU-Zr. This report is mainly intended as a user's manual for the DIMAC code. The general description on this code, the description on input parameter, the description on each subroutine, the sample problem and the sample input and partial output are written in this repo0008.