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Thoughts from a thorium ‘symposium’

You have probably heard at least a little about thorium. There are certainly advocates out there who strongly believe it could help solve the world’s energy problems. The idea is that thorium-based nuclear…

There’s no shortage of hype around thorium, but how justified is the excitement? AzureGrackel

You have probably heard at least a little about thorium. There are certainly advocates out there who strongly believe it could help solve the world’s energy problems.

The idea is that thorium-based nuclear energy (it is nuclear) would have all the advantages of a uranium-based system – producing large-scale electricity with low emissions – without any of the disadvantages, real and imagined.

Of course, life is a little more complicated than that, otherwise we would have thorium based systems already. In fact, thorium technology in various guises has been around since the start of the nuclear age. But the threat of climate change has thrown the technological challenges facing all energy production into sharp relief.

Spruiking thorium

I recently attended a meeting at Parliament House in Canberra entitled “Thorium, a Base Load Power Source?”. The meeting was billed as an international symposium but seemed to be more of a promotional exercise. The proponents were there to tell us why thorium is an attractive option and why Australia should get involved.

The meeting was organised by Peter Stepanek from Thorium Energy Pty. Ltd. – an Australian company with Czech roots – and Bob Stephens from the “green” energy company SDH Australia. The conference was arranged around presentations from members of a consortium including Australians but mainly from the Czech Republic.

The Czech delegates were current and ex-diplomats, representatives of key sectors involved in nuclear technology and various university research groups from Pilsen, Prague, Brno and the Nuclear Research Institute in Rez.

The aim was to convince us of their cause (thorium to save the world!) and to gain a formal collaboration between the Czech Republic and Australia. This alliance would occur at a political level and through relationships with Australian universities and institutions such as the Australian Nuclear Science and Technology Organisation (ANSTO).

While many in the audience didn’t need convincing, the Czech visitors pointed out Australia has lots of thorium as well as the capacity for technological research.

It wasn’t clear to me precisely what the lobbyists were after (or why) – there has been a nuclear co-operation agreement with the Czech Republic since 2002. But SDH and others have apparently put real money into a pot to help the project proceed. In this way they’ve temporarily bypassed the vagaries of political negotiations.

Thorium and molten-salt reactors

The interest in thorium is neither new nor limited to the West. Since the early 1950s, India has hoped to develop a thorium-based nuclear energy system in the absence of indigenous uranium resources. However, their current configuration envisages using a fast reactor system for breeding the Uranium-233 isotope from Thorium-232.

The plan is to eventually replace the Uranium-235 fuel in their fleet of conventional reactors with the newly-bred Uranium-233.

In contrast to the Indian approach, the reactor technology being promoted by the Czechs (and being pursued by the Chinese) is the molten-salt reactor (MSR).

There are numerous advantages claimed in using an MSR to exploit thorium:

  1. There is no shortage of fuel, given it can be bred
  2. There is no chance of a meltdown or explosion because of the properties of the salts and the absence of water and zirconium used in traditional reactors
  3. Nuclear waste, including actinides, can be burnt
  4. No long-lived waste is created
  5. There is no risk of proliferation since plutonium is not produced.

The first three of these attributes are features of the MSR system itself. MSR uses graphite moderation and a liquid fuel at a relatively high temperature (as the coolant) rather than the water-cooled solid fuel rods found in a typical Pressurised Water Reactor.

The liquid flows through the reactor and can therefore be modified offline to:

  • remove contaminants and fission products that would otherwise build up
  • add heavy waste products to be incinerated (more efficiently than in a traditional reactor), and
  • replenish and modify the fuel as required.

The MSR is an elegant and flexible system, but one, it must be remembered, that can also be used with uranium salts, as it was originally.

The last two of the above attributes are peculiar to thorium. First, the long-lived alpha-particle-emitters that are a problem in the long-term management of waste from uranium, are not produced from thorium. The waste is more radioactive but shorter-lived.

Second, in the thorium cycle, Uranium-233 is bred as the fissile material rather than Plutonium-239 – the favoured isotope for nuclear weapons. (Some would argue that Uranium-233 is still a proliferation risk.)

So where are all the molten-salt reactors?

MSRs are not currently available at an industrial scale, but test reactors with different configurations have operated for extended periods in the past. But there are a number of technical challenges that have been encountered along the way.

One such challenge is that the hot beryllium and lithium “salts” – in which the fuel and heavy wastes are dissolved – are highly reactive and corrosive. Building a large-scale system that can operate reliably for decades is non-trivial. That said, many of the components have been the subject of extensive research programs.

At the “symposium”, the Czech consortium discussed their plan to construct a demonstration system on an existing nuclear reactor site. The system would be built some time after 2014 before proceeding to a small prototype (60 megawatts capacity) that would deliver electricity to the grid.

Whether that prototype system becomes a game-changer depends on many factors, not least of all the cost of deployment.

A thorium-rich future?

I sometimes sense more than a whiff of spin in the way thorium is promoted (if indeed spin has an odour). Take, for example, the attempt to distance thorium-based systems from “uranium” and concerns voiced about the “power of the uranium lobby". I don’t think this is the right approach.

Thorium mining and thorium-based reactors in Australia would have to face the same regulatory hurdles as uranium-based nuclear technologies, most of which are currently banned.

More egregious is the claim along the lines of: “all of the thorium can be used but only a fraction of uranium produces energy”. This is based on the erroneous comparison between the low abundance of the fissile isotope Uranium-235 in nature (only 0.7% of uranium is Uranium-235) with Thorium-232 (100% of natural thorium).

The correct comparison should be between Uranium-238, which is 99.3% abundant, and Thorium-232 which is 100% abundant. Both of these are so-called “fertile isotopes” from which one can breed fissionable material to produce energy. Sadly, this claim of “more energy per unit mass” was repeated by Federal Minister for Resources and Energy, Martin Ferguson in his opening address at the symposium, and is widespread in media reports. Pity.

No doubt thorium and other nuclear technologies have the potential to transform energy production. That said, there may be some years to go before that potential is likely to be realised.

Join the conversation

31 Comments sorted by

  1. Ross James

    Engineer

    Solar and wind can never be more than very expensive supplements to a main grid. Geothermal is still a long way from being technically reliable. Thorium offers a potential realistic replacement for existing fossil fuel and a nuclear reactors. Australia should be embracing this opportunity to become a world leader in thorium reactor research.

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    1. Tim Scanlon

      Author and Scientist

      In reply to Ross James

      That isn't supported by the data Ross. Solar and wind have been steadily becoming cheaper since they have been taken seriously. Technology is getting better and better and the more common it becomes the more cost effective it becomes.

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    2. Tim Scanlon

      Author and Scientist

      In reply to Ross James

      I'm glad that thorium reactors are better nuclear reactors, but being a better nuclear reactor is like changing politicians.

      Nuclear and gas are these "stepping stone" technologies that I think should be skipped straight over. They still cause toxic waste or CO2 emmissions, so why not invest in the renewable energies now? At some point we will need to move to these energy sources, so might as well be sooner rather than later IMHO.

      Oh, and by renewables I do not include biomass energy power plants. That is right up there with the gas power plants in terms of "clean energy", a complete furfy.

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    3. Ross James

      Engineer

      In reply to Tim Scanlon

      Tim - I have to disagree. Our household electricity costs have greatly increased to subsidise the government's solar energy projects. All data that I've seen show wind and solar to be much more expensive than coal and gas. Due to their intermittant operation, some wind farms have been asked to shut down, due to the variations they cause on the main grid. I've driven past the huge wind farm in Hurghada Egypt, with not one of them turning. (The Egyption government heavily sunsidises electricity costs). It's a cute idea, but solar and wind are not long term solutions. The sun only effectively shines 20% of the time. As I said earlier, they can never be more than expensive inconvenient supplements to a main grid.

      You mentioned that my comments aren't supported by data - from what I've seen, they certainly are. I look forward to your data to show otherwise.

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    4. Tim Scanlon

      Author and Scientist

      In reply to Ross James

      Ross, I'm a big fan of the Zero Carbon Australia work:
      http://www.skepticalscience.com/Zero-Carbon-Australia-2020.html
      http://www.energy.unimelb.edu.au/uploads/ZCA2020_Stationary_Energy_Synopsis_v1.pdf
      It has holes in it, but every report does.

      In terms of costs, there are a number of business reports on solar and wind around, e.g.
      http://au.ibtimes.com/articles/248685/20111114/renewable-energy-getting-cheaper.htm

      I actually live next to the largest wind farm in the southern hemisphere…

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    5. Ross James

      Engineer

      In reply to Tim Scanlon

      Tim - I'm not opposed to solar for special situations. I actually build solar panels which I donate to Cambodoa for use in hospitals that have no electricity. In remote locations they can be justified.

      I'm wondering if the number crunching for the person living off the grid included government subsidy for the solar system, and how it looked if the same subsidy was available for running power lines. Also, did it allow for deterioration of the panels over time, and replacement as they fail, along with battery replacement.

      Again, this example doesn't represent the bulk of the population living in higher density cities.

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    6. Tim Scanlon

      Author and Scientist

      In reply to Ross James

      The report does outline a system by which solar and wind would be more than just special, but they wouldn't be located in silly locations like they tend to be now. So I agree with you on that point, just the special situations would be mined for power for a larger population. The main thing is the power grid has to be close enough for it to work, which is one of the problems with geothermal. Solar and wind have less of an issue with this as they are planned for rural areas that are serviced by the…

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    7. Mark Harrigan

      PhD Physicist

      In reply to Ross James

      Ross, while I agree we should be pursuing the Thorium option as it seems promising your comments about wind and solar are simply not correct.

      1) It shows you are stuck in the paradigm of all electricity generation having to come from a "main grid". The "Grid" has actually been around for barely a century - it was not uncommon for power generation to be localised before that.

      2) Rooftop Solar PV is on a strong declining cost curve and is now at a point where it will match, or even go below…

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    8. Ross James

      Engineer

      In reply to Tim Scanlon

      I'm very aware of the salt ion solar system, though my knowledge of the economics and present technical problems is limited. As a manufacturer of electric glass furnaces, I'm fully aware of the complexities of dealing with high temperature processes. I see this as a more sensible approach than banks of PV cells sitting of roof tops. I believe all these will be dead in a few years, when panels fail, and the owners can't afford to repair them without government assistance.

      Re DC vs AC, DC might…

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    9. Tim Scanlon

      Author and Scientist

      In reply to Ross James

      Good point about the appliances, hadn't considered that. The DC generation was what I saw to be a major flaw in solar, as you need site inverters to go into the grid or to use it. I can't see this part of the tech becoming much cheaper, but the rest is steadily becoming cheaper.

      In terms of the costs for replacement, I'm not sure how that compares to the industry level coal/oil/etc replacements. I'd imagine that the only difference is in direct household costs. Although the current energy industry seems to rely on being antiquated and inefficient rather than upgrading, so they have unrealistic costs to compare to currently.

      I agree that thorium nuclear is the option for nuclear energy, hands down. I'm just not sold on nuclear being a big part of our energy needs into the future. It may have a role, but the Zero Carbon report was able to rule it out, so I'd be happier with that route.

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    10. Mark Harrigan

      PhD Physicist

      In reply to Tim Scanlon

      Tim, that is a disingenous comment. You dismiss a viable nuclear option by semar - not by evidence.

      There is abundant evidence that new generation nuclear offers a very viable solution. There is almost zero evidence that renewables can deliver anything like 100% of our requirements. BZE, as I'm sure you are aware, makes heroic assumptions and has been thoroughly debunked on more than one occasion. I suggest you spend some time on Brave New Climate to get a more balanced perspective.

      The…

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    11. Tim Scanlon

      Author and Scientist

      In reply to Tim Scanlon

      Sorry, forgot to add: I also have a number of friends and collegues who have taken up solar recently. One friend has already paid for his entire installation with his power generation, the others are all generating much more than they use. Most will be on track to pay out the startup cost in power generation within 5 years.

      Before you ask, I don't know what difference the subsidy would make to this. I do know that one of the people upgraded their unit without the subsidy (extra panels only) and it was well worth it.

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    12. Tim Scanlon

      Author and Scientist

      In reply to Mark Harrigan

      Mark, refer to my discussion with Ross above, especially to the Zero Carbon report. This report illustrates that renewables are viable to produce 100% of Australia's power by 2020. There is a further report internationally that talks 100% renewables worldwide by 2050 (although I can't remember if they included a proportion of nuclear).

      I take your argument that those reports are full of holes, I stated as much myself. But I think the implications of the report stand well enough. E.g. The example…

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    13. Mark Harrigan

      PhD Physicist

      In reply to Tim Scanlon

      Tim I suspect we are not that far apart. But the BZE and other reports are, on any rational reading, unrealistic and i think it does the issue more harm than good to overpromise and under-deliver. Realism not wishful thinking is what is needed

      If you look at th science it is pretty clear that we would be idiots to rely solely on renewables - we would either end up a LOT poorer and with significantly less reliable power or we would end up with a lot of CO2 emissions that we are trying to abate…

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    14. Tim Scanlon

      Author and Scientist

      In reply to Mark Harrigan

      I have done some reading, admittedly not huge amounts on nuclear. My bias comes in that the discussions of nuclear propose large chunks of energy to be contributed by nuclear. Even with thorium you are talking a lot of long term waste (30 years or 10,000 years is still long term) that has to be disposed of. So essentially I'm giving larger weighting to the cost (and possible impacts) of long term waste rather than the short term energy benefits.

      I agree that worldwide nuclear will figure in the energy mix, a la the "energy wedges" model. What I like about BZE, is that despite its flaws, it shows that coal isn't needed, gas isn't needed and nuclear, well we could continue to debate that one. It also works on the "energy wedges" approach, which gets us away from that stupid political approach of a panacea being needed.

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    15. rob alan

      logged in via email @orakk.net

      In reply to Ross James

      This whole debate is about what Industry needs. Domestic supply is a no brainer at current solar/wind pricing.

      Our home installed solar power without purchase rebate and are running no pay meter for power returned to the grid. Our wheel spins backwards and no power bill last quarter. That current pricing is one fifth of what we paid just a few months back also worth considering.

      The public will be self powered in the next decade no problem. Surly industry can find their own solutions without bagging the systems which do work well for the citizenry?

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  2. Canon Bryan

    Chief Executive

    @Professor Dracoulis,

    I wonder if you'll allow me to disagree with your claim that the "energy per unit of mass" argument is disingenuous?

    I think you realize, or should realize, that this claim is meant to address:

    a) thorium's superior ability to successfully transmute into U-233 [~90% statistically, to the extent of the fissile agent enrichment] (as compared to uranium's ability to transmute into Pu-239 [~66%]) prior to carrying on to fission, and;

    b) thorium's superior neutron-absorption…

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    1. George Dracoulis

      Professor, Department of Nuclear Physics at Australian National University

      In reply to Canon Bryan

      I agree Canon but there are claims out there that thorium has an energy density 100 times that of uranium because of the confusion between fissility and fertility. Unfortunately they get a bit more press than more considered discussions about conversion factors.

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  3. Michael Tibben

    logged in via Facebook

    @Professor Dracoulis

    If MSRs have these significant benefits, why has there not been more interest and funding over the past 50 years by government and industry?

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  4. Nick Kermode

    logged in via email @hotmail.com

    Informative discussion guys.

    Ross, I think saying " Solar and wind can never be more than very expensive supplements to a main grid " is a bit narrow minded. After all a minute on a mobile was the equivalent of about a hundred dollars when the technology was first available. It seems a repeatable course that new technology starts out very expensive and then gets cheaper and cheaper. It is already happening with solar and efficiency is improving as well. Never say never would be my thoughts…

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    1. Ross James

      Engineer

      In reply to Nick Kermode

      Nick - it's not a matter of cost. It's a matter of physical reality. The wind doesn't always blow, and we can go a couple of weeks without sunshine. This isn't the type of main energy source for a grid. The main grid needs something reliable 24/7. Thus my comment - wind and solar can only supplement a grid.

      As for cost, just as their cost reduces, so can coal, gas and nuclear decrease with technology developments.

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    2. Mark Harrigan

      PhD Physicist

      In reply to Ross James

      Ross, while I agree nuclear is an important part of the mix, with due respect your comments on cost curves are just plain wrong. It also still stays stuck in the "grid" paradigm

      Solar PV benefits from a production volume learning cost curve reduction measured in millions of units. There have been only around 500 nuclear power plants ever built.

      Costs do not automatically reduce with time- only with actual production volume– we collectively learn most by making and doing

      here is the cost…

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    3. Ross James

      Engineer

      In reply to Mark Harrigan

      Mark - I don't recall making any comment about cost curves. I stated that currently, wind and PV solar are much more expensive alternatives. I acknowledge that there may be some limited potential for solar/molten salt generation. PV costs will certainly reduce with time.

      I think you are limiting your thinking of you think the cost of nuclear can't come down. I agree that it doesn't have the same advantage of volume growth. However, after spending 40 years designing glass furnaces, I've learned that there are always cost savings as technology develops. The same applies to nuclear. You're saying thorium nuclear can't experience significant cost savings, when production scale technology hasn't even been developed yet.

      My main arguement remains - The main grid needs something reliable 24/7. Thus my comment - wind and solar can only supplement a grid.

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    4. Nick Kermode

      logged in via email @hotmail.com

      In reply to Ross James

      Ross, a few things...Firstly you brought up cost ie "very expensive", secondly, how does a finite product reduce in cost over time(?). The tech might but the resource required most certainly wont. Thirdly, do you include any of the many externalised costs of fossil fuels in your last statement?? As these become scarcer and harder to extract the costs will rise, dramatically. And also why is it we need a grid as in current form? I think there are better more efficient aspects to decentralising such as some of the newer tech proposes.

      This was an interesting read.... anyones thoughts?http://www.monbiot.com/2011/12/05/a-waste-of-waste/

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    5. Ross James

      Engineer

      In reply to Nick Kermode

      I had a read of this, and nearly fell of my chair when it said "the Greens are right about most things".

      It raises the question of fast neutron reactors, which can use waste fuel. I don't have detailed knowledge of this, so can't really comment. From what I do know, it's worthy of consideration, before the world knowledge source dies off. I see wind generation as fairly useless as a long term solution, and would rather see the money go into investigating realistic safe nuclear, whether it be thorium, or fast nuclear (if it's safe). I understand that Russia has had one running for many years, and China has had one for a couple of years, and now feeds its grid.

      Perhaps there's a reader here with some knowledge of these.

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  5. brendan

    logged in via Twitter

    It am intrigued by the line you are pushing here. The MSR the Czechs propose is demonstrably more efficient than any reactor currently running. It is the only reactor design which shows promise of being able to be produced at a lower unit cost, and run cheaply because of it's inherent safety features. As a class of reactor, the MSR is capable of being run in either the slow, resonant and fast spectrum. It is capable of operating as a breeder, without going to the fast spectrum, by optimizing the…

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    1. George Dracoulis

      Professor, Department of Nuclear Physics at Australian National University

      In reply to brendan

      Dear Brendan X

      Sorry if I got the dates of the Demo reactor wrong but I believe I did say in my article that MSR was an elegant reactor technology, and it is one that has held a lot of promise. But it isn't exclusive to using thorium as a fuel. Your list (b) to (h) are the advantages of MSR and you would have to admit that number (a) on commercial cost is a bit of an open question as yet.

      Your statement that "Thorium is abundant and cheap, and because it gives you the extra bite of the cherry…

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    2. Ross James

      Engineer

      In reply to George Dracoulis

      Is the main problem simply that any nuclear approach meets a negative reaction at government level? We know that the Australian government is largely a technical void, and driven by the Greens who put them in power. Most of them wouldn't know what fission and fusion are. The recent Japanese nuclear problems, and the European reaction to it, makes nuclear a dirty word.

      MSR is branded with the same brush, due to ignorance.

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    3. brendan

      logged in via Twitter

      In reply to George Dracoulis

      regarding the transmutation series, this slide sets it out reasonably well http://dl.dropbox.com/u/14413877/transuranics_20111220_144653.png along with the fission probabilities

      using wikipedia as a source
      U233 provides 200.3 MeV/fission & 91% fission probability
      U235 provides 202.5 MeV/fission & 81% fission probability
      Pu239 provides 211.5 MeV/fission & 64% fission probability
      Pu241 (say 211.5 MeV) & 73% fission probability

      In an idealized environment where we assume full transmutation…

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    4. George Dracoulis

      Professor, Department of Nuclear Physics at Australian National University

      In reply to brendan

      As you know Brendan,
      the details depend on the configuration, fuel mix and the resultant neutronics.
      While the thorium gives you marginally more energy we have sufficient natural and depleted uranium around that breeding from U-238 - the U/Pu path (in an MSR) is easy enough.

      I agree about the advantages of a liquid system which can be modified dynamically as opposed to a solid fuel system and there are distinct advantages in not requiring a pressurised system, economically and in terms of safety.

      I am not arguing that the same regulatory hurdles should be put in the way of an MSR-based system, just pointing out that the current regulatory regime (overseas) for PWR will be seen by others as the minimum standard. The Pebble-bed reactors were going to face the same problem about the need or otherwise for containment vessels etc.

      A nuclear reactor will be treated like a nuclear reactor.

      I know it's unreasonable!

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    5. Shirley Birney

      retiree

      In reply to George Dracoulis

      A thorium mine will be treated like a uranium mine.

      I know it's unreasonable!

      Australia's Uranium Mines - World's Worst Practice.

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