The joint European torus (JET) was the only tokamak capable of deuterium–tritium (D–T) operations in the last 30 years. The first D–T operations were in the 1990s and again in 2004. In 2020/2021/2023, JET operated a much larger D–T and pure T campaigns aimed at sustained high fusion power, requiring a much higher tritium throughput. This paper presents operational aspects of the recent tritium injections into the JET tokamak. Tritium injection into the JET tokamak involves transfer of tritium between the Active Gas Handling System (AGHS) and the tritium gas injection modules (TIMs) and neutral beam injectors (NBIs), the control of TIMs, and NBI, gas inventory (pre-pulse estimate, post-pulse usage), gas limits (explosive, tritium) etc. Operations require close collaboration of staff in the JET Control Room,), AGHS, vacuum, and cryogenic groups.
This paper discusses the operational challenges of injecting tritium into the JET tokamak, a fusion reactor, to achieve high fusion power. It covers the transfer of tritium between systems, control of tritium injection, gas inventory management, and safety limits to prevent explosions.