Jack Oughton - A Layman's Guide To Nuclear Fusion v1.0

Layman’s Guide To Nuclear Fusion V1.0: Creative Commons Attribution-NonCommercial-ShareAlike 3.0

Material by Jack Oughton – available for writing assignments, contact: | [email protected] | www.writing.xijindustries.com

.∞§Contents§∞. Part 1: Why Fusion? Humanity’s Growing Resource Problem Part 2: Fusion – A Primer Part 3: Fusion Energy Cycles Part 4: Fusion Confinement Devices Part 5: Public Awareness Of Fusion Part 6: Conclusion Part 7: Appendixes “But if you wanted to know what the perfect energy source is? The perfect energy source is one that doesn't take up much space, has a virtually inexhaustible supply, is safe, doesn't put any carbon into the atmosphere, doesn't leave any long lived radioactive waste, it's fusion. But there is a catch. Of course there is always a catch in these cases. Fusion is very hard to do. We've been trying for 50 years. .. And we have 30 million years worth of fusion fuel in sea water..” – Prof. Steven Cowley – Director of the United Kingdom Atomic Energy Authority's Culham Laboratory - Source: TED Talks http://www.ted.com/talks/steven_cowley_fusion_is_energy_s_future.html

Introduction: This project is intended as a primer on nuclear fusion and is written in mostly non-‐technical language for the non scientific reader. It is a research project on the applications of nuclear fusion as a power source. This is a large area of science, but I have done my best to condense the large amount of available information into an easily understandable format. As a research document this work is compiled from a variety of sources, adding my own commentary in the context of this work. Though much of this is my own work, I make no assumptions or claims to any of it – I have credited the authors whenever I have used information they have provided I will not discuss the application of fusion in weaponry. The world has seen the effects of this already and there is ample information on it. This document is not intended to discuss the entire field in great detail, which is far beyond the scope of a short document like this. It is instead a carefully arranged, ordered primer and a signpost. Ample links provide further roads for the intrigued reader to explore fusion on his own terms. There is far more coherent information than I could reasonably express, or fit in to the document. On another note, I am not a fusion scientist, simply a very interested undergraduate. I have done my best, but have probably made mistakes, I acknowledge this. I hope that you find this information both useful and informative. The energy shortfall and pollution problems are huge hurdles to human progress. The realisation of commercially viable fusion presents a very real solution.



Part 1. Why fusion? Humanity’s worsening resource problem In grossly simple terms, there are two problems quickly becoming apparent that effect modern civilization. These problems are: 1) Increasing energy costs due to limited availability of fuels with finite deposits. 2) Increasing pollution due to increased economic development and global energy usage Both problems clearly derive from the our reliance upon, and the burning of fossil fuels, which are finite, cause atmospheric pollution and in some areas are unable to be obtained in quantities fully able to satisfy demand. In 2007, the world consumed an estimated 531 exajoules of energy [one exajoule, [denoted as EJ], is 10 exponential 18 joules]. This is equivalent to the energy released by detonating about 9.73 million A-bombs. Sources: EIA: www.eia.doe.gov/ BP: www.bp.com/

World Energy Shortfall Predictions – Note: prediction around 2050 of a beginning of a shortfall.



Even an ‘acceptable’ release of C02 is double the amount the world faced before fossil fuels became widely used in industry!

Modern man consumes around 35 times the amount of yearly energy of primitive, pre-‐agricultural man.



World Energy Consumption 2006 by Fuel Type [Sources: BP, EIA] Note: In 2006 around 86% of our energy came from fossil sources.

Evolution of World Total Fuel Consumption by type Note: energy usage roughly doubles between 1972 and 2005.



World Energy Use and Reserves circa 2001 – Source: WEA Note: in 2001 renewables comprised less than 14% of our energy supply.

UN Predicted world growth 1950-‐2050. Note that the scale is logarithmic and the population value is given in millions! -‐ Source data calculated from: http://esa.un.org/unpp/ According to the U.S. Energy Information Administration (EIA), the demand for global energy is projected to grow 44% between 2005 and 2030. This will be



caused by a number of factors, such as continuing economic growth and increasing populations in developing countries. -‐ Source: http://www.eia.doe.gov/oiaf/ieo/highlights.html This same report also stated that China is the largest consumer of the world’s coal supply, and since 2000 it’s coal usage has doubled. Given the country’s expanding economy, and large coal reserves, China’s demand for coal is expected to remain strong. In the reference case, world coal usage grows by 2% every year, between 2005 and 2030, with coal’s share of the world’s total needs reaching 29% by 2030. Two of the main consumers of energy will be China and India, as they are both developing very quickly and have very large populations. In 1990 both the countries where consuming on average, 10% of the world’s total energy expenditure, but in 2006 their combined share had grown to 19%. It is expected that with continued strong economic growth, both countries will increase their energy consumption twofold, making up 28% of total world consumption by 2030. Fission reactors have been suggested as an alternative to this problem. But nuclear fission power has its own problems. Licensing and building reactors take a very long time. If the fuel were used directly (non-‐breeder reactors), the finite Uranium sources would limit the available operation in a relative short time (several decades). Going to breeder reactors can greatly extend this time, breeder reactors can utilize more abundant Thorium in fission, and consume Uranium at a slower rate. However, these reactors produce Plutonium, which is very, very dangerous. Concerns about the safety of nuclear fission reactors include the possibility of radiation-‐releasing nuclear accidents, the problems of radioactive waste disposal, and the possibility of contributing to nuclear weapon proliferation. Spent fuel elements contain plutonium-‐239. This plutonium could be separated chemically and diverted to nuclear weapons production.



Remaining oil reserves by source. Over 38% is unrecoverable.



Chernobyl Nuclear Power Plant, reactor 4– site of the April 1986 disaster and along with Three Mile Island in the USA, a significant reason why nuclear fission’s reputation amongst the lay public (at least in the USA) retains a negative stain. (Yim 2003)

Decay timeline of fission biproducts. Note: the immense amounts of time taken for radioactivity to decay to 0.



Diagram comparing radiotoxocity of materials in various fission and fusion reactors.

Note two points.

1. The extremely steep decline in fusion radiotoxicity relative to fission radiotoxicity. Fusion reactors have much shorter radioactive half lives than fission reactors

2. A fusion reactor with a vanadium alloy is no more radioactive than coal plant ashes after around 50 years.

Renewables

Renewable energy sources are an excellent alternative to finite and polluting fuels, being sustainable and a lot more environmentally friendly. However on average they do not provide energy as cheaply as fission or other finite resources. Furthermore, they are not always suitable in many locations. For example, geothermal plants can only be sighted in areas where geological conditions allow for subterranean heat to be accessed. Solar panels are not as effective in countries which receive on average, less sunlight, and wind farms, obviously require a significant amount of wind.

It should be emphasized that all alternative methods of generation of electricity on Earth, wind energy, wave energy from the sea, solar radiation converted by solar cells, etc, are all indirectly derived from the energy emitted by the Sun, i.e. they originate



from solar fusion. Even the atmosphere, the rivers and the forests providing other energy alternatives for electric power are driven by heat and light from solar fusion.

Great efforts will be needed to achieve the sustainable energy surplus we require in the time we have available, before other options begin to run down.

-‐Source: Met Office Hadley – Datasets | http://hadobs.metoffice.com/hadcrut3/diagnostics/global/nh+sh/ Environmentally speaking, I believe it would be prudent to hedge our bets in regards to climate change, as the many of the predictions brought about by climate change could be disastrous if they turn out to be accurate. One must remember that a reduction in atmospheric CO2 levels would take many years even if emissions were drastically reduced today. Economically speaking; we require the economic infrastructure in place to make up the shortfall that a combination of increased consumption and declining fossil stocks will present in the coming decades.

Energy is undoubtedly the food of civilization. With enough cheap and clean energy, we can produce unlimited clean drinking water from desalinating the oceans, grow almost unlimited food in the desert, and reverse environmental damage through terraforming. We can easily power the technological, electronic systems that are so essential in both our personal lives, and to society as a whole. With planning we can live in a world where our needs are met, and not at the expense of the environment. The path to an infinitely abundant energy source? Nuclear Fusion.

Part 2.



Fusion – a primer on possibly the world’s most useful energy source It may almost seem too good to be true, but fusion has a number of properties that, technological challenges aside, make it the most promising energy source yet.

Plasma being channelled in a fusion torus

Fusion – The Benefits SAFE

• If there is an accident and the magnetic containment is breached, the reaction immediately stops! The metallic walls of the vessel surrounding the plasma would cool the expanding plasma in a short period, collapsing the reaction cleanly and quickly.

• A fusion reactor is like a gas burner – the fuel which is injected into the system is burnt off. There is very little fuel in the reaction chamber at any given moment (about 1g in a volume of 1000 m3) and if the fuel supply is interrupted, the reactions only continue for a few seconds. Any malfunction of the device would cause the reactor to cool and the reactions would stop.

• These instabilities in the plasma act as an inherent safety mechanism. A fusion reactor cannot melt down like a conventional nuclear reactor, it simply degrades to gas

• Though fusion is the main energy source of hydrogen bombs, fusion alone has never



produced a bomb; the hydrogen bomb requires a fission-‐ based atomic bomb to set it off. This uncontrolled fusion reaction used in a bomb is a completely different mechanism to the controlled fusion which is utilized in peaceful fusion.

• Day-‐to-‐day-‐operation of a fusion power station would not require the transport of radio-‐active materials

• There are no byproducts that could be adapted for military purposes.

CLEAN AND ABUNDANT • No carbon emissions are generated by fusion.

• The raw fuels are abundant and equally distributed around the globe. This prevents

geopolitical and economic issues such as countries gaining political advantages from the scarcity of the resource

• It also prevents economic inequalities. Fusion’s raw materials are available to all.

• Raw materials for hydrogen will last for millions of years. They are a type (isotope) of hydrogen – deuterium (found in seawater) – and lithium (a light metal which is found in the Earth’s crust and in seawater). The lithium in the fusion reactor wall produces tritium (another isotope of hydrogen)

• The waste product from a deuterium-‐tritium fusion reactor is ordinary (and harmless) helium. There are no complicated nuclear byproducts and therefore no nuclear reprocessing, or complicated fuel cycling is required.

• Although radioactive materials will be generated in the walls of a fusion power plant they would decay with half-‐lives of about 10 years and the whole plant could be re-‐cycled within 100 years. There is no long-‐lasting radioactive waste to burden future generations.

EFFICIENT



The oceans offer us an effectively limitless source of Deutirium.

• Fusion is a very efficient form of energy production. 1 kg of deuterium and tritium would supply the same amount of energy as 10 million kg of coal.

• The fuel consumption of a fusion power station will be extremely low. A 1 GW fusion plant will need about 100 kg of deuterium and 3 tons of natural lithium to operate for a whole year, generating about 7 billion kWh.

• The lithium in one laptop battery plus the deuterium from half a bathtub of water would provide the UK’s per capita electricity production for 30 years.

Source -‐ Culham Centre For Fusion Energy-‐ fusion.org.uk/fusion_energy.pdf

Fusion – The Drawbacks Though I argue that fusion is extremely promising, it would not be balanced for me to leave out the shortcomings of nuclear fusion.

As an energy source, fusion has very few fundamental shortcomings. The main problem with fusion today is that, technologically it is still beyond our grasp. Though great advancements have been made, most expert sources believe that commercially viable fusion is many decades away. And at the current rate of funding, this will remain to be a problem…

PROBLEM: Escalating research costs Many countries perceive fusion funding as a research risk. Essentially it is seen to have a huge possible payoff in the far future, and the timescales involved are too long. The energy problem is pressing and we need



results now! Other renewable energy sources compete with fusion for finite R&D funding. Sadly, many green energy advocates have yet to catch on. Many commentators, particularly those greens who have fought long campaigns against nuclear fission, are deeply suspicious of fusion. They doubt fusion will deliver and believe the money earmarked for research would be better spent on renewables, such as wind, wave and solar energy. Many of these other resources are already in commercial use, which makes them perceived as a more credible source of funding. “The ITER fusion reactor was originally costed at €10bn (£9bn), but the rising price of raw materials and changes to the initial design are likely to see that bill soar, officials confirmed today. The warning came as scientists gathered in Finland to unveil the first component of the reactor, which will effectively act as its exhaust pipe. The reactor is expected to take nearly 10 years to build and is scheduled to be switched on in 2018. It began as a US-‐Russian project in the 1980s, but has since grown to include the EU, China, India, Japan and South Korea.” (Sample 2009) – Ian Sample, The Guardian SOURCE -‐ http://www.guardian.co.uk/science/2009/jan/29/nuclear-‐fusion-‐power-‐iter-‐funding

SOLUTION: CONSIDER THE ALERNATIVES! There is no ‘real’ solution to this. However, there is an alternative way to consider the issue. 1. Fusion may be expensive but, how expensive would it be to transfer most of humanity away from low-‐laying coastal areas, assuming that global warming raises sea levels over the next 100 years? 2. Fusion should be considered an investment. Simple economics suggests that the growing scarcity of fossil fuels will result in rising prices to provide power from these sources over time, assuming they become harder to source and extract. Extending this idea further, the raw materials of fusion; deuterium and tritium are abundant enough to be practically considered infinite. As technology improves, costs of extracting deuterium and lithium and converting them to energy should fall. Eventually we could see fusion to be a source of extremely cheap power: no scarcity, massively efficient energy transfer. 3. Commercial fusion reactors greatly outperform other renewable energy sources.

PROBLEM: Net Energy Gain In experimental fusion reactors the main goal is to achieve a net energy gain. Essentially, we want to generate more power from the fusion reactions within reactor than we put in to start and maintain those reactions. At the moment, incredible amounts of energy are expended to create the conditions for fusion to occur, and as of yet, no reactor has yet produced a gain. Running a nuclear fusion reactor costs more energy than it generates. At the moment, a fusion reactor expends energy.



SOLUTION: Continue research! Reactor energy efficiency has increased every decade since fusion research began(Andreani 2000). In fusion research, achieving a fusion energy gain factor Q = 1 is called breakeven, and is the current goal in fusion research. With every year the value of Q that we obtain climbs closer to 1. In a commercial fusion reactor, a value around Q = 20 would be more suitable. Some external power will be required for things that help us regulate the plasma, such as like current drive, refueling, profile control, and burn control. Encouragingly, in 1997 The JET tokamak at Culham in the UK produced 16 MW of fusion power – which is the current world record for fusion power.

The interior of the JET torus.

PROBLEM: Heat/ Thermal Pollution An unusual yet still valid argument against freely available cheap energy is a phenomenon known as heat pollution. The idea is that with cheap abundant energy, most will be wasted as heat. This can have detrimental effects on marine life.

Thermal Pollution’s Implications For Marine Ecosystems Thermal pollution can have a great influence on the aquatic ecosystem. There are various effects on the biology of the ecosystems when heated effluents reach the receiving waters. The species that are intolerant to warm conditions may



disappear, while others, rare in unheated water, may thrive so that the structure of the community changes. Respiration and growth rates may be changed and these may alter the feeding rates of organisms. The reproduction period may be brought forward and development may be speeded up. Parasites and diseases may also be affected. An increase of temperature also means a decrease in oxygen solubility. Any reduction in the oxygen concentration of the water, particularly when organic pollution is also present, may result in the loss of sensitive species. For example, in summer fish may have high metabolic rates because their body temperatures are elevated in the warm water. At the same time they are faced with relatively low oxygen availability because warm water holds less dissolved oxygen than cold water. The interaction of these factors may prove critical. Heated water can kill animals and plants that are accustomed to living at lower temperatures. -‐ Source: http://www.lenntech.com/aquatic/heat.htm#ixzz0drT24IFS

SOLUTION: Ecological Safeguards The technology already exists to cool water before it is returned to the ecosystem. Heat pollution isn’t really a problem with effective planning. The problem is not complicated but may be expensive; redesign of sites which are discharging hot water may be required. Installing the following hardware at offending sites would be an effective solution to heat pollution:

Cooling ponds: man-‐made bodies of water designed for cooling by evaporation, convection, and radiation Cooling towers: which transfer waste heat to the atmosphere through evaporation and/or heat transfer Cogeneration: a process where waste heat is recycled for domestic and/or industrial heating purposes.



A cooling pond in Novovoronezh, Russia. Many such sites have secondary, recreational purposes that include fishing, swimming, boating, camping and picnicking. The warm waters are often used as a fish hatchery.

PROBLEM: Neutron Production in a DT Fusion Reaction DT fusion reactions produce free neutrons moving at high speed. These fast neutrons create radioactivity when they bombard the materials of which the fusion reactor is constructed. Thus, while the fusion process does not produce nuclear waste directly, the fusion reactor itself does become radioactive, and its components must be disposed of safely when the reactor is finally shut down, after the normal life of an electric power plant.

SOLUTION: Utilize Unreactive Materials in Reactor Construction Neutron shielding is rather simple. Neutrons are easily shielded with 24 inches or so of water, plastic, or anything else with high levels of hydrogen to provide collision partners of nearly equal mass for the neutrons to collide into. The problem with radioactive materials are not a particular hurdle. This problem can be minimized by deliberately choosing construction materials that either produce less radioactivity or produce radioactivity that dies away more rapidly. Such materials are estimated to lose their radioactivity within 50-‐100 years, as oppose to the thousands of years required for fission waste.



Due to it’s low level of radioactive activation in neutron bombardment, vanadium is a promising candidate for DT fusion reactors.

Part 3.

Fusion Energy Cycles The fusion process can occur in a number of different ‘energy cycles’. Each one fuses different materials, with different quantities of matter, and releases energy in different ways.



A graph comparing the performance of the 3 main reactions; The Deutritium-‐Tritium reaction, The Deutirium-‐Deutrium process and the proton-‐Boron11 process.

Note: A Deuterium – Deuterium (DD) fusion reactor would provide limitless energy; it requires only water as a resource. However, even higher temperatures would be required for a DD reaction, it is unlikely to be considered in the near future.



Helium 3 fusion (3He3He) though another promising aneutronic reaction, is rare on the earth. Helium 3 fusion has been proposed for confinement in both magnetic or inertial fusion reactors. This isotope of helium is thought to be common on the moon!

THE DT FUEL CYCLE

The DT Fusion reaction. The release of the neutron is the main drawback of this power cycle.

According to the Lawson Criterion, the DT fuel cycle is the easiest fusion process to start and maintain within a terrestrial reactor. It also has the highest power production rate of the fusion reactions. The generated power density is about 1 W per cm3.



In simple terms, the ‘extra’ neutrons on the D and T nuclei make them "larger" and less tightly bound, and the result is that the cross-‐section for the D-‐T reaction is the largest. Also, because they are only singly-‐charged hydrogen isotopes, the electrical repulsion between them is relatively small. It is relatively easy to throw them at each other, and it is relatively easy to get them to collide and stick. Furthermore, the D-‐T reaction has a relatively high energy yield.(Kobres 1994) Disadvantages However, the D-‐T reaction has the disadvantage that it releases an energetic neutron. Neutrons can be difficult to handle, because they will "stick" to other nuclei, causing them to become radioactive, or causing secondary reactions.

ANEUTRONIC FUSION Aneutronic fusion means fusion that does not produce neutrons as a by-‐product. There are several candidates for aneutronic fusion, but at current the Hydrogen and Boron 11 cycle seem to be the most credible.

As energy equation below shows -‐ no neutrons are produced, however this cycle requires more energy to start than the DT cycle.

p + B11 -‐> 3 He4 + 8.7 MeV

The pB11 cycle is the most promising candidate for aneutronic fusion.

The nuclear energy from the p-‐B reaction is different because it comes from the proton-‐ triggered fission of a light element, and no neutrons are released. (Light



elements are considered to be those with a mass number less than 56, which is the mass number of iron.) This is unusual for at least four reasons: 1. Light elements more often “combine” or fuse to make heavier elements; they don’t normally fission to make elements that are lighter yet. 2. Heavy elements such as 235U (Uranium isotope – mass number 235) are traditionally considered to be the more likely candidates for fission reactions. 3. Fission reactions are normally triggered by the absorption of a neutron, not a proton. 4. Fissions usually result in the emission of neutrons. “Focus Fusion” refers to electricity generation using a Dense Plasma Focus (DPF) nuclear fusion generator. It uses the aneutronic hydrogen-‐boron fuel (pB11) cycle. If Focus Fusion reactors are made to work, they will provide virtually unlimited supplies of cheap energy in an environmentally sound way -‐ no greenhouse gases, and no radiation -‐ because the reaction of pB11 is aneutronic.

Focus Fusion faces two main technical challenges:

• It requires much higher ion temperatures and plasma density-‐confinement time product than Deuterium-‐Tritium fuel;

• and x-‐rays produced by the reaction reduce temperatures.

The plasma focus device consists of two cylindrical copper or berillyum electrodes nested inside each other. The outer electrode is generally no more than 6-‐7 inches in diameter and a foot long. The electrodes are enclosed in a vacuum chamber with a low pressure gas (the fuel for the reaction) filling the space between them.

Focus fusion reactors are expected to be less expensive for the same amount of power. Using this power cycle, a wheelbarrow load of the Boron in Boraxo, a brand of American hand soap would be sufficient to provide all the electrical needs of a small city for a year.

-‐Sources: http://focusfusion.org/index.php/site/article/focus_fusion_reactor/ William W. Flint -‐http://www.polywellnuclearfusion.com/Clean_Nuclear_Fusion/Download_Book.html

MAGNETISED TARGET FUSION / SPHEROMAK FUSION



General Fusion's reactor design consists of 220 pistons that simultaneously ram a metal sphere. This creates a shock wave inside the sphere, so that plasma rings in the center create a fusion reaction.

General Fusion plans to try a relatively low-‐tech approach to fusion called magnetized target fusion (MTF).

The reactor consists of a metal sphere with a diameter of three meters. Inside the sphere, a liquid mixture of lithium and lead spins to create a vortex with a vertical cavity in the centre. Then, the researchers inject two donut-‐shaped plasma rings called spheromaks into the top and bottom of the vertical cavity -‐ like "blowing smoke rings at each other," explains Doug Richardson, chief executive of General Fusion, the Canadian energy company that is driving the MTF project. The last step is mainly well-‐timed brute mechanical force. 220 pneumatically controlled pistons on the outer surface of the sphere are programmed to simultaneously ram the surface of the sphere one time per second. This force sends an acoustic wave through the spinning liquid that becomes a shock wave when it reaches the spheromaks in the center, triggering a fusion burst. Specifically, the plasma's hydrogen isotopes -‐ deuterium and tritium -‐ fuse into helium, releasing neutrons that are trapped by the lithium and lead mixture. The neutrons cause the liquid to heat up, and the heat is extracted through a heat exchanger. Part of the resulting heat is used to make steam to spin a turbine for power generation, while the rest goes back to recharge the pistons.

General Fusion has just started developing simulations of the project, and hopes to build a test reactor and demonstrate net gain within five years. If everything goes according to plan, they will then build a 100-‐megawatt prototype reactor to be



finished five years after that, which would cost an estimated $500 million.

Source: Lisa Zyga, Physorg.com | http://www.physorg.com/news168623833.html

INERTIAL CONFINEMENT FUSION/ INERTIAL FUSION ENERGY [IFE] While magnetic confinement seeks to extend the time that ions spend close to each other in order to facilitate fusion, the inertial confinement strategy seeks to fuse nuclei so fast that they don't have time to move apart Directed onto a tiny deuterium-‐tritium pellet, the enormous energy influx evaporates the outer layer of the pellet, producing energetic collisions that drive part of the pellet inward. The inner core is increased a thousandfold in density and its temperature is driven upward to the ignition point for fusion. Accomplishing this in a time interval of 10^-‐11 to 10^-‐9 seconds does not allow the ions to move appreciably because of their own inertia; hence the name inertial confinement.

Atmosphere Formation Laser beam rapidly heats the surface of the fusion target forming a surrounding plasma envelope.

Compression Fuel is compressed by the rocket-like blowoff of the hot surface material.

Ignition



During the final part of the laser pulse, the fuel core reaches 20 times the density of lead and ignites at 100,000,000 degrees Celcius.

Burn Thermonuclear burn spreads rapidly through the compressed fuel, yielding many times the input energy. Key: Laser energy

Blowoff

Inward transported thermal energy

The National Ignition Facility (NIF) at Lawrence Livermore Laboratory is exp-‐erimenting with using laser beams to induce fusion. In the NIF device, 192 laser beams will focus on single point in a 10-‐meter-‐diameter target chamber called a hohlraum. A hohlraum is "a cavity whose walls are in radiative equilibrium with the radiant energy within the cavity"

A hohlraum mock up to be used on the NIF laser

Other effects like the symmetry of the implosion are also important for the ignition. The IFE laser must operate at five to ten shots a second depending on the target yield per shot and the desired electric output of the power plant. Currently two classes of



laser are being considered in the United States: the krypton-‐fluoride (KrF) gas laser and the diode-‐pumped solid state laser (DPSSL). Like the magnetic-‐confinement fusion reactor, the heat from inertial-‐confinement fusion will be passed to a heat exchanger to make steam for producing electricity. -‐ Source: Rochster University | http://www.lle.rochester.edu/02_visitors/02_grad_inertialconf.php

In the resulting conditions — a temperature of more than 100 million degrees Celsius and pressures 100 billion times the Earth’s atmosphere — the fuel core will ignite and a thermonuclear burn will quickly spread through the compressed fuel, releasing ten to 100 times more energy than the amount deposited by the laser beams. Only a few NIF experiments can be conducted in a single day because the facility's optical components need time to cool down between shots. In an IFE power plant, targets will be ignited five to ten times a second!



In direct-‐drive, the capsule is directly irradiated by the laser beams. In indirect-‐drive, the capsule is placed inside a hohlraum; made with high-‐atomic-‐mass materials like gold and lead with holes on the ends for beam entry.

Source: Rick Hodgin -‐ http://www.geek.com/articles/chips/national-‐ignition-‐facility-‐preps-‐self-‐sustaining-‐fusion-‐tests-‐for-‐2010-‐20090415/

The HiPER Laser Fusion Reactor HiPER is a European ICF facility being designed to demonstrate the feasibility of laser driven fusion as a future energy source. This is made feasible by the advent of a revolutionary approach to laser-‐driven fusion known as 'Fast Ignition'. HiPER will use a unique laser configuration, currently estimated at 200kJ long pulse laser combined with a 70kJ short pulse laser.

The HiPER Science Programme It will also enable the investigation of the science of truly extreme conditions – creating environments which cannot be produced elsewhere on Earth (temperatures of hundreds of millions of degrees, billion atmosphere pressures, and enormous electric and magnetic fields).

The new research programs will include the following areas • Astrophysics in the laboratory • Behavior of matter in truly extreme conditions • Material science in the challenging “warm dense” regime • Nuclear physics and nucleosynthesis • Atomic physics • Turbulent flow at very high Mach numbers



• Relativistic particle beam studies and applications • plasma physics at high energy density

• Laser plasma interaction physics • Quantum vacuum studies • Fundamental physics in ultra-‐strong electric fields.

Artist’s impression of the HiPER facility

The project was accepted onto the ‘European Roadmap’ in October 2006, with the UK agreeing to take a leadership role in January 2007.The HiPER facility is anticipated to open towards the end of the next decade dependent on the success of the preparatory phase project. The UK is the leading contender to host the HiPER laser facility. Source: The Hiper project | http://www.hiper-‐laser.org/keyfacts/KeyFacts.asp

Part 4. Fusion Confinement Devices Regardless of the energy cycle of nuclear fusion we use, certain conditions are required to start the reaction and contain the temperamental plasma environment in which the atomic process takes place.



Another view inside the JET torus, a tokamak design.

THE TOKAMAK The Tokamak was first discussed in the 1950s by Igor Tamm and Andrei Sakharov in the Soviet Union. The word Tokamak is actually an acronym derived from the Russian words toroid-‐kamera-‐magnit-‐katushka, meaning “the toroidal chamber and magnetic coil.” This donut-‐shaped configuration is principally characterized by a large current, up to several million amps, which flows through the plasma. The plasma is heated to temperatures more than a hundred million degrees centigrade (much hotter than the core of the sun) by high-‐energy particle beams or radio-‐frequency waves. The Problem and Importance of Heat In The Tokamak In an operating fusion reactor, part of the energy generated will serve to maintain the plasma temperature as fresh deuterium and tritium are introduced. However, in the startup of a reactor, either initially or after a temporary shutdown, the plasma will have to be heated to 100 million degrees Celsius. In current tokamak (and other) magnetic fusion experiments, insufficient fusion energy is produced to maintain the plasma temperature. Consequently, the devices operate in short pulses and the plasma must be heated afresh in every pulse. Ohmic Heating Since the plasma is an electrical conductor, it is possible to heat the plasma by passing a current through it; in fact, the current that generates the poloidal field also heats the plasma. This is called ohmic (or resistive) heating; it is the same kind of heating that occurs in an electric light bulb or in an electric heater. Neutral-‐Beam Injection Neutral-‐beam injection involves the introduction of high-‐energy (neutral) atoms into



the ohmically -‐-‐ heated, magnetically -‐-‐ confined plasma. The atoms are immediately ionized and are trapped by the magnetic field. The high-‐energy ions then transfer part of their energy to the plasma particles in repeated collisions, thus increasing the plasma temperature. Radio-‐frequency Heating In radio-‐frequency heating, high-‐frequency waves are generated by oscillators outside the torus. If the waves have a particular frequency (or wavelength), their energy can be transferred to the charged particles in the plasma, which in turn collide with other plasma particles, thus increasing the temperature of the bulk plasma. The Magnetic Field In a Tokamak Because of the electric charges carried by electrons and ions, a plasma can be confined by a magnetic field. In the absence of a magnetic field, the charged particles in a plasma move in straight lines and random directions. Since nothing restricts their motion the charged particles can strike the walls of a containing vessel, thereby cooling the plasma and inhibiting fusion reactions. But in a magnetic field, the particles are forced to follow spiral paths about the field lines. Consequently, the charged particles in the high-‐temperature plasma are confined by the magnetic field and prevented from striking the vessel walls. The flow in the plasma is mainly used to generate the enclosing magnetic field. In addition, it provides effective initial heating of the plasma. The flow in the plasma is normally induced by a transformer coil.

This simplified diagram of a tokamak describes what part each component plays in confining plasma.



In order to minimize particle losses caused from leaking along the magnetic field lines, the chamber is bent, which also bends the magnetic field lines. This creates the distinctive torus shape also known as a “toroidal pinch”. However, the curvature of the magnetic field lines introduces new problems. Strong externally produced toroidal magnetic fields are necessary to stabilize the plasma. These are generated by the solenoidal magnet The solenoid works by passing a current through an electromagnet wrapped, one turn after the other, along the full length of the tube. It reduces the kinking problem in the plasma by adding an external source of magnetic field that "stiffens" the plasma column.

A solenoid is a 3 dimensional coil which creates the magnetic field that envelopes the torus. A tokamak consists mainly of a toroidal tube big enough to hold the plasma that serves as fuel; a solenoidal magnet wrapped around the tube; and a transformer to drive a current in the plasma.



Diagram showing how particles are trapped within the cross section of plasma constrained within a tokamak. The Energy Generation Process Within The Tokamak

• The fusion reactor heats a stream of deuterium and tritium fuel to form high-‐temperature plasma. It squeezes the plasma so that fusion can take place.

• The lithium blankets outside the plasma reaction chamber absorb high-‐energy neutrons from the fusion reaction to make (‘breed’) 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. Source: Princton Plasma Physics Laboratory | http://www.pppl.gov/fusion_basics/ At this time, of all the fusion projects, tokamak confinement is getting the most funding and the most media attention. There are 2 major new tokamak projects under construction, ITER in Europe and SST-‐1 in India. Both are designed to showcase current advancements in magnetic confinement technology to the world, and to provide the environment to research the next phase of tokamak technology.

THE POLYWELL/ BUSSARD FUSION REACTOR



Robert W. Bussard (August 11, 1928 – October 6, 2007) was an American physicist who worked primarily in nuclear fusion energy research, and who pioneered the polywell concept. The name polywell is a portmanteau of "polyhedron" and "potential well." The Polywell is spherical instead of the donut shape of the Tokamak. The polywell method of achieving fusion has often been referred to as the “long shot to fusion” and sadly, has been treated this way by the fusion community at large As a fusion source, polywell researchers compete with tokamak derived technology for funding. And in the funding battle, the polywell is definitely losing, However in 2009 a R&D contract worth $2 million a year from the US Navy was issued, who believe the polywell may be a useful power source for ships. This is promising, and many polywell advocates have stated that positive results can be seen with a fraction of the funding expended on Tokamak technology (which is a good thing because it looks like that’s what they will get!). Source: Federal Business Opportunities.gov | https://www.fbo.gov/index?s=opportunity&mode=form&id=fc9fd44171017393510d46e2f8154296&tab=core&_cview=0&cck=1&au=&ck= The Polywell community is a small but vocal ‘open source‘ collective of scientific enthusiasts and independent researchers. Confinement Within The Polywell The Polywell uses inertial electrostatic confinement (IEC) to create the conditions for fusion. When all six electromagnets within the polywell are energized, the magnetic fields meld into a nearly perfect sphere. Electrons are injected into the sphere to create a superdense core of highly negative charge. Given enough electrons, the electrical field can be made strong enough to induce fusion in selected particles. Positively charged protons and boron-‐11 ions are injected into the sphere and are quickly accelerated into the centre of the electron ball by its high negative charge. Protons and boron ions that overshoot the centre are pulled back with an oscillatory action of a thousand or more cycles. Source: R. Colin Johnson | EE Times http://www.eetimes.com/showArticle.jhtml?articleID=199703602



The current, third-‐generation prototype uses six doughnut-‐shaped electromagnets to create a cube in which to confine the fusion reactions in a strong magnetic field. The original prototype operated in air and was just centimetres in diameter; the current design operates in a vacuum chamber and measures roughly a cubic yard.

A 2D representation of the magnetic fields operating in a polywell. The coils trap electrons and keep them in a very small, tightly packed group called a potential well. This well attracts and accelerates the Hydrogen and Boron nuclei. When they collide, the nuclear reaction is triggered. If there is a system failure, the polywell simply loses its magnetic field and the process stops.



Conclusion It is evident that there are a great many different possibilities for fusion; in both the choice of fuel cycle and confinement method used. Though now over 50 years old, the field is still very young. A great deal of emerging technologies look promising within fusion. Advances in other areas such as materials technology, could be a boon to the efforts of fusion researchers looking to create more efficient reactors. Similarly, disruptive technology such as the polywell and the plethora of projects lumped under the term ‘cold fusion’ could have payoffs, though the odds of this are not considered certain.

It appears that within the fusion community, current preference is towards the DT cycle, magnetically confined in a tokamak environment. This is obvious in the amounts of money being spent on in Europe on the ITER project, although the USA is actively researching a variety of inertial confinement technologies in tandem with their own tokamak efforts. With advancements in future we may be looking at aneutronic fusion, though the road to commercial fusion is ‘still’ some decades off.

The next section addresses public awareness and opinion of fusion, with data gathered from Europe and the USA.

Part 5. Public awareness of fusion -‐ Getting The Message Out Obviously, informed public and political awareness of nuclear fusion will be an extremely important factor in ensuring that fusion gets the attention it deserves. To be viable as an energy source, fusion must be understood, at least at some level, by the lay public who would one day reap its benefits.

Policymakers in energy must better understand what the fusion is, its economic implications, and long term performance predictions. Educators and thought leaders such as teachers need to be given a clear understanding of the subject so that the message is communicated properly by these vocal, credible sections of the population.

Furthermore, it is important to educate the public on the distinctions between fusion and fission, especially as the definition nuclear (especially thermonuclear) has a negative association with weaponry, which is unavoidable.

Finally, the obvious benefits of fusion must be communicated in a compelling, but impartial and factual manner. I believe that encouraging public support and indeed, approval of fusion could help contribute to maintaining political pressure that ensures fusion gets the economic support that it needs to become a reality.



However, it is clear that competition for public mindshare is extremely tough. In this time of mass media the amount of information the average person is exposed to is greater than ever before. The fusion message has to contend with popular culture, constant marketing, and the concerns of normal day to day life; a great many global and personal issues take up the average person’s attention and time. Fusion is simply not a priority for most people. This is understandable perhaps in the context of a low awareness of the extent of the energy problem facing us in the coming decades.

Worse still, certain anti nuclear pressure groups approach fusion in the same combative manner they have reserved for fission. For example, a consortium of French pressure groups Sortir du Nucleaire (Get Out of Nuclear Energy),claimed that ITER was a hazard because “scientists did not yet know how to manipulate the high-‐energy deuterium and tritium hydrogen isotopes used in the fusion process.” -‐ Source: Deustch Welle -‐ http://www.dwworld.de/dw/article/0,,1631650,00.html

In a report entitled Public Information in European Fusion Energy Research: Methods and Challenges, released by specialists working at fusion policy and research institutions around the EU, the opinions and awareness of the public in the EU towards fusion where measured. The following social groups where identified as communication targets. Each requires a different outreach strategy and message. Note: PI: Public information • Decision makers: due to direct link between the EU energy policy and the European fusion research this group needs to be informed on both European and national levels about the mission progress. The group consists of judicious, motivated, busy people. • Media: as a key intermediate to pro-active communication with general public, media (TV, radio, newspapers, journals) deserve high priority PI, namely personal relations. In fusion, media relations are established, as a rule, on national levels. • Schools & Universities: Teachers act as efficient intermediates to young people who will probably decide about the industrial future of fusion. Even before, fusion R&D will need a supply of new determined experts. Notice that fusion has relatively sparse professional links to Universities compared to other major research projects. • Interested Public: Although fusion cannot hope for a major pro-active influence of general public, any of those who are interested and request information must feel free to obtain it, hence the passive PI must be very broad and highly responsive. • Industry: Nowadays, the main topics in fusion research have expanded from basic plasma physics towards more technological tasks, e.g. to material research, which calls for direct involvement of different industries including their R&D. PI activities have to follow these developments and promote the opportunities. • Fusion Community: Due to international dimension of the research it is vital to foster good relations among fusion centres, calling for broad communications. • Scientific Community: support from the influential category of “other scientists” can be expected only if fusion community manages to inform them properly about the fusion research, its mission, results and strategy, as well as about joint interests. Source: http://www.iop.org/Jet/fulltext/EFDP05027.pdf

Findings: The report’s findings on the public awareness of nuclear fusion where not very promising.



• For the general public the challenge of producing energy from nuclear fusion is quite abstract

• It turns out that the level of education and social background tend to play a major role in awareness of nuclear fusion as future energy source.

• The European public is badly informed about nuclear fusion research in the EU (~3% informed)

• As far as energy-related research in the EU is concerned, nuclear fusion appears to be at the third position on the priority list of those areas where people would like the EU to do more, with 21% of support, well far behind renewable energy sources for instance (69%).

• There are significant concerns regarding the capability of nuclear fusion power to meet the public safety and environmental requirements: almost 35% believe it won’t be safe (!), will produce long-term nuclear waste and will contribute to global warming.

• These negative opinions are remarkable namely in relation to very low public awareness of fusion, which contradiction can be clearly ascribed to the prejudices associated with the tag “nuclear”.

• Nuclear fusion is also viewed as the second most efficient potential energy source (22%) and

• It is believed (59%) that it needs much more research to confirm its potential.

The report made the following conclusions on designing an effective communication strategy: • Clear messages: Key messages need to be simple and easy to find. Moreover, the communication has to be comprehensible and adapted to the target group, avoiding specialized terminology without compromising on the message contents. The requirements for reliable translations and interpreters call for considerable involvement of individual Associations in this respect. • Empathy: The form in which information is presented (including its emotional impacts) needs to be thoroughly appreciated. In particular, application of professional graphics has to be encouraged. Use of illustrations, photographs and videos beyond technical documentation should become routine • Division of responsibilities: In the new era of fusion, with many different world cultures working together on extraordinarily broad technological projects like ITER, it will be beyond capacity of scientists alone to assume all aspects of communication. Implementation of these three recommendations will put strain namely on internal communication, for scientists - they may feel that the above efforts are not a high priority activity. Anyway, in near future this will represent just one of many similar challenges for fusion scientists, who will find themselves among industrial engineers, nuclear regulators, managers from different countries etc. A highly professional communication team, combined with good communication training for a sufficient number of managers, scientists and engineers, can actually relieve many of these strains while concentrating on the primordial objective, the improvement of public understanding of fusion.



PANS (Public Awareness Of Nuclear Science)

The PANS was a prototype Public Information society, which has formed the framework for much of the more organized communication efforts now being made in fusion. The objective of PANS (Public Awareness of Nuclear Science) was to establish a European-‐wide network for communicating information on positive achievements, techniques and diverse applications of nuclear physics to the general public. The network comprises a group of about 23 nuclear scientists from all over Europe. A number of specific activities were developed, aiming at: • Secondary school pupils and teachers • The general public • Opinion-‐ and decision-‐makers, government and administrations The project’s leading achievement was the science communication book “Nucleus -‐ A Trip into the Heart of Matter” published in 2001 (Canopus and John Hopkins University Press in the US). Many of the original collaborators went on to create a web-‐based science communication system (webSCS), which carries factual and topical information about the various uses of nuclear science. Source: http://ec.europa.eu/research/infocentre/article_en.cfm?id=/research/star/index_en.cfm?p=03_main&item=Energy&artid=1900



American organizations are also using the internet for educational outreach.

EFDA (European Fusion Development Agreement)

In 1999, the European Fusion Development Agreement (EFDA) was created to provide a framework between European fusion research institutions and the European Commission to strengthen their coordination and collaboration, and to participate in collective activities.

Between 1999 and 2007 EFDA was responsible for the exploitation of the Joint European Torus, the coordination and support of fusion-‐related research & development activities carried out by the Associations and by European Industry and coordination of the European contribution to large scale international collaborations, such as the ITER-‐project.



To reach its objectives, EFDA carries out the following group of activities: • Collective use of JET, the world´s largest fusion experiment, which is located

near Oxford (United Kingdom).

• Training and carrier development of researchers, promoting links to universities and carrying out support actions for the benefit of the fusion programme

• Reinforced coordination of fusion physics and technology research and development in EU laboratories

-‐Source: European Fusion Development Agreement | http://www.efda.org/about_efda/what_is_efda.htm

Conclusion: In Europe, there are a number of public outreach organizations attempting to inform the public about fusion (specifically though magnetic confinement). The EFDA works as something of an umbrella organization and is developing a series of very effective communicational tools on its website, which it is encouraging teachers and other educators to make use of. There is a well-‐informed academic and amateur fusion community with excellent internal, trans-‐national communication links. However, European public understanding of fusion is terrible; many are unaware of its proper definition, and the ‘nuclear’ stigma has remained. Some groups are even opposed to it, thinking research budgets better spent elsewhere!

Main concerns in the public perception of fusion are as followed.

• High costs; • Uncertainty of payoff from R&D investments; • The feasibility of the technology; • The visibility of the results; • The need to set financial limits on R&D expenditure.

Generally speaking, the lay public seems to be more interested in technologies ‘closer to their lives’, such as health or environment related. They pay little attention and are not aware of the wider social and political dimensions of the associated R&D programme.

ITER is without a doubt, our main opportunity to bring public awareness to fusion. (Prades López et al. 2008). The entire process should be orchestrated with as much media furor as possible, making use of all the modern tools of communication the internet offers, such as social media and blogging. As the fusion community is extremely technologically savvy, co-‐coordinating this sort of effort should not be particularly hard, as we are already seeing organizations such as JET maintaining their own YouTube channels and proactively communicating with the public. Via online and offline outreach.



“In contrast with the past, the proponents of nuclear fusion are to some extent attempting to come to grips with the social circumstances. Until now they have taken the optimistic view that if they simply built a nuclear fusion reactor, society would accept it. Now they are sensing the need to make an effort to gain the acceptance of society. Even greater vigilance will be necessary in future.” -‐ (Tadahiro Katsuta, CNIC, Japan)

Expert Interviews In researching fusion I thought it would be best to obtain opinions from people better informed than me. Below are two interviews I conducted with internationally recognised experts on the subject.

Chris Warrick (Culham, UK) is a member of the Public Relations team at the UKAEA Culham Science Centre. After graduating with a degree in physics from the University of Wales, Chris joined UKAEA at Culham in



1990 working as an experimental physicist on various fusion devices until 2001. He was particularly involved with plasma microwave heating systems and plasma radiation measurement devices. Since 2001, Chris has been a member of the Public Relations team with particular responsibility for education and public outreach

When are we looking at the first commercially operated fusion plant? Easy question to begin with! If we assume 10 years to build ITER, and time then to get the results to enable the design of the first demonstration power station and then 5-10 years to build this first demo power station, we are looking at 25-30 years. For widespread commercial power from fusion - probably 40-50 years.

What method of confinement is most likely to prevail in commercial fusion?

Here at Culham, the JET and MAST tokamak devices employ magnetic confinement of the fusion plasma. There are parallel research streams into laser induced fusion - fusion of tiny fuel pellets by implosion with laser beams. It is fair to say, that in terms of scalability to fusion power stations, the magnetic confinement research is probably closer to economically viable power.

Could a child born today be seeing 'free' energy in his/her lifetime? Fusion would never profess to offer free energy. Modelling predictions suggest fusion will be economically competitive with other forms of generation - but it will never be free. Neither will any other generating method.

Is 'cold' fusion believed to be scientifically feasible?

No is the quickest answer. There is no firm evidence that neutrons observed in cold fusion experiments are actually generated from fusion. There is clearly interesting physics going on here - but this is almost certainly not fusion.

What is the best way we have for obtaining naturally occurring elemental hydrogen?

We require two forms (or isotopes) of hydrogen to make magnetic fusion here on earth. These are Deuterium and Tritium. Deuterium is easily obtained from water - all water has traces of Deuterium - about one in every 8000 water molecules. Tritium is very rare - so we are going to need to generate this ourselves from a fusion power station. It is envisaged that the neutrons we will produce from the fusion reaction will react with a surrounding blanket of Lithium - and make the Tritium we will need. Hence, we will use up Lithium to make the Tritium we need. Lithium is a very common element - so we have abundant fuel reserves.

How many fusion plants would we need to supply the energy needs of the planet?

It is expected that fusion power plants will produce 1-2 GW of electricity - about the same as a modern fossil fuel or fission power station will produce. This about enough electricity for 2-3 million people - so for the UK - about 30 fusion power stations would be enough for all our electricity needs. However, we would never argue that fusion should generate all electricity - there should be a balanced portfolio with other sources (renewables, fission etc).

How aware would you say the public are of nuclear fusion?



Probably not enough. We strive very hard here - through public and schools outreach programmes and through media coverage - to increase the public's knowledge of fusion - and its potential as a future source of energy. This is not always easy - and one reason is how long it will take to be commercially available.

What are the most effective ways of educating them?

See above. Media is the way to get the message out to millions of people - when we had some coverage on BBC Horizon last year - that created a lot of interest.

Are there any possible disaster scenarios that could result from misuse of a fusion reaction?

No! The plasma inside one of our machines - although incredibly hot - 100s of millions of degrees C - is very small in mass (fractions of a gramme). If we push the plasma in any way (increase its mass too much, lose its confining magnetic field) it will become unstable, strike the wall of the container, cool rapidly and extinguish. This inherent feature if the plasma - that it will stop itself if pushed away from its natural stability limits - ensures that an internally driven accident is impossible to conceive.

Are there any other hypothetical power sources that could surpass fusion in our far future?

In a sense, I could say "maybe - but they have not been discovered yet". My own view is that the three large scale electricity generating options that can make a big contribution in the future are fusion, solar (much potential here but tend to be uneconomic at present) and new generation fission. I would like to see a world where these three are pushed as hard as possible .



Tadahiro Katsuta (Tokyo, Japan) has a PhD in plasma physics from Hiroshima University (1997). He is currently a Research Associate at the University of Tokyo. From 1999-2005 he researched the economics of nuclear power relative to other sources of electrical power, as an analyst at the Citizens Nuclear Information Centre in Tokyo.

Apr. 10th, 2010

*When are we looking at the first commercially operated fusion plant?*

In my understanding, thermonuclear fusion commercial reactor stands little chance of realization. According to the project of International Thermonuclear Fusion Experimental Reactor (ITER), fusion experiment will begin in 2018 and operation period is expected to last 20 years. Following DEMO reactor is planed to put into the grid as early as 2040. However, nobody knows physics of thermo nuclear fusion plasma and how to control it in the large facility. Based on my experience on nuclear fusion experiment, the hurdle is very high. It must be set the project back. Even if the physics is realized, nuclear fusion method confronts to other commercial plants which have economic benefit. In addition to this, it is doubtful if any country needs such large amount of electricity.

*What method of confinement is most likely to prevail in commercial fusion?*

One of the most important requirements for commercial reactor is a stable operation. Otherwise electric companies and customers do not accept the installation. It is difficult that the continuous operation of thermo nuclear fusion reaction by the magnetic confinement system. On the other hand, laser implosion system will be operated with the pulse drive. Such a large pulse driving system seems to me unstable. Furthermore, if the technology becomes regulated in terms of nuclear nonproliferation, the introduction speed will slow down.

*Could a child born today be seeing 'free' energy in his/her lifetime?*

Children may realize solar power is the source of real 'free' energy.

*Is 'cold' fusion believed to be scientifically feasible?*

There is big difference between scientific and commercial feasibilities. Scientifically it has a potential but may not become a commercial big power supply.

*What is the best way we have for obtaining naturally occurring elemental hydrogen?*

We can get hydrogen by the electrolysis using renewable energy.

*How many fusion plants would we need to supply the energy needs of the planet?*

You can get total electrical power plant capacity when you divide the world electricity demand by a capacity of one nuclear fusion reactor. However, we have to consider the daily load curve and net system energy demand. Since it is too difficult to control the output of nuclear fusion reactor, it may be only used for the base load. Nuclear fusion commercial reactor has difficulties to find a position as base load power source because of existence of other safe and cheap supplies.

*How aware would you say the public are of nuclear fusion? *

I have no idea.



*What are the most effective ways of educating them?*

The education of historical survey of science, technology and society that don't contain value judgments

*Are there any possible disaster scenarios that could result from misuse of a fusion reaction?*

If the energy use succeeds, it brings unnecessary electricity demand and radioactive waste management problem. In addition to these, it cause nuclear proliferation problem about H-‐bomb.

*Are there any other hypothetical power sources that could surpass fusion in our far future?*

Hydrogen energy created by renewable energies

Part 6. Conclusion It seems a cliché, but for decades we have been “just decades away” from commercially applied fusion . In spite of this, fusion has advanced in leaps and bounds. Though we have not yet seen any energy gains, the ongoing trend is of our reactors moving closer to breakeven point. The main problem is the time that it has taken to do this. Most people agree that we are going to see breakeven, but when is the point of contention. Most media sources are quoting a commercial start date of at least 2040.

However, the timescale to fusion power could be accelerated with increased funding. Overall research spend on fusion is tiny – less than 0.1% of the total energy market worldwide. This is astonishingly small compared to what a large hi-‐tech or automotive firm would spend on research (e.g Toshiba, Ford). ITER’s expected lifetime cost is less than the amount being spent on the London Olympics. source – Culham Centre For Nuclear Fusion



Diagram showing advancements in fusion technology performance compared with Moore’s Law and Particle Energy Accelerators. Note: Fusion performance (quantified by the triple product of the Lawson Criterion -‐ density, temperature and energy confinement time) doubles every 1.8 years, at a slightly higher rate than Moore’s law. Considering the commercial and societal implications of Moore’s law, once fusion becomes commercially viable, technological acceleration at this rate could have a huge effect on society. For example, transistor advancement over the last 15 years has seen the computer industry move at amazing speed. This suggests that this kind of exponential growth in fusion would result in a similar scenario.

Research in magnetic confinement fusion energy over the past 50 years has made tremendous progress with the Lawson parameter (nτET) in magnetic fusion devices increasing by 10 million to within a factor of 10 of that needed for large scale fusion power production. The next major step in magnetic confinement fusion is to be taken by ITER with the production of ∼500MW of fusion power for ∼400s. Similarly, inertial confinement fusion has made impressive progress with the increase in laser driver power by 1 million, and the completion of a major facility, NIF, aimed to produce ignition of small DT pellets and 20–40 MJ of energy per pulse.

The overall highlights can be summarized: (Meade 2010): • A strong scientific basis has been established for proceeding to the next stage, fusion energy production, in the development of magnetic and inertial fusion. • Diagnostics and plasma technology (auxiliary plasma heating, current drive, pellet



injection and plasma facing components) have made enormous progress and have facilitated a deeper understanding of the physics, thereby enabling progress. • There are several promising paths to both magnetic and inertial fusion energy and, each is working on optimization and sustainment (or increased repetition rate). • Temperatures (>100 million ◦C) needed for fusion have been achieved in many facilities. • Confinement needed for fusion is being approached in the laboratory. • Complex fusion systems have been operated reliably at large scale. • Fusion systems using fusion fuel (DT) have operated safely. • The international fusion programme is on the threshold of energy producing plasmas in both magnetic and inertial fusion. The next 50 years of fusion research… The stage is now set for the international fusion programme to begin planning for the step to a fusion demonstration facility (DEMO -‐ designed to produce 2000-‐4000MW of power!).

Source: Dale Meade -‐ 50 Years Of Fusion Research -‐http://iopscience.iop.org/0029-‐5515/50/1/014004

Even NASA is currently looking into developing small-‐scale fusion reactors for powering deep-‐space rockets. Fusion propulsion would boast an unlimited fuel supply (hydrogen), would be more efficient and would ultimately lead to faster rockets.



Diagram detailing past and predicted milestones in DT fusion research. Note the Q value for the cyan line which represents the JET test in 1997



ITER (International Thermonuclear Experimental Reactor)

• Vacuum vessel - holds the plasma and keeps the reaction chamber in a vacuum • Neutral beam injector (ion cyclotron system) - injects particle beams from the accelerator into the

plasma to help heat the plasma to critical temperature • Magnetic field coils (poloidal, toroidal) - super-conducting magnets that confine, shape and contain

the plasma using magnetic fields • Transformers/Central solenoid - supply electricity to the magnetic field coils • Cooling equipment (crostat, cryopump) - cools the magnets • Blanket modules - made of lithium; absorb heat and high-energy neutrons from the fusion reaction • Divertors - exhaust the helium products of the fusion reaction

ITER Main Parameters Total Fusion Power (MW) 500



Machine Height (m) 26 Machine Diameter (m) 29 Plasma Volume (m3) 837 In Latin, Iter translates to The Way. The ITER project is now seen as the way to fusion, and is the next big step for magnetic confinement.

• ITER is a tokamak fusion experimental reactor with superconducting magnets and other systems that will enable the facility of generating 500 megawatts of fusion power continuously for at least 400 seconds! Its plasma volume will be close to the size of future commercial reactors.

• ITER is the world’s biggest energy research project. It is an example of

international scientific collaboration on an unprecedented scale that will provide the link between plasma physics, engineering and future commercial fusion-‐based power plants.

• The reactor is expected to take 10 years to build with completion scheduled for 2018. ITER is designed to produce approximately 500 MW of fusion power sustained for up to 1,000 seconds (compared to JET's peak of 16 MW for less than a second)

• ITER will demonstrate and refine key technologies, as well as generate ten times more power than is required to produce and heat the initial hydrogen-‐tritium plasma.

• The Seven international Parties that are co-‐operating to develop ITER are: China, EU, India, Japan, Russia, South Korea, and the United States. The negotiations take place under the auspices of the International Atomic Energy Agency (IAEA).



The ITER site is located in the south of France in Cadarache, not quite one hour to the north of Marseille.

Source: www.iter.org | ITER Organization

Note: http://www.iter.org/mach/Pages/Tokamak.aspx provides a more detailed and interactive description of the components and workings within ITER.



ITER will be constructed from many separate parts produced from many contractors. Its production schedule is a meticulously planned and co ordinated international effort.

ITER’s predicted performance as compared to previous reactors. Note how far away it is from the rest of the reactors; The scale is logarithmic!



ITER’s predicted energy output will dwarf any previous fusion project.

Part 7: Appendixes

APPENDIX I: SCIENTIFIC INDEX i. What is a fusion reaction?



Fusing elements releases enormous amounts of energy Nuclear fusion is the process by which multiple atomic nuclei join together to form a single heavier nucleus. It is accompanied by the release or absorption of energy. At short distances the attractive nuclear force is stronger than the repulsive electrostatic force. As such, the main technical difficulty for fusion is getting the nuclei close enough to fuse. The Sun can sustain its fusion reactions in part because it is so large that heat is conducted away slowly. To create a practical fusion reactor, we must compensate for size by using good insulation to prevent rapid heat conduction. When do nuclear fusion reactions occur in a plasma? They can only occur when the temperature is very high, many millions of degrees. The reason is that the repulsion which always exists between the positive electric charges of colliding nuclei has to be overcome by attractive nuclear forces. This can only happen when nuclei with high mutual velocity come within the grasp of the strong but short-‐range (1013 cm) nuclear forces, which occurs only for enormously high plasma temperatures about 200 million degrees for deuterium-‐tritium reactions. We can characterize the fusion power (the rate of heat production) in terms of the plasma pressure, since higher pressure allows more plasma density, and more density means more fusion power We characterize the effectiveness of the magnetic insulation in terms of the “energy confinement time,” which is simply the time that would be required for the plasma to cool off if all heating ceased(by convention, it is the time required for the temperature to drop to about one-‐third its original value). We can characterize the fusion power (the rate of heat production) in terms of the plasma pressure, since higher pressure allows more plasma density, and more density means more fusion power The pressure rule says that the more current we have, the higher the plasma pressure



we can achieve. The limit on the pressure is simply proportional to the square of the magnetic field strength. Doubling the field allows four times the pressure. While it is possible to take any two nuclei and get them to fuse, it is easiest to get lighter nuclei to fuse, because they are less highly charged, and therefore have less repulsive force. The probability that two nuclei fuse is determined by the physics of the collision, and a property called the "cross section" which (roughly speaking) measures the likelihood of a fusion reaction. A simple analogy for cross-section is to consider a blindfolded person throwing a dart randomly towards a dartboard on a wall. The likelihood that the dart hits the target depends on the cross-sectional area of the target facing the dart-thrower. ii. What is a plasma?

Lightning is a plasma that exists naturally on the earth. Plasma temperatures in lightning can approach ~28,000 K! There are many varieties of plasma, however they all have one main thing in common, which is called ionization. This means that within the plasma itself, some electrons have been released from atoms they used to be bound to . It is these free electrons that makes a plasma respond so well to electromagnetic fields. In a fusion reactor At 150 million K the "fuel" exists as a plasma. The American scientist Irving Langmuir pioneered the field of plasma physics. He discovered that oscillations, so-‐called plasma oscillations, could occur in a plasma at a particular frequency, he also introduced the term 'plasma' and was awarded the Nobel prize for chemistry in 1932.



Plasma is the fourth state of matter Plasma as a state of matter can be shown in the diagram below. Solid (least energetic) > liquid > gas > plasma (most energetic) The quark gluon soup at the beginning of the universe, superheated and super compressed would have been classified as a plasma.

iii. THE LAWSON CRITERION Self-‐sustained fusion (ignition) requires the fusion triple product of density, energy confinement time and temperature to be greater than a certain value:

nτET > 5 × 1015 (cm3 s keV).

This is the value that relates to Q = 1 in the fusion energy gain factor, and is also known as breakeven. It does not matter whether we achieve this criterion by having a very large confinement time (excellent insulation) or a very high pressure, or any combination of the two. The number obtained by multiplying the pressure and the time is all that matters. Problems with Energy Loss through radiation The Lawson criterion depends only on heat loss via conduction, the direct transmission of heat between objects that are touching each other, such as you experience if you grasp an object hotter than your hand. Plasmas do conduct heat to their surroundings, and it is this conduction process that magnetic fields suppress throughout the plasma volume. But like all hot objects, plasmas also emit radiant heat, on which the magnetic field has no effect. For fusion plasmas, heat is radiated in the form of x-‐rays, because the temperature is so high. Heat loss by x-‐ray radiation, being a consequence of collisions of electrons and ions, is unavoidable, as is additional energy loss via the microwave radiation created by electron motion in a magnetic field, though most of the microwaves would be reflected from the vessel walls and reabsorbed by the plasma. However the main problem is to concentrate on heat loss by conduction, which has proved a far more important obstacle to achieving ignition in tokamaks than is radiation.

iv. Lorentz' Law Hendrik Lorentz's law describes the motion of charged particles, such as those moving within a magnetic field. It is useful as it helps us visualize how the phenomenon works. The Lorentz law says that I must measure all three quantities; the electric field, the magnetic field, and the particle velocity from the same vantage point, or “reference frame.” This is because all three quantities would appear to be different if my equipment and I were mounted on a cart moving through the room. For example if the



cart could move as fast as the charged particle, I would find no magnetic for on the particle, since it would appear to be at rest if I moved beside it. But now I would measure a stronger electric field to compensate for the missing magnetic force. In other words, electric and magnetic fields are one and the same thing, interchangeable depending on the state of motion of the observer

v. The Principle of Magnetic Confinement

Diagram showing how magnetic confinement affects the paths of electrons in an a 3d field.

Confinement refers to all the conditions necessary to keep a plasma dense and hot long enough to undergo fusion: the remarkable property of magnetic fields is essential to fusion plasma confinement; Free motion of charged particles in the plasma is not allowed in directions transverse to the magnetic field. Instead, the particles will spiral around the magnetic field lines. In this way, we use magnetic field lines to control the shape of the plasma.



Trajectory of an ion, ‘trapped’ in a magnetic field The starting point is to find a state of equilibrium, in which all forces are balanced. Otherwise, the plasma would collapse straightaway, like a badly designed building. A plasma in the vicinity of a magnetic field always produces a current, and this is the electromagnetic mechanism we can use to control the plasma. The loss of particles and heat in all channels must be sufficiently slow, as these cause a slow leakage of energy from plasma and degradation over time. The plasma must be shaped in such a way that small deviations are restored to the initial state. If we do not achieve this, instabilities will occur and grow exponentially until the plasma is destroyed (it literally falls apart). This is the mechanism that also makes fusion so safe. Unless it is under control, it cannot remain as plasma. Understanding magnetic fields Let us take a metaphor; compare the electrons with cars which move on a road at a certain speed with a certain distance between them. For some reason one of the cars brakes. To avoid collisions the following cars will also brake, and so on, until the first car decides to recover its earlier speed followed by the others. The processes may be repeated. Along the line of traffic there will be a bunching of cars accompanied by a depletion of the density of cars. Motions of this character, longitudinal oscillations and waves, occur frequently in plasmas as in mechanical systems. The accompanying electric oscillating fields are obviously in the direction of the motion. Maintaining a stable “pinched” plasma in a magnetic field is very difficult at best. If a solid vessel is used to maintain the plasma and the plasma comes into contact with the vessel wall, then the plasma will immediately transfer heat to the vessel and cool off to below the required fusion temperatures. Likewise, the chance of the solid vessel vaporizing when coming into physical contact with the plasma is extremely high. Plasma tends to “stick” to magnetic field lines. Even if the plasma does stick to field line



it would leak away rapidly un-‐ less the field lines themselves remain inside the superheated environment. Therefore we must confine The thinning of the magnetic field lines indicates a weakening of the field on the outside. This is where a “blowout” might occur. In a blowout, the stability of the plasma fluid ruptures. This destabilizes the plasma, and could cause collapse of the structure. For a real life metaphor for this, think of the surface of a large soap bubble. If pierced with a sharp pin, its surface is broken and the delicate fluid collapses under the pressure of the surrounding environment.

A weakness building up in fluid, causing it to deform.

APPENDIX II: ELEMENTS AND ISOTOPES INVOLVED IN NUCLEAR FUSION

• Hydrogen (p): Ordinary hydrogen is everywhere, especially in water. • Deuterium (D): A heavy isotope of hydrogen (has a neutron in addition to the

proton). Occurs naturally at 1 part in 6000; i.e. for every 6000 ordinary hydrogen atoms in water, etc., there’s one D.

• Tritium (T): Tritium is another isotope of hydrogen, with two neutrons and a proton. T is unstable (radioactive), and decays into Helium-3 with a half-life of 12.3 years. (Half the T decays every 12.3 years.) Because of its short half-life, tritium is almost never found in nature (natural T is mostly a consequence of cosmic-ray bombardment). Supplies have been manufactured using fission reactors; world



tritium reserves are estimated at a few kilograms. Tritium can also be made by exposing deuterium or lithium to neutrons.

• Helium-3 (He3): Rare light isotope of helium; two protons and a neutron. Stable. There’s roughly 13 He-3 atoms per 10 million He-4 atoms. He-3 is relatively abundant on the surface of the moon; this is believed to be due to particles streaming onto the moon from the solar wind. He3 can also be made from decaying tritium.

• Helium-4 (He4): Common isotope of helium. Trace component of the atmosphere (about 1 part per million?); also found as a component of "natural gas" in gas wells.

• Lithium-6 (Li6): Less common isotope of lithium. 3 protons, 3 neutrons. There are 8 Li-6 atoms for every 100 Li-7 atoms. Widely distributed in minerals and seawater. Very active chemically.

• Lithium-7 (Li7): Common isotope of lithium. 3 protons, 4 neutrons. See above info on abundance.

• Boron (B): Common form is B-11 (80%). B-10 20%. 5 protons, 6 neutrons. Also abundant on earth.

-‐http://abob.libs.uga.edu/bobk/caseof.html (Kobres 1994)

APPENDIX III: An Annotated list of Fusion Reactions Among Various Light Elements Note: D = deuterium, T = tritium, p = proton, n = neutron; D+D -> T (1.01 MeV) + p (3.02 MeV) (50%)

• > He3 (0.82 MeV) + n (2.45 MeV) (50%) <- most abundant fuel • > He4 + about 20 MeV of gamma rays (about 0.0001%; depends somewhat on

temperature.) • (most other low-probability branches are omitted below)

D+T -> He4 (3.5 MeV) + n (14.1 MeV) <-easiest to achieve D+He3 -> He4 (3.6 MeV) + p (14.7 MeV) <-easiest aneutronic reaction T+T -> He4 + 2n + 11.3 MeV He3+T -> He4 + p + n + 12.1 MeV (51%)

• > He4 (4.8) + D (9.5) (43%) • > He4 (0.5) + n (1.9) + p (11.9) (6%) <- via He5 decay

p+Li6 -> He4 (1.7) + He3 (2.3) <- another aneutronic reaction p+Li7 -> 2 He4 + 17.3 MeV (20%)

• > Be7 + n -1.6 MeV (80%) <- endothermic, not good. D+Li6 -> 2He4 + 22.4 MeV <- also aneutronic, but you get D-D reactions too. p+B11 -> 3 He4 + 8.7 MeV <- harder to do, but more energy than p+Li6 n+Li6 -> He4 (2.1) + T (2.7) <- this can convert n’s to T’s n+Li7 -> He4 + T + n - some energy -‐http://abob.libs.uga.edu/bobk/caseof.html (Kobres 1994)



APPENDIX IV: Financial Data on Fusion Research and Development Funding “I have long felt that an investment by the Department of Energy of a million dollars a year for the next 30 years would pay a higher return than any other investment this country could ever make. “ Wilson Greatbatch -‐

Information on fusion funding in the UK and USA is very transparent, Europe’s funding is somewhat more complicated and was harder to come by. I was not able to obtain data for Japan and the rest of the world.

USA Funding USA funding information Source: Steve Dean @ Fusion Power Associates | http://aries.ucsd.edu/FPA/OFESbudget.shtml





2 Graphs showing the US fusion budget from start of research to current date

Note: MFE = Magnetic Fusion Energy IFE = Inertial Fusion Energy

Deflator = adjusts the dollar value of the year in which spent to today's dollar value using the cost of living index

UK Funding



“Figures for the Government funding of nuclear fusion research in the UK are available from financial year 1974/75 and are given as follows. The Engineering and Physical Sciences Research Council (EPSRC) took over the responsibility for funding the fusion programme in 2003/04 and its subsequent funding is also provided.

EURATOM also fund fusion research in the UK through the United Kingdom Atomic Energy Authority. The UK contributes indirectly to the EURATOM European fusion research programme through its payments to the EU budget.

UK figures include UK funding of JET (which is about 13% of the total cost of JET). While most of the UK funding is for Culham including JET in later years the figures have included EPSRC funding for fusion-related research in UK universities.



European Funding Generally speaking could say that until recently typical total spend in Europe has been nearly 500 MEuro per year, of which about 40% is by EURATOM (effectively, via the European Union) and 60% is by national governments (note Switzerland, not in the EU, is included). Note that it is not that EURATOM funds some activities, and the Governments others; rather all activities are part-funded by both (for example, the UK programme is funded about 20% by EURATOM and 80% by the UK Government via EPSRC; whereas JET is funded approx 75% by EURATOM, 13% by the UK and 12% by other European countries).

However, the EURATOM figure has now doubled to provide Europe's share of ITER construction and may need to rise further.

Overall it used to be said that around 1B$ per year, or perhaps a little over, was spent on fusion R&D, but it must be much more now (approaching 2B$?) due to ITER construction.

Funding in the rest of the World Spend in other countries is relatively small. Historically Japan spend a little less than the US.”

Europe and UK funding Source: Martin O’Brien, Fusion Programme Manager, Culham Centre for Fusion Energy www.ccfe.ac.uk, Interview conducted via email. (O'Brien 2010)



APPENDIX V: Recommended and Educational Resources http://www.ted.com/talks/steven_cowley_fusion_is_energy_s_future.html -‐ TED Talk with a summary on the benefits and progress in fusion so far. http://focusfusion.org/ -‐ The Focus Fusion Society’s website. http://www.iter.org/default.aspx -‐ ITER’s website www.fusion.org.uk/ -‐ Culham Centre For Fusion Energy http://video.google.com/videoplay?docid=1996321846673788606 "Should Google Go Nuclear? Clean, cheap, nuclear power (no, really)" -‐ Google tech talk on fusion with Dr. Bussard – fusion pioneer and designer of the Bussard Ramjet engine. | http://www.askmar.com/Fusion.html -‐ summary, transcript and additional information on Bussard’s tech talk. http://fusedweb.llnl.gov/sites.html -‐ Online fusion educational resource, continually updated by the Lawrence Livermore National Laboratory and the Princeton Plasma Physics Laboratory http://www.cnic.jp/english/ -‐ Citizen’s Nuclear Information Centre – A Japanese public information site on emerging nuclear technologies. http://www.efda.org/multimedia/ -‐The educational portion European Fusion Development Agency’s website. Contains a variety of learning resources including books, online movies and DVD.

APPENDIX VI: Errata Extremely useful materials that had to be included here, somehow.. Two very well designed and communicative posters on fusion. Note: use high zoom value in your word processor to see full details on these posters.



TWO IMPORTANT FUSION PROCESSES

CREATING THE CONDITIONS FOR FUSION

FusionPhysics of a Fundamental Energy Source

Con

fine

men

t Q

ual

ity,

n!(

m-3

s)

1970-75

1990s

1975-80

1980s

Ion Temperature (K)

1021

1020

1019

1018

1017

106 107 108 109

Inertial

Magnetic

Expected reactor regimeExpected reactor regime

Useful Nuclear Masses(The electron’s mass is 0.000549 u.)

Label Species Mass (u*)n (1n) neutron 1.008665p (1H) proton 1.007276D (2H) deuteron 2.013553T (3H) triton 3.0155003He helium-3 3.014932

" (4He) helium-4 4.001506* 1 u = 1.66054 x 10-27 kg = 931.466 MeV/c2

Nuclear Mass (u)

Bind

ing

Ener

gy

Per

Nuc

leon

(MeV

)

1 20015010050

10

0

5

62Ni

FusionReactions

ReleaseEnergy

FissionReactionsReleaseEnergy

EXPERIMENTAL RESULTS IN FUSI O N RESEARCH

Fusion requireshigh tempera-ture plasmasconfined longenough at highdensity torelease appre-ciable energy.

Flames

Lightning

102

Tem

pera

ture

(K)

Number Density (Charged Particles / m3)

106

104

10211015

108

1027109103 1033

Solar core

Solar wind

Interstellar space

Magneticfusion

reactor

Inertialconfinement

fusion

Nebula

Solarcorona

Aurora

Neon sign

Fluorescent light Solids,liquids,

and gases.Too cool and

dense for classicalplasmas to exist.

Solids,liquids,

and gases.Too cool and

dense for classicalplasmas to exist.

power the sun and other stars. In fusion reactions, low-mass nuclei combine, or fuse, toform more massive nuclei. The fusion process converts mass (m) into kinetic energy (E), as described byEinstein's formula, E = mc2. In the sun, a sequence of fusion reactions named the p-p chain begins withprotons, the nuclei of ordinary hydrogen, and ends with alpha particles, the nuclei of helium atoms. Thep-p chain provides most of the sun’s energy, and it will continue to do so for billions of years.

happen on the earth, atoms must be heated to very high temperatures, typically above 10 mil-lion K. In this high- temperature state, the atoms are ionized, forming a plasma. For net energy gain, theplasma must be held together (confined) long enough that many fusion reactions occur. If fusion powerplants become practical, they would provide a virtually inexhaustible energy supply because of the abun-dance of fuels like deuterium. Substantial progress towards this goal has been made.

ACHIEVING FUSION CONDITIONS

n

4He

Fusion ProductsReactants

T

D20 keV

3.5 MeV

14.1 MeV20 keV

D + T # 4He + 1n

1 eV = 1.6022 x 10-19 J. Average particlethermal kinetic energy is 1 eV per 11,600 K.

“p-p”: S O LAR FUSI O N C HAI N

4He

$

D

D

$

e+

%%

e-

3He

p

p

p

p

p

p

3He6Be

e+ %%e-

p

%

p

%

For first generation fusion reactors

•Compression•Fusion Product Energy

•Compression (Implosion driven by laser or ion beams, or by x rays from laser or ion beams)

•Fusion Product Energy

•Electromagnetic Waves•Ohmic Heating (electricity)•Neutral Beam Injection

(beams of atomic hydrogen) •Compression•Fusion Product Energy

Typical Scales:

Heating Mechanisms:

N uclear M ass (u)0 2010

10

2468

0Bin

din

g E

ne

rgy

p

er

nu

cle

on

(M

eV

)

4He12C

DT

3He

16 OLi

<- - - - - - - - - - Size: 10 m - - - - - - - - - ->

Plasma Duration: 10-2 to 106 s

<- - - - - - - - - Size: 1019 m- - - - - - - - - ->

Plasma Duration: 1015 - 1018 s

Low-Mass Elements Only

Sources Conversion Useful Energy

Chemical,Gravitational, Nuclear , Solar, etc.

MechanicalMechanical

ElectricalElectrical

ThermalThermalWaste

MaterialsWaste Energy

Waste Materials

Waste Energy

Useful Eout = & Ein& = thermodynamicefficiency; 10-40% is typical.

<- - - - - - - - - - - - Size:10-1 m - - - - - - - - - - - ->

Plasma Duration: 10-9 to 10-7 s

Both inertial and magnetic confinement fusion research have focused on understanding plasmaconfinement and heating. This research has led to increases in plasma temperature, T, density, n,and energy confinement time, !. Future power plants based on fusion reactors are expected toproduce about 1 GW of power, with plasmas having n! ' 2 x 1020 m-3 s and T ' 120 million K.

Fusion of low-mass elements releases energy, as does fission of high-mass elements.

Binding Energy per Nucleon as a Function of Nuclear Mass

Plasmas consist of freely moving charged particles, i.e., electrons and ions. Formed a t high tempera-tures when electrons are stripped from neutra l a toms, plasmas are common in nature. For instance,stars are predominantly plasma . Plasmas are a “Fourth State of Matter” because of their unique physi-ca l properties, distinct from solids, liquids and gases. Plasma densities and tempera tures vary widely.

D + T

10710 –50

10 –46

Tion (K)

Rat

e C

oeff

icie

nt,

R (

m3

/s)

10 –28

10 –24

108 109 1010

p + p

10 –20

Primary process in our sun

Fusion Rate Coefficients

Nuclear Reaction Energy: (E = k (mi-mf) c2

From Einstein’s E = m c2. (E = energy change per reaction; mi = total initial (reactant) mass; mf = total final (product) mass. The conversion factor k is 1 in SIunits, or 931.466 MeV/uc2 when E is in MeV and m is in atomic mass units, u.

Plasma Fusion Reaction Rate Density = R n1 n2n1,n2 = densities of reacting species (ions/m3); R = Rate Coefficient (m3/s).

Multiply by (E to get the fusion power density.

CPEP is a non-profit organization of teachers, physicists, and educators, with substantial student involvement. Corporate and private donations as well as national laboratory funding have been and remain crucial to the success of this project.

This chart was created by CPEP with support from the following organizations: the AIP journal Physics of Plasmas, the Divisionof Plasma Physics of the APS, General Atomics, Lawrence Livermore National Laboratory, Massachusetts Institute of Technology,Princeton Plasma Physics Laboratory, the University of Rochester Laboratory for Laser Energetics, and the U.S. Department ofEnergy, Office of Fusion Energy Sciences. Images courtesy of NASA, the National Solar Observatory, and Steve Albers as wellas the organizations listed above. CPEP Charts are distributed by Science Kit and Boreal Laboratories (1-800-828-7777).

C H A R A C T E R IST I C S O F T Y P I C A L P L A S M A S

Reaction Type: Chemical Fission Fusion

Physical Parameters of Energy-Releasing Reactions

Sample Reaction C + O2 1n + 235U D (2H) + T (3H) # CO2 #143Ba + 91Kr + 21n # 4He + 1n

Typical Inputs Coal UO2 (3% 235U Deuterium(to Power Plant) and Air + 97% 238U) and Lithium

Typical Temp. (K) 1000 1000 100,000,000

Energy Releasedper kg Fuel (J / kg) 3.3 x 107 2.1 x 1012 3.4 x 1014

Confinement: Gravity Magnetic Fields InertiaLaser-Beam Driven FusionLaser Beam-Driven FusionTokamakStar Formation Plasma

ENERGY SOURCES & CONVERSIONS

N UCLEAR PHYSICS O F FUSI O N

P L A S M A C O N F I N E M E N T A N D H E A T I N G

Energy can take on many forms, and various processes convert one form into another. Whiletotal energy always remains the same, most conversion processes reduce useful energy.

A N O VERVIEW O F ENERGY C O NVERSIO N PRO CESSES

HOW FUSION REACTIONS WORK

Star Formation Plasma Tokamak

FusionPhysics of a Fundamental Energy Source

To make fusion

Fusion reactions

PLASMAS – THE 4th STATE OF MATTER

Copyright © 2000 Contemporary Physics Education Project (CPEP) – CPEPweb.org



First Poster Credit: FusEdWeb | Fusion Energy Education | http://fusedweb.llnl.gov/ Second Poster Credit: EFDA | http://www.efda.org/multimedia/posters_educational.htm

This poster was developed by Verdult - Kennis in Beeld (www.kennisinbeeld.nl) and was

commissioned by the FOM-Institute for Plasma Physics Rijnhuizen (www.fusie-energie.nl,

www.rijnh.nl) and EFDA (www.efda.org). See also www.iter.org.

This publication, made possible by the financial support of the European Commission, was produced within the framework of the European Fusion Development Agreement (EFDA). The EFDA-partners are the European Com-

mission and the parties associated with the European fusion program. Neither the Commission, nor the associated parties or anyone representing them, can be held responsible for damage that results from the information in this

publication. The opinions expressed are not necessarily those of the European Commission.

Nothing in this publication may be reproduced and/or made public by means of printing, offset, photocopy or microfilm or in any digital,

electronic, optical or any other form without the prior written permission of FOM-Rijnhuizen and Verdult – Kennis in beeld.

Verdult - New Media Design. Copyright © 2005 FOM-Rijnhuizen/Verdult - Kennis in Beeld, the Netherlands. All rights reserved.

12

4

1

2

3

4

3

33 mg of deuterium 50 mg of tritium 360 litres of petrol

2002 2050

5 grams of lithium-ore 1 barrel = 159 litres1 litre sea water

1650 kgoil/year

per person6 billionpeople

total energy usage expressed in kilogrammes oil-equivalent*

sources of primary energy in theyear 2003, source IEA Energy Statistics

*

*3000 kgoil/year

per person9 billionpeople

Fusion

Two light atomic nuclei,

deuterium and tritium, fuse

together and form a helium

nucleus, a neutron, and a

lot of energy.

Magnets

Strong magnets ensure that the hot plasma

does not touch the wall but that it continuously

travels around and around in the vessel.

human

height 1.85 m

reactor vesssel

approximately 10 m high

plasma

The plasma in tokamaks

can be ten times hotter than

the centre of the Sun.

microwaves

One method of heating the plasma

is by using microwaves, just as

in a microwave oven.

turbines transformer

electricity

steamcooling water

34,5 %oil

coal

gas

biomass,waste

nuclearfission

hydropower

geothermal

wind

sun

tidal

24,5 %

21,2 %

10,6 %

6,5 %

2,2 %

0,416 %

0,051 %

0,039 %

0,0005 % *

100 %

200 %

fossil fuels80 %

deuterium

tritium

helium

neutron

Tokamak

Ring-shaped reactor vessel

for nuclear fusion on earth.

Energy is importantFor almost everything we do and use – driving a car, heating, cooking, TV, music, traveling, telephone, clean water – we need energy. If we want to continue to live the way we do now, then we must ensure that we have enough energy for the future.

We use more and more energyIn 50 years time there will be 9 billion people on earth compared to the current population of 6 billion. All those extra people will also need energy. Furthermore, countries like China and India are developing rapidly. The result will be that in 2050 the global population will use twice as much energy as they do at present.

We must protect our environmentAlmost 80% of our energy is produced by burning coal, oil and gas (fossil fuels). This also releases CO2, a greenhouse gas. Greenhouse gases change our climate, resulting in more dramatic weather patterns like storms, hurricanes and droughts. If the temperature on earth rises too quickly, plants and animals can become extinct. If we do not want this to happen we will need to stop emitting CO2.

Oil, coal and gasare running outOil, gas and coal are formed from prehistoric plants and animals that lived on earth about 300 to 400 million years ago. We are deplet-ing fossil fuels much faster than they were formed. If we continue using oil, gas and coal as we do at present, we will run into severe shortages during this century. The oil will become much more expensive and we will become more and more dependent on the import of energy from other coun-tries.

A mix ofCO2-freeenergyIn 100 years our entire energy production must be CO2 free. There is no single solution to achieve this. We must use all available energy sources: sun, wind, hydropower, biomass, geothermal energy, nuclear fission, fossil fuels with CO2 sequestration and nuclear fusion. This is the only way to ensure that there will be enough energy available for everyone.

What is fusion?Fusion is the process that powers

the Sun and the stars. It is the

reaction in which two atomic nuclei

combine, or fuse, to form a heavier

atom. When light atoms such as

hydrogen fuse, a lot of energy is

released. Fusion is the opposite of

nuclear fission, where heavy

atoms are split into smaller pieces.

Atomic nuclei repel each other due

to their positive charge. For nuclei

to overcome the repulsive forces

and fuse, they need to collide at a

very high velocity, which means

that fusion only occurs at very high

temperature.

Fusion on earthOn earth we want to use fusion as

an energy source because it is safe,

environmentally responsible

– fusion releases no greenhouse

gases that affect the climate – and

there is abundant fuel available for

everyone on earth to produce

energy for millions of years.

Fusion fuelTo use fusion on earth as an energy source, a special mixture of gases is heated to an

extremely high temperature. When the gas is hot enough, fusion takes place. The gas

mixture (this is the fuel of the fusion reactor, just like petrol in a car) is made up of two sorts

of hydrogen: deuterium and tritium.

Deuterium is present in seawater, tritium can be made from lithium (a metal which is widely

available). Lithium is also used in lithium batteries, which provide electricity for laptops and

mobile telephones. One litre of water contains 33 mg of deuterium. This produces the

same amount of energy as 360 litres of petrol (when you fuse it with 50 mg of tritium).

There is enough fusion fuel in the world for millions of years of energy production.

Status of Fusion ResearchFusion research is carried out by people all over the world. The

largest fusion experiment in the world is the Joint European Torus

(JET) in England. JET is still too small to be used as a power

plant. Small things cool down faster than large things (think of soup in

a spoon and soup in a bowl), and if a fusion reactor is too small then

the energy needed to keep it warm is more than the energy which is

released in the fusion reactions.

Today, the international fusion community is getting ready to take the

next important step: the ITER project (see below).

The ITER projectThe next step in fusion research is the large international ITER

project. Together, the European Union, Japan, India, China, Russia,

South-Korea and the United States want to show that fusion works

and that it can produce energy on a large scale. ITER will be twice as

large as JET and is designed to produce 500 MW of energy – ten

times as much as that needed to keep the fusion process going.

ITER will be built in Cadarache, in the South of France.

The construction of ITER will take ten years

and should be finished around 2016. If ITER is

a success, a demonstration fusion power plant

can be built.

Operation of a fusion plantIn a future fusion power plant, the fusion fuels deuterium and tritium are heated

to a temperature of 150 million degrees using a variety of methods. One

method uses microwaves, like those used to heat up food. The resulting hot

plasma is contained in a ring-shaped vessel. To make sure that the hot plasma

does not touch the walls (otherwise the plasma would cool down too much) a

strong magnetic field is produced in the vessel . The plasma particles

follow the magnetic field and travel continuously around and around in circles,

for literally tens of thousands of kilometers, without touching a wall. Such a

vessel with magnetic field coils is called a tokamak.

As they are not contained by the magnetic field, the

high-speed neutrons are released during the fusion process

fly into the wall of the vessel. In a future fusion power plant,

they would transfer their energy to a coolant and convert

lithium into tritium. Outside of the reactor the warm coolant

would be used to make steam, with which electricity can be

produced (or for example hydrogen) .

Fusion is the energy source of the SunIn the centre of the Sun, 600 billion kilograms of hydrogen fuse every second, forming

helium. This releases an enormous amount of energy, of which a small part sustains

life on Earth.

The temperature in the centre of the Sun is 15 million degrees Celsius. At high

temperatures, the atoms in a gas lose their electrons, and together they form a gas of

charged particles called a plasma. The Sun is a plasma, and so is a bolt of lightning or

the gas in a fluorescent light bulb.

Fusion produces no harmful substances and no

greenhouse gases that affect the climate.

Safety & Environment

In the fusion process itself no radioactive waste is produced. The metallic components

of the plant itself will however in time become radioactive. By choosing appropriate

materials the level of radioactivity should decrease quickly, so that after about 100

years, it is expected that the material can be recycled, or stored relatively easily.

3

Safety & EnvironmentTritium is a radioactive substance, but because it is produced inside the plant (from lithium)

and is also used there, the transport of tritium outside the plant is limited. Strict safety

measures and confinement structures will ensure that the tritium stays inside the plant.

4

Safety & Environment 2A fusion power plant will work just like a gas heater. At each instant

there will be a limited amount of fuel, enough for a few seconds,

present in the reactor vessel. If the fuel supply is closed, the fusion

process stops, and therefore the reaction can never run out of hand.

Safety & Environment 1

Fusion Energy FUSIONFUSION SUNSUN

Cleaner energy for the futureon earthon earth

==

Nuclear fusion is the energy source of the Sun and the stars. Scientists and engineers over the whole world are working together to learn how to use nuclear fusion on earth.

If successful, fusion energy can help fulfill the world s energy needs in a more sustainable way.

neutronproton

Today s sources



The ITER platform in Cadarache. This is the site of the future reactor, and is obviously a work in progress!

Acknowledgements: I would like to acknowledge the tireless work of the researchers, engineers, theoreticians and science communicators advancing our understanding of and spreading the public awareness in fusion. May they achieve all the funding they could ever need... I would like to thank the following people in person. Chris Warrick and Martin O’Brien from Culham. Both where very patient with my pestering emails answering questions and summoning up no end of statistics and figures for me.

Tadahiro Katsuta, for taking the time to answer my questions articulately even though English is not his first language



T Kenneth Fowler, author of The Fusion Quest, who has kindly allowed me to use sections of his book in the scientific appendix. I recommend his book as an excellent resource for understanding the technical and theoretical aspects of Nuclear fusion. It is semi technical, and although slightly dated, explains many concepts in fusion in very understandable terminology.

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