JET Active Gas Handling System–operating experience and lessons learned from recent D-T campaigns

The Active Gas Handling System (AGHS) stores, supplies and re-processes tritium for the JET fusion experiment. The plant had not operated in this capacity in recent years and required upgrade and recommissioning to enable use during the latest JET tritium campaigns. Thousands of tritium transfers and operations have now been performed with over 1 kg tritium in total supplied to JET and subsequently recovered and reprocessed. This paper summarises AGHS plant operations providing examples from the recent campaigns, and presents the knowledge gained and lessons learnt. A summary of AGHS sub-system upgrades and usage during campaigns is presented. This paper includes data captured from those operations, which have been extracted from the control system as part of a wider AGHS data capture project. Findings are presented from an initiative to capture operator knowledge from AGHS, which brings together operational team input in working groups, a targeted survey and an ideas repository. Key operations are discussed with reference to plant data presented graphically. Operational challenges and lessons learnt are presented from which improvements to design and operations have been proposed. Topics discussed include system design and limitations, process control and automation, tritium accountancy, operating instructions, and ergonomics. Many of the lessons learnt and improvements presented here are relevant to the wider fusion community planning to design and operate tritium plants.