The aim of nuclear fusion is
to produce the energy of the stars on earth.
When matter reaches very high temperatures and
densities, as in the centre of the sun, hydrogen atoms fuse and release
great amounts of energy. This is the reaction that scientific
researchers are attempting to reproduce on earth.
To accomplish this, temperatures at about 100
million degrees must be reached and maintained while isolating the
matter in an ionised gas state (plasma) from the walls of the machine
through the use of powerful magnets: this is the configuration of the
tokamak.
Research on fusion at Cadarache is currently
being carried out in the TORE SUPRA facility, a supraconductor magnet
tokamak. Beginning in 2016, further research will also be carried out
in the international ITER reactor.
Since 1988, the date of its commissioning, the
TORE SUPRA research facility is the largest supraconductor magnet
tokamak in the world. It is supervised by the European association of
EURATOM/CEA
In this machine, confinement of the plasma is
obtained through the superimposition of two magnetic fields that act as
invisible rails guiding the particles. The constant, uninterrupted
functioning of its magnet, associated with actively cooled components
confers the capacity of TORE SUPRA to produce high performance plasma
over long periods of time.
To achieve these scientific objectives, TORE
SUPRA has a means of heating the plasma using microwaves for a total
available power on the order of 15 MWth*.
The internal wall of the tokamak is permanently
cooled by a high-pressurised water circuit.
In addition to this, a specific device called the
circular limiter, enables researchers to evacuate most of the power
released by the plasma; this is what allowed TORE SUPRA to obtain a
record plasma in 2003 with a pulse of more than six minutes during
which time, energy on the order of 300 kWh was injected and extracted.
Teams from Cadarache have also been involved in
programmes led by the JET tokamak project in the United Kingdom, which
in 1997 succeeded in establishing a world record of 16 MW.
* MWth (thermal Mega Watt) unit measurement of thermal power (heat) MWe
(electric Mega Watt) unit measurement of electrical power
With ITER, Cadarache prepares to welcome one of
the most important research projects of the 21st century
In choosing to build ITER on the site of the
Cadarache Research Centre, the partners of the ITER project will
benefit from an exceptional environment of researchers and remarkable
technological and scientific expertise. ITER, constituting a key stage
in the history of fusion research, will be the first research facility
in the world to integrate technological developments perfected in
Europe with the TORE SUPRA facility at Cadarache, at the JET facility
in England and in the rest of the world with the JT-60 in Japan and the
TFTR in the United States.
The goal of ITER is to demonstrate the
feasibility of fusion as a potential source of energy. Once this final
stage of research has been completed, it will be up to the DEMO
demonstrator to produce electricity in 2040. Very high temperatures
must be reached in ITER in order to create fusion reactions that
resemble those existing in the centre of the sun. These temperatures
allow deuterium and tritium atoms (hydrogen isotopes), introduced in a
gaseous state in the core of the research reactor, to fuse. With ITER,
the main objective is to obtain fusion reactions ten times greater (500
MW) than those obtained up to the present time (50 MW). Equipment in
ITER must also be tested for future industrial fusion reactors.
ITER is one of the most important international
collaborations in the world. The project combines the efforts of China,
the United States, Europe, the Russian Federation, India, Japan and the
Republic of South Korea – more than half of the
world’s population.