A software subsystem for the formation of forecasts of coal production in Ukraine has been developed under the conditions of instability of the structure of the country's fuel bases, which arise as a result of force majeure factors, in particular, martial law, temporary occupation of the territory, destruction of mining enterprises, etc. The program was created with the aim of providing opportunities for a quick assessment of the impact of emergency situations in the country on production volumes in the coal industry and their further consideration during developing forecasts of the fuel supply of the economy, and the energy balance of the country as a whole. The software is created on the basis of databases detailed by coal mining facilities, and professional forecasts of the development of the coal industry, which take into account the mining and geological, technological, economic, and social features of the functioning of mines, as well as possible scenarios of their technological conversion, optimization of production areas and allows to make such forecasts by changing the expected production state of the mine upon the occurrence of force majeure circumstances. The developed forecast adjustment subsystem enables change quickly the structure and composition of the country's coal base; calculate the aggregate volumes of coal production, differentiated by grades of coal and its technological purpose and according to several scenarios of the technological development of the coal industry, which will take place under selected changes in the structure of the mine fund; form general production forecasts, which contain calculated aggregate volumes for all terms of the forecasting period. With the loss of all mines in the Luhansk region and some mines in the Donetsk region as a result of the full-scale invasion of Russia into Ukraine, the forecast scenarios of the development of the coal industry of Ukraine for the period until 2040 were adjusted using the software subsystem for forecasting the volume of coal production. Keywords: coal industry, software subsystem, forecasting, mining, development scenarios.

The successful supply of an economy with coal fuel, for a country that carries out its large-scale extraction and import, is a complex production and logistics problem. Violations of the usual supply scheme in conditions of crises in the energy markets, international conflicts, etc., lead to the problem of simultaneous restructuring of the entire supply scheme. This requires changes in the directions and capacities of domestic production and imports. In this article, the above problem is solved by the economic and mathematical model of production type. The developed model includes subsystems of domestic production and import supply. The results of modeling economy supply with thermal coal for different values of demand are given. The model was used to determine the amounts of coal production for Ukraine with the structure of the coal industry of 2021 and under the condition of anthracite consumers’ transformation to the high volatile coal. Simulations have shown that eliminating the use of anthracite requires the modernization of existing coal mines. Under those conditions, the import of high volatile coal will amount to 3.751 million tons in 2030 and 11.8 million tons in 2035. The amounts of coking coal imports will be 5.46 million tons, 5.151 million tons, and 7.377 million tons in 2025, 2030, and 2035, respectively.

The mechanisms of cable ageing at nuclear power plants (NPPs) mainly depending on the insulation material, as well as the damaging factors affecting cables that are determined by the operating conditions are considered in the paper. The main and additional mechanisms of aging resulting from the effects of damaging factors are provided. The paper presents the main methods of cable aging management: determining the actual service life and testing using field methods and other means. The basic principles for the arrangement of cable aging management at Ukrainian NPPs, as well as the methods used to investigate the technical condition of cables, are presented. A list of mandatory lists has been defined when performing activities on cable aging management. A methodology is described for lifetime extension of cables, and conditions for extending the service life of cables that are in service are provided. A number of methods of testing cables for aging management are considered: visual inspection of insulation and measurement of crack size, discoloration, etc.; insulation hardness test; insulation chemical analysis; electrical insulation tests; tensile strength measurement; measurement of elongation at break; measurements of dielectric loss at low frequency or sweep frequency; testing by dynamic reflectometry method; AC and DC current impedance measurements. The paper presents results of separate laboratory studies for selected 1 kV representative power cables with PVC insulation of SUNPP-1, ZNPP-1 and KhNPP-2 conducted within Ukrainian NPP long-term operation, which included a stage of laboratory examination and examination of cable samples in operating conditions. The following results were obtained: dependence of VVGng 4x6 cable lifetime on operating temperature; dependence of AVVG cable lifetime on operating temperature; dependence of AVVG (a) cable lifetime on operating temperature. There are possibilities and conditions under which the use of cables within long-term operation is permissible.

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