Nuclear energy is the potential energy
of the particles inside an atomic
Nuclear binding energy is the energy
required to split a nucleus of an atom
into its individual protons and
neutrons. It is equivalent to the energy
an atom releases when it is split.
• Heavy nuclei release energy when they split.
• The product nuclei weigh less than the
• Light nuclei like hydrogen & helium release
energy when they fuse.
• The product nuclei weigh less than the
The loss of mass in a nuclear reaction is
known as MASS DEFECT denoted by ‘m’.
This ‘mass defect’ is converted into energy as
can energy can be generated by both
joining of two nuclei and splitting of the
The explanation lies in the size of the nuclei.
Light elements such as hydrogen have small
nuclei that release lots of energy when they join
together. Moving to heavier atoms, less energy is
released in each fusion event, until, at iron no
more energy is released by fusion. Any bigger, it
takes energy to make the fusion happen.
Atoms with really huge nuclei, such as uranium
do the opposite of fusion. They release energy
when they break apart..
Nuclear fission is the process of splitting a
heavy nucleus releasing energy and neutrons
in the process.
These neutrons when captured by another
unstable nucleus, causes fission in it as well
leading to a chain reaction.
If the fission reaction is releasing more
neutrons than it absorbs it is referred to as a
self-sustaining chain reaction.
Fission reactions are complex.
Uranium-235 can break apart a number of
different ways, and many of the atoms produced
are unstable and radioactive:
U235 + neutron 2 neutrons + Kr92 + Ba142 + ENERGY
U235 + neutron 2 neutrons + Sr92 + Xe140 + ENERGY
1. A uranium-235 atom absorbs a neutron and fissions into
two new fission fragments, releasing three new
neutrons and some binding energy.
2. One of those neutrons is absorbed by an atom of
uranium-238 and does not continue the reaction.
Another neutron is simply lost and does not collide with
anything, discontinuing the reaction. But, one neutron
does collide with an atom of uranium-235, which then
fissions and releases two neutrons and some binding
3. Both of those neutrons collide with uranium-235
atoms, each of which fissions and releases between one
and three neutrons, which can then continue the
Raw material unavailability
Nuclear fusion involves joining of
smaller nuclei to form a larger
nucleus and giving out a large
amount of energy in the reaction.
In the picture alongside, two
isotopes of hydrogen, deuterium
and tritium, combine to form a
helium atom, releasing a neutron
and a large amount of energy.
The idea of fusion is literally to
put ‘sun in a box’. But the
problem is how to make the
The vessel in which the fusion
takes place has to withstand
temperatures in excess of
Fusion occurs in celestial bodies
Tritium is an isotope of hydrogen, which has two neutrons. It
does not occur naturally. It can however be easily produced
form the neutron bombardment of lithium, which is naturally
abundant. Currently accessible reserves of lithium could
supply all the world’s energy demands for more than 1000
Deuterium is an isotope of hydrogen, which has one neutron.
Its abundance is approximately 33 g of deuterium in every
cubic meter of water. As water is available aplenty, we have a
whole lot of deuterium.
Nature of the byproducts
Why fusion research?
Ever increasing energy demand.
Limited fossil fuels.
Global climate change.
Limited scope of renewable energy.
High energy output by fusion.
Collision of the charged nuclei.
Overcoming the electrostatic repulsion.
High kinetic energy
Heat & electro-magnetic fields.
Why is the energy released?
Conditions for fusion
Combination of three parameters –
temperature, density and time
Sun in a box problem!
Two ways of confining Fusion:
Inertial confinement fusion - ICF:
Increase density of fusion plasma.
Magnetically confined plasmas:
Increase confinement time & plasma speed.
Before compression and ignition
During the burn phase
solid DT ice at 0.225 g/cm3 and gas
300 to 1000 times liquid density
300 to 1000 g/cm3 ≈ 1026 cm-3
around 10.000.000 K or 10 keV
around 1012 bar
Confinement time needed: around 200 pico seconds
real NIF target
National Ignition Facility (NIF, Livermore, USA)
Record 1.875 million joule pulse of ultraviolet laser light to the target
chamber on March 15, 2012
Laser Mega-Joule (LMJ, France)
Commissioning (full scale) in 2011
FIREX I and FIREX II (ILE, Osaka, Japan)
Fast ignition experiments showed prove-of-principle
Fully integrated experiments in 2010 / 2011
HiPER project (Europe, R.A.L. ???)
European fast ignition proposal based on NIF
Design work funded last year; full funding pending
High Power laser Energy Research facility (HiPER),
is a proposed experimental laser-driven inertial confinement fusion (ICF) device undergoing
preliminary design for possible construction in the European Union. HiPER is the first experiment
designed specifically to study the "fast ignition" approach to generating nuclear fusion
Magnetic confinement uses magnetic
and electric fields to heat and squeeze
the hydrogen plasma.
Microwaves, electricity and neutral particle beams
from accelerators heat a stream of hydrogen gas.
This heating turns the gas into plasma. This
plasma gets squeezed by super-conducting
magnets, thereby allowing fusion to occur.
The most efficient shape for the magnetically
confined plasma is a donut shape (toroid).
A reactor of this shape is called a tokamak
"Tokamak" is a Russian acronym for "toroidal
chamber with axial magnetic field
The ITER tokamak will be a self-contained
reactor whose parts are in sections.
These sections can be easily inserted and
removed without having to tear down the
entire reactor for maintenance.
The tokamak will have a plasma toroid with a
2-meter inner radius and a 6.2-meter outer
The fusion reactor will heat a stream of deuterium and
tritium fuel to form high-temperature plasma. It will
squeeze the plasma so that fusion can take place.
The lithium blankets outside the plasma reaction
chamber will absorb high-energy neutrons from the
fusion reaction to make more tritium fuel. The blankets
will also get heated by the neutrons.
The heat will be transferred by a water-cooling loop to
a heat exchanger to make steam.
The steam will drive electrical turbines to produce
The steam will be condensed back into water to absorb
more heat from the reactor in the heat exchanger.
JET or the Joint European Torus, is a magnetic
confinement plasma physics experiment
located in Oxfordshire, UK.
Its main purpose is to open the way to nuclear
fusion experimental tokamak reactors such as
ITER and DEMO.
potential of fusion power as
a safe, clean, and virtually
limitless energy source for
The largest tokamak in the
world, it is the only
producing fusion energy.
JET is collectively used by
laboratories, scientists and
TIMELINE OF JET
Beginning of design work
Culham site is chosen and the construction work begins
25th June 1983
Very first plasma achieved at JET
9th April 1984
JET officially opened by Her Majesty Queen Elizabeth II
9th November 1991 The world’s first controlled release of fusion energy
JET converted to diverter configuration
JET produces 16 megawatts of fusion power
Remote Handling first used for in-vessel work
The collective use of JET and its scientific programme becomes
managed through the European Fusion Development
JET starts operation with ITER-like magnetic configurations
Installation of the ITER-Like Wall
Weight of the toroidal field coils: 384 tonne
Weight of the iron core: 2800 tonnes Weight of the
vacuum vessel: 100 tonnes.
Wall material: Entirely Beryllium save Tungsten
Plasma major radius: 2.96 m
Plasma minor radius: 2.10 m (vertical), 1.25 m
Currently the JET is shut down for maintenance
and upgradation purposes.
International Thermonuclear Experimental Reactor,
ITER is a nuclear fusion research project established
on 24th October, 2007.
Currently the world’s largest and most advanced
experimental tokamak nuclear fusion reactor at its
Cadarache headquarters in France.
The ITER project aims to make the long-awaited
transition from theoretical studies of plasma physics to
fullscale electricity producing fusion power plants.
The project is funded and run by its member entities :
European Union, India, Japan, China, Russia, South
Korea and The United States.
To momentarily produce a Q value of 10.
To produce steady-state plasma with a Q value
greater than 5.
To maintain a fusion pulse for up to 480 seconds.
To ignite a self-sustaining plasma.
To develop technologies and processes needed for
a fusion power plant including superconducting
magnets and remote handling.
To verify tritium breeding concepts.
To refine neutron shield/heat conversion
TIMELINE OF EVENTS
Participants agreed to fund the creation of the reactor.
Site preparation start.
Site preparation completion.
Tokamak complex excavation start.
Tokamak complex construction start.
Predicted: Tokamak assembly start.
Predicted: Tokamak assembly completion, start torus
Predicted: Achievement of first plasma.
Predicted: Start of deuterium-tritium operation.
Predicted: End of project.
Demonstration Power Plant, DEMO will be
constructed once designs which solve the many
problems of current fusion reactors are engineered.
These problems include:
• containing the plasma fuel at high temperatures
• maintaining a great enough density of reacting
• capturing high-energy neutrons from the reaction
without melting the walls of the reactor.
While ITER's goal is to produce 10 times as much
power as is required for breakeven, DEMO's goal
is to produce 25 times as much power.
Where ITER's goal is to produce 500 megawatts
of fusion power for at least 500 seconds, the
goal of DEMO will be to produce at least four
times that much fusion power on a continual
DEMO's 2-4 gigawatts of power output will be on
the scale of a modern electric power plant.
DEMO is intended to be the first fusion reactor to
generate electrical power.
Prototype power plant, PROTO is a beyond
PROTO would act as a prototype power
station, taking in any remaining technology
refinements, and demonstrating electricity
generation on a commercial basis.
PROTO is only expected after DEMO, ie a
If it happens, it would make PROTO the first
commercial nuclear fusion power plant in the
The price tag of ITER alone is € 15 billion.
Nuclear fusion R&D will need further promotion
totalling around € 60-80 billion over a period of
On the other hand:
The annual R&D budget of Beyond Petroleum was
450 Million Euro in 2009
Europe’s contribution to Fusion research is less
than 1% of the total money spent by it on oil
This initial investment will be worthwhile if
fusion will turn out to be an economical way
to generate power.
Having negligible negative impact to the
nature, Fusion promises to be the answer to
our energy crisis.
Indeed nuclear fusion is
‘Energy in our hands’