NUCLEAR FUSION‘The holy grail of the energy world’

Presented byMr. Shenoy Anush

• What is energy? Energy is the ability of a physical system to do work.

• Where does energy come from? Sun, wind, tides, coal, oil, gas, fusion, fission, etc..

INTRODUCTION

• Why is this energy needed?

% Energy consumption by different sectors

While the population has tripled in the last 80 years, energy consumption has increased almost 6 times!

Electricity generation in Power plants1. From fossil fuels (88%)2. From hydro energy(6%)3. From other renewable sources (0.3%)4. Nuclear energy (5.7%)

Electricity

The energy requirements for the 21st century assuming that (a) mankind doesn’t act on global warming

(b) mankind acts on global warming.

(a) (b)

Nuclear energy is the potential energy of the particles inside an atomic nucleus.

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.

NUCLEAR ENERGY

Fission• Heavy nuclei release energy when they

split. • The product nuclei weigh less than the

original nucleus.

Fusion• Light nuclei like hydrogen & helium release

energy when they fuse.• The product nuclei weigh less than the

parent nuclei.

TYPES

The loss of mass in a nuclear reaction is known as MASS DEFECT denoted by ‘m’.

This ‘mass defect’ is converted into energy as

E=mc2

MASS DEFECT

Why can energy can be generated by both joining of two nuclei and splitting of the nucleus?

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..

PARADOX

GRAPH OF BINDING ENERGY v/s ATOMIC MASS

Seeing is believing!

POWER OF NUCLEAR ENERGY!

THE SUN

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.

NUCLEAR FISSION

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

SCHEMATICS OF A NUCLEAR FISSION CHAIN REACTION

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 energy.

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 reaction.

Radiation

Radioactive wastes

Raw material unavailability

Uncontrolled reaction

THE CONS

FUKUSHIMA DAIICHI INCIDENT 11th March 2011

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.

Nuclear Fusion (brief)

The idea of fusion is literally to put ‘sun in a box’. But the problem is how to make the box?

The vessel in which the fusion takes place has to withstand temperatures in excess of 1000000000C.

Fusion occurs in celestial bodies like stars.

TRITIUM: 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 years.

DEUTERIUM: 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.

RAW MATERIALS FOR FUSION

Raw material Definition Natural occurrence Nature of the byproducts  Conditions  Energy Requirement  Energy Released Nuclear weapon

FISSION V/S FUSION

Why fusion research?• Ever increasing energy demand.• Limited fossil fuels.• Global climate change.• Limited scope of renewable energy.• High energy output by fusion.

NUCLEAR FUSION

COMPARISON OF FUSION AND FISSION OUTPUT

Collision of the charged nuclei. Overcoming the electrostatic repulsion. High kinetic energy Heat & electro-magnetic fields. Plasma

ACHIEVING THE FUSION

Why is the energy released?• Mass defect• E=mc2

Conditions for fusion Fuel Temperature Density Time

Fusion product• Combination of three parameters –

temperature, density and time

Q-factor

•

Important terms

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.

Different Ways of Fusion

Inertial Confinement Fusion Concept

Before compression and ignition

Density : solid DT ice at 0.225 g/cm3 and gasTemperature : few Kelvin

During the burn phase

Density : 300 to 1000 times liquid density 300 to 1000 g/cm3 ≈ 1026 cm-3

Temperature : around 10.000.000 K or 10 keVPressure : around 1012 bar

Confinement time needed: around 200 pico seconds

Plasma Conditions During ICF

Compare Driver to Target Sizes!

real NIF target

Computer GeneratedSchematics

DT capsule

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►

Interesting Experiments in ICF

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

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.

How Does It Work?

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

Tokmak

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 radius.

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 electricity.

The steam will be condensed back into water to absorb more heat from the reactor in the heat exchanger.

Working of a fusion reactor

Flow diagram of fusion process

Joint European Torus

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.

JET investigates the potential of fusion power as a safe, clean, and virtually limitless energy source for future generations.

The largest tokamak in the world, it is the only operational fusion experiment capable of producing fusion energy.

JET is collectively used by many laboratories, scientists and engineers.

TIMELINE OF JETDATE EVENT1973 Beginning of design work

1977 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

1993 JET converted to diverter configuration

1997 JET produces 16 megawatts of fusion power

1998 Remote Handling first used for in-vessel work

2000 The collective use of JET and its scientific programme becomes managed through the European Fusion Development Agreement (EFDA)

2006 JET starts operation with ITER-like magnetic configurations

2009-2011 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

'exhaust' Plasma major radius: 2.96 m Plasma minor radius: 2.10 m (vertical), 1.25 m

(horizontal)

Currently the JET is shut down for maintenance and upgradation purposes.

Technical specifications:

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.

Website: www.iter.org

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 technology.

ITER GOALS

TIMELINE OF EVENTS

Date EventNovember

2006 Participants agreed to fund the creation of the reactor.

2008 Site preparation start.

2009 Site preparation completion.

2010 Tokamak complex excavation start.

2011 Tokamak complex construction start.

2015 Predicted: Tokamak assembly start.

2018Predicted: Tokamak assembly completion, start torus pump down.

November 2019

Predicted: Achievement of first plasma.

2026 Predicted: Start of deuterium-tritium operation.

2038 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

ions • capturing high-energy neutrons from the reaction

without melting the walls of the reactor.

DEMO

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 basis.

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.

Goals of DEMO

Prototype power plant, PROTO is a beyond DEMO experiment.

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 post-2050 timeline.

If it happens, it would make PROTO the first commercial nuclear fusion power plant in the world.

PROTO

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 50 year.

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 alone

ECONOMICS

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.

Conclusion

Indeed nuclear fusion is‘Energy in our hands’

THANK YOU