Major New Tokamak Planned in Italy

May 4, 2018

One of the main challenges for tokamak-based fusion is to design a heat and power exhaust system able to withstand the large loads expected in the divertor of a tokamak DEMO fusion power plant. Therefore, in parallel with the program to optimize the operation with a conventional divertor based on detached conditions to be tested on the ITER device currently under construction in Cadarache, a specific project has been launched by the Italian energy and technology agency ENEA to investigate alternative power exhaust solutions for DEMO fusion power plant, by constructing a Divertor Tokamak Test facility (DTT).

This new tokamak would be capable of hosting scaled experiments integrating most of the possible aspects of the DEMO power and particle exhaust. DTT will retain the possibility to test different divertor magnetic configurations, liquid metal divertor targets, and other possible solutions for the power exhaust problem. The DTT design aims to a set of parameters selected so as to have edge conditions as close as possible to DEMO (in terms of the temperature and the normalized collisionality, pressure and ion gyro radius), while remaining compatible with DEMO bulk plasma performance in terms of dimensionless parameters within a set of constraints related to flexibility and costs.

A site near Rome has beaten eight other locations in Italy to host the €500 million DTT. Italy’s energy and technology agency ENEA says that its research centre in Frascati will host the facility with construction set to start in November. The DTT will take seven years to complete.

The divertor for ITER, which is currently being built in Cadarache, France, is made from tungsten tiles. However, this material is unlikely to be adequate for an actual demonstration fusion power plant that would feed electricity to the grid continuously. The DTT, being 10 m high and with a 5 m radius, will therefore investigate alternatives types of divertor that could suit a future reactor. The machine will use superconducting magnets to contain a plasma and would have space around the edges of its plasma chamber to incorporate divertors of different shapes to spread the heat load over a larger area. It could also test divertors made of more resistant materials, such as liquid lithium.

ENEA says about 1500 people would be involved in building the DTT. They expect the project to be funded by €60 million from Eurofusion, (reserved but not yet committed), while another €80 million would come from the Italian government. They expect the regional government to supply €25 million, while China would provide €30 million and ENEA partners another €50 million. The remaining €250 million would come from the European Investment Bank via a loan.

For more information visit: http://www.fsn-fusphy.enea.it/DTT/?jjj=1522916773320