The paper states that various emergencies may occur at nuclear power plants under different negative conditions. Such emergencies pose a significant risk for the natural environment, health of personnel and the public of the adjacent territories. There are examples of the major accidents at NPPs worldwide, which lead to serious radiation contamination of the environment. It is noted that one of the main tasks of the Energoatom in the sphere of emergency preparedness and civil defense in the nearest future is to improve the systems and equipment, engineering, software and hardware support of the emergency preparedness and response system dealing with NPP emergencies. The improvement of this system requires the knowledge of causation chains of emergency progression in specific conditions. Therefore, the paper is devoted to the in-depth analysis of possible causes of different emergencies at NPPs that will allow the development of new and more efficient approaches and methods of their prevention. There is a definition of emergencies and their main types. The researchers analyzed a number of references on the studies in civil defense of radiation hazardous facilities and presented that despite the implementation of technologies and automated NPP monitoring systems, the threat of potentially hazardous situations remains relevant. Besides, the most significant are the emergencies that cause radioactive and chemical contamination of the environment. The paper provides the dynamics of emergencies in Ukraine and experience of applying the IAEA Unified System for Information Exchange in Incidents and Emergencies (USIE). It describes the main operational events at Ukrainian NPPs in 2017 and presents the distribution of operational events at Ukrainian and Russian NPPs. There are safety factors considering national regulatory documents and IAEA recommendations to assess the current safety level of NPP unit and the main causes of emergencies on NPP sites. The example of SUNPP-2 shows the quantitative characteristics of internal and external impacts on its safety. Provides an example of the system for prevention and mitigation of emergencies at Ukrainian NPPs, as well as lists its main tasks.

Analysis of informational provision level of complex environmental monitoring system in surveillance zones of Ukrainian NPPs was carried out. It was established that different subsystems are used for solution of monitoring tasks. The systems are separated, heterogeneous, hardware-software incompatible, and aimed at observation and state assessment of specific components of the environment and natural resources. Such situation is not in compliance with the up-to-date European requirements and standards for environmental monitoring information systems in areas of influence of man-made facilities. It is demonstrated that solution of this problem is possible by developing an information and analytical expert system for evaluation of NPP environmental impact on the environment (EcoIES). The main tasks that will be solved by EcoIES and its specific functions during emergencies or corresponding emergency exercises were described. The main requirements for the system are consistency, openness, standardization and adaptation. Specific requirements are the completeness and hierarchy of information, comprehensive integration and rational use, semantic unity, compatibility of system components, integrated security. Three options of conceptual approaches to creation of EcoIES have been developed, each of which is characterized by its structure, level of hardware-software provision and organization of information exchange. The option, which to major extent is in compliance with the European requirements has been substantiated, and which allows to fully solve radiation and environmental safety tasks, as well as civil protection of population, territories and the environment in the surveillance zones of Ukrainian NPPs. Therefore, this approach is recommended for further practical implementation at NPPs in Ukraine. The basic scheme of structural organization and interconnections between the EcoIES and other subjects of environmental monitoring that are part of the State environmental monitoring system has been developed.

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Purpose: The main problem with the use of rescue instruments during emergency response is the low strength of the tool’s cutting edge. The consequence of this is the low efficiency of rescue operations. The purpose of this study is to substantiate experimentally the choice of material for the tool’s cutting edge and the method of surfacing it on the cutter of a hydraulic tool, operating under the simultaneous influence of friction and cyclic loading. Design/methodology/approach: The choice of material was carried out by the way of analytical analysis with subsequent experimental verification. For this purpose, specially made samples of cutters from various grades of alloyed steel were used. With these cutters the steel rod Ø 12 mm made of St3 steel was cut; the number of cutting cycles preceding blunting or destruction of the cutting edge of the tool was counted. Analytical study of the possibility of cutter’s surface hardening by fusing the cutting edge onto it was carried out by the way of analyzing scientific research in the area of improving the technical characteristics of a mechanized hydraulic tool. Findings: It has been experimentally established that Steel 30HGT gives the greatest number of working cycles before blunting, while steels of the manufacturer (Steel 65G and Steel 12M) are destroyed in 180 and 200 working cycles, respectively. Other steels are not destroyed, but can stand fewer number of cutting cycles. To reduce the cost and increase the efficiency of rescue operations, it is proposed to perform surface hardening of the tool cutter by fusing the cutting edge made of Steel 30 HGT steel (analogs: in Germany – 30MnCrTi; in the Czech Republic – 14231). Analytical research has shown that manual arc welding as a method of welding metals is widely tested, reliably reproducible, allows for surfacing in any conditions outside the fabrication facility and is carried out with non-bulky equipment. This will increase the life of the hydraulic rescue tool. Research limitations/implications: The study was conducted for steels that meet the requirements of national standards. Practical implications: Equipping rescue workers with a mechanized tool that has been upgraded by the proposed method improves the efficiency of rescue operations in emergency situations. Originality/value: It is proposed to increase the strength and reliability of a mechanized tool for rescue operations. For the first time, an attempt to substantiate the choice of method for hardening the cutting edge of an instrument by applying reliably reproducible technologies was made.

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