The Thorium Cycle, Part One

Rightly or wrongly, I consider myself to be a reasonably educated sort of fellow. But a few years ago, it struck me as rather odd that I had never heard of the Thorium cycle or the molten salt reactor (MSR).

I’m neither a nuclear scientist nor a physicist (nor much of a scientist neither) and I don’t pretend to be one. But I found it rather surprising that apparently a few chapters had been airbrushed out of the history of nuclear science, namely the before mentioned Thorium cycle and the MSR. Now, you might at this point wonder why this is even a thing, and never having heard of them neither, I would share the sentiment.

As we all know, to run a successful economy an abundant supply of safe and cheap energy is essential. And ever since someone on the Asian steppes bartered the first sack of bailey for a goat or a lamb, successful business transactions were at the heart of the human endeavour – no energy, no progress. Simple as that.

Without economic activity, there would have been no cuneiform script, no mathematics, no Pyramids along the Nile, and of course no classical antiquity along the Med from Jerusalem to Athens, and later beyond.

Guardian Council, Going Postal

Without coal, which was then considered an ample source of cheap and safe energy, the Industrial revolution would never have happened in Britain, yet probably somewhere else. Modern life would now look very different indeed had this been the case as we might either be writing and reading this blog in German or Chinese for all we know, dear readers.

So, I suppose we’re all pretty much agreed on cheap and safe energy being very desirable – if there is to be human progress in the form of emancipation from the confines of nature and unless we really do want to go back to living in mud huts and dying at 38 after the short and laborious lives of misery and depravity that the eco-nutters apparently crave and envision for everybody but themselves, that is.

There is of course a point in wanting our energy supplies to be environmentally friendly but let’s not delude ourselves about the fact that “renewables” are neither environmentally friendly nor economically sustainable as it is technically quite impossible for a wind turbine or a solar panel to yield the equivalent amount of usable energy that went in to its production, and will have to go into its decommissioning.

And that’s not even considering the dismal environmental impact of rare earth mining, or the employment of child labour in the pits that appears to be endemic in parts of this “green” and “peaceful” industry.

So-called renewables may be many things to many people, but they’re neither environmentally friendly nor ethically acceptable. All who invest in them ought to be made aware of the fact that it is a technical and social impossibility to make this thing work on a large enough. Because they require huge amounts of subsidies through tariffs and taxation and this would put a staggering burden on the economy.

This is why  “green energies” are in no way a means of meeting the energy demand of ten billion people globally. Or, in other words: achieving the greatest amount of happiness for the greatest number of people is utterly impossible with “renewables”.

Now, ever since the Neanderthals kindled their first precarious embers on the windswept plains of Northern Europe, energy had to be produced and consumed locally. The whole endeavour was hopelessly inefficient and productivity increases in energy generation were marginal at best for the next twenty millennia or so.

To this day, wood and dung remain the mainstay of energy generation in the many underdeveloped countries. The use of fossil fuels such as coal, oil and natural gas for heat, power and locomotion opened a new stage of human development, but their environmental track record is questionable.

Already, China is creaking under the strain large scale carbon oxidisation puts on air quality. And we’re not talking about the rather homeopathic dosage of air pollutants as in developed nations, but “can’t see the hand in front of my eyes” smog of Victorian proportions there.

In future, energy generation from fossil fuel may have niche applications in the aviation industry, but it is in no way conceivable that the energy needs of ten billion people could be met using fossil fuels without half the planet dying because of the resultant air pollution.

The still relatively controlled release of “renewables” into the energy environment already has led to a marked demand for more energy from fossil fuel sources with the consequential release of more nitrogen compounds (NOx) in to the atmosphere – and the resultant increase in lung and heart diseases of course. Even now, “green” energy is already hastening people in their thousands to their untimely demise, but I suppose that’s what the eco-nutters wanted all along as long as it’s not them doing the dying.

Meeting the energy demands of ten billion people globally is technically, economically, environmentally and ethically impossible with fossil fuel just as well as it is unfeasible with windmills and solar panels who need to be backed up with energy generated from conventional sources in case the sun doesn’t shine, or the wind doesn’t blow.

There’s no denying the fact and neither is there the slightest bit new or surprising about it at all. And yes, these challenges were well known and fully understood by the 1950s, when research in a new form of energy got underway and nuclear energy appeared on the scene.

To hasten the end of the Second World War, nuclear research yielded its first practical fruits in the form of two shapely atom bombs, one of them dropped on Hiroshima and Nagasaki each. The display of these awesome powers is said to have surprised even the scientists who worked on the Manhattan Project. In their minds, it quickly became apparent that apart from its obvious military use there must be a civil application for nuclear power if one could slow down the chain reaction just so far that the energy equivalent of a Hiroshima bomb would be released slowly enough to generate heat and light for homes, instead of turning them into radioactive cinders.

Guardian Council, Going Postal

Now, there happen to be a few things worth remembering when one is talking about the harnessing of atomic power for civil application. There are principally two approaches to the whole thing: one’s called fission and another one’s called fusion. We’re not interested in the latter now as it is said to be at least another twenty years away, just like the twenty years before that, and the twenty years before that.

Fusion looks great on paper, but it’s always been twenty years away from even a remotely practical application. While guzzling away tremendous quantities of taxpayers’ cash over the last sixty years, none of the fusion projects the world over have generated a single kilowatt of usable energy. But they should certainly give us a call when they think they’ve finally found something that could work, I think we’d be delighted. But for the time being at least, we can safely discard fusion and carry on with fission.

Unlike fusion, fission derives power from the breaking up of the atom’s nucleus. Some elements are prone to do this all by themselves. Those in which atomic decay occurs naturally are called radioactive elements or radioactive isotopes, as they may also be variants of elements that are not radioactive unless something happens to them in the form of the addition of an excess neutron to their nucleus.

There are several naturally decaying elements but most of them and their isotopes are too radioactive by far – they decay much too quickly to make commercial harnessing of their atomic power even remotely possible. The three elements which lend themselves to controlled fission are: Plutonium, Uranium and Thorium. Wait a minute, many of you will now say, you’re making this up! I’ve never even heard of Thorium – what’s that?

Thorium is an element named after one of these ludicrous Germanic deities; this one is supposedly sparking huge flashes of lightning across the sky. In more scientific circles, Thorium is known as the element just two steps down from Uranium in the periodic table of the elements, much like Uranium is two down from Plutonium.

It is highly abundant in the Earth’s crust: parts of Australia, India and North America contain between 12 and 14 % Thorium per cubic yard of top soil. But not only is Thorium cheap due to its abundance, it’s also safer and easier to mine than Uranium as it can be mined in open-pit operations.

Thorium is slightly radioactive but due to its rather slow atomic decay it does not pose an imminent danger to life and limp even by the wildest stretch of the imagination. It is estimated that Thorium decay (into more stable elements) accounts for almost half of the Earth’s internal energy generation.

The other thing to bear in mind when speaking of atomic power is the difference between fissile and fertile elements and/or their isotopes. Due to its inherent nature, nuclear reactivity increases the higher up you get in the periodic table of the elements. With it increases energy yield per atom. Therefore, for many years a Plutonium reactor appeared to be a nice thing to have.

Billions and billions of taxpayers’ hard-earned cash have gone into such schemes in the UK, France, Germany and the USA. After decades of fruitless endeavour, none of the ruins of this technology are operational any more, and today only India has a fast breeder up and running, so there’s Our Third World after all.

Plutonium reactors are also called “fast breeders” because they take fertile Uranium-238 and pimp it into Plutonium-239 by adding one more neutron to its nucleus. This is best accomplished by exposing U-238 to fast neutrons which result from – you guessed it – nuclear fission of elements somewhere in the same reactor, or at least nearby.

Therefore, and theoretically at least, a “fast breeder” could create almost all the nuclear fuel it is meant to consume out of fertile isotopes of Uranium which can be bumped up one step in the table of the elements. That’s breeding, and it can be done either fast or thermal – the latter makes do with the neutrons from the U-235 or Pu-239 chain reaction to turn fertile Thorium-232 into fissile Uranium-233. In contrast, conventional reactors use fissile U-235, which is a naturally occurring fissile isotope that can be harvested by removing (fertile) U-238 from the mined material – with no needs for accelerated neutrons as in the “fast breeder” type.

All you should remember for now is that both Thorium-232 and Uranium-238 can be pimped into something readily fissile but much more energetic than before: Th-232 can be bred into U-233, U-238 can be bred into Pu-239, and both make for good nuclear fuel. This can be made to happen with fast neutrons (in the case of U to Pu) or thermally, when Th-232 becomes U-233.

What a Thorium reactor does, therefore, is to turn a rather abundant fertile element (Th-232) into a fissile Uranium isotope that can be harnessed to generate nuclear energy mainly for civilian purposes. It is within the nature of the Thorium cycle to produce almost equal amount of U-233 and U-232, the latter of which makes the military applications of its product rather complicated, if not impossible.

For now, it is important to remember that we could basically take dirt, extract the 12 to 14 % Thorium therein, put it in a reactor, turn it into fissile material and have a safe and cheap supply of energy for at least another millennium. What’s not to like?

In part two, we shall be looking at practical applications of the Thorium cycle in reactors all over the developing world (which by definition excludes the EU, of course).
 

© Guardian Council 2018