At the present time, the work is being carried out related to the development of a new pulsed reactor NEPTUN at the New neutron source and moderator complex department. One of the key components of the pulsed reactor NEPTUN is a reactivity modulator (RM). Its design is of interest in terms of the reactor safe operation.

The report presents the results of numerical calculations of the reactivity modulator construction obtained in ANSYS software:

• Natural frequencies and oscillation shapes of the reactivity modulator disk;
• Distribution of stresses, strains and displacements in the RM construction during its rotation at idle mode of the reactor. Also, the safety factor of the RM during its rotation is estimated;
• Temperature distribution in the RM “window” area at nominal capacity mode of the reactor. The calculations were carried out for two versions of the RM: with and without nickel inserts.