System of Quality Control and Risk Assessment of Power Equipment During Operation of NPP Power Units
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Abstract
The paper develops a new system for monitoring the tightness of fuel elements (fuel rods), which is implemented in a fuel reloading machine. The proposed system enables to detect quickly fuel assemblies with leaking fuel rods during overloading, which is critical for improving the safety and efficiency of nuclear power plants. The mechanical and technological components of the fuel element cladding leakage monitoring system were improved. The mechanical part includes a bubbling pipeline and a sampling pipeline located on the sections of the working rod. The technological part includes units for compressed air preparation, gas sampling and activity measurement, as well as a data management system. The principle of operation of the system is to bubble air through a heat-emitting assembly, which allows detecting gaseous fission products that indicate the presence of leaky fuel rods. The system was found to reduce the amount of radioactive waste associated with overloading and also reduces the daily workload of personnel. Implementation of the fuel rod cladding leakage monitoring system ensures control of the tightness of each fuel assembly undergoing overload, which is an important step in improving the safety of nuclear power plant operation. Reducing the risk of accidents, shortening the time of reloading and reducing the need for clean borated water are significant advantages of the new system. The economic effect from the implementation of the fuel rod cladding tightness control system can range from 17.5 to 26.5 million UAH per power unit, which is equivalent to saving 4—5 fuel assemblies of fresh fuel. Thus, the article provides important recommendations for improving the quality of fuel element leakage control, which is relevant in the current energy security environment. Implementation of a leakage control system will help improve the overall reliability and safety of nuclear power plants, which is an important task for the energy industry.
