Development of a differential pressure switch to be operated correctly, under negative pressure at the Tokai Reprocessing Plant

Yasuo, Kiyoshi ; Morimoto, Kenji; Seto, Nobuhiko; Watahiki, Seiichi

Cells and vessels as well as buildings have maintained as a negative pressure to keep nuclear materials inside. Differential pressure switches, detecting change of liquid level and pressure at reprocessing plant, have been required airtightness for the nuclear materials containment under negative pressure. Problem of using the conventional airtight switch is, however, that could not meet the acceptable range with deep negative pressure. We have designed and made a prototype airtight switch applying a new type of pressure detection component. The prototype switch has been reliable on the actual usage, which has been evaluated by an operation, a vibration and an endurance test. We are improving its quality for adapting to the reprocessing process.