Authors & Affiliations
Vaivod A.A., Yudov A.A., Sergina D.I., Kasyanov S.Yu., Prokopyev D.A., Kostenko I.I.
Zababakhin All-Russia Research Institute of Technical Physics, Snezhinsk, Russia
Yudov A.A. – Head of Laboratory, Cand. Sci. (Phys.-Math.). Contacts: 13, Vasilieva st., Snezhinsk, Chelyabinsk region, Russia, 456770. E-mail:
Vaivod A.A. – Research Engineer.
Sergina D.I. – Research Engineer.
Kasyanov S.Yu. – Research Engineer.
Prokopyev D.A. – Research Engineer.
Kostenko I.I. – Head of the Group, Cand. Sci. (Phys.-Math.).
Abstract
The article presents the results of critical experiments and experiments on neutron transmission were performed on a critical assembly stand FKBN-2 in 2017–2019. The experiments were performed using multiplying systems of highly enriched uranium with end reflectors made of lithium-6 hydride, lithium-7 hydride, and lithium-6 deuteride.
In the critical experiments, the size of the gap between the parts of the multiplying system, corresponding to the critical state on delayed neutrons, was determined for different thicknesses of the end reflector (from 0.5 to 12 cm).
Uranium multiplying systems with lithium-7 hydride and lithium-6 deuteride end reflectors were also used in the experiments studying the transmission of the fission spectrum neutrons. In the course of the experiments, neutron activation detectors based on nickel, indium, titanium, aluminum, and copper, placed in fixed positions between the disks of the end reflector at a distance of 0, 0.5, 1, 1.5, 2, 3, 4, 6, 8, 10, and 12 cm from the surface of the uranium disk of the upper part were irradiated at a power of ~25–30 W during 1–1.5 hours. In the experiments, activation integrals (the numbers of neutron interactions normalized to one nucleus of the target isotope) were determined.
To normalize the results obtained in different experiments, a nickel detector-monitor was additionally installed in the multiplying system. It was placed in a fixed position at the center of the upper disk of the lower part of the system.
The obtained results were used to determine the spectral indices (ratios of the normalized values of the activation integrals of detectors of various types to the normalized values of the activation integrals of nickel detectors), which provide information on the neutron spectrum.
The experiments were aimed at validating the libraries of nuclear-physical constants used in codes for neutron physics calculations.
Keywords
benchmark experiments, highly enriched uranium, lithium hydride, multiplying system, critical assembly stand, energy spectrum of fission neutrons, neutron activation method, neutron activation detectors, gamma spectrometry, activation integrals, spectral indices
Article Text (PDF, in Russian)
UDC 539.125.5
Problems of Atomic Science and Technology. Series: Nuclear and Reactor Constants, 2023, no. 3, 1:1