4 power supply sources for the experimental EFDA-JET fusion reactor

JEMA has been contracted directly by the European Commission (commissioned through the European Fusion Development Agreement, EFDA) to design, construct and install 4 sources of power supply, each capable of producing 20 million watts of energy, for the European experimental fusion reactor installations located at Culham in the United Kingdom. The project is expected to last three years.

The contract is a sound example of the confidence these European agencies have in the work of JEMA, especially as this is a re-order on a previous contract in 2003 when the company supplied 2 units of these energy supply sources for the same centre.

Fusion reactions are produced within the stars at extremely high temperatures, thus generating energy in the form of light and heat, mainly with hydrogen as the raw material. In this type of reactor these reactions inside a star are being imitated in order to obtain energy. In fact the EFDAJET reactor is the largest in the world currently in operation and, as such, the reference for the scientific community throughout the world working in this field. At the same time, it is the system from which the new ITER reactor is to be developed, and which is to built thanks to an international agreement which will be the greatest scientific-technical project undertaken by mankind.

To explain in a nutshell the importance and scope of the project, the JEMA supply sources feed energy to the microwave systems that heat up the deuterium (hydrogen isotope) stored inside the reactor, with the aim of reaching a temperature of some 150 million degrees, necessary for the initiation of a fusion reaction

These power supply sources consist of special-characteristics equipment that are manufactured in a customised manner and are at the cutting edge of what is today manufacturable and the latest available technology.

Each supply source produces 20 million watts of electrical power (about 10% of the energy produced at the power station in the Basque port of Pasajes) in pulse format and using 130,000 volts d.c. power supply at 130 amperes, with high quality and precision specifications: less than 1,000 volts of error; 150 microseconds rising ramp and 7 microseconds falling ramp. Over a period of 20 seconds the power supply source is capable of generating 256 pulses, which is equivalent to short-circuiting the energy source itself on its exit.

To achieve the specifications required it has been necessary to develop a wide range of innovative elements and configurations (260,000 volt insulating transformers, high-voltage static crowbars, DSP control, refrigeration systems for water, etc.), which have required joint work with various research centres.