Nuclear Reactor Theory Department

(Head – Dr. Sci., Professor V. M. Pavlovych)

The Department was created in 1995

Main directions of scientific activity: 

• Theoretical investigation of the nuclear reactor safety in stationary and transition conditions;
• Development of the methods of monitoring the fission materials in the “Shelter” object.
• Analysis of the nonlinear and stochastic neutron processes in the wide range of feedbacks and controlling parameters, stationary and non-stationary regimes in the critical state; investigation of the stability boundaries; development of the self-consistent nonlinear model of kinetic phenomena of the neutron subsystem in the critical and subcritical state.

The most important scientific results: 

• Calculations of the neutron multiplication factor of the fuel-containing bulk masses of the “Shelter” object based on the models with the random fuel position were performed.
• The method of measuring the neutron multiplication factor in the “Shelter” object was developed.
• The principal schemes of reactors with the new methods of the neutron fluxes control were developed; their reliability estimation based on model calculations was performed.
• General expressions for the statistical system lifetime applying the information theory and nonequilibrium statistical operator methods were obtained.
• The concept is proposed and primary calculations of the subcritical neutron amplifier, which together with the particle accelerator can be the base for a prospective research reactor, were carried out.
• Reasons of the accident on the nuclear fuel plant in Tokai-Mura, Japan, were analyzed and occurred kinetic processes were investigated The parameters of neutron bursts close to those observed while the accident were calculated.
• The thermal nuclear reactor neutron collective lifetime different from the individual neutron lifetime and tending to the duration of reactor cycle is calculated.
• The possibilities of constructing a nuclear reactor based on the subcritical neutron amplifier are considered. The ways of the parameters optimization for such an amplifier from the point of view of the neutron amplification factor increase are analyzed. The factor is possible to be increased by three orders.
• To characterize the neutron behaviour in a nuclear reactor the method of random branching processes was applied. With the help of this method three reactor critical behaviour regimes depending on feedbacks and controlling influences were discovered.