tore supra - CEA Cadarache

TORE SUPRA
The Sun shines because the matter of which it is composed reaches densities and
temperatures high enough to allow hydrogen nuclei to fuse and transform into helium
nuclei. The reaction is accompanied by an enormous release of energy in the form of
heat and radiation. The gravitational pull enables this ball of fire to sustain these fusion
reactions in its centre where a temperature close to 15 million degrees reigns.
Reproducing this same fusion reaction on Earth is quite another story!
The fuel must be a mixture of deuterium and tritium, two hydrogen isotopes1. Temperatures
of approximately 150 million degrees must be reached and continuously maintained in
order to ensure the effectiveness of the fusion reaction. At these temperatures, the matter
is in a “plasma”2 state (Electrons are no longer linked to the nucleus). In addition to this,
a non-solid wall must be built around this plasma using extremely powerful magnets (No
matter whatsoever can withstand such temperatures.)
This idea has come a long way since the 1920’s. The Russians were the first scientists in the
1950’s to obtain conclusive results in their quest to develop controlled fusion in a machine,
called the Tokamak3.
1
Two atoms are termed “isotopes”
if their nuclei have an identical
number of protons but a different
number of neutrons.
2
The 4th state of matter: This is
composed of charged particles
(ions and electrons).
Russian acronym which stands
for the words “Toroidalnaya
Kamera Magnitinymi katushkami”
(meaning: “Toroidal vacuum
chamber and magnetic coil”):
This literally designates
a machine in the form of a torus.
A torus is a tubular-hooped
metal vessel shaped like
an American doughnut!
3
4
Materials that, cooled to a
low temperature, present zero
electrical resistance.
Fusion reaction
In France, within the framework of the EURATOM/CEA association, research on fusion energy has been
centralized in the TORE SUPRA facility which was commissioned in 1988 at the CEA Cadarache Research
Centre.
TORE SUPRA is the first tokamak in the world to be equipped with superconducting magnets4 and other
equipment that has enabled researchers to produce long-length plasmas (6 minutes and 30 seconds
obtained in 2003). The JET (Joint European Torus) machine, located in the United Kingdom and the largest
tokamak in the world, for its part holds the world record of fusion power (16MW of power resulting from
fusion reactions in one second using a mixture of deuterium and tritium) since 1997.
The technical and scientific success of both TORE SUPRA and JET has helped in the elaboration of the
ITER International Project, now under construction at Cadarache with a two-fold purpose of sustaining
duration and power. Based on deuterium and tritium, ITER must be able to produce ten times more power
(500 MW) than necessary to heat its plasma (50 MW).
The objective of the ITER programme is to acquire enough knowledge and experience to design and
eventually operate a pre-industrial reactor called, “DEMO” that will produce electricity.
Interior view of the
TORE SUPRA machine
Preparing the Future:
TORE SUPRA, a facility of The Institute of Research on Magnetic Fusion (“IRFM”) is devoted
to the technology and physics of “continuous” plasmas
Development of the first large-scale magnets composed of superconductor materials (niobium, titanium),
which, when cooled at low temperature (-271° C for Tore Supra), enable researchers to create powerful
continuous magnetic fields.
A current of 1200 amperes in the coil generates a magnetic field of 4 Teslas at the center of plasma without
heating the coil.
Superconductor filaments
A heating means in the plasma that uses waves. These waves are created by different
types of generators depending on their frequency and coupled to the plasma through
antennae. Certain antennae are used to generate direct current in the plasma to
ensure its permanent flow. A total of 15 MW is thereby available on TORE SUPRA.
The development of elements opposite the plasma that can withstand continuous high
thermal fluxes, with particular attention focused on the property changes occurring in
the component due to its continuous exposure.
THE WEST PROJECT: moving toward an evolution in the machine to become
the test facility for the ITER project involving any thematic strategy
concerning long-length plasma performances in the ITER environment.
The toroidal pumped
limiter
Numerical simulation (Gysela):
an example of plasma turbulence
Experiments coupled to
numerical simulations in
order to understand and
predict the behavior of the
plasma.
Tore Supra
West
CEA Cadarache • 13108 Saint-Paul-lèz-Durance
+33 (0)4 42 25 33 60 (visites) • +33 (0)4 42 25 70 00 (standard)
www.cad.cea.fr
Crédit photos : CEA, P. Stroppa-CEA, NASA, EFDA, ITER • Design PUBLICOM • March 2013
A heating antenna