Atomic Energy最新文献

The present paper considers a promising method for maintaining the water chemistry regime of water-cooled nuclear reactors with adjustment treatment of the coolant with microadditives of zinc as part of a colloidal solution of high-purity zinc oxide. The aggregate stability of the colloidal solution is achieved by a special method for synthesizing finely dispersed zinc oxide powder from gaseous diethyl zinc, followed by grinding the initial particles and separating the largest particles of zinc oxide to prevent their coagulation or adhesion. The latter is confirmed by zeta potential measurements of the colloidal solution. The method proposed in the article ensures simple and safe zinc injection.

The paper presents the results of an experimental study on the static sorption extraction of cesium from a real solution of alkaline liquid high-level waste using Fersal-MD inorganic finely dispersed sorbent. Three-stage sorption with repeated use of sorbent was carried out; the solution purification coefficients were determined. An application of the method for industrial use was experimentally assessed. Fersal and Fersal-MD sorbents were compared for use in the technology of extracting cesium from alkaline high-level waste.

This study aims to determine the thermophysical properties of industrial uranium-gadolinium oxide fuel pellets containing 3.35, 5, and 8 wt % Gd₂O₃ in order to evaluate the performance and safety of VVER-type reactor fuels. The obtained experimental data included thermal expansion, specific heat capacity at constant pressure, and thermal diffusivity. In addition, the temperature dependence of thermal conductivity was calculated up to 1900 K for fuels with varying Gd₂O₃ content. Figures: 5; Tables: 6; References: 12.

Radioisotope thermoelectric generators for biomedical purposes require high-purity ²³⁸Pu. The present article examines a model for its production in NaCl–2CsCl eutectic melt. For this purpose, physicochemical properties of plutonium, americium, and curium treated with an oxygen-chlorine-argon mixture in NaCl-2CsCl melt were studied at the JSC “SRC RIAR” (Dimitrovgrad, Russian Federation). The developed model provides for determining the modes of plutonium dioxide precipitation without americium and curium, as well as for assessing its possible contamination with actinides.

E110 zirconium alloy is widely used as a cladding for fuel rods in the core of transport reactors, in particular, nuclear icebreakers. The corrosion of these claddings in the conditions of the icebreaker core tends to convert from uniform to pitting. Operational and post-reactor studies show that the performance of fuel rods with E110 zirconium alloy claddings may be limited due to the development of pitting corrosion. The paper provides assumptions aimed at explaining corrosion mechanisms in the core of nuclear icebreakers.

The paper substantiates the necessity of developing new models of real-time remote systems for monitoring of the radiation situation in difficult conditions. The expediency of using optical fiber systems for this pupose is noted. A sensor for remote real-time measurement of γ‑radiation absorption dose or its rate is presented. The measurement technique is considered, and the features of the sensor operation are noted. The presented research results confirm the measurement error to be less than 6–8%. The prospects for using the developed fiber-optic sensor for long-term monitoring of the radiation situation are noted.

The present paper considers the possibility of improving the neural network forecast for a power reactor operating in a daily load schedule. We have prepared two simplified one-dimensional models of a VVER reactor: one as the reactor itself and another as its calculation model including several types of deviations from the reactor model for simulating the calculation error. A simple single-layer neural network is trained by comparing data obtained from the calculation and reactor models. The trained neural network effectively refines the results of the calculated forecast for the reactor model beyond the training time interval.

The paper presents the results of the research conducted by the JIHT RAS (Moscow, Russian Federation) on plasma reprocessing of spent fuel. The method is developed within the framework of the “Proryv” project direction as one of the operations in the reprocessing of spent nuclear fuel from industrial energy complexes. Experiments were carried out with substances simulating the elements moving in separating plasma. The physical viability of the selected concept for plasma mass separation is substantiated both theoretically and experimentally. The results will be used in a model of a plasma unit with a capacity of up to 0.2 kg/h for the mass separation of spent nuclear fuel. The model is planned for construction to practice technological processes and engineering solutions on various simulating compositions, including those based on depleted uranium.

The present paper investigates the radiation resistance of plastic composite materials with a 24–25 wt% boron-containing filler for printing by the fused deposition method. The polymer matrix is acrylonitrile butadiene styrene and polyethylene terephthalate glycol plastics. The introduction of boron reduces the penetration depth of thermal neutrons by 56–78% from 3 to 0.65 mm. Samples of composite and matrix materials were exposed to a plutonium-beryllium neutron source for 130 days. Mechanical tests showed an increase in strength and ductility by ~20% for irradiated polyethylene terephthalate glycol with amorphous boron. No significant changes in the mechanical properties of irradiated plastic matrix samples, as well as acrylonitrile butadiene styrene plastic with boron nitride, were found.

The paper considers two methods developed for calculating squared-off cascades of gas centrifuges taking into account variable separation factors of gas centrifuges and a given concentration of the target isotope in outlet streams. The first method optimizes feeding streams of stages in individual sections corresponding to the stage type; the second uses a calculation scheme varying the cuts of partial component streams for profiling the stage feeding stream changing along the cascade. A computational experiment was conducted to separate molybdenum hexafluoride in a three-stream cascade of two stage types. An example of ⁹²Mo concentration demonstrates characteristic features of cascades calculated by the compared methods.