Analysis of Possible Causes of NPP Emergencies to Minimize Risk of Their Occurrence

Abstract

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.