[en] The code has been developed for core dynamics analysis of the experimental multi-purpose very high temperature reactor. Utilizing 60 degrees rotational symmetry, the code models the 1/6 part of core in three dimension. Space-time dependent diffusion equation is integrated in time to solve neutronic dynamics of the core. Temperature effect is taken into consideration by solving coolant channel models distributed over the core. The control rods can be adjusted by built-in control systems so that reactor power and coolant temperature at reactor outlet are kept constant. (author)