News & events
It's T time for JET | 23/06/2014
Engineers at CCFE have begun to prepare Europe's flagship fusion device JET for a new set of full-power experiments using tritium fuel.
The tests, currently scheduled for 2017-18, will be the first with tritium since 2003 and will act as an important ‘dress rehearsal' for the key international ITER project, due online in the early 2020s, in preparation for ITER's own operation with tritium.
To generate large amounts of power in commercial tokamak reactors, a combination of two heavy hydrogen nuclei – deuterium (D) and tritium (T) – will be required to fuel the fusion furnace. However, supplies of tritium are scarce and its radioactivity makes it impractical for use in most fusion research labs. For fusion power stations neither issue should be a problem; a lithium ‘blanket' around the tokamak will react with the fusion neutrons to produce tritium fuel within the device itself, and remote-controlled maintenance systems will ensure safe handling of material exposed to tritium and fusion neutrons. (JET has been at the forefront of the development and highly successful implementation of remote handling technology.) Today though, to avoid the complications of tritium, the vast majority of fusion research is conducted with deuterium fuel only. This provides very accurate results that can be scaled up to predict the performance of future D-T reactors. But for the best simulation of how ITER will operate with D-T, there is nothing like the ‘real thing' – a series of fusion tests with both fuels.
That's where JET comes in. As the world's largest operating tokamak and the only such device capable of storing, using, recovering and recycling tritium, it has a unique role in fusion research. And upgrades since the 2003 tritium campaign – particularly the ‘ITER-like' inner wall of beryllium and tungsten – have effectively turned JET into a ‘mini-ITER'; as close as any present-day device can get to its operating conditions. Another series of D-T experiments on JET will therefore provide scientific information to help make ITER a success, as well as giving physicists and engineers vital experience of running fusion machines with tritium.
Although 2017/18 seems a long way off, much work has to be done to get JET ready and the countdown has already started. Many systems on JET (plasma heating, diagnostics, vacuum and pumping to name just a few) are being assessed, upgraded and commissioned, and safety arrangements revised and authorised. This is a significant undertaking for CCFE as the operator of JET, and there is no time to lose. With this in mind, the ‘Delivering JET D-T Capability' project team of 70 staff was formed earlier this year to co-ordinate the plethora of tasks involved.
These engineering preparations are noted by Ben O'Meara, D-T Project Lead Engineer: “Preparing for the D-T campaign is a very intricate and complex project in its own right; there are literally thousands of interlinked tasks to be completed before we can start the first plasma pulse. We are utilising a broad foundation of engineering and science-based expertise within our focused project team to ensure that we deliver an efficient and safe set of D-T experiments.”
Just as important as ensuring JET equipment is fit for purpose is training staff members in how to operate JET with tritium – something that is new to many recent employees. This is an activity that Robert Warren, D-T Project Manager is fully aware of: “We have not operated JET with significant amounts of tritium since 1997, so we need to re-learn how to do this safely and effectively. The staff training aspect is vital if we are to succeed in JET fully exploiting its unique tritium capability.”
JET is a major part of the overall EUROfusion research programme co-funded by Euratom, and D-T operations will be the highlight and culmination of JET's programme in the present funding period (up till 2018). The world of science and technology – not least ITER – will be watching the results, and researchers will be hopeful of setting new fusion performance records. So the pressure is on the CCFE team, as project sponsor Tim Jones recognises:
“It's a big challenge, but we're up for it. We know how important the D-T experiments are for JET, ITER and the wider fusion programme. We've done it before, we have a clear timetable and we will be ready by 2017.”
Above: the project management team from left to right - Ben O'Meara (Project Lead Engineer), Robyn Davies (Technical Clerk), Tim Jones (Project Sponsor), Alex Rowley (Requirements/Systems Engineer) and Robert Warren (Project Manager).