Operational aspects of the JET tritium introduction modules

• Published in: Fusion engineering and design 2017-11, Vol.124, p.841-845
• Main Authors: Carvalho, Ivo S., Wilson, David, Keenan, Tom, Felton, Robert, Belonohy, Eva, Banks, Joe, Omolayo, Sol, Sips, Adrianus C.C., Price, David, Camp, Patrick, Knipe, Stuart, Medley, Sarah
• Format: Article
• Language: English
• Subjects: Atmospheric pressure; Control valves; Deuterium; Flow velocity; Fusion; JET tokamak; Joint European Torus; Modules; Nuclear fusion; Nuclear power plants; Orifices; Piezoelectric valves; Piezoelectricity; Prototypes; Reactors; Tritium
• ISSN: 0920-3796; 1873-7196
• DOI: 10.1016/j.fusengdes.2017.03.069

•Five tritium introduction modules (TIMs) fed from the Active Gas Handling System (AGHS) are to be installed in JET.•The TIMs were designed to accommodate a reliable and redundant operation while maximizing the operational space.•6000 JET pulses were analyzed in order to find the best TIM distribution.•A prototype injector was tested to access the maximum flow rate at sub-atmospheric pressure. As part of the JET Programme in Support for ITER, campaigns with pure Tritium (TT) fuel and Deuterium-Tritium (DT) mixtures are planned at JET. Unlike previous DT campaigns a much higher tritium flow rate, particularly during TT operation, is required. Five Tritium Introduction Modules (TIMs), fed from the Active Gas Handling System (AGHS), are to be installed; three in the divertor region, one in the mid-plane and another at the top of the machine. The selected TIM locations, the design and operational characteristics, were chosen so that most of the existing deuterium experiments can be replicated in tritium. The purpose of the TIMs is to supply precisely controlled quantities of tritium to the JET machine and this is achieved by controlling the piezoelectric valve openings. These control valves are located after the reservoir volumes, which contain tritium at sub-atmospheric pressure (charged initially to ∼800mbar). Prototype piezoelectric valves developed by VAT Vacuumvalves AG, require an estimated stroke of 160μm for the valve orifice area of 5.2mm2. These valves are at present being tested, with the aim of delivering a maximum flow of 1.6bar.l/s with tritium at 800mbar. This paper presents statistics to justify the operational requirements and details the TIM design including the operation sequence.