Your questions about fusion…..answered
First, some fundamental questions:
What is fusion?
See our introduction to fusion, click here.
What is the likely environmental impact of fusion power?
See our feature on fusion and sustainable development, click here.
The following are some questions that we have been asked about fusion power, mainly by sixth-form students, and our answers. If you have a question to ask, email Culham Public Relations
How is the plasma contained?
A helical magnetic field of typically a few Tesla is sufficient to provide good insulation from the material surfaces and to balance the plasma pressure. This allows the low density of plasma to be heated to the very high temperatures required for fusion. The combination of very high temperature and low density leads to a plasma pressure comparable to atmospheric pressure.
How are the very high temperatures achieved?
The magnetic field provides insulation some 40 times better than loft insulation and is up to 10 times thicker. With such good insulation, the application of high power (in the Megawatt range) leads to very high temperatures, above 100 million Celsius.
Why are toroidal devices used?
The effect of the magnetic field is to confine the charged plasma particles by applying a force that opposes the motion across the field. There is no such force in the direction parallel to the magnetic field so, if the magnetic field lines were to connect the ends of a linear device, for instance, particles would be able to escape rapidly to the ends. In a toroidal device, the particles primarily spiral along the field lines, travelling around the machine typically a million times before escaping.
How do charged particles escape from the magnetic field?
Although the forces applied to the charged particles are such as to prevent them moving to the plasma edge, the effect of Coulomb collisions and turbulence is to lead to a random walk of particles, reaching the plasma edge on a timescale of order 1s.
What are the dominant costs foreseen in a fusion power plant?
As you might expect in a magnetic confinement system, the largest cost item is anticipated to be the superconducting magnets. The next largest cost is anticipated to be the buildings needed to house the plant. These two items together are estimated to make up more than half of the cost of a fusion power plant. There is the expectation that the cost of superconducting magnets will reduce with time.
Are the fuel costs significant?
The fusion energy obtained from each kg of fuel is very high (10 million times higher than from fossil fuels) so the fuel costs are a very small part of the expected costs. Using present costs, the fuel would contribute much less than 1% to the cost of electricity.
How is deuterium obtained from water?
The conventional method of concentrating deuterium in water uses isotopic exchange in hydrogen sulphide gas, although more advanced techniques are being developed. Separation of different isotopes of hydrogen can also be done using gas chromatography and cryogenic distillation, which use the differences in physical properties to separate the isotopes.
Where is lithium found?
Lithium is a light alkali metal found in several different minerals, e.g. spodumene. It is presently of particular interest for use in batteries.
Is any use made of advances in superconductors?
Most experimental devices do not use superconducting magnets since the required experimental plasmas, lasting less than 1 minute, can be achieved without the additional complexity. Those experiments that do use superconducting magnets have so far relied on conventional technology.
Is the depletion of water significant?
Deuterium represents approximately 0.015% of hydrogen in water. Even so, there is enough deuterium to generate present levels of energy consumption for billions of years. Depletion of water is not an issue.
Is the atmospheric pollution due to helium significant?
Because of the large amount of energy produced per unit mass of fuel, the production of helium is rather low, 10 million times less than the CO2 production of an equivalent fossil fuel power plant. If the whole world’s energy requirements were met by fusion, the helium production would still be small compared to the present helium production of around 25,000 tonnes per year.
What is the power input to the fusion reactor used for?
The best existing experiments need as much power to heat the plasma as they produce in fusion power. In a power plant, which would be larger, the fusion power would be around 20 to 30 times higher than the heating power.
How is electrical energy created from the reactors (heat)?
In a future power plant, it is envisaged that the heat from a fusion power plant would generate electricity in just the same way as existing plants e.g. coal, in which the heat is used to raise steam, driving turbines. The possibility of using the plasma energy more directly has been considered but never seems practical.
Are there any negative safety/environmental implications of a fusion reactor?
It is an intrinsic property of fusion that powerplants can be designed that are inherently safe with low environmental impact. Extensive studies over the last decade have shown that no internally-generated accident could result in the need to evacuate public from around the site, and that the waste products from fusion power will not be burden of future generations.
Do you think that fusion is a viable energy resource for the 21st century?
Fusion provides one of the few options for future baseload electricity generation and it is essential that we develop it, along with other sources, particularly renewables. We cannot reliably predict the future, but the trends towards less polluting energy sources are clear and we must do our best to establish ways of electricity production that are consistent with those trends.
How much energy could you get from a litre of water compared with a litre of petrol?
One litre of ordinary water contains enough deuterium to provide the energy content (when fused with tritium) of more than 500 litres of petrol.
What is the calculation that shows, in terms of binding energies, that 17.6 MeV of energy is released per colliding D-T pair, and why is it split 14.1/3.5 between the neutron and the alpha particle?
The masses of the particles concerned, in terms of the proton mass are:
| D |
1.99900 |
| T |
2.99371 |
| alpha |
3.97260 |
| neutron |
1.00138 |
The gain is that the alpha is more tightly bound. The net energy gain is mc2, where the mass difference is 0.01873 proton masses. This gives 17.6 MeV (or 2.8×10-12 J) per reaction. In order to conserve momentum, the heavier alpha particle must take a smaller part of the energy (smaller by the ratio of alpha to neutron mass, that is 1/4).
Could fusion be powered by other hydrogen isotopes or other light elements?
Yes. We concentrate on fusion of deuterons and tritons for energy production as it is the easiest way we know of getting a net energy gain. We have also investigated D-D and D-3He. Other reactions are demonstrated in the sun, for instance p-p, D-p, 3He-3He. There are a large number of possible fusion reactions, other than D-T, that produce energy. However, their usefulness in a terrestrial power source remains to be demonstrated.
How much fuel would a fusion power plant consume in a day?
A large power station generating 1500 MW of electricity would consume approximately 600 g of tritium and 400 g of deuterium each day.
Can the economic cost of fusion’s environmental impact be estimated, including the costs of constructing and dismantling the power plant?
Yes, estimates are made using the method developed by the EU’s ExternE project. This considers the total environmental impact of power production, from the original extraction of materials, through to the operation and subsequent recycling/dismantling of the facility. This is done by associating a cost to everything from CO2 emissions to accidents at work. The conclusions in published work have been very favourable, with fusion estimated to be considerably less harmful than conventional oil, coal, and gas.
When can we expect electricity generated from fusion to be available?
Experimental fusion devices have now produced fusion powers of more than 10 megawatts. We are presently awaiting approval for a new machine, called ITER (just one in the world), capable of 500 megawatts of fusion power. ITER is expected to take 8 years to build.
Although that is on the scale needed for a power station, there will still be technological issues to address to produce steady, reliable electricity, so it is anticipated that a prototype power station will be needed after ITER. Electricity generation is expected in 30 to 40 years, depending on how focussed the research and funding decisions remain.
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I have performed an experiment never done before in science- I used a Tesla coil for its use in high voltage high frequency and apply its discharge plasma not upon the dielectric of free air- but to the dielectric of water itself- specifically I used ultrapure reagent grade water from manufacture NERL-this is to establish the high degree of insulation needed for plasma (you cannot have contaminants for conductivity)- I doped my water with heavy water from the manufacturer UNITED NUCLEAR-(however- a full concentration of heavy water is desired)- I built my 1 million volt Tesla coil entire tunable- every aspect of it- as it must be done to TUNE THE OUTPUT DISCHARGE OF THE TESLA COIL to the water itself- once the arc is stable- the voltage may be increased- I have written in my pdf file in my website of noblefuse.com that a prerequisite of 750 kv is needed as an electric field gradient about the charged particles used in fusion( in this case the hydrogen bound in the water molecule) because of voltage drops as expected as in all electrical systems upon the load (load here is the water)- a much higher voltage is needed in order to distribute the voltage gradient upon entire arc plasma length between electrodes in water- THUS- THE HIGH THE VOLTAGE- THE BETTER- within my website you will find a link to youtube showing my primitive experiment- BUT MAKE NO MISTAKE ABOUT THIS- THIS IS THE FIRST TIME EVER DONE BEFORE - I propose nuclear fusion of water/heavy water- my little experiment IS THE ROAD TO NUCLEAR FUSION- we must universally connect the dots- put two and two together- and conclude this- MY EXPERIMENT MUST BE REPEATED ON A LARGER SCALE- my system is a direct replacement of nuclear power plants particularly of the pressurized water reactor which uses heavy water already - a vessel already built for gamma radiation and other high energy flux which will emit with the plasma arc-
Power reactor in which the heat is dissipated from the core using highly pressurized water (about 160 bar) to achieve a high temperature and avoid boiling within the core. The cooling water transfers its heat to the secondary system in a steam generator. Example: Grohnde Nuclear Power Plant in Germany with an electrical output of 1,430 MW.
Replace the rod assemblies and use electrodes to conduct the Lightning bolt! High Voltage High frequency will create the magnetic pinch to slam the isotopes of hydrogen together which is bound in water- helium and oxygen are the outgassed products recaptured by expansion tanks-it is absolutely perfect!
_ I HAVE FOUND THE TRUE PURPOSE OF THE TESLA COIL- the answer was always in the lightning bolt- understanding of gamma bursts from lightning discharges have only been recently vindicated from satellite in late 90s—
CA 94305 United States
Said, R ( ) , STAR Lab, Electrical Engineering, 350 Serra Mall, Stanford, CA 94305 United States
Smith, D M ( ) , Physics Department and Santa Cruz Institute for Particle Physics, University of California, Santa Cruz, 1156 High Street, Santa Cruz, CA 95064 United States
Lopez, L I ( ) , Astronomy Department and Space Sciences Laboratory, University of California, Berkeley, CA 94720 United States
The observation of brief (<1 ms) bursts of intense γ-rays, the so-called Terrestrial Gamma-ray Flashes (TGFs), by the BATSE γ-ray experiment was one of the most unexpected discoveries by the Compton Gamma-Ray Observatory.
Let me try to give another analogy to make the point. think about striking a match, if all conditions are proper , one knows that to strike a match, you must go a minimum speed- you cannot strike the match too slowly- this is understood as more speed is more friction and thus more activation energy necessary to create combustion of the match material. the same applies to this fusion system, first, imagine my system as inside a pressurized water reactor used in fission plants- the moderator is already heavy water- we shall use it as the fuel. I have said the plasma arc looks exactly like our friend the electric lightning bolt- but I talk about in my pdf file- that the so called lightning bolt must be understood in regards to high voltage and frequency- just like the minimum speed needed for the match- so it is with the combination on high voltage and frequency to not only resonate with the dielectric molecule of heavy water- but more so- to create a minimum velocity upon charged particles in the fuel water. this velocity is also exhibiting itself as a magnetic field-think of the cathode ray scope- in a snap shot instant in time for analysis, look at when the maximum energy is being applied on a per strike basis of the input cycle- or shall we say the highest amplitude of the ac signal. if for example- an input energy of one megawatt was injected into the strike of the arc- a magnetic pinch shall be directed upon the charged particles in transit of the discharge- in a thermodynamic extraction process such as this - we need at least 5 times more energy out of the system to recoup our initial energy input- and a surplus for commercial energy supply- thus- via fusion of hydrogen to helium- with each strike- a minimum voltage and frequency SHALL give the minimum activation energy required for magnetic pinching and fusion of the isotopes of hydrogen. to increase the q of the reaction in this system- a magnetic toroid may be used around the plasma arc for increased efficiency= such as used in tokamak devices. I hope this analogy helps those who question this system- THANK YOU–
Here is a thought experiment for electromagnetic fusion with Einstein in mind
Pretend you are water-you are an oxygen atom- you are stable- you are noble- 8 protons-8 neutrons-and 8 electrons- there are only 5 magic shell nuclear elements of the periodic table- oxygen is one of them- it is very stable-
Therefore- you are stable and noble- you have no need for fusion- yet it could happen- but the probability of another element such as hydrogen and its isotopes would be made to fuse together in some kind of fashion mankind tries will occur way before oxygen does- - ok-so now you are this noble one and you have outstretched in your hands a hydrogen atom and or its isotope deuteron and you hold it out to mankind as a gift-
Man understands the gift of fusion for many years and is desperately trying to do such-
I propose electromagnetic fusion- I propose the BENNET pinch used in poloidal currents used in plasmas of tokomaks- but much further-
Here we go – the thought experiment- you are this oxygen atom with two hydrogen’s and you stand amongst your friends similar in nature. You are placed in a large vessel filled of your kind-now imagine that two walls opposing in this vessel are the plates of a capacitor- who cares what is applied to the capacitor plates (electrodes of system)-for all you know as a noble oxygen and the hydrogen you have in your hands is nothing more than the electric field upon the plates-
You are composed of charged particles- thus you will interact with the applied electric field of the plates-this is common electronics and electric knowledge-
However, I speak of dielectric breakdown- I speak of the lightning bolt- let us now assume we have made the capacitor plates oscillate at 1 million volts peak to peak as way of a tesla coil
Think of the electric field- everything will be controlled by this field- a dielectric breakdown will occur- and all discharge current will begin to flow and oscillate as a function of the applied voltage-
Now- you are in the heart of a lightning bolt- you who are noble as a oxygen probably lost all your valence electrons due to the magnitude of such a high electric field- every charged particle in transit of the discharge current is surely ionized and talks of being a complete water molecule should be erased- the state of this plasma current is nothing more than ionized hydrogen and oxygen and a complete sea of electrons-
Let us think first of the electrons- 1896 times smaller than protons- no question it will oscillate much faster as a function to the applied voltage- remember the cathode ray scope- basic physics also will say this charged particle will also have a magnetic field about itself because of the electric field that has driven it-thus- this oscillating electron current will have an intrinsic magnetic field
Let us now think of the protons- oxygen has 8 and surrounded by 8 neutrons and is far less likely for reaction than isotopes of hydrogen for fusion- this should merely be understood by refereeing to atomic tables of elements and known theory- but this hydrogen is a singly bound proton with mass one- unless we speak of a deuteron- it will also be controlled exactly the same way as the electron is affected by the external applied voltage- however- it is opposite to the electrons motion-and much slower by its mass – however-its magnetic field will add to that of the electrons- this is standard knowledge of magnetic field generation of charged particles by way of electric fields-
Thus, in this thought experiment- within this state of dielectric breakdown- I like to say the lightning bolt- can you now see the oscillation of the charged particles by such a large magnitude of the applied voltage plates- can you now see the probability at a certain moment in time- particularly when the applied ac signal is greatest- that all magnetic fields of charged particles in transit can have the power to be magnetically pinched-
Magnetics have push and pull- it is well known that high frequency causes a constriction upon electrical currents- whether in copper lines and forcing such to the surface- or in plasma and made use to constrict it - high frequency is known to constrict the currents- thus- do you see the forces I am referring to as this dielectric breakdown has occurred upon the most perfect fuel of the heavens- water- this oxygen atom holds the hydrogen for us- we shall apply a high voltage (high is relative- I have stated 750kv in the vicinity of the hydrogen for fusion- I come to this by way of understanding the beta decay of a free neutron- if it can disintegrate- it can come together- made into a deuteron- then made into helium)-
Thus –we make helium and oxygen is then unbound and must also be recaptured- this is easy in expansion tanks- the byproducts are helium and oxygen-truly noble-
To increase the q of this system- a simple toroidal magnet as used in tokamaks for plasma control may be used for additional pinching-
I hope this helps- however- you must always think of the applied electric field and its magnetic inducement upon the charged particles- we will stably run the Tesla coil upon the dielectric of water itself (more appropriately heavy water) and turn up the voltage for greater acceleration speeds and thus magnetic fields- we can control pressure in this vessel- we can control electrode spacing and so much more-
that is my thought experiment for you to understand it is my intention to use all input energy by way of oscillating a very large electric field which will induce the proper magnetic flux density in units of Tesla for a pinching- not established hot fusion whereby all energy input is chaotic and the probability of fusion comes by way of statistics from a gas equation- no- high voltage and high frequency in an orderly manner by the construction of a man made lightning bolt with controllable parameters inside an existing pressurized nuclear reactor- everything is off the shelf- the world will run on steam power again globally-from trains-factories-ships-and all power plants- I offer the Watt steam engine again- not with two sticks to make fire and boil the water- but electromagnetic fusion with two electrodes to induce fusion of hydrogen isotopes to boil water and make steam- it is absolutely perfect.
To the CEO’s of nuclear power plants-or pressurized coal fired- you have spare reactors in the back yards of your plants- take a 1 million volt tesla coil and do what I have said- you will measure its fusion reactions and you will conclude this - I have found the road to safe clean energy.
I speak plain science- please connect the dots and let us end this energy crisis for a world that desperately needs energy- May the light of God shine upon all our actions for the betterment of mankind
Solomon Sami Azar