Том 123, № 1 (2017)

Severe accidents in NPP with VVER can be accompanied by hydrogen entering the containment space. The aim of the present work is an experimental and computational study of the possibility of hydrogen stratification in the containment in a scenario replicating the sequence of events occurring during a severe accident with hydrogen emission in a light-water reactor taking account of the impact of accident control on the distribution of a light gas. Euratom and the government corporation Rosatom performed the studies as part of two parallel projects – ERCOSAM and SAMARA. The experimental studies show that heat exchangers aand recombiners do bring about complete mixing of the light gas; a sprinkler system affords mixing of the stratified layer. The experimental studies confirm the results of numerical modeling.

The possibility of applying multicriterial and robust optimization methods as well as stochastic methods of determining the effect of uncertainties in the parameters of a system to structural optimization of nuclear power is discussed for the example of a hypothetical nuclear-power system consisting of thermal and fast reactors. It is shown that the optimal structures of nuclear power systems obtained by such methods are balanced in terms of conflicting criteria and technologically more diversified than those determined by single-criterion deterministic optimization. Cost-based innovative technologies, which can be adopted only by imposing additional external limitations in a single-criterion problem, appear in such structures. The examined methods make it possible to determine on a systematic basis the structures of nuclear power that are balanced in terms of a set of conflicting criteria, since factors having both positive and negative effects on the development of nuclear-power systems are included in the calculations, and to find economically efficient directions of structural changes in the system in order to improve stability and efficiency.

The results of experimental studies of a next-generation fast reactor performed using an integrated water model (scale 1:10) are presented: local velocity over height and radius of the top chamber in a plane in a direction from core center to the intermediate heat exchangers and coolant temperature in the top chamber and other elements of the circulation loop with forced circulation and emergency cool-down by natural convection. The data were obtained using a specially designed system for performing measurements which is incorporated in the bench and provides high accuracy and rate of acquisition. Stable temperature stratification of the coolant is observed in the top, cold, and pressure chambers of the reactor, elevator enclosure, and reactor vessel cooling system as well as at the exit from the intermediate and autonomous heat exchangers in different operating regimes.

This work is devoted to the application of a numerical method of solving Boltzmann’s equation for modeling the behavior of radionuclides (Kr, Xe, Rb, Sr, Cs, Ba) in the cavity of the interelectrode gap of a multielement electricity generating channel. Modeling methods were developed and software system implemented in the course of this work. Calculations were performed for two structural arrangements: with uni- and bilateral extraction of radionuclides into the vacuum-cesium system. Data on the pressure and flow distributions were obtained. The krypton and xenon pressure near the collector as functions of their flow and the cesium gas pressure at the gap exits were determined computationally.

This article is devoted to obtaining the α-emitter ¹⁴⁹Tb for radioimmunotherapy. A method for producing ¹⁴⁹Tb based on the reaction ¹⁵¹Eu(³He, 5n)¹⁴⁹Tb is proposed. It is proposed that europium with native isotopic composition (¹⁵¹Eu – 47.81%, ¹⁵³Eu – 52.19%) or enriched ¹⁵¹Eu be used as the target. The 29 MeV threshold of the indicated reaction makes it possible to use accelerators with the initial ³He energy 40–70 MeV.

The title of the article should read “Solid-Phase Interaction of Uranium Tetrafluoride with Phyllosilicates.”