Finland gets it, and has done for decades. Nuclear power is the largest source of energy in Finland, with a current capacity of 2,794 Mega Watts. To which another 1,600 MW is about to be added when the new third reactor at Olkiluoto is commissioned soon.
No doubt prompted by the suicidal wind and solar obsession playing out across Germany, the incoming Finnish Government has announced that the first order of business is expanding Finland’s nuclear power generation capacity as soon as humanly possible.
Small nuclear reactors
Most countries now have an interest in small nuclear power reactors. At present, these reactors are fission reactors. The interest is generated by lower capital costs and the need for power in more remote areas. These units can be factory assembled and transported to a location for installation and can be used for industrial applications or in remote areas with limited grid capacity. Small reactors have a capacity of up to 300MW(e) per unit.(That’s 300 million Watts or 300 Mega Watts.) This compares to large scale reactors which have a capacity of about three times that amount. These small reactors can be sited on locations not suitable for larger reactors. They take up only a tiny fraction of the area of wind and solar farms. Of course there is the continuing problem of disposal of radioactive waste. An inevitable by-product of nuclear fission is the production of fission products which are highly radioactive. Strontium 90 and Caesium 137 are the radioisotopes which should be the most closely guarded against release into the environment. They have a long enough half life to be around for hundreds of years. Most is disposed of in caves, which are sealed. Nuclear reactors today are very safe and are clean energy forms in themselves in that they do not produce any pollution while running.
Fission Reactors
Operating nuclear reactors at present are fission reactors. Below, is a typical fission reaction
Diagram; Wikimedia Commons. Author Stefan –Xp
Uranium 235 is an isotope of normal Uranium 238. Uranium 238 has 146 neutrons in its nucleus and 92 protons. Uranium 235 has 143 neutrons and 92 protons. So isotopes are elements with the same number of protons but different numbers of neutrons. Both protons and neutrons are found in the nucleus of an atom. Both isotopes are radioactive. Uranium 235 has a half life of 703 million years and Uranium 238 a half life of 4.4 billion years. The half life is the time for a radioactive substance to lose half of its radioactivity. Uranium 238 is about 99% of uranium found while Uranium 235 is only about 0.7%. So Uranium 238 is called natural Uranium.
Now Uranium 235 is the one used in fission reactors because it is fissionable. That means it can sustain a nuclear reaction itself. Uranium 238 cannot –it needs help.
In the diagram above Uranium 235 is bombarded with a neutron. The Uranium 235 splits into two different atoms- Barium and Krypton. (Actually these are isotopes of each). The splitting is called fission. At the same time more neutrons are produced, plus energy is released.
To get a neutron in the first place, radioactive elements are used. Three such elements are Polonium, Radium, and Plutonium. These are naturally emitting neutrons.
Now the Krypton and Barium isotopes together, are actually lighter in mass than the Uranium 235. This mass is not lost, it is converted to energy.
An isotope is an atom that has a different number of neutrons than normal.
I will not go through the actual calculation to work out the energy obtained for the sake of the non-mathematicians.
We find the loss of mass in the reaction and then use the famous Einstein equation E=mc2 to calculate the energy released.
This comes to 7.1667 x 1013 Joules. Expanded out this is 71,667,000,000,000 Joules or in words 71 million million Joules.
Compare this to a kg of coal. This gives approximately 3 x 107 Joules of energy. Expanded out this is 30,000,000 , in words about 30 million Joules.
So a kg of Uranium gives about 2.3 million times the energy of a kg of coal.
The cost of a kg of unprocessed Uranium is about $100 and the cost of a kg of coal is about 23 cents.
How do we control a fission Reaction?
You will have noticed in the fission reaction diagram that three neutrons are produced after U235 splits. Now, if there is more Uranium in the reactor then these neutrons can collide with this Uranium too and split each Uranium atom into two different isotopes as before, with the release of three more neutrons and more energy. If there is sufficient Uranium present we have a chain reaction . The amount of Uranium present to have an uncontrolled chain reaction is 52kg.
Obviously in a power station we do not want uncontrolled fission. So the fission reactions need to be controlled. The rate at which nuclear fuel undergoes fission is controlled using control rods- often made of cadmium. Cadmium can absorb neutrons. The rods are inserted into the reactor core to absorb a portion of the neutrons released. When the reactor is started up, the rods are partially withdrawn but once the chain reaction starts they are inserted more into the core. This slows the rate of fission to a value sufficient to give the energy needed and no more.
There is also a moderator- commonly just pure water, but sometimes heavy water, or graphite. The neutrons emitted after fission travel at speeds of about 50 million km/hr. These very fast neutrons do not cause many fission reactions, so they are slowed by the moderator to a speed of about 8000km/hr and this will enhance nuclear fission. A coolant- water usually, carries the heat produced to an external boiler and the steam produced is used to drive turbines which create electricity.
Diagram: Wikimedia Commons, Author: Emoscopes
A reactor can be shut down by fully inserting the control rods.
Uncontrolled Fission
If fission is uncontrolled and a chain reaction proceeds unchecked, then we have an atom bomb.
The fissionable material is in total more than the critical mass but it is separated into two parts as shown. An explosive device electronically detonated, brings the two pieces together into a small volume and the neutrons cause a chain reaction and a very large explosion producing much heat.
Today’s nuclear weapons work on a slightly different principle.
FUSION REACTORS
Power stations generating power by fusion reactions will be the main generating source in the future. They are now very close to becoming a reality.
Diagram: Wikimedia Commons. Author: Wykis
Deuterium and Tritium are isotopes of Hydrogen. Remember an isotope is an atom which has different numbers of neutrons than normal. Normal Hydrogen has just 1 electron and 1 proton and no neutrons. So Deuterium has 1 Neutron and Tritium has 2 neutrons. Deuterium can easily be extracted from sea water and Tritium from Lithium or from energy producing nuclear fission reactions.
The aim is to fuse the two Hydrogen isotopes together to form another element- in this case Helium. So fusion is the opposite of fission. Note that a neutron is also produced. In order to do this you must force two positively charged particles together. Nuclear forces are extremely powerful and the energy needed to overcome this force of repulsion is enormous. To ignite the fusion reaction a temperature of 108 degrees Kelvin is required. ( 0 degrees C is 273 degrees Kelvin) . So it’s near enough to 100 000,000 degrees C. That’s a hundred million degrees C. Clearly no ordinary container will be suitable for this reaction. It will have long since melted. Any substance at that temperature will exist as a completely ionised gas or plasma. Once again, if fusion takes place then the Helium produced is lighter than the initial two products, so that the loss of mass is given out as energy.
At present doughnut ( toroidal ) shaped magnetic fields are being tried to hold the plasma.
European scientists in the JET laboratory say they have made a major breakthrough in their quest to develop practical nuclear fusion. Their experiments Produced 59 Megajoules (59 million Joules) of energy over 5 seconds. They consider it is very easy to go from 5 sec to five minutes to five hours or even longer. It validates design choices that have been made for an even bigger fusion reactor now being constructed in France. This is called the ITER reactor. ITER is designed to produce 500 MW of power for a 50 MW input. So it will have a power amplification of 10. It will maintain fusion for longer periods. Thirty five nations are participating. At extreme temperatures (150 Million Deg C), electrons are separated from the nuclei in the atoms, and the gas becomes a plasma. Fusion plasmas provide the environment in which light elements fuse and provide energy. ITER hopes to be starting plasma experiments in 2025 or soon after.
Picture: Wikimedia Commons. Author: IAEA Imagebank
Model of the Iter reactor at the International Fusion Energy days 2013, Monaco
There are many advantages of nuclear fusion: Reactors take up very little space compared to the enormous acres of land taken up by wind and solar farms. Often, this is valuable farm land. The fuel is easily obtained. Since there is no chain reaction there is not the prospect of a nuclear accident. Any material used cannot be used for nuclear weapons. The products are Helium- an inert non toxic gas, plus Tritium which is radioactive but has a very short half life of only 12.3 years. So after 12.3 years half of its radioactivity has gone. Tritium is a relatively weak source of Beta radiation. A Beta particle does not have enough energy to penetrate skin. It decays to Helium. It only becomes a problem for humans if highly concentrated. Tritium is produced naturally in the atmosphere when cosmic rays strike atmospheric gas. We are all exposed to small amounts most of the time. Tritium is nothing like the dangerous radioactive products of fission. Storage of Tritium is not a problem. The only problem to be taken care of in fusion is the neutrons inside the container. Fusion is undoubtedly the power of the future. It is completely safe, and does not produce any pollution. Products are not a problem and it can produce a great deal of energy.
What Should New Zealand Do?
New Zealand must get over the very restricting “No Nuclear Policy”. It is time to move on. Today’s nuclear reactors are very safe, even though they are fission reactors. Ships have been running on them for years without mishap. A few Russian submarines have sunk but the reasons are not attributed to any nuclear reactors. Most of these sinkings seem to be non-nuclear powered submarines. However, I do not advocate that the country should install fission reactors at this stage. It would be good to keep our caves free of radioactive by-products. Since working fusion reactors are only a few years away, we should wait till they become a reality. To tide us over for those few years we need to keep the Huntly power station in operation. It is pathetic to think those who sit in parliament close down just ONE coal fired power station, when China is operating 3037 at present and is building two more each week. We could also consider building one more hydro power station. That is if the Greens don’t object as they have done to all recent attempts to build one. Instead they advocate wind farms and solar farms. They don’t seem to care that wind farms kill millions of birds and bats each year, and now it is found that offshore wind farms kill whales as well. On top of this are the health effects on humans and animals.
The point is nuclear fusion is undoubtedly the power source of the future. So what happens to the very unreliable wind turbines and solar farms. Who will be responsible for removing them, or will they just sit and deteriorate over time- forever an eyesore. One thing is certain. We should not build any more, but I can’t imagine anyone in Parliament taking any notice.
Ian Bradford, a science graduate, is a former teacher, lawyer, farmer and keen sportsman, who is writing a book about the fraud of anthropogenic climate change.
11 comments:
Thank you Ian. It does seem an appropriate time for us to thinking about revisiting the anti-nuclear issue. If not that, then we certainly need to start thinking about what limit on the population are we prepared to accept?
But but solar and wind are soooo green Ian!! A typical oxymoron spouted by morons.
Nuclear is the way forward and in Europe it is now even considered 'Green' as they try to save face because solar/wind fail to keep lights/heat on.
'Since working fusion reactors are only a few years away.'
We have heard this same line since last century. Much like a thorium reactor is just round the corner. Waiting is unrealistic and stupid.
Thorium holds great potential as a nuclear fuel. It's abundant and cleaner than uranium. And as a fuel it uses fission technology.
To CXH
Actually there are working Fusion reactors NOW. In The USA and in the UK.
Ian
Barend - and has been the holy grail yet just round the corner for a long time.
Good things sometimes take a while to come on stream. Patience is a virtue. I have been thinking it's a pipe dream for years too but I am very heartened by your great explanation. At least it's not a puff piece written by a daydreaming reporter. Perhaps we need fewer reporters and cynics and more physicists. Nah, cynics can eat humble pie one day.
MC
The small plants described are not very demanding in terms of location so long as there is a cooling medium available. This would enable much needed generation north of Auckland.
Yes, it is time to abandon NZ's 'No nuclear Policy'. I believe that Rolls Royce have small modular factory built reactors available which are no bigger than the size of two football fields and capable of powering approximately 1 million homes. The first one should be located north of Auckland for 2 reasons. It would eliminate the necessity for across city transmission from the south and is in a low risk earthquake area in NZ.
Brilliant article Ian.
Shut the Greens up ( in jail ???) and plow on.
The only country in Europe without a power crisis is France.
They kept their Nuclear plants going, while Germany did shut them after Tokoshima and is now struggling to have enough power to charge their EV's.
Where in Germany can they ( the Merkel thinkers ) expect a tsunamy after a huge earthquake.
NOWHWERE !!!
Switzerland is even worse, because their hydro plants can't deliver enough.
Great post but I do not believe that fusion will be viable in the next 20 years and if it is it will be enormously expensive. It will take decades for the price to be affordable for most countries.
Small modular fission reactors are available now and are affordable so we should start with one near Auckland.
The Greens have caused enormous damage to most countries in the world through their intransigence and ignorance. Unfortunately none of our politicians have the balls to confront them.
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