Space

Published on November 17th, 2009 | by Yellow Magpie

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Mining The Moon: Nuclear Fusion And The Next Economics

Mining The Moon Future Moon Colony Photo By NASA

Nuclear Fusion is heralded as the solution to our energy crisis. It is what powers stars and it is what powers our own star, the Sun. Nuclear Fusion may lead to mining the Moon for a very valuable resource. A substance so rare on Earth that it makes the cost of purchasing gold and diamonds seem a pittance.

Nuclear fusion fuses nuclei together into a larger nucleus. Through fusion massive amounts of energy are released.

Fusion may well be the most important discovery of the 21st century. Deriving energy from water may be one of man’s greatest achievements and should result in a cleaner, healthier planet for all to live in.

Later on Yellow Magpie will be discussing the significance our lunar neighbour may play in humanity’s future.

Solution To Our Energy Crisis

Fusion is incredibly energy efficient. The power needed to create fusion is ten times less than the energy that fusion creates. Thus nuclear fusion is seen to be the solution to our energy crisis.

To power a power-station, one kilogramme (2 lbs) of fuel would be required. This is compared to 10,000 kg (22,000 lbs) of fossil fuel in a normal power-station.

Advantages of Fusion

The beauty about nuclear fusion over current nuclear fission power plants (which split atoms rather than fuse them together) is that much more energy is produced with little or no radioactive drawbacks. The by-product of fusion is water whereas in fission it is radioactive waste.

Another great advantage is that the reaction can be stopped at any time as plasma cools and losses its energy the moment it is not contained. Thus out of control reactions are not possible.

The Sun Photo By NASA

The Fuel For Fusion

Nuclear fusion uses hydrogen as its energy source or fuel. Hydrogen is one of the most abundant elements on Earth and is one of the key constituents in water, the other of course being oxygen. Deuterium and Tritium, the isotopes of Hydrogen, creates a helium nucleus and a neutron when fusion occurs.

Deuterium Tritium Fusion

The neutrons that are created are not charged particles and this allows them to penetrate the magnetic field cage and produce thermal energy. This thermal energy or heat can then be converted into electricity. Much of our energy could be gotten from one of the most abundant compounds on the planet, water.

High Temperature And Containment

Nuclear Fusion uses plasma energy at huge temperatures of 100 to 200 million degrees Celsius to fuse nuclei together. Because these temperatures are so high they are very difficult to sustain and they must be contained with some sort of barrier. There are currently thought to be three main ways of containing plasma energy.

Gravitational Confinement

The sun uses its own gravity to confine plasma to provide fusion. Therefore, nuclear fusion is contained by the huge gravitational forces that the sun exerts.

However, on Earth (or on any other planet in the Solar System for that matter) this is impossible as the planet lacks the necessary mass required. As of now, it is impossible to artificially create these conditions.

Inertial Confinement

This is a process in which a fuel, generally deuterium and tritium (isotopes of hydrogen), is heated and compressed to provide fusion. This type of confinement is generally used in nuclear warfare.

In a nuclear fusion bomb such as the Hydrogen bomb or more specifically the Teller-Ulam design Hydrogen Bomb, a nuclear fission reaction is the catalyst that causes the fusion fuel cell to fuse providing nuclear fusion.

Typically lasers are used for energy production to provide nuclear fusion. However, success with this type of confinement has been overshadowed by a more favoured means of restriction.

Teller-Ulam Nuclear Fusion Bomb (Possible Variant)

Magnetic Confinement

By far the most successful and widely favoured method of confinement is through the use of electromagnetic fields. Powerful electromagnetic fields trap plasma energy and prevent it from touching the wall of a reactor using a Russian-invented device called a tokamak. This allows the nuclei to fuse and provides fusion.

Inside A Tokamak Torus Photo By CRPP-EPFL Association Suisse Euratom Creative Commons ShareAlike Licence

How The Plasma Is Heated

Currently, there are two distinct methods for heating plasma which occur in two phases. The first phase sees ions heated by rapidly accelerating voltage to over 140,000 volts. As these particles are electrically charged they cannot get past the electromagnetic barrier. Therefore, in the second phase the ions are neutralised allowing them to be injected into the plasma. This process is called Neutral Beam Injection.

So far in early experiments over 50 megawatts of electricity have been produced in tests. ITER (International Thermonuclear Experimental Reactor), in Cadarache, France, hopes to do better and produce 500 megawatts of power, enough for large scale commercial operations.

Nuclear Fusion Reactor Photo By Princeton Plasma Physics Laboratory

Difficulties With Nuclear Fusion

Unfortunately, scientists have hit a major stumbling block. Although preliminary tests have produced enough power to supply vast quantities of energy, the process results in the formation of highly destructive neutrons. Experiments with JET (Joint European Torus) in Oxford, England, have revealed problems with current nuclear fusion reaction with neutrons damaging the wall of the reactor and so far, according to Dr David Wade, only 1/100 of a gram of fuel at any one time has been used.

In the current models of nuclear fusion reactors, the nuclei which are emitted past the electromagnetic barrier cause damage to the reactor wall and renders it radioactive. This provides an enormous obstacle for the long term use of nuclear fusion as an energy supply.

Helium Three: A Potential Solution

Professor Gerald Kulcinski has proposed a solution to this dilemma which would see hydrogen being replaced by helium-3. The reaction is said to produce far fewer destructive neutrons than a hydrogen reaction. Helium-3 neutrons are far less damaging to the reactor’s wall. In real terms this means that reactors last much longer.

Helium-3 is a non-radioactive isotope of helium that consists of one neutron and two protons. It is incredibly sought after for research into nuclear fusion.

Helium Three Availability And Mining The Moon

Helium-3 is incredibly rare on Earth. Although there is estimated to be somewhere between 100 to 200 million tonnes of helium-3 present in the mantle of the Earth, all of this is inaccessible.

It is possible to manufacture helium-3 from tritium, a radioactive isotope of hydrogen, but this is both cost-prohibitive and a form of nuclear fission is required in the process. This would create radioactivity and negate some of the perceived benefits of helium-3, namely its non-radioactivity. According to Wikipedia, only 150 kilogrammes of Helium-3 have been manufactured.

Most of the available helium-3 on Earth is contained in nuclear weapons and is very scarce. There is certainly not enough for any form of long term production.

The Earth Photo By NASA

Mining The Moon For Helium Three

Although helium-3 is incredibly scarce on Earth, there is an abundance of it on the Moon. There is estimated to be roughly one million tonnes of helium-3 on our nearest neighbour. The reason why there is so little helium-3 on Earth is because of the atmosphere which prevents exposure to the solar winds which carry helium-3 with them.

Mining The Moon Photo By Gregory H. Revera Creative Commons ShareAlike Licence

The Moon has little or no atmosphere and is constantly exposed to solar winds. Over hundreds of millions of years constant exposure to the sun has resulted in a huge stockpile of helium-3 on our lunar satellite. It therefore stands to reason that mining the Moon to obtain helium-3 should be an option.

The Problems With Helium Three

However, mining helium-3 from the Moon would create huge logistical issues. The material would have to be processed on the Moon and more than likely a colony of people would be required to run this operation. Mining the moon might not be technically possible for decades to come.

Secondly, spacecraft would have to be redesigned to be as efficient as possible at bringing back helium-3 supplies after mining the Moon for them. Although there would be a great financial outlay at undertaking such an operation, the potential value of helium-3 would more than compensate for these investments.

Though proponents of helium-3, such as Kulcinski,view it as being able to provide energy to all the world, they have been criticised for their estimations of how much energy can be obtained per unit of helium-3.

NASA Proposed Inflatable Lunar Modules Perhaps Making Mining The Moon Closer To Reality

Does Helium Three Provide As Much Energy As Claimed?

Wikipedia argues that a 1,000-megawatt power station would need 17.5 kilogrammes (38 lbs)of helium-3 fuel even if the process was 100% energy efficient, a physical impossibility. Scaling up on these figures, a country such as the United States would require 20 tonnes of Helium-3 per year.

Logistical Reality Of Mining The Moon

In 2005, according to the United States Energy Information Administration, America consumed one-fifth of the world’s total primary energy. Therefore, the world would need a minimum of 100 tonnes of helium-3 a year. In reality this figure would more than likely be over 200 tonnes of helium-3 per annum. This would equate to one spacecraft carrying a four tonne payload making a trip from the Moon to the Earth once a week.

Artist’s Impression Of A Lunar Colony For Mining The Moon Image By NASA

It is estimated that for every tonne of helium-3 on the Moon, 100 tonnes of regolith, a loose material covering rocks, would have to be processed. Whether or not the Moon is successfully mined for helium-3 huge logistical problems would still have to overcome.

Future And Fusion

Although it remains to be seen whether helium-3 will be used as a fuel source for fusion, it is clear that fusion represents the future of energy production. Whether or not the Moon will be mined is another matter. Not everyone agrees that something as poorly understood as the Moon should be mined. Something potentially more valuable than helium-3 could be destroyed in this process.

What is certain is that if fusion is successful (whether using hydrogen, helium-3 or another fuel), humans’ reliance on fossil fuels will be greatly diminished and so will the rate of carbon being pumped into the Earth’s atmosphere. Economics will have changed forever as a result.

Potential Damage To Life On Earth

New scientific research being conducted into the origin of the Moon has revealed how life on Earth was shaped by our lunar neighbour. It indicates that the Moon played an enormous part in the creation of life on our planet and helped to sustain our ecosystems and delicate climate.

However, research also reveals that the Moon is responsible for preserving life on Earth and mining it may do reprehensible and irreparable damage. If you would like to read more on the critical role the Moon plays in providing life on Earth check out Yellow Magpie’s post About The Moon: Vital In The Creation And Preservation Of Life On Earth.

Here is an interesting video of a future world on Earth in which nuclear fusion is commonplace.

Further Reading

You may like to check out The Solar System And Beyond: A Guide To The Cosmos.

Fusion: The Energy of the Universe is an accessible book for both general audiences and physics students.

The Moon: Resources, Future Development and Settlement is an interesting look at developing the Moon from transportation to colonisation and is well worth reading.

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For France: Fusion: The Energy of the Universe and The Moon: Resources, Future Development…

About the Author

Yellow Magpie

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