Fast trains or fusion?

The surprising thing is that someone else has finally noticed that we are not spending enough money on developing fusion as the power source of the future!

Andrew Steele wrote in the Guardian:

In among a raft of new infrastructure spending announced by the UK government in the wake of last week's spending review, it was revealed that the cost estimates for the HS2 high-speed train line had been revised significantly upward. According to the new projections, HS2 will be completed in 2033 at a total cost of £42.6bn for construction and £7.5bn for trains – a total of just over £50bn.

What is immediately striking about this figure is that it's about the same as estimates of how much it will cost to develop nuclear fusion to the point at which it could supply affordable electricity to the grid.

What is also strikingly missing is that the £50 billion for HS2 is being paid by the British taxpayer, whereas the $50 billion estimated for fusion could be shared by all the countries in the world.  That makes it much more affordable.

However, in general Steele gets the point.  Good for him!

JET - 30 years old, and still state-of-the-art!

Today is the 30th anniversary of the first day of operation of the Joint European Torus, JET, and it is still the most successful fusion device in the world.  That's both a great opportunity to celebrate and a tragedy at the same time

During two days of celebration various eminent speakers told stories of their experiences and shared anecdotes.  Paul-Henri Rebut, the father of the JET project spoke of the friendly rivalry between the JET team and their American competitors in Princeton who built the machine called TFTR.  He explained that there had been a wager relating to a specific milestone in the operation of the two machines.  It was agreed that the team that first achieved a plasma current of one million amps for one second would host the other team for a celebration meal.  The losing team would travel across the Atlantic and bring the wine.  As a Frenchman, Rebut was glad to have won the wager but regretted the consequential need to drink Californian wine!


Other speakers spoke of the fun of operating the JET facility (which is still true) and yet the responsibility for delivering results to compensate for the expenditure (which is also true).   At least twice it was claimed that JET is the oldest operating tokamak in the world, but that is assuredly untrue.  As they could easily discover at www.tokamak.info, this honour probably goes to a machine that is currently called GOLEM, in Prague, having been moved and renamed three times.  It was built in about 1963, under the name TM1 (with the M translating from Russian as "small".)

However, nobody could doubt that JET has been the most successful.

The successful life of JET is indeed worthy of celebration, and with good fortune it will run for several years to come.  However, real progress in fusion depends on many challenges in addition to the obvious technical issues.  One of them is the recruitment, training and retention of the next generation of 'fusioneers'.  Given that the 'industry joke' says that fusion is 30 years away and always has been, some might be reluctant to join the field.  (I have blogged about that topic before - with optimism, here and here).

One of the speakers reported that recruitment of brilliant young students is still not difficult but retaining their enthusiasm in a field that moves so slowly can be more challenging.  This is made worse by the lack of that friendly spirit of competition that drove progress in the 1980s.

The tragedy that I mentioned at the beginning is that 30 years ago fusion scientists had big plans to build a machine to take over from JET and push the research forwards.  They designed a bigger and better machine in a project called "NET".  This 'Next European Torus' was a machine big enough to prove the success of fusion technology.  In USA, Russia  and Japan similar large projects were being proposed at the same time, and politicians and bureaucrats managed to resist these ambitions in every case.  How sad. How tragic.

Instead of doing NET we got ITER and lost 20 years. 

Is there any hope of regaining some competition for the international project ITER?  Officially and diplomatically the answer has to be 'no'.

However, China has been training fusions scientist at the rate of 100 per year for at least a decade.  Should we worry about that or should we celebrate the likely source of competition from China?  Certainly they have the ambition to take things forward and they have built an impressive machine called EAST.  One way or another, Europe needs to take fusion much more seriously and face up to the investment.  Instead of spending the equivalent of a pint of milk per European per year, in the spirit of standardising on sensible units of measurement couldn't we at least push that to the equivalent of a litre of beer, if not cognac? After all, by comparison the photo-voltaic power industry last year alone had a turnover of around 100 billion Euros. This is big money and comes from the pockets of the taxpayers too.

Neither technology is the perfect solution but the world needs both (along with the rest of the power portfolio) if an energy crisis is to be avoided.

Fusion Fuels part 5 - Tritium.

This is part of a series examining how the fuels for a fusion reactor are likely to be obtained.  In part 1, I described the Isotopes of hydrogen and named them.  In part 2, Mining deuterium, we saw how deuterium can be extracted from ordinary water, and brought up to a concentration of 20 to 25%, and in part 3 we saw how it can be 'vacuum distilled' to produce 'heavy water' with a purity of 99% deuterium (and a 1% impurity of protium).  Part 4 described how that water can be turned into deuterium gas by a process called electrolysis.

The other component of the fuel, namely tritium, is made by a completely different process. 

I mentioned previously that tritium is not found in nature in any significant quantities.  There is a tiny amount in the upper atmosphere where it is produced by high energy cosmic rays interacting with the gases that are present there.  Most of that tritium escapes into space, and the rest decays into ³He (which also then escapes).

It is true that there was a lot more tritium in the atmosphere in the past - particularly in the 1960s when USA and USSR were detonating hydrogen bombs and making a nuisance of themselves to the inhabitants of islands in the Pacific and in desert regions of USA and USSR.  Some people estimate that there may have been more than one tonne of tritium in the atmosphere at the time.  It is still a tiny quantity.

Tritium in air, peaked in 1963

The surprising thing is that all of that tritium was man-made in the arms race, using nuclear fission reactors.  You can look this up for yourself if you like.  I won't dwell on it because it is not the way that tritium is expected to be produced for fusion reactors in the future and therefore I don't care about it very much, except to acknowledge that the tritium used for fusion at the moment comes from a Canadian plant at Darlington in Ontario.  There they run a process to remove the tritium from the cooling water of the CANDU reactors.  In most CANDU reactors, the tritium is an inconvenient by-product.  However, just a few years ago, South Korea proposed building more CANDU reactors specifically in order to make tritium for the ITER project.

The fusion programme has other plans for the long term though.  There is another way to breed tritium and it is one of the greatest benefits of fusion as a future power source.  In principle, you can make your own tritium in your fusion reactor, as long as you get the engineering right.  That means that you will not have to transport the one and only radioactive material that you need to make fusion work.  This is all due to a fortuitous bit of physics.  Since all the physics of the production of deuterium seems to go against us, perhaps it is about time that something went the right way!

In the process of nuclear fusion, the heavy isotopes of hydrogen are forced to combine at high temperature.  As they fuse together to create helium, they have one neutron to spare.  About 80% of the huge amount of nuclear energy released by the reaction is in the kinetic energy of this neutron, and the remainder is in the energy of the helium ion.  Neutrons are not constrained by magnetic fields, so they escape from the hot plasma in the reactor, travelling in all directions.  The doughnut shaped plasma will be surrounded by a 'blanket' which is designed to stop as many of these neutrons as possible and force them to give up their energy as heat.  The heat will generate steam, and the steam will drive turbines to produce electricity.

But the cunning part of the plan is that if this blanket contains a widely available and relatively cheap metal called lithium we get an additional benefit.  If you can slow the neutrons down and 'collect' them with lithium, the metallic element gets turned into two gaseous elements, tritium and helium.  Hey!  Tritium!  As if by magic, the fusion process produces part of its own fuel.  All you have to supply to the system is fresh lithium (and good technology).

Obviously there is an additional step to the process, to separate the tritium from the helium (which is easy) and from the cooling water, which is a little more complex.  However, these aspects of the process are similar to the methods described to separate deuterium from ordinary water.

Each phase in this process has been demonstrated to work, and the ITER tokamak will eventually include a test module to prove the process on an experimental scale.  Industrialisation of the whole process is just one of the steps required to make the concept of fusion power into reality, but it is already well beyond the science-fiction stage.

Now one question remains.  Is it worth all the energy that is used to make the fuel?  Do you get more energy back from nuclear fusion than you put into manufacturing of the fuel.

The answer is affirmative.  The cost of the deuterium is trivially small and the indications are that the processing of lithium ore and production of tritium will cost about the same as the fuel for a fossil-fuel power station.

Now we just need to build a full scale fusion reactor!

Read other articles in this series:
Fusion Fuels: Part 1 - The isotopes of hydrogen
Fusion Fuels: Part 2 - 'Mining' deuterium.
Fusion Fuels part 3 - Making 'heavy water'
Fusion fuels 4 - Electrolysis of heavy water

As free as the wind

In the news this week, I saw an item about the world's largest offshore wind farm having produced its first power. The London Array Offshore Wind Farm is a 630MW scheme, located in the Thames Estuary.

This has got to be good news hasn't it?  Well . . .  OK . . .  I know that not everyone will agree with that statement, but when the lights start to go out (which seems not to be wholly unlikely over the next few years) I think even the most ardent critic of wind farms might start to see the advantage of diversity.

But this brings me to another point.  Diversity is only achieved by . . . yes . . . diversifying!  One other new and promising source of power is nuclear fusion, and the international ITER project is now under construction.

Critics in Europe continue to question the cost of the project.  People always object to anything new, and the fusion seems to be a little pricey compared with most people's personal expenditure.  But in the context of energy expenditure, are the numbers really all that high?

Rumours are beginning to emerge that the sheer cost of offshore wind might be a threat to the UK's renewables commitment.  A budget of £30 billion had been earmarked for the construction phase, up to 2020.  But now it is clear that this has been a serious underestimate because the price of concrete is rising.  In a kind of spiral, the cost of concrete depends mainly on the cost of the energy needed to produce it, and that energy needs to be made by the machines that consume the concrete.  The net result is that the offshore wind costs for the UK alone might reach £90 billion by 2020.

Now tell me again that ITER is expensive!  I suggest that you can't do that with any degree of intellectual honesty.  Even if ITER reaches a cost of £20 billion (which is way over the current expectation) this £20 billion is spread between most of the richest countries in the world, whereas the £90 billion for wind is from one small country alone.

Let's be reasonable.  Context is key.

Fusion is not all that expensive.

Fusion fuels 4 - Electrolysis of heavy water

This is part of a series examining how the fuels for a fusion reactor are likely to be obtained.  In part 1, I described the Isotopes of hydrogen and named them.  In part 2, Mining deuterium, we saw how deuterium can be extracted from ordinary water, and brought up to a concentration of 20 to 25%, and in part 3 we saw how it can be 'vacuum distilled' to produce 'heavy water' with a purity of 99% deuterium (and a 1% impurity of protium).  This liquid now has to be turned into deuterium gas by a process called electrolysis.

In chemistry or physics lessons at school you might have electrolysed water.  You probably added a bit of salt to the water so that it conducts electricity, put two electrodes into the water, and connected one end of a battery to each electrode.  You would have seen bubbles rising from the two electrodes and you might remember that one electrode produces bubbles of hydrogen and the other produces bubbles of oxygen.  Collecting the bubbles in a test tube, you probably enjoyed igniting the gas and hearing a loud pop.

In doing that, you are releasing the chemical energy of the hydrogen as it recombines with oxygen and becomes water again.  Hydrogen contains quite a lot of chemical energy, and this is why it is being considered as an alternative, carbon-free, fuel for cars.  But hydrogen contains massively more energy than this if you can release its physical energy by fusing its atoms together to turn them into helium.  This is the power source of the sun and stars.  The heavy form of hydrogen, called deuterium, will be even better for that because it fuses more easily.  Stars contain almost no deuterium at all.  As soon as a deuterium atom is created it fuses with another almost immediately.  This is why we want it as a fuel for fusion reactors.

If we carry out this electrolysis process on the 'heavy water' that we have made by the processes of isotopic exchange and vacuum distillation, we find that something useful happens.  Remember that we want to get rid of the protium and keep the deuterium.

Fortunately, they do not electrolyse at the same rate as each other. 

Unfortunately, as with vacuum distillation, the protium is more easily produced than the deuterium!

But knowing this, you can remove the protium first to leave a higher concentration of deuterium in the water, and then choose when the deuterium concentration is high enough to start collecting it.

Concentrations of 99.9% can be reached by this method.  This is high enough for fusion reactors to use.

At last we have one half of the fuel we need for fusion.  The other half is potentially a little less complicated except for the problem that it is still a little more conceptual. 

Next time I will cover the production of tritium before returning to discuss the energy balance of the production of deuterium.  Is it really worth spending all this energy to make the fuel for fusion?  I hope to convince you that the answer is an emphatic YES!

Next time:  Fusion Fuels part 5 - Tritium

Other articles in this series:

Fusion Fuels: Part 1 - The isotopes of hydrogen
Fusion Fuels: Part 2 - 'Mining' deuterium.
Fusion Fuels part 3 - Making 'heavy water'

Fusion Fuels 3 - Making 'heavy water'

This is part of a series examining how the fuels for a fusion reactor are likely to be obtained.  In part 1 I described the Isotopes of hydrogen and named them.  In part 2, Mining deuterium, we saw how deuterium can be extracted from ordinary water, and brought up to a concentration of 20 to 25%.

In order to get the water to higher concentrations, a process called 'vacuum distillation' is often adopted.  That is the subject of this post.

Water that contains almost all deuterium and almost no protium is often called 'heavy water'.  You might remember that the 1965 movie "Heroes of Telemark" was a dramatisation of the true story of the destruction of a German heavy water plant in occupied Norway during the second world war.  This was necessary because heavy water is useful in some of the techniques used to produce enriched uranium for a nuclear weapon.  (As it turned out, German technology was not going in quite the right direction, but that was not known at the time.)

However, heavy water is also a source of the deuterium that is needed for the entirely peaceful and environmentally friendly fusion reactors of the near future, and it is only for this reason that I care about it enough to write this series.

In the last instalment, we reached the point where we have water with 20 to 25% deuterium atoms and the remainder still containing protium.  You might remember that I explained in part 1 that some lakes around the world (which have no rivers flowing out of them) have slightly higher concentrations of deuterium than 'ordinary' water.  This is because water molecules containing deuterium evaporate slightly less easily than water molecules containing protium.

Now you might be able to imagine a method of using this process on an industrial scale.  If you study the physics of the evaporation of water, you find that you can choose the right conditions of temperature and pressure where the H₂O evaporates preferentially and leaves the HDO and D₂O behind.  In fact it turns out that the best conditions for this are at a temperature slightly above the freezing point of water, and in rather a good vacuum. 

In an ideal world you would like to be able to evaporate the product that you want to keep in preference to the waste product.  After all, the whisky industry in Scotland makes its living by doing exactly this 'distillation'.  They warm a dilute mixture of alcohol in water and the alcohol evaporates preferentially.  The liquid that is distilled contains more alcohol and less water.  They usually repeat this distillation a few times in order to concentrate the alcohol further, taking the product from the first distillation and putting it through the process again and again to increase the purity. 

Unfortunately, in making heavy water the opposite is true.  The part that evaporates first is the part that you want to 'throw away' although in practise it will still contain much more deuterium than most of the water in the world.  It will not be discarded but returned to an earlier stage in the process.

The water that is left behind will be a bit more concentrated than it was before the H₂O was distilled away, and the last water to evaporate will be the most concentrated in deuterium.  Of course the whole process has no clear cut off points where all the H has been removed, leaving all the D behind.  But an iterative approach can yield higher and higher concentrations of deuterium and, in practise, a concentration of 99% can be achieved.  This might be good enough for most applications of heavy water. 

As a fusion fuel, a slightly better concentration might be preferred.

Fortunately the next stage in the process helps further.  It is in this stage that the heavy water is converted into deuterium gas, by a process known as electrolysis.  This gas is one half of the fuel we need for fusion.

More next time: Fusion fuels 4 - Electrolysis of heavy water

Other articles in this series:
Fusion Fuels: Part 1 - The isotopes of hydrogen
Fusion Fuels: Part 2 - 'Mining' deuterium.
Fusion Fuels part 5 - Tritium

Fusion Fuels part 2 - 'Mining' deuterium.

Last week, in Fusion Fuels: Part 1 - The isotopes of hydrogen, I described the three isotopes of hydrogen and why we might need them as fuel when we finally develop a fusion reactor on earth.  If deuterium and tritium are foreseen to be the fuels for fusion, where do we get deuterium?

Deuterium exists in all the water that you ever see anywhere.  On average in Standard Mean Ocean Water (SMOW) there is one deuterium atom for every 6400 hydrogen atoms, so although it is somewhat dilute it is not particularly rare.  In some places on earth you can find water that is slightly enriched in deuterium - with perhaps double the concentration.

Browsing around the internet you can find claims that the Dead Sea is one of these areas.  Lake Tangyanika is another.  These claims are plausible.  The one thing in common between these places is that they have rivers and streams running into them, but no river running out of them.  Water only leaves them by evaporation and the vapour evaporating from a water surface tends to be richer in the light isotope, protium, than in the heavier deuterium.  Therefore the water left behind in closed bodies of water is likely to be slightly enriched in deuterium.  The water might reach double the concentration of normal water, but no better than that. 

You might also find claims that the water in the deepest ocean trenches is enriched in deuterium.  One could propose that this is because the 'heavy water' sinks to the bottom of the ocean and collects there.  For now I am going to resist the temptation to address this topic very much, because I am very skeptical about it.  In fact the only evidence that I have ever found about the deuterium concentration in deep ocean water suggests that the claim is unfounded.

In order to obtain pure deuterium, water has to be processed in a variety of ways.  There is no single process that produces pure deuterium from ordinary water in one step.  In fact it is usually achieved by three distinct and sequential processes.  The first is designed to concentrate the deuterium to between 20 and 30% in water and the others to increase the concentration further and to generate deuterium gas from this 'heavy water'.

The initial stages are usually achieved by a technique known as 'isotopic exchange'.  The three different hydrogen isotopes very easily swap places with each other in molecules.  Hydrogen, deuterium and tritium are chemically and physically equivalent in most situations, and a water molecule containing two hydrogen atoms and one oxygen atom can easily become one that contains a hydrogen, a deuterium and an oxygen.  The forms of water that can be produced in the presence of H and D are H₂O, HDO, D₂O.  If tritium is included in the equation, three other forms can be produced, specifically HTO, DTO, T₂O.  Tritium doesn't exist for long in nature so let's ignore it for now. 

So it is not very inaccurate to say that all the water you have ever seen or drunk, or washed or swum in was almost all H₂O, but that one molecule in 6400 was HDO.  There is so little D₂O in nature that we need not worry at all about the health hazards associated with drinking pure heavy water. 

If we want to increase the concentration of D in the water and to make significant amounts of D₂O, we have to 'trick it', and one way to do that is to use another molecule containing hydrogen.  Hydrogen sulphide (H₂S) and ammonia (NH₃) are both commonly used but for simplicity I will just describe the use of the former of these two. 

Less than 100 years ago, two people spotted that if you bubble hydrogen sulphide through hot water (say 130 degrees celsius, at high pressure to prevent it boiling), the deuterium can be made to jump from the HDO molecules into the H₂S to make HDS. They also noticed that in colder water (say 30 degrees celsius) the deuterium tends to jump the other way to make HDO or D₂O.  They carefully explored how this property changed as they varied the temperature and the end result was the Geib-Spevack (GS) process. The process was industrialised by a North American company called Girdler, and no doubt there was ill feeling about admitting that the inventors were German at the time, because the company quietly made sure that it mutated the apparent meaning of 'GS' to 'Girlder Sulfide'.  In the English-speaking parts of the world, that name has prevailed.  (Although I know a lot of Germans, none of them have admitted to me that they know about industrial processes to separate deuterium so I can't confirm what they call it.)

GS process (annotated in Greek) but still useful
to an English speaking audience (from here)

By circulating the hydrogen sulfide through hot and cold water continuously, you can deplete the deuterium from the hot water and concentrate it in the cold water.  This sounds easy enough, and you might think it could be engineered properly to ensure that it doesn't take a huge amount of energy, but there are a few practical difficulties.  For a start, hydrogen sulphide is toxic, so you have to be very careful with it.  (Ammonia is not much better by the way.)  Secondly, the physics only works for you until the concentration of deuterium reaches about 30% (limit), and for most practical purposes not much more than 20%.  After that you can wait as long as you like, but you won't improve it further.

Still - looking at it positively, you have concentrated the deuterium from 155 parts per million to more that one part in five.  That's not a bad start!

To go further than this, you have to change tactics and use a process known as vacuum distillation to do what nature does in the lakes I mentioned earlier - but to do it better.

More next time.  Fusion Fuels part 3 - Making 'heavy water'

Other articles in this series:

Fusion Fuels: Part 1 - The isotopes of hydrogen
Fusion fuels 4 - Electrolysis of heavy water
Fusion Fuels part 5 - Tritium

Beautiful Heavy Ice

Searching for pictures for my series about Fusion Fuels, this beautiful photograph came to my attention.

Heavy-water ice cubes sink in ordinary water (left).

Here is the source.  They don't explain (as far as I can see) what is happening here.   Both glasses contain cold water, and the glass on the right has an ordinary ice cube floating in it, just as you would expect.

But the ice cube in the left glass is frozen 'heavy water' - deuterium oxide.  As you can see, it is heavy.

Just WOW!

p.s.  If I'm right, that was an expensive photograph!

Fusion Fuels: Part 1 - The isotopes of hydrogen

Believe it or not, I am sometimes asked a question that most people would never have thought of:

"Where do you get your deuterium from?" 

The reason that I am asked this unusual question is that my 'day-job' is in the field of nuclear fusion research - fusion being the safe form of nuclear - the one that can't run away.

You might ask "What is deuterium?"  So, let's start from the basics and then cover the rest of the process in a series of other posts. 

The simplest type of atom on the periodic table is normally known to you and me as 'hydrogen'.  Its nucleus contains one proton and nothing else.  A single electron accompanies that simplest-possible nucleus to make a hydrogen atom.

We know hydrogen in its gaseous form as the light gas that filled the magnificent but ill-fated German airship Hindenberg, which crashed in flames in the 1930s.  We also find hydrogen in water, in natural gas (methane) and in all organic molecules that go to make up life.  Hydrogen is the fuel of the whole universe.  Stars 'burn' it in their nuclear fires to make heavier elements.  It might even become a conventional fuel that will be burnt to generate energy in the future, but only if a few of its inconvenient features can be overcome by good engineering.  (As a gas, if it is mixed with air it tends to be extremely explosive.  It is also very good at escaping from containers used to store it. Clearly these are potential inconveniences.)

This common form of hydrogen is sometimes known to scientists as 'protium'.  This term is used to distinguish it unambiguously from its heavier sister, 'deuterium'.  Deuterium atoms contain a single proton, but their nuclei also contain a neutron, making them roughly twice as heavy as protium.  Add a single electron and you get a stable atom called deuterium.  When two different types of atom vary only in the number of neutrons, we call them 'isotopes'.  That doesn't mean that they are radioactive, even though science fiction and the popular press tend to use the term for something that is.  In fact both protium and deuterium are stable in nature, and both can correctly be called 'hydrogen' because they are both hydrogen isotopes.

Hydrogen (protium), deuterium and tritium

There is a third isotope of hydrogen which contains two neutrons.  It is still quite stable, but slowly over time it decays, turning itself into the lighter isotope of helium, known as helium 3, and emitting a beta particle.  If you start off with 100 tritium atoms and simply wait for about 12 years . . . half of them will have turned into helium 3.  After a further 12 years half of the remainder will have decayed . . . and so on.  Therefore you don't find much tritium in nature, even though small amounts of it are created by natural processes in the upper atmosphere.

Fusion of protium powers the sun as I mentioned earlier, because the sun produces conditions of high pressure and reasonably high temperature that are suitable to fuse ordinary hydrogen. But if we want fusion to be the power source of the future on earth (where we can't easily develop very high pressures, and don't have anything like as much volume as the sun) we would need much higher temperatures than the sun produces.  The sun gets away with being relatively cold because it only burns its hydrogen very slowly.  A cubic metre of the sun produces only about as much energy as a cubic metre of a compost heap (on average).  We should be quite happy that the sun works so slowly, because otherwise it could have burned up all its protium a long time ago, and life on earth would have ceased to exist before humans evolved.

In order to get an efficient enough reaction in fusion reactors on earth - to develop a 'sun on the earth' - we know from experiments that it will be easier to fuse the two heavy isotopes of hydrogen; namely deuterium and tritium, instead of protium.  We can use these fuels to produce fusion even now, with 'small' machines built in the 1980s and 1990s, but they are only big enough to produce tens of megawatts.  It works, but not yet well enough.  However, a large international technical project called ITER aims to achieve a power of around 500MW in the mid 2020s, to demonstrate fusion on the scale needed for a power station.

So - where do we get deuterium?

Read the rest of the series: 
Fusion Fuels: Part 2 - 'Mining' deuterium.
Fusion Fuels part 3 - Making 'heavy water'
Fusion fuels 4 - Electrolysis of heavy water
Fusion Fuels part 5 - Tritium

Small note:  The glib answer to the original question is "Out of a high pressure gas bottle delivered to us by our supplier".  That would be accurate and true, but not altogether in keeping with the spirit of the question.

Papillons in flames - putting out a flame with electricity

A spectacular physics demonstrations with a candle flame in a high electric field.

Educational AND amusing.

Profusion of Lego

Sometimes you have to admire the way that people can have fun in science.  It seems that the staff of Scientific American have been following the progress of construction of the ITER tokamak and that they are more-or-less prototyping the assembly of the machine . . . in Lego bricks.

ITER - the way forward as envisaged in lego bricks

Read on about it at this link.

Meanwhile, Europe's flagship machine, which is still the largest and most successful tokamak in the world - state of the art but 30 years old - has already been depicted in Lego.  Or at least a relatively realistic version of the JET control room has been built, with nice pictures of the inside of the machine while a pulse is running.

JET Control Room in Lego - by Fernanda Rimini (source here)

I wouldn't like to speculate about which member of staff is represented by Darth Vader.  I think I ought to keep those thoughts to myself!

Small and surprising note:  Did you know that 'Lego' is a name constructed out of the Danish expression leg godt, meaning 'play well'?

Nolympic hysteria and fusion funding

Am I allowed to use the word "Olympic"?

It would seem that the organisers of the £11 billion sporting extravaganza would like to reserve the word for their own use and prevent anyone else from using it or the well known five circled symbol.  And as was mentioned on the BBC's surprisingly satirical TV show, 'Have I got News for You', someone had described the Olympic Games as "the 11 billion, tax funded advertising campaign for some of the world's worst companies".  (I don't know which companies they meant though!  Perhaps I will find out when all the advertising starts in earnest!)

Naturally there must have been businesses in London which already used the Olympic theme in their names, and I have no idea how they have been treated.  The whole event was billed as an opportunity to improve the economic climate for business.  It was going to bring prosperity to an area that has been run down for decades.  So, just imagine the pettiness of a legal challenge to a small cafe called Cafe Olympic.  Fortunately the owner managed an inexpensive solution to the problem by painting out the O.

Cafe Lympic's new improved look
(61 West Ham Lane, Stratford
London, E15 4PH)

It is now only three months to the beginning of the the Olympic farce, but more importantly it is only four months until it is all over.

I for one will have to adopt an avoidance strategy.  I'm not interested in the competition and to be honest I think it is an outrageous waste of a lot of money.  The £11 billion is just the cost to UK to build the facilities.  How much more has it cost to train the athletes around the world?  We shouldn't just include the successful competitors.  For every one of them there must be 50 who failed.  Then the costs of transport to London are hardly likely to be trivial.  The real costs of the whole event are massively higher than anyone ever mentions.  Estimates of £25 billion are not hard to find.  Isn't it interesting to compare this with the original estimate of £2.37 billion.

Illegal use of the Olympic symbol.
At least someone in Beijing had a sense of humour!

I'm not saying that sporting events do not have any social value.  Even I can recognise that many people enjoy partaking in sport, and an even greater number enjoy being inactive armchair experts.  But I do object to the fact that for a few weeks the whole world will appear to revolve around an event that will bore me silly.  Even more than that I feel strongly about another thing.

Is it worth the cost?  Most people will say that it obviously is, and they will point out the benefits to society and global international relations.  Think of all the jobs created in arranging for the games and think of the legacy in an area of London that needed to be improved.  (Notice one thing that is not included in the legacy - new technology!)

But . . .

Think of another project that costs the same amount of money.  The ITER fusion reactor that is being built by international cooperation (in possibly the most inefficient way conceivable!) will cost about £11 billion, give or take say 30%.  Just as many jobs will be created, but these are jobs that will teach scientists and engineers things that will actually be useful for the world.  Think of the legacy that a working fusion reactor would represent - clean and reliable carbon-free energy, virtually for ever!  The value of ITER is so much greater to humanity than the value of the Olympics, and yet there is only one of it, and it has taken decades to get the project off the ground because of . . . the cost!  Not because of lack of technology!

Yet somehow ITER is referred to as a 'black hole' and the Olympics is not.

Where is the logic in that?

Small note: I don't suppose there is any point in proposing that the next three Olympic events are postponed, and the money spent building machines to compete with ITER in order to get the most efficient possible power source for the future.  You could probably build two devices for the cost of each Olympics if you did it efficiently.  Competition, after all, brings out the best in the market.  We are always being told that by those conservatives who object so strongly to spending money, unless they spend it on a sporting event.

Keep Fusion's intellectual property public

USA is proposing to close down one of its most significant 'magnetic-confinement' nuclear fusion facilities next year to save cost.

USA might not be leading in fusion technology, but
the work on the Alcator C-MOD tokamak is a vital
part of the effort to make fusion power a reality

As is often said, (at least by me), "Global trade in peanuts amounts to $30 billion per annum. Fusion doesn't cost peanuts - it costs MUCH less!"

One of my colleagues tried to write an open letter to US Director of the Office of Science, Dr. William F. Brinkman
(at this link)

I write to you today as an active participant in the world-wide fusion community. The proposed cuts to the U.S. domestic fusion program in the Fiscal Year 2013 Presidential Budget Request seem to me to show a disappointing lack of confidence in the one and only technology that is likely to provide a reliable and substantial source of power in the future, long after fossil fuels have become too rare and expensive to burn.

You may not realise that the countries in the Far East have been advancing much more rapidly in their implementation of fusion engineering technology than the countries that have traditionally led the field.  You only have to look at the tables on the web site http://www.tokamak.info to see how many significant new machines have been built in the last decade.  None of them have been funded by USA, Europe or Russia and it would be irresponsibly optimistic to assume that the intellectual property developed with them will be in the public domain.

I strongly urge you to provide sufficient funding for a strong domestic fusion research program in addition to the American contribution to ITER. Thank you.


*******************

If you care about the future of our planet and want to support the idea that we should all contribute towards it, you can follow this link too.  If, like me you spend the time writing a letter and then get this message,

you will probably agree with me that open government is not what it claims to be!

As for me - I'll keep trying!  The future of the world is quite important to me.

Fusion gets a bad press - a personal view on the reasons

Why has there been so much negative news about fusion energy this month?  I suppose it is because the EU has finally committed itself to spending some extra funds on the ITER project, and a few people still try to pretend that 1.3 billion Euros is a lot of money.

Is it?  What can you buy for a few billion?

How much did CERN's LHC project cost?  I have heard figures up to 10 billion Euros spent over about 10 years, with most, if not all the funds coming from European countries.  (The LHC itself admits to a figure nearer 3 billion, but I'm sure it depends what you count as LHC and what infrastructure was already there.)  Its a beautiful project and it is sure to produce some beautiful science.  But it is also certainly not going to be part of the solution to the world's energy crisis.

The London Olympics comes with a similar price tag, but this time it is being funded almost entirely by a single country.  For a few weeks of sporting 'fun', (or to me, a few weeks of sheer tedium), the UK tax payers are paying out £10 billion after private investment failed to materialise.  Is that value for money?  No doubt many will claim that it is, and I have to try to respect their opinions.  However, it will also not be part of any solution to the world's energy crisis.

The International Space Station is another $10 billion scale project.  And many people point out what a sheer waste of money that has been!  It has a certain fascination for the inner child, but none of the excitement of earlier manned missions and certainly less value for money than the unmanned space programme.

These three examples - and believe me, there are countless others - show that it is actually a paltry investment when you consider how the ITER project is being funded.  Half the world's population are paying towards it, and the total cost is a mere £1 billion dollars per year.  (I am deliberately changing units of currency as I regard them as broadly equivalent, within the measurement errors that we are dealing with.)

Is it part of the solution to the energy crisis though?

The answer to that is clearly not known with absolute certainty, but I can tell you that it has a much better chance of returning value for money in this endeavour than big science, big space missions or big sport.  I don't consider ITER to be big science in the same sense as CERN.  It is more of a technological challenge where we know what we want the machine to do and just need to find the best way to make the most efficient and reliable machine.  The science that we get from ITER is interesting and relevant, but its main value (to me) is that fusion might finally come to the rescue as the fossil fuels dry up.

I'm not saying 'don't invest in renewables' at the same time.  I'm not even advocating an end to spending on other things.  I'm just saying that the coming energy crisis will affect us all and if you open your eyes to the possible consequences of shortage of energy you will realise that the world as a whole cannot afford not to invest in every possible solution however weird and wacky.  And as weird and wacky goes, ITER is very much towards the sane end of the spectrum.  Fusion already works on a smaller scale and all the indications are that bigger is better, and that ITER is at least nearly big enough.

Given the context of the level of spending on other things around the world the 'gamble' of building ITER is certainly worth it and at least construction is progressing now.  Buildings are starting to appear on the site and large contracts have been placed with industry.

ITER construction site.  More photos from here

Fusion might be thirty years away, and it might always have been 30 years away, but since the last credible device built to take the technology forwards is now over 30 years old I wonder why anyone would expect that to have changed.  Can you think of any other area of technology where a 30 year old device is still 'state of the art'?

Let's just keep in mind that 'the huge price tag' is not huge in the context of the things happening in the 'real world'.

As in everything - context is king!

Small note:  This is the private opinion of an almost irrepressible enthusiast - not representing the views of any official organisation in the fusion community.  Far from it in fact!

100,000 year old light!

How 'old' is the light from the sun?  I mean the light that you can see when you go outside today.

You might be surprised to know that the light took something like 100,000 years to get from the centre of the sun where it was first created by the process of nuclear fusion to the surface.  Then took only about 8 minutes to get from the surface to the earth.

Most of the fusion takes place close to the centre of the sun where the pressure and density are high enough.  Photons that are created in this process can't escape as they are surrounded by hot plasma.  Every time the photon 'hits' another nucleus or electron it is reflected in a random direction, and you can use some simple mathematical physics - known as the 'random walk' - to estimate how long it takes a photon (traveling at the speed of light of course) to get away from the core.

This is almost analogous to trying to get out from the centre of crowd of people. You couldn't just run straight through because you would be pushed back by people and be bounced around. You might have to go back to the centre to get past a tightly packed area. The other people represent the nuclei and electrons that make up the sun.

Incidentally - you might remember reading my post Indecisive Neutrinos about the speed of neutrinos measured from the 1987A supernova. I mentioned that they arrived 3 hours ahead of the first light from the event, having traveled for 168,000 years and I half-explained that the reason for the three hour difference was because the neutrinos hardly interact with matter but that the light does.

'In the light' of what you have just read, that comment might make more sense now.

In fusion, size REALLY matters!

The old cliche that size matters is actually true in nuclear fusion.  Over two hundred 'tokamaks' have been built at various sizes from a bit larger diameter than a compact disk or DVD, to huge machines the size of JET.

Scientists have done experiments to study how the performance scales with size.  Broadly speaking, the answer is 'the bigger the better'.

Why is this?  The analogy of a camp fire is a useful comparison.

Imagine making a camp fire that is the size of a golf ball.  It is difficult to keep it burning.  The size of a tennis ball is a bit easier, but a fire the size of a soccer ball will produce a lot more heat and be harder to extinguish.

Similarly with a tokamak it is better to have a larger volume of plasma.  Not only is the heat retained better because the volume rises faster than the surface area, but impurities are likely to have less chance of contaminating the plasma and the fuel particles can be kept in the plasma longer so that they have more time to meet and fuse together.

None of the machines built so far have been big enough to achieve better performance than breaking even (which would be called Q=1).  In other words we are not yet producing more energy than we put in.  JET is around about the size needed to reach 'break-even' and the next time it is operated with deuterium and tritium it should be able to break its own world record (Q=0.65) because the understanding of the performance of the plasma has improved since 1997 when the record was set.

ITER will be ten times larger than JET and it is expected that it will produce about 500 MW of power (at Q=10 or so).  The only question is how easily the larger volume of plasma can be controlled.  Don't worry - it only weighs as much as a few postage stamps so even though it is enormously hot it will not escape, but until it is in good control the machine would not be considered reliable enough to be a good power station.

Don't hold your breath.  A machine as big as ITER will take another 10 years to be ready for operation.  But starting construction is a step forward, at least!

Fusion and 'the 30 year problem'

Nuclear fusion made the news again this week but the one thing that the news item shows is that the 'inertial fusion' (or as they sometimes call themselves 'laser fusion') people are much more active at public relations than the 'magnetic confinement' community.

That doesn't mean that they are closer to the goal of making fusion a commercial reality.  Realistically speaking, both approaches can predict a similar timescale to reach fruition, and I personally believe that it is important that both are pursued with vigour - greater vigour than they currently have.

The BBC news article UK joins laser nuclear fusion project is a good example of making news out of a classic non-announcement.  Laser fusion research in the UK is rather in the doldrums at the moment, significant funding not being forthcoming.  One might conclude that this has resulted in certain leaders of the HIPER project going over to work at the National Ignition Facility, contributing to the continuing brain-drain from UK.  NIF is close to its first operation, but to paraphrase the industry 'joke' that 'fusion is 30 years away and always has been', fusion (or ignition) at NIF is one year away, and let's face it . . . it has been for several years.  If I remember correctly, the latest delay was due to a concern about something called 'sky-shine' - not a new problem that had not been considered but something that had been analysed a decade ago.  It was probably just a scare story of the type that often delays progress in anything that the public does not understand. 

NIF also benefits from funding from military sources to pay for its multi-billion dollar price tag.  Even though only a few percent of its operational time will be spent on military work they have gone to the huge expense of a second independent control room to protect the 'classified data' that they will collect to teach them how to make better hydrogen bombs.  (Does this explain the interest of the UK's AWE now?)  Meanwhile magnetic fusion has no military applications at all and can't gain from such funding.

If there is one thing to demonstrate the media hype from NIF I can tell you this.  I have personally visited the facility, after seeing a series of presentations about it, heard about how huge and impressive it is, how it is going to be the answer to the world's energy problems and seen numerous stunning photographs.  It was a nice facility but I was totally 'underwhelmed' by it.  It is much smaller than I had been led to expect. However, I wish them well and would not be at all surprised if they achieve 'ignition', for a short period, earlier than the magnetic confinement devices achieve the same. When I say a short period though, it will be for a micro-second or so, not really rivalling  the current record of 16 MW for 1 (whole) second on JET.

The other good news is that there is now hope on the horizon for magnetic confinement fusion too.  This '30 year problem' (not 50 years as the BBC claimed) might actually be realistic at last.  I don't say this out of sheer optimism, but from the observation that the world has now started to take the issue a little bit more seriously and the ITER project is progressing quite well now.  International squabbles aside, there are actual buildings on the site and at long last a commercial reactor-sized tokamak is finally being built.  In about 10 years time we will know a lot more about the feasibility of magnetic confinement fusion.

When I said 'a little bit more seriously' we have to set the spending in context.  In total, ITER is costing as much as one beer per year for each person in Europe.  Its quite a lot of cash but as it is spread over a period of two decades it is not all that much per head  This is especially true since this cost is spread between the governments representing half the world's population, and not just Europe.

 

JET site on Google maps

The international media has missed another important real event on the subject.  The most successful tokamak in the world so far is based at Culham in Oxfordshire.  The strange thing is that this 'break-even' sized device, called JET, is still in many ways the 'state-of-the-art' in spite of the fact that it has been operating since 1983.  This is a testimony to the design of this incredible machine.  At the time it was 100 times larger (in volume) than any previous machine.  Now, 28 years later, it is the only tokamak in the world capable of running with the 'real fusion fuels' of tritium and deuterium. All the other tokamaks in the world produce good data too, but JET is currently the closest to ITER in almost every way.  (ITER will be only 10 times larger than JET in volume.)

Just 3 weeks ago JET went back into operation after a 2 year shutdown to upgrade its internal components and its heating systems.  By all accounts, the first weeks of experiments are producing excellent data.  You can bet that the people at ITER are keen to get their hands on the intellectual property that is being gained there.

But the media have commented on this almost nowhere!  A few techy journals have mentioned it, but real progress on a real machine has not had the world-wide coverage that has been achieved by the non-existent UK device called HIPER.  HIPER should perhaps be renamed HYPEr.

Our relatively small machines have paved the way for real progress towards a plausible future energy source.  Fairly detailed and credible designs and project plans for a machine like ITER - which is big enough - have been available for at least 20 years, so . . .

Progress in fusion is not being held back by the technologists as much as by lack of funding and ambition of the governments setting the targets! 

There is one message that we should all keep in mind.  There is a global energy crisis coming and it is coming soon.  Many people reading this will experience it in their own lifetimes.  If we as a race do not invest much more heavily in developing alternative energy of all kinds it will be difficult to see how humanity can survive.

Governments should be setting aggressive and competitive targets and asking why the technologists have not solved the problems - whereas at the moment it is, to a larger extent, the technologists begging for breadcrumbs to make any progress at all.

This isn't a game and it isn't a hobby for pure scientists.  Seriously!  This is a matter of life and death.

Death of a photon

A dear friend asked me some questions about photons recently, (photons being, at least by analogy, 'particles' of light).  I might have misunderstood the deepness (or otherwise) of her real question.  She is a good christian, and to give her credit she is definitely up for a hard hitting debate about the existence of (her particular) god.  I think she was seeking more of a metaphysical reply with significance to an analogy about the nature of god, but having failed in that respect it seemed a shame to waste a friendly lesson in sensational physics.

But before that, I will mention another related question.  Working, as I do, on a rather successful nuclear fusion device, I often take groups of people around the site on tours.  Interestingly, some of the most interesting questions come from young people.

Now that is not to say that you get good questions from school groups, who's main objective in life is to look cool in front of members of the opposite sex.  But when young people come to visit with parents in tow they often want to find out about the mysteries of physics and engineering.  Naturally, the fact that they are there with their parents limits their age to a maximum of about 12 or 13, but already some of them have a real insight into the world.  One day I was asked "where do all the photons go?  A good question.  See the end for a considered answer, but at the time it took me a minute or two think of a good explanation.

Let's return now to the original topic, which was about the 'life' of a photon and whether it ever dies, and what would happen to a photon created at the beginning of time.  One might speculate what it is like to be an photon, and whether time seems to pass in its frame of reference.  But it is of course not like anything at all and there is no way that a photon could be aware of anything that it might be like, or to sense that it ages or changes.  So it is a meaningless question but it is interesting to examine the creation and ultimate doom of an individual photon.

Photons are produced inside atoms when one of their electrons 'jumps' from a higher energy state to a lower energy (as they do spontaneously e.g. perhaps when their host atom gets energy from bumping into another atom).  Quantum mechanics tells us that these jumps can only be of certain discreet sizes and that for a particular type of atom the number of options is limited, immutable and predictable.

The difference in energy has to go somewhere and that somewhere is a photon.  It is just a packet of energy, and a very small packet at that, but with a very specific and fixed amount of energy.  We see the energy as colour and specific atomic transitions produce specific colours.

The photon is not is produced from nothing.  There is no creation of mass involved and conservation of energy is all that matters.  The photon will then 'live' and travel at the speed of light until it bumps into another atom.  At that point it might bounce off the atom (called scattering).  However, if the atom happens to be receptive to a photon of that particular and exact energy, the photon is absorbed, thus raising the energy level of an electron in that atom.  (In astronomy these are also observable as specific 'absorption bands' and their existence helps us to know what other stars are made of).

Photons no more 'live forever' in space than they live for ever if you put on the light in a dark room.  The photons are created at the light and absorbed at the walls, maybe after bouncing around for a while to find an atom that can absorb them.  Indeed, those photons that were produced near the beginning of time (whatever that means) may well have been reabsorbed, by interstellar dust long ago, and then re-emitted at lower energies.

So that seems to me to explain the physics in terms that I can understand, with just a little reference to the incomprehensibility of quantum mechanics. 

Going back to that intuitive student question, 'what happens to all the photons' . . . it seemed that the best way to answer it was to ask another question.  "Do you know where photons come from?"  Fortunately the young man gave me quite a nice description about energy levels of electrons, and he seemed happy with the explanation that

"That is where the photons go back to".  

At least that was one satisfied customer!

To the moon! (1961)

I missed the actual 50th anniversary on May 25th, but we are still within the same week, so I suppose I could claim some degree of topicality.

50 years ago this week, President Kennedy announced that America would put a man on the moon by the end of the decade.

What an exciting announcement that would have been.  Does anyone remember whether it sent a ripple around the world?  I don't, but then again I was only 4 months old at the time.  At least I remember Apollo 11 and even Apollo 8's first orbit of the moon.

The burning question for me is whether people actually believed presidents in those days.  If an announcement like that was made today, I think we would all expect it to be canceled again within a few years, usually having wasted half the money with nothing much to show for it.  (Think of the Superconducting Super Collider.)

How long will it be before USA pulls out of the international fusion project ITER (again)?

Fusion costs less than peanuts!

To continue yesterday's theme here's a thought.  "Fusion research costs peanuts".  I have often heard people ask why such a promising technology gets so little funding when it looks so promising.  Fusion costs peanuts.

Wrong!

Do you know how much money is spent on peanuts?  A little googling reveals that 30 million tonnes of peanuts are produced worldwide per annum.  Even at wholesale prices, (say $1200 per tonne at today's prices, mixing US and metric units entertainingly!) this amounts to much more than $30 billion per annum.

Compare that with the price of ITER.  At present estimates, the whole project will cost much less than $20 billion, spread over 20 years.

Fusion costs MUCH less than peanuts . . .  or ring-tones . . . or beer . . . or football . . . or church collections . . . or 2 weeks of Olympic sport . . . so where shall I stop?  Fusion might actually save the world.  The others only cost the world.

Food for thought.

(And just in case you think I am a fan of ITER, please don't.  It is the best hope we have, but the way it is planned it could be argued that it stands as a monument to global political nonsense.)