29th Symposium on Fusion Technology (SOFT 2016)

P4.170 Operational aspects of the JET Tritium Introduction Modules

8 Sep 2016, 14:20

1h 40m

Foyer 2A (2nd floor), 3A (3rd floor) (Prague Congress Centre)

Board: 170

Poster H. Fuel Cycle and Breeding Blankets P4 Poster session

Speaker

Ivo Carvalho (Instituto de Plasmas e Fusão Nuclear)

Description

As part of the JET Programme in Support for ITER, campaigns with pure Tritium-Tritium (TT) fuel and Deuterium-Tritium (DT) mixture are planned at JET. Unlike the previous DT campaign at JET, these campaigns require a much higher tritium flow rate, particularly, the TT campaign can require up to 3.7 grams of tritium on a single pulse. Five tritium introduction modules (TIMs) fed from the Active Gas Handling System (AGHS) are to be installed; three on the divertor region, one in the mid-plane and another on outer top of the machine. The TIMs location, design, operational characteristics were chosen so that most Deuterium experiments can be matched in Tritium.Since the access to the machine will be severely limited, the TIMs were designed to accommodate a reliable and redundant operation while maximising the operational space. Each TIM includes two five litre reservoirs and two high flow piezoelectric valves (1.6 Bar.L/s) that can be operated together or independently, thus maximising the system flexibility and compatibility with different experiments requirements. The low reservoir volume combined with a high flow valve requires a precise control of the valve opening in order to reproduce a pre-set gas flow waveform, this is achieved by adjusting the opening request according to the reservoir depletion throughout the pulse. Several use cases are described in the paper.In addition Tritium accountancy will play a critical role in the future Tritium campaigns. In total 60 grams of Tritium will be used and recycled through the AGHS. Safety considerations limit the quantity of Tritium inside the JET tokamak to 15 grams, implying that the tritium calculation pre-pulse, correct operation during the pulse and accountancy after it have to be accurate and reliable. This paper provides a guidance on the Tritium inventory monitoring system while detailing the operation sequence.