Safeguards equipment for the spent nuclear fuel of pressurized heavy water reactors

Abstract

This paper describes the implementation of newly developed safeguards equipment for the spent nuclear fuel of heavy water reactors stored in a wet interim storage facility. The developed equipment compensates for imperfections in the existing equipment including the optical fiber probe system (OFPS) and improves the performance and user convenience. Specifically, the lithium glass scintillator currently used in the current OFPS was changed to a plastic scintillator with efficient and cost-effective detectors, and the probe design for the radiation measurements was also changed to facilitate replacement of the scintillator. In addition, the manual cable loading method, which is an obstacle method for implementing safeguards, was designed to be automatically loaded onto a drum-shaped structure using a motor. All analog systems such as radiation signal processing systems and cable loading systems that used to run along all the equipment were digitally replaced so that all operations could be done with display panels. Through these efforts, the new equipment resulted in improved performance and enhanced user convenience. The replacement of the scintillators and probes improved the performance by about 10 times, and the new equipment design reduced the number and weight of the parts to less than half that of the existing equipment. The performance of the newly developed equipment was verified so that it can be used as new IAEA safety equipment, and it is expected to have a major role in implementing safeguards for spent nuclear fuel through its registration as IAEA inspection equipment.