Rationalization of maintenance at the Krypton Recovery Development Facility by adding nitrogen replacement equipment and removing liquid nitrogen storage tank

Furuuchi, Yuta; Okada, Jumpei; Kimura, Norimichi*; Watanabe, Kazuki ; Hayashi, Yoshitsugu*; Hirayama, Yusuke*; Tashiro, Yoshiyuki*; Uchida, Naoki

At Krypton Recovery Development Facility in Tokai Reprocessing Plant (TRP), the nitrogen gas, which was supplied from the liquid nitrogen tank, was used instead of compressed air to manage the enclosure function of the facility during the compressor was broken. It was necessary to remove the liquid nitrogen tank possible because it had the possibility of being tsunami debris which affect significant impact on the other TRP facility. Before the tank removal, the automatic switching function was attached to the air compressors as nitrogen replacement equipment. This function switches the starting and stopping the compressors, opening and closing valves after detection of equipment failure. When attaching this function, additional equipment was minimized by utilizing existing equipment. Then, the liquid nitrogen tank was dismantled after transporting outside TRP. These works eliminated the cost of purchasing liquid nitrogen and inspections of the equipment.