Reducing the Level of Power Vibrations in the NEPTUNE Pulsed Reactor

Dubna’s IBR-2 periodic pulsed research reactors are the most effective source of slow neutrons in extracted beams for studying various structures by using diffraction, small-angle scattering, reflectometry, inelastic scattering, and neutronography, thanks to their short-pulse neutrons and high average flux (reaching 1014 cm–2 s–1). At the same time, due to the specificity of the kinetics, fluctuations in the power energy of pulses in such a reactor are tens of times higher than in stationary reactors and create problems when trying to control the apparatus. This paper proposes and substantiates a method to significantly reduce the level of fluctuations in the power pulses of such reactors using the NEPTUNE pulsed reactor project with the Np‑237 threshold isotope as a nuclear fuel as an example.