radioactive waste and works with readily
obtainable fuel.
A typical fusion reactor uses two isotopes of
hydrogen: deuterium and tritium. Isotopes are
variants of an element with different numbers of
particles in the nucleus. Where the standard form of
hydrogen has a nucleus that is just a single proton,
deuterium adds one neutron and tritium two. It’s easy
enough to extract deuterium from seawater, while
tritium can be made from lithium, the element used
in the batteries in much of our portable technology.
This is done by bombarding the lithium with
neutrons – and once a reactor is set up, it can generate
this component of its own fuel, since fusion reactors
produce neutrons as waste.The remarkable thing about a fusion power plant
is the tiny amount of fuel it needs. A 1GW coal-fired
power station uses around 10,000 tonnes of coal a day.
A similar-sized fusion plant would consume around
1kg of deuterium/tritium fuel. This was so obviously
a good thing that work on fusion power began shortly
after World War II. Yet we still have a number of
decades to go before any of the contenders will be
able to provide practical power generation. Why has
it taken so long? Simply because it’s an incredibly
difficult process to keep going.“A 1GW coal-fired power
station uses 10,000 tonnes of
coal a day. A similar sized
fusion plant would consume
1kg of deuterium/tritium”
TECHNOLOGY – JET is the world’s
largest functioning tokamak, using a
doughnut-shaped ring of plasma, held
in place by a magnetic field to produce
nuclear fusion at high temperatures. An
essential tool in preparing for ITER, JET
uses deuterium alone, but is the only
tokamak that can use the deuterium/
tritium needed for generation.
ODDS OF WINNING RACE* – Evens
*All odds are our best guess as to the chances of the design
leading
to a successful fusion reactorJET
(JOINT EUROPEAN TORUS)
DATE STARTED 1978
METHOD D cross-section magnetic
confinement plasma tokamak
SIZE 6m in diameter
LOCATION Culham, Oxfordshire
COMPLETED 1982FISSION
Nuclear power stations use
the fission reaction. When
a Uranium-235 (U-235)
nucleus absorbs a neutron
it is transformed into an
unstable U-236 nucleus. This
then splits into two pieces,
for example Barium and
Krypton, and a number of
free neutrons. Each of these
neutrons can then trigger
a split in a further Uranium
atom causing a chain
reaction. Heat is caused
by the kinetic energy of the
decay products.FI
Nuc
the
a Ur
nuc
it is
unst
then
for e
Kryp
free
neut
a sp
atom
reac
by t
decaNeutronNeutronsU-235U-236Barium Krypton*All odds are our best guess as to the chances of the design
leadingto a successful fusion reactorordshireDeuterium TritiumHeliumNeutronFUSION DESIGN #1
FISSION VS FUSION
FUSION