Výběr zpráv ze sítě NucNet - 11. týden 2006
China’s Fusion Research Programme
17 March (NucNet): China’s fusion research programme
has reached another milestone with scientists working on
the China Tokamak HL-2A reactor confirming stable
operation close to the design limits after major
modifications since 2004.
The China National Nuclear Corporation (CNNC) said the
reactor’s plasma electric current reached 400
kiloamperes and the plasma state lasted almost three
seconds. Twelve reiterative stable discharge cycles were
carried out one after each other. The highest temperature
reached was 20 million degrees Celsius.
The HL-2A is China’s first tokamak with divertors –
extra magnetic coils and target plates that remove
impurities and fusion products from the plasma. The outer
radius of the HL-2A torus – a doughnut-shaped vacuum
chamber containing the plasma in a magnetic field – is
The HL-2A was built by CNNC’s Southwestern Institute of
Physics (SWIP) on the outskirts of Chengdu, the capital
of Sichuan province. Construction was based on the
original ASDEX tokamak using its main components. The
ASDEX (axially symmetric divertor experiment) was
successfully operated during the 1980s by the Max Planck
Institute of Plasma Physics at Garching near Munich.
Operation of the HL-2A started in December 2002.
The SWIP is China’s largest research establishment for
controlled nuclear fusion and plasma physics. Its HL-2A
tokamak is used for research into divertor physics,
auxiliary heating, advanced diagnostics and plasma
China has listed controlled nuclear fusion in its
national programme for science and technology development.
At Hefei, capital of east China's Anhui province, the HT-7U
tokamak fusion device is being commissioned by the
Institute of Plasma Physics of the Chinese Academy of
Sciences. This will be the first Chinese fusion
experiment with superconducting magnets enabling
discharge cycles lasting several minutes.
Since 2003, China has been a member of the International
Thermonuclear Experimental Reactor (ITER) project with
the EU, Russia, Japan, the US, South Korea and India.
These countries will share the estimated 4.57 billion
euro (5.56 billion US dollar) cost of constructing ITER,
a tokamak experiment designed to show the scientific and
technological feasibility of a full-scale fusion power
A fusion power reactor provides energy through the fusion
of atomic nuclei. The fuel is a mix of the heavy hydrogen
isotopes deuterium and tritium in the form of an ionised
low-density gas, hydrogen plasma. The plasma is confined
in magnetic fields and heated to temperatures exceeding
100 million degrees Celsius. At this temperature,
deuterium and tritium nuclei collide with so much impact
they merge into helium nuclei, releasing thermal energy.
Fusion reactors with a torus or doughnut shaped
confinement are called tokamaks.
JET, the Joint European Torus in Oxfordshire, England, is
the largest nuclear fusion experimental reactor yet built.
It has a radius of 2.96 metres, the plasma electric
current is 3,200 to 4,800 kiloamperes, and the pulse
length up to 60 seconds.
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