Monitoring and Recovery of Tritium in a Fusion Test Facility

Abstract

In a large fusion test facility, when a deuterium-plasma experiment is conducted a small amount of tritium is produced by the d(d, p)t reaction. From the viewpoints of radiation management and public acceptance, the tritium monitoring and recovery systems were developed and installed for the fusion test device. As for the tritium monitoring equipment, an expiratory test system of tritium was utilized for the internal dose assessment of workers. Active tritium samplers were operated continuously to monitor the amount of tritium released from the stack. As for the tritium recovery equipment, an exhaust detritiation system (EDS) for the plasma experiment has been developed and installed at the downstream of the vacuum pumping system in the fusion test device. All of the exhausted tritium from the vacuum vessel was treated by the EDS during the deuterium-plasma experimental campaign. Then, the tritium recovery rate achieved was more than 95%.

Keywords:

• Radiation management
• tritium monitoring
• tritium recovery
• fusion test facility
• exhaust gas

Acknowledgments

This study was supported by the National Institute for Fusion Science budget (ULAA023, ULAA708) and the Japan Society for the Promotion of Science KAKANHI Grant-in-Aid for Scientific Research C (grant number 17K06998). One of the authors (M. T.) is grateful to Ms. M. Nakada, Mr. S. Hashimoto, and Mr. T. Nishimura of the NIFS for their technical support.