Q: But aren't there any real downsides to fusion power? It can't be all great, can it?
A: There are downsides to fusion power but we believe the potential advantages (almost limitless fuel supply, no greenhouse gas emission) heavily outweigh them.

The main downside is that it is difficult to achieve - hence we are still researching the concept rather than actually generating electricity through fusion! Keeping the plasma confined (by powerful magnetic fields) and heated to high temperatures is rather tricky, although recent results from JET and other fusion experiments around the world have suggested the whole idea is feasible.

Also, fusion is a nuclear process and the structure of a commercial fusion power station will be radioactive when it has finished producing electricity. However, by selecting the right materials, the structure should become safe to handle in a relatively modest timescale (50-100 years) - comparing favourably to the much longer lived radioactive waste (many thousands of years) generated by fission power plants. Other advantages are that no radioactive waste needs to be transported and disposed of or reprocessed, and that the fusion fuels (Deuterium and Lithium which will produce the Tritium in the power plant) are widely abundant.

Q: Who will use fusion power? What precautions will be taken to ensure that one group of people can't control global fusion energy?
A: The use of fusion power is only being considered to generate electricity in the future and this technology, once proved and commercially available will be available to any country as an alternative to conventional forms of energy production. Indeed, the next experimental machine (called ITER) which will follow JET, will be funded internationally. No one country has a monopoly on fusion power.

Q: Why, if we have fission, do we need fusion?
A: Energy demands will increase even more dramatically over the next fifty years as the developing world comes to expect the same standard of living as the industrialised countries. Kyoto focused the world's attention on the dangers of global warming from the unrestrained use of fossil fuels. Although nuclear fission is now being actively considered as an energy source, nuclear fusion, along with renewables, will be an important long-term energy source, with the following advantages:

• no atmospheric pollution: the fusion reaction produces helium which is an inert gas
• low-cost, abundant fuels
• no long-lived radioactive waste
• an inherently safe system: even the worst conceivable accident would not require evacuation of the surrounding population

Q: Why aren't governments funding this research a lot more? Nearly free limitless power coupled with little environmental impact would be a great boon to our world. Clearly the science is sound - we can look up into the sky and see that it works, that large glowing orb is powered by the same method. Could it be that governments are afraid that the loss of dependence upon fossil fuels could hurt the global economy as they collect huge sums of money from taxing oil companies and end users (we the people) of fossil fuels?
A: This is difficult to answer. The demonstration of steady fusion plasmas in ITER (the successor to JET, currently designed and planned to be built in the next ten years or so) with ten times more power out than that used to heat the plasma will, we believe, prove the physics and technology of fusion powerplants and convince people it will work...

Q: Is EFDA conducting the only serious research into fusion power? I read somewhere that the USA's program was shutdown during the Reagan administration. Has the USA (other than its physicists) lost interest in fusion power?
A: EFDA laboratories all across Europe are very active in magnetic fusion research via their own domestic programmes and via EFDA-JET (a joint European device run by UKAEA here at Culham on behalf of the rest of Europe). The EU has been investing almost twice as much into fusion research as Japan or the US. However, we are by no means alone in this research. Japan is very active in fusion and operates JT60-U - one of the largest tokamaks in the world. Indeed, magnetic fusion research in the USA is still vibrant with major experiments operating in San Diego, Boston and Princeton. It is true that fusion research in the US was downgraded somewhat in the 1990s, after a major budget cut, resulting in the US pulling temporarily out of ITER, an international tokamak, 2-3 times larger than JET which will act as single stepping stone to fusion power plants. Today, not only is the US back and have set ITER as No. 1 priority in their Department of Energy 20 year science facility plan, but also China, South Korea and India have joined the four powers that initially signed the ITER agreements (EU, Japan, USA and the Russian Federation). ITER should be built in the next ten years or so in France.

Q: Since plasma is a super heated substance, will it cause the burning of the reactor and, if so, how far will the burning reach if the magnetic confinement or one of the control or safety systems fails ?
A: The answer is one of the key advantages of fusion as a potential energy source over nuclear fission power stations - its inherent safety. Although the plasma in a tokamak is extremely hot, its total heat energy can not reach very high levels due to low plasma density. Plasma is kept away from the vessel containing it by the use of magnetic fields. The magnetically confined fusion plasma (that we are researching here at EFDA-JET in Culham) can only operate under strict conditions. If any of the systems fail (such as the confining toroidal magnetic field) of if, by accident, too much fuel is put into the plasma, the plasma will naturally terminate (what we call "disrupt") - losing its energy very quickly and extinguishing before any sustained damage is done to the structure. There is no concept of 'meltdown' in a fusion reactor.

Q: Could you please explain to me some of the safety measures that assure against accidents that may occur during a fusion reaction?
A: Unlike nuclear fission, the nuclear fusion reaction in a tokamak is an inherently safe reaction. An uncontrolled increase in fusion fuel (Deuterium and Tritium) would lead to the plasma being extinguished as it cannot be sustained when the plasma density is too high. Equally, a cut off of D or T would also lead to a natural termination of the plasma reaction.

Q: Is more power currently generated by fusion or by fission?
A: At the moment, the only nuclear powerplants are fission ones. Nuclear fusion is currently very much at the research stage and we need quite a lot of development before fusion will be used to produce electricity commercially.

Q: Does fusion give off radiation?
A: Yes, the fusion powerplant will be quite radioactive when it has finished its operation, but the radioactive products are short lived (50-100 years) compared to the waste from a fission powerplant (which lasts for thousands of years). Also, the radioactivity in a fusion powerplant will be confined to the powerplant itself and will not need to be transported for disposal, storage or reprocessing. Other advantages of fusion include the hydrogen-like fuel being freely available in water, and no greenhouse gas emissions.

Q: Is fusion less or more expensive than fission?
A: Studies have concluded that the cost of producing fusion power will be roughly the same as clean coal or fission.

Q: Is there a connection between nuclear fusion research and atomic bombs?
A: Firstly, we do not endorse the research, development or production of nuclear weapons in any form.

Both fission ("A-bomb") and fusion ("H-bomb") bombs already exist. The fission bomb is based on exceeding the 'critical mass' of a highly fissile material, eg isotope 235 of uranium. Fortunately it is very difficult to obtain just one isotope from natural uranium. However, the threat of A-bomb abuse is one of the reasons why democratic countries insist that all nuclear industry worldwide is under the close control of the IAEA (International Atomic Energy Agency).

Fusion bombs are based on Deuterium-Tritium fusion reactions and are yet more powerful. Production of H-bombs is not straightforward. There are two main challenges: first, the only "igniter" that can fire a fusion bomb is a fission bomb, ie the H-bomb is "the A-bomb plus the fusion part". Second, one needs a large volume of Tritium in the fusion reaction. The proper H-bomb produces Tritium during the A-bomb blast via Lithium fission, and that is why it is sometimes called "fission-fusion-fission bomb".

The US were the first to master both the A-bomb and the simpler version of H-bomb (with a fixed Tritium supply, ie not mobile). The Soviet Union was the first to master the proper H-bomb with Lithium. The competition was extreme and there were many tests done until 1963 when the increasing amount of radioactive isotopes in the atmosphere led the superpowers to ban at least tests in the atmosphere, in outer space and under water.

Last but not least, neither nuclear fission reactors nor fusion energy research have any potential to produce blasts similar to nuclear weapons. The fission reactors simply do not have above-critical mass (the worst tragedy, Chernobyl, was a fire in the uncontrolled reactor leading to the release of radioactive gasses, not a fission blast). In fusion energy research we do not use chain reactions at all. Consequently, a fusion reactor would be safer than a fission reactor as it would operate with continuous supply of very low amounts of fuel which can be turned off almost instantaneously.