Improving the Method of Quality Control of the Fuel Element Shell in Order to Improve the Safety of a Nuclear Reactor

The analysis of existing methods for controlling the quality of nuclear reactor fuel element shell was carried out and it was found that the methods use to detect surface and internal defects is characterized by limited efficiency and requires additional assessment. To evaluate the quality of the surface of the shell material in case of damage and destruction, it is proposed to use a computing device based on the method of fractal theory. It is proposed to use the fractal properties of the structure and the quantitative fractal values. These values make it possible to estimate the degree of the shell material volume change during depressurization of the fuel element. The mathematical model has been developed to describe the process of destruction of the fuel element shell material under the simultaneous impact of high temperature and internal pressure. The criterion for assessing the quality of the fuel element shell integrity has been developed, which сonsiders changes in fuel element shell geometric parameters during damage and destruction of the structure. The obtained practical recommendations can be used to implement the proposed method of quality control of fuel elements shell integrity in modern control system of a nuclear power plant power unit. This method application will make it possible to detect potential depressurization of fuel elements at an earlier stage, which, in comparison with standard methods, can increase the efficiency of the quality control system for the tightness of the shells.