THORIUM: The Future of Global Energy Demand

Published by: Steve on 14th Apr 2011 | View all blogs by Steve

Recent events in Fukushima, Japan, have once more brought the safety of nuclear reactors under global scrutiny.  The Fukushima plant is uranium based, which is the most common type of reactor worldwide.


There is, however, an alternative technology based on the element thorium.  Thorium nuclear reactors have several critical advantages over other types, including: safety; reduced waste output; consumption of existing nuclear waste; energy efficiency; cost-effectiveness; plus, the relative abundance of the fuel source.


Examining the advantages in greater detail, safety is the most prominent issue.  In an appropriately designed thorium reactor, there is no possibility of a meltdown.  Without priming, thorium cannot sustain a nuclear chain reaction, so fission terminates by default.  Consequently, there would be no threat of incidents such as those that occurred at Fukushima, Chernobyl, and Three Mile Island.  All research to date indicate that the safety of thorium as a nuclear fuel is intrinsic and not in doubt.


Although thorium waste can produce a dangerous level of radioactivity for hundreds of years, this is a considerable reduction from uranium waste, for which it is in the tens of thousands of years.  Thorium reactor waste is also virtually impossible to turn into plutonium, so there are no concerns that some nations might attempt to produce weapons-grade material from it.  Furthermore, one of the overriding benefits of thorium reactors is that they can make efficient use of, and burn up, existing high-level radioactive waste, and decommissioned nuclear weapon stockpiles.


The energy potential of thorium is not merely significantly better than uranium, it is better by a vast degree.  One tonne of thorium can produce as much energy as 200 tonnes of uranium. It has been calculated that the amount of energy used by the average American during their lifetime could be provided from just 8 tablespoons of thorium.


Thorium is at least 4-5 times more abundant in the Earth's crust than all isotopes of uranium combined.  It also comes out of the ground as almost 100% pure, usable isotope (thorium-232), which does not require enrichment.  Conversely, natural uranium contains only 0.7% fissionable uranium-235, and preparation requires isotopic separation. 


Thorium is present on most continents, and due to the ease and cost-effectiveness of extraction in its required form, many countries already have large supplies.  For example, there is enough in the United States alone to power the country at its current energy level for over 1,000 years.  India is currently thought to have the largest easily accessible deposits and, globally, thorium is abundant enough to satisfy planetary demand well beyond the next millennium.


The direct monetary cost-effectiveness of thorium itself is predominantly based upon the abundance of the element, the natural state in which it is found, the energy potential it contains, and the potential consumption of other nuclear waste.  There is a clear financial case for thorium being used to generate safe, clean, inexpensive power in the long term.


More significantly, the cost of constructing a 1-gigawatt thorium plant could be less than a quarter of the equivalent uranium plant, which would cost about $1.1 billion (US).  The key reason it would be so much cheaper is that expensive safety features to prevent meltdown are not required, due to the lack of meltdown potential with thorium reactors.  The implications in relation to the economics of nuclear power are, therefore, substantial.


Indirect cost advantages have also been put forward.  In the US, for example, medical costs from breathing coal pollutants have been estimated at up to $160 billion annually.


So if thorium-based reactors are so much better from all of these perspectives, the intelligent question is: why aren’t they more widespread already? 


Whether or not the advantages are considered compelling in themselves, there are disadvantages and arguments as to why the thorium energy route has not been exploited.  Continuing with the cost issue, there is the current short-term problem of funding the building of thorium-based power plants at a time of global austerity.  This does not preclude, however, a gradual shift towards replacing ageing uranium reactors with thorium reactors, particularly if new and more costly uranium plants would otherwise be constructed.  Of course, the uranium fuel cycle technology is proven and well established, and, although thorium-based technology is advanced, there are still aspects that require further research. 


Ultimately, the financial cost of nuclear energy is governed by the cost of building and decommissioning reactors, not the fuel used to power them.  A ten-fold increase in the cost of the fuel itself, for example, would only translate to an increase in the cost of nuclear energy output of a small fraction of a penny per kWh.


A separate disadvantage for the UK specifically is that no significant thorium deposits have yet been identified, although the incentive to look for thorium has not been strong. This may explain why countries with abundant supplies of thorium have, or are planning to progress the technology, whereas the UK has not.  Incentives to explore for natural deposits of thorium within the UK aside, issues relating to imports are comparable for both thorium and uranium.


It should also be noted that a thorium-based programme requires process instigation by a neutron source, such as waste from a uranium reactor.  Although this might explain why a uranium energy initiative would have been required initially, this does not in itself justify a continued uranium programme.  A second thorium reactor could activate a third thorium reactor, and so on.


Perhaps the key argument for why we have uranium rather than thorium plants centres on the development of nuclear weapons.  It is much harder to retrieve weapons-grade material from thorium liquid-fuel cycle MSRs (Molten Salt Reactors) than it is from uranium (U-233) or plutonium (Pu-239) plants.


The weapons argument is double-edged.  Historically, the race for nuclear supremacy among leading nations governed policy.  The specific requirement for uranium plants within each major nation was justified from a defence perspective alone.  Beyond that, there were subsequent political difficulties preventing other nations from developing their own programmes.  The control of uranium shipment worldwide was regulated on a basis of ensuring other countries could use uranium for power needs, but not weapons development.  The demand for thorium was potentially negated by the race for uranium and plutonium development.


This raises the question of whether the safety and wellbeing of members of the public has been jeopardised and overridden by leading governments for decades.  The argument centres on whether the national defence and nuclear weapons deterrent was in the public interest to a greater degree than the threat of nuclear incidents from a technology with demonstrated relative safety issues.  The argument becomes increasingly hard to justify as the disadvantages of using uranium or plutonium for nuclear energy are weighed against the advantages of thorium.


Perhaps conventional thinking up until now has been centred on the status quo.  The effort required to switch to thorium has not seemed worth it while abundant uranium is available and uranium plants are widespread.


It’s not that thorium hasn’t already been examined.  The US, for example, ran a Molten-Salt Reactor (MSR) programme between 1964 and 1969.  Most of the initial test reactors were closed down due to a lack of funding, and the MSR program was discontinued in 1976.  The following year, a Light-Water Reactor (LWR) at the Shippingport Atomic Power Station, Pennsylvania, was used to establish a thorium-based fuel cycle.  Decommissioned five years later, the significant safety and efficiency advantages of MSRs have since been recognised. 


Canada has over 50 years’ experience with thorium-based fuels. Designs of reactors in Canada allow thorium to be used as a fuel source.


But it is only in recent years that the race for thorium has begun.  India leads the way with the first thorium-based Advanced Heavy Water Reactor (AHWR) at the Kakrapar plant in the west of the country.  Motivated by a desire to become energy-independent, combined with restricted availability of uranium, the nation is exploiting large natural deposits of thorium within its borders.


Last month it was confirmed that China has initiated a project to develop MSR technology.  Russia has plans to establish a programme, and Norway has considered thorium as a potential key source of energy.


The dash for thorium, however, should not be interpreted as a commodity investment opportunity.  Because of its abundance, ease of extraction, and reserve levels, its price is unlikely to become volatile.  Investment opportunities are more likely to come from the growth of private organisations specialising in particular areas of technological advancement related to thorium.  In 2010, the founder of Microsoft, Bill Gates, announced that he would be investing in thorium-based technology as a ‘miracle’ that would help solve global energy problems relating to CO2 emissions and world poverty. 


Renewable sources of energy, like wind, wave/tidal and solar power, may provide a long-term solution in the future, but the technology is not yet viable for the majority of energy production.  The interim solution for the coming years and decades would appear to be best-served by a switch to thorium-based power production.



Bullet point box for thorium (Th):


Radioactive chemical element

Discovered in 1828

Named after Thor, the Norse god of thunder

Atomic number: 90

Out of the 90, four are valence electrons

Occurs naturally in the isotope Th-232

Half-life of approximately 14.05 billion years

Decays slowly by emitting an alpha particle


Professor Carlo Rubbia, from the European Organization for Nuclear Research (Cern), is one of the leading global experts on thorium.  On Tuesday, he gave a short interview to the BBC World Service's One Planet, which can be heard here:



  • stephenterry
    by stephenterry 7 years ago
  • Charlie
    by Charlie 7 years ago
    Very good article Steve, thanks for the info. Still looking into the nuclear waste thing myself, as this is currently the only strong and credible argument against Thorium power.

    I am looking forward to the first reports from the world's first Thorium reactor going on the grid in India this year. Rubbia's own design hasn't been built yet, but it does look very promising (at least on paper).

    I do wonder, though, if Fukushima might not turn out to be good for Thorium plants as Uranium or Plutonium ones might be hard to sell to the public after this accident.
  • Steve
    by Steve 7 years ago
    Thanks for the comments, Stephen & Babblefish. Charlie, the waste issue was one of the things I focused on in the research. It's not a perfect scenario for thorium reactors, but it's a vast improvement on current circumstances. The overriding factor, however, is that something so hugely beneficial could be done with, for example, the vast amount of depleted uranium that has already been generated.

    My excitement and optimism is fuelled [sorry] by the potential technological advances that could be made through the race for harnessing thorium power, including Prof. Rubbia's design. And I do hope that out of something terrible like Fukushima (and previous incidents like Chernobyl), some extraordinary good can come.
  • Tony
    by Tony 7 years ago
    Very interesting stuff, Steve. For your published version, do you reference any source notes?
  • Steve
    by Steve 7 years ago
    No published version of this, Tony, but the reference notes would be longer than the piece itself, bizarrely. And I've tried to keep this as short as I can, while packing in as much info as possible. I think it makes it a bit clunky in places, and it doesn't flow so well as a piece of writing, but I'm quite happy with how many angles are crammed in.

    Many of the papers on the subject area are written by Prof. Rubbia, so it would be much easier if my references could be, simply, "See Carlo."
  • Mighty Jock
    by Mighty Jock 7 years ago
    Search it online and you'll get the ref. - It's a reasoanble run through the benefits of thorium, but nothing that we haven't known for 20 years or more already. Thorium as a concept isn't new and there are groups looking at it as a contender for gen 4 reactors.

    It's worth noting that it is still a uranium reactor as the thorium neautron captures and after a bit of messing around becomes fissile as uranium 233.

    The mention of the MSR concept is interesting - i studied these very power dense reactors for a year and the main problems are material (pretty much the universal problem for all new gen 4 concepts)- very high temp and corrosive enviroment, hasteloy-N was the front runner as i remember, but it failed some significant tests in a recent study. there are also some safety concerns in terms of the number of barriers to fission product release given that the fuel circulates within the salt 'coolant'. This would cause licening problems and issues when compared with other planst taking into account the Safety assessment Principles.

    I'm also pretty sure, without checking i should add, that the MSRE never ran as a thorium reactor per se. They were looking at sustainability and breeding concepts and were looking to combine thorium with a uranium core to breed the fuel and power for longer. It wasn't a pure thorium reactor.

    I'm sure of you google 'Thorium group UK' or some such thing you will find the site of the company championing thorium for the furture. I atteneded a conference a year or so ago where they had a rep and he was quite knowledgable and gave a lot of info - so the site may be a good stopping point.

    The indians are leading as they have huge natural reserves - but it's also produced (i'm pretty sure) as a by product of mining uranium in australia and other such sites.

    One quote - Decommissioned five years later, the significant safety and efficiency advantages of MSRs have since been recognised.

    there are some safety advantages - but as with everything it is not as cut and dried as you may think. as with everything there is give and take. I would ask you to consider a japanese scenario and then consider a plant were the fuel is not contained in fixed fuel rods. Add a tsunami and a fire - more or less safe now???

    Thorium has legs and will undoubtedly become more prevalent over the next few years - but before comparing with a firty years old below standard reactor plant you should have a good look at the AP1000 and EPR models. they too have some excellent safety features and, in my opinion, would have withstood the events in Japan with little or no damage.

    I should also point out that the three accidents you mentioned were worlds apart.

    TMI - a calamity of errors - manmade and materiel. - tiny release and no harm done

    Chernobyl - way too complicated to to discuss here -but essentially a mixture of plant design and operation shortcomings - large release but realtively few deaths in terms of the fallout. (unless you read the fanatic sites where everyone who dies in russia for the last 50 years did so because of it)

    Japan - Natural disaster that had been forseen and not protected against - I still believe that there will be very few deaths as a result of radiation (so not inculding the guys who were killed in explosions etc). I will be suprised if the number is more than 10.

    To put it in persepective - after the bombs in Nagasaki and Hiroshima - around 1000 people are believed to have died as a result of radiation (above the national average and obviously not including those killed by the detonation)

    This real information along with many studies has l;ead to changes in world law as to how we calculate the likely effects of radiation. Google ICRP 103 for more info.

    all the best

  • Steve
    by Steve 7 years ago
    Cheers, Jock. Strong perspective from the inside - I should've interviewed you for this piece. Got loads to come back with, but that's possibly better put in whole other articles than long thread responses here. This is just a general overview piece attempting to present on overall picture in confined words. Each angle could easily be explored in much greater detail.
  • Steve
    by Steve 6 years ago
    A book covering the issues in this subject has now been published and launched in the last couple of weeks. If you're interested, then here is a link to it:
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