[en] Short communication

[en] The probe experimental results of investigation of uranium hexafluoride plasma produced in the centre of nuclear reactor core were demonstrated. Study of uranium hexafluoride plasma is continued by the following reasons: a possibility of U F₆ utilization as nuclear fuel, the utilization of U F₆ as volume source o ionization, search of active laser media compatible with U F₆ that is complicated by lack of constant rates data for most of plasma-chemical reactions with U F₆ and his dissociation products. Cylindrical probe volt-ampere characteristics (VAC) measured in U F₆ plasma at pressure 20 Torr and different thermal neutron fluxes and have following features: -firstly, it is possible to choose a linear part in the field of small positive potentials of probe (0-1) V; - secondary, ion branches of VAC have typical break which current of satiation corresponds to; -thirdly, probe VAC measured at small values of thermal neutron flux density are symmetrical. Diagnostics approaches were used for interpretation VAC of probe. The values of satiation current and linear part of electron branch were calculated, and such plasma parameters as conductivity, diffusion coefficient values of positive and negative ions were determined. The resonance recharge cross section was estimated on diffusion coefficient value

[en] Description of the set-ups and measurements for in-core and laboratory research of non-equilibrium nuclear-exciting plasma of various gas mixtures are demonstrated in this paper. Excitation of gas medium was produced by products of the ³ He(n,p)T, ²³⁵ U(n,f)F nuclear reactions at in-core experiments, and by products of the radioisotopes ²¹⁰ Po, ²³⁹ Pu fission at laboratory ones. The data of these investigations allows as to estimate threshold parameters of the nuclear pumped laser as to study the electron kinetics characteristics of nuclear-exciting plasma. The developed optical diagnostic methods allows to measure spectral and integral luminescence characteristics, in particular absolute population of excited states of atom and molecules and elementary processes constant rates. The probe methods of diagnostic allows to determine such plasma parameters as conductivity, concentration of charged particles and in some cases the coefficient of positive and negative ions and electron mobility and recombination coefficients. Some experimental results of the investigation are shown

[en] Values of power release of spent nuclear fuel of WWR-K reactor are determined. This value is fixed equal to 2.48 W for fuel assemblies (FA) with maximum burnup of 40 % and duration of cooling in wet store of 10 years. Methodic of layers consistent removal from high-reactive spent FA with help of which is probed a depth of bedding fission products in fuel shell is carried out. On distant of 190 μm from surface to deep into of fuel element shell the traces of products fission have been revealed. Evolution time of fission products diffusion yield from fuel element shell outside showed that yield of fission products practically does not exerted influence of radiation safety of dry depository