Development of Accident Tolerant Instruments for Nuclear Safety

This technical report outlines the development and implementation of new accident-tolerant instruments designed to enhance the reliability of measurements during severe accidents in nuclear power plants. Following the Fukushima Daiichi Accident, regulatory requirements have mandated improvements in instrumentation and monitoring systems for severe accident management. The report details the design and functionality of new sensors, including pressure, water level, and hydrogen monitoring systems, which are capable of withstanding harsh environmental conditions such as high temperatures, high pressures, and radiation exposure. It discusses the intended applications of these sensors, their specifications, and the qualification testing they underwent to ensure operational reliability in extreme conditions. The report also highlights the current status of these sensors in domestic Pressurized Water Reactors (PWRs) and the ongoing standardization initiatives to further enhance safety measures in nuclear energy systems.