Vol 126, No 5 (2019)

The concept of a small gas-cooled reactor for the Brayton cycle using reactor technologies, design solutions, and existing experience of NIKIET is proposed. The concept is based on the optimal use of existing materials in the design and implements the principles of universality, modularity, and compactness. Variants of the reactor design, design of the transport lock system, cooling channel of the critical components of the reactor vessel, and radiation protection are presented.

The specifics of an NPP operating organization’s deferred financial liabilities for SNF management and the impact on them of the infrastructure formation rate at the final stage of the NFC are examined. The financial aspects of the problem and the current state and plans for the formation of an industrial complex for SNF management are examined. As an example of a computational analysis, it is shown that shifting the commissioning dates for the spent fuel reprocessing facilities greatly affects the deferred liabilities and, correspondingly, the financial stability of the company. Analysis of the dynamics of the change in the liabilities over time determines the importance of creating and managing a special reserve fund, taking into account the attendant risks of increasing the NPP’s cost of electricity production as a result of an increase in the current expenses for spent fuel management. Conclusions are drawn about the effect of individual reactor technologies on the structure of the deferred liabilities.

A cascade scheme allowing two intermediate-mass isotopes to be concentrated in a single cascade above the maximum admissible concentrations at the outputs of ordinary cascades is proposed. A cascade with two flow expansions and two additional product flows is used for this. For the example of a mixture of tungsten isotopes, it is shown that the concentrations of ¹⁸³W and ¹⁸⁴W can be increased simultaneously up to 70 and 80%, respectively. In addition, additional product flows can be equal to 50–70% of the primary (end) product flow of the cascade.

The activation method was used to determine the cross sections of the nuclear reactions ⁸²Kr(³He, 3n)⁸²Sr, ⁸³Kr(³He, 4n)⁸²Sr, and ⁸⁴Kr(³He, 5n)⁸²Sr in the ³He energy range 20–75 MeV on targets with highly enriched krypton isotopes. The results were used to calculate the ⁸²Sr yield in a yield-optimized cascade target with ^82,83,84Kr and initial ³He energy 75 MeV. The computed ⁸²Sr yield was equal to 2.9 MBq/(μA·h), which makes it possible to count on the practical application of the method of ⁸²Sr production based on the reactions ^82,83,84Kr(³He, xn)⁸²Sr in a cascade target.

The aim of this work is to evaluate variants of the calculation of the average multiyear meteorological dilution parameters based on a Gaussian dispersal model for constant emissions. Three variants of the calculation of the meteorological dilution parameters which are distinguished by different degrees of detailing of the atmospheric stability categories and their characteristic wind speeds, which determines the difficulty and complexity of the calculations, are examined. It is shown that at distances >1000 m from the source of emissions all three computational variants give comparable results and can be used to estimate the radioecological conditions in the environment. The computational variant 1, which takes account of the realization of the atmospheric stability category and its corresponding gradations of wind speed, is the preferred option. It makes it possible to obtain more accurate estimates of the constant radioactive fallout density.

The topical problem of increasing scientific and technical support for level 5, associated with emergency planning and response, of the protection-in-depth system of NPP is examined. As severe accidents have shown, the greatest socioeconomic harm is associated with the excessive response by decision makers. There is a need to increase scientific-technical and methodological support for level 5 of the protection-in-depth system. It is shown that the use of risk-based approaches and the methodology of level-3 probabilistic safety analysis will make it possible to avoid scaling-up the socioeconomic consequences of radiation accidents and to optimize the available forces and means for mitigating the consequences of accidents.

The 15th author’s name should read I. A. Gulidov.

The caption for Fig. 3 on page 336 should read