This site uses cookies. By continuing to use this site you agree to our use of cookies. To find out more, see our Privacy and Cookies policy.
Skip to the content

[IOP] A community website from IOP Publishing

Tag Archives: thorium

Why not nuclear and renewables?

By Dave Elliott

Nuclear plants do not generate carbon dioxide, so why can’t we have nuclear AND renewables, supporting each other, as a response to climate change? In evidence to the Energy and Climate Change Select Committee in July Amber Rudd MP, DECC Secretary of State, suggested that despite its high cost nuclear baseload ‘enables us to support more renewables’ and was needed since, ‘as we all know, until we get storage right, renewables are unreliable’. Can nuclear really support renewables, and is it really low carbon?

(more…)

Posted in Renew your energy | Tagged , , , , , , , | 2 Comments | Permalink
View all posts by this author  | View this author's profile

Nuclear Problems

The European Pressurised-water Reactor (EPR) being built at Olkiluoto in Finland is now unlikely to be completed until 2014- five years late- and $3bn or more over-budget. Similar problems face the EPR being built at Flammanville in France. And similar problems have emerged at the two 1.7GW EPRs being built at Taishan in China, 140km west of Hong Kong: variable concrete quality, unqualified or inexperienced subcontractors, poor documentation, language issues. Unit 1 is meant to be ready in 2013, Unit 2 in 2014, followed by two more. China has also had some problems with rapidly deploying its re-engineered version of the Westinghouse AP1000, but there are reports that it may be interested in a revised version of the EPR. Indeed some reports say that EDF may ditch the current EPR design for future EU plants and go for a cheaper, smaller, simpler franco-chinese design. All this has not helped the industries finances: French nuclear company Areva has operating losses of between €1.4bn and €1.6bn, the first loss for the 10-year-old group.

Matters were not improved by the report in January from the French nuclear power watchdog ASN, which, in its post-Fukushima review, said that EDF must install flood- proof diesel generators and bunkered remote back-up control rooms at its 19 plants across the country, at a cost of perhaps €10 bn,. Overall EDF estimated the cost of extending the lifespan of its nuclear plants from 40 to 60 years at €40-50 bn over the next 30 years. ANS didn’t call for any plant closures and EDF was bullish, claiming that it invested ‘more than €11 bn a year across the world.’ However it has decided to diversify its nuclear-dominated portfolio by building strong businesses in gas and coal, as well as hydropower and renewables. But its shares fell a further 4.06% after the ANS review.

However nuclear faces more than just technical and economic problems, but also significant political shifts. In addition to the German, Swiss and Italian decisions to abandon nuclear, in France the Socialist candidate in the presidential election wants to cut nuclear by 50% by 2025 -the party has secured agreement with the greens to campaign for the closure of 24 nuclear reactors by 2025 in the election, though the Greens would prefer a 100% shut down. And in Belgium political parties seeking to form a government (it did not have one for over a year!) conditionally agreed to revert to the original 2003 plan to shut Belgiums three oldest plants in 2015 and the remaining two by 2025. Meanwhile a new tax has been imposed on nuclear operators. They currently supply 55% of Belgium’s power.

In Japan, only five plants are still operating, out of the original 54, and three of them are scheduled to shut for annual maintenance and safety checks in April. With local opposition very strong and growing, it may be hard to restart them, or any of the others- they need the local municipalities to agree to that. So Japan may end up becoming nuclear free by default. Certainly long term nuclear looks like to be very constrained. In January, Japan’s new prime minister, Yoshihiko Noda, said that Japan’s dependence on nuclear power must be reduced to the ‘maximum extent.’

The UK keeps going

There are no visions (yet) anything like that in the UK: indeed, in what some might see as a reversal of its policy on nuclear subsidies, the government has offered Sheffield Forgemasters a loan of up to £36 million “to continue its drive into civil nuclear and steelworks plant production.” A similar offer had, you may recall, been withdrawn earlier.

Horizon Nuclear Power- a 50/50 RWE nPower/ EOn UK joint venture – plans to submit a planning application for a new plant at Oldbury around 2014. They say ‘given the right market conditions, and subject to a final investment decision, preliminary works could begin in 2016, followed by main construction from 2019.’ They have also bought land for a proposed new plant at Wyfla, with a planning submission scheduled soon, and operation by perhaps 2020. But they have yet to decide whether to go for Areva’s EPR or Westinghouse’s AP1000 for these sites. However, EDF and Areva have been pushing ahead with their plans to build EPRs at Hinkley and Sizewell: they submitted a site licence application for Hinkley Point C last July. And despite SSE pulling out of the consortium, NuGen is still planning a plant alongside Sellafield, with a possible 2023 start up date.

Will the nuclear plants really happen? EDF Energy is the most advanced so far. It said that before it finally committed to a go ahead it was imperative that ‘transitional arrangements for the Contract for Difference are in place, arrangements for the funded decommissioning plan are set, and, we have a high level of confidence in the cost and timetable for construction.’

Although they have not given hard dates for the Sizewell and Hinkley projects, they originally said they wanted them to begin operating by the end of 2017 and in 2019 respectively. Fukushima and the need to extend the Generic Design Assessment process may have altered that but, though they have talked of an ‘adjusted timetable’, EDF have stressed that ‘an adjusted timetable has never meant a suspended timetable, the project continues. It is on track.’

Longer term

With uranium fired reactors out of favour after Fukushima, for the longer term, some in the nuclear lobby have been promoting thorium as an allegedly safer fuel- looking at molten flouride salt systems.

The Weinberg Foundation was launched last year to promote the Liquid Flouride Thorium Reactor (LFTR) which was portrayed as one of ‘the world’s safest reactor designs which cannot burn or melt down, breeds its own fuel, consumes most of its highly radioactive products, and will not release any radioactive materials into the environment’.

Canada, China and India all have projects underway but the technology is still some way off as viable commercial option. Certainly it’s not without its problems. Thorium is not fissile, so to make a reactor work you have to mix it with U235 or plutonium or provide some other source of neutrons (e.g. a particle accelerator) to convert it to U233, which is fissile. What you then get, as well as heat energy, radiation, and fission products from the Plutonium and Uranium, is U232. U232 (and its decay products) emit very hard gamma radiation. That’s seen as ensuring that no one would try to steal fuel from thorium reactors to make bombs – since it would be so hard to work with or shield from detection. But it also makes it hard to design safe reactors or deal with their wastes- you need very much thicker shielding for the reactor core or for waste transport containers. We are probably talking a meter of lead or so!

Some thorium enthusiasts say that nearly all the wastes can be burnt up within the reactor, but there will still be some to deal with- and there’s always the chance of fuel/waste escapes/ leaks. And you really wouldn’t want to be around then.

So will it happen? Should it? The LFTR may be better than the current range of uranium designs, but it will be a while before we know for certain- there’s a host of unknowns and risks. Friends of the Earth seems content to leave it as a possible long term option, and certainly it’s an argument against rushing into a new wave of current types of reactors. But will anyone really trust the nuclear lobby when it says ‘we have the answer’, as so often before? Technologies like this also seem to attract single-minded lobbyists and believers in ‘silver bullet’ fixes, which can distract from the development of a wider range of arguably more realistic renewable options.

For a different view see: www.theecologist.org/blogs_and_comments/commentators/other_comments/962512/response_dont_dismiss_the_potential_of_thorium_ nuclear_power.html

In my next Blog I’ll look at the prospects for nuclear in the developing world- some see that as its best hope.

Posted in Renew your energy | Tagged , , | Leave a comment | Permalink
View all posts by this author  | View this author's profile

Is Thorium the answer?

After Fukushima, the nuclear industry is facing some serious problems. Some are simply plugging on ahead, but adding promises that they will upgrade existing reactor safety and operations, but others are looking to new technology. High on the list of new ideas is the use of thorium as a new fuel, with one favourite being the molten flouride salt thorium reactor. This allegedly will generate fewer wastes and might even be able to burn some of them up.

The attraction of thorium is that there is three times more of it in the world than uranium, but its disadvantage, at least as a reactor fuel, is that it is not fissile. You have to supply neutrons- the options being to use a particle accelerator as a source or to use uranium/plutonium fission. One idea is to have a blanket of thorium around a plutonium core. But you could also mix them up, possibly using this mix as a fuel in conventional reactors, or dissolve them in molten form- as in the liquid fluoride molten salt concept, with the liquid acting as both fuel and coolant. Doing it all in one reactor would be ideal- then, arguably, there would be less risk of illegal diversion of plutonium, or the production of weapons material.

India has been looking at thorium for some while, since, as a non signatory to the Nuclear Proliferation Treaty, it has faced problems importing uranium for its nuclear programme- whereas it has plenty of thorium. But they have approached it in a different way.

WNN reported that ‘The long-term goal of India’s nuclear programme has been to develop an advanced heavy-water thorium cycle. The first stage of this employs the pressurized heavy-water reactors and light water reactors, to produce plutonium. Stage two uses fast neutron reactors to burn the plutonium and breed uranium-233 from locally mined thorium. The blanket around the core will have uranium as well as thorium, so that further plutonium is produced as well. In stage three, AHWRs burn the uranium-233 from stage two with plutonium and thorium, getting about two thirds of their power from the thorium.’
Pretty complicated then, with several stages.

However , earlier this year, but before Fukushima, China announced that it would be developing a molten fluoride salt thorium system. Whether that, and China’s High Temperature helium cooled Pebble Bed modular reactor project, survived the post Fukushima review of nuclear policy remains to be seen- all new projects were temporarily halted.

The UK nuclear industry does not seem very interested in thorium,- it’s seen as a very long shot. Instead it is pinning its hopes for expansion on upgrades of the conventional pressurised water reactor- the French EPR and the US AP1000, even though neither of these have yet been built or operated yet.

A report from the UK’s National Nuclear Labs (NNL), based at Sellafield, was pretty dismissive of the thorium option- it would take years to develop land there weren’t many obvious benefits, given that uranium was plentiful.

NNL estimated that it would be likely to take ’10 to 15 years of concerted R&D effort and investment before the Thorium fuel cycle could be established in current reactors and much longer for any future reactor systems’. It went on ‘Thorium fuel concepts which require first the construction of new reactor types (such as High Temperature Reactor (HTR), fast reactors and Accelerator Driven Systems (ADS)) are regarded as viable only in the much longer term (of the order of 40+ years minimum)’.

What about the thorium breeder concept? NNL says ‘The use of thorium in place of U-238 as a fertile material in a once-through fuel …only yields a very small benefit over the conventional U-Pu fuel cycle. For example it is estimated that the approach of using seed-blanket assemblies (the blanket being the surrounding fertile thorium material) in a once-through thorium cycle in PWRs, will only reduce uranium ore demand by 10%. This is considered too marginal to justify investment in the thorium cycle on its own.’

And on the alleged avoidance or reduction of proliferation risks NNL says ‘Contrary to that which many proponents of thorium claim, U-233 should be regarded as posing a definite proliferation risk. For a thorium fuel cycle which falls short of a breeding cycle, uranium fuel would always be needed to supplement the fissile material and there will always be significant (though reduced) plutonium production’.

On the economics, NNL says that ‘while economic benefits are theoretically achievable by using thorium fuels, in current market conditions the position is marginal and insufficient to justify major investment. There is only a very weak technical basis for claims that thorium concepts using seed-blanket PWR cores will be economically advantageous. The only exception is in a postulated market environment of restricted uranium ore availability and thus very high uranium prices. This is not considered very likely for the foreseeable future.’

It’s not totally dismissive though. It says that ‘claims that thorium fuels give a reduction in radiotoxicity are justified. However, caution is required because many such claims cite studies based on a self-sustaining thorium cycle in equilibrium. More realistic studies which take account of the effect of U-235 or Pu-239 seed fuels required to breed the U-233 suggest the benefits are more modest. NNL’s view is therefore that thorium fuel cycles are likely to offer modest reductions in radiotoxicity. It is considered that the realistic benefits are likely to be too marginal to justify investment in the thorium fuel cycle’.
www.nnl.co.uk/positionpapers

So there is some faint praise, but otherwise it’s a pretty damning review. Moving to perhaps even more exotic ideas, some see sub-critical particle accelerator driven systems (‘ADS’) as being useful, in that they could also possibly transmute some nuclear wastes, but that too is seen as a long shot option. A 2002 OECD/NEA study noted that ADS would require ‘fuel cycles with multiple recycling of the fuel and very low fuel losses’ and concluded that ‘the full potential of a transmutation system can be exploited only if the system is utilised for a minimum time period of about a hundred years’.www.oecd-nea.org/ndd/reports/2002/nea3109.html

And more recently UK Energy Minister Charles Hendry has noted that ‘As yet, industry has not indicated that they would be looking to develop and deploy sub-critical nuclear reactor designs in the UK in the near term future’.

Overall then it doesn’t look too good for thorium based systems, at least in the UK. Some work is going on in the USA on ADS under the Generation IV programme. For example, Aker Solutions, is developing a subcritical 600MWe fast neutron reactor which sustains a chain reaction in thorium and MOX fuel by using an accelerator to shoot a beam of protons into the molten lead coolant. The theory is that if anything went wrong the beam could be shut down instantly, halting fission. It’s a scaled-down version of Rubbia’s Energy Amplifier idea, developed as a concept at CERN some years ago, but with a smaller, cheaper, accelerator. But that means it runs closer to criticality- with safety implications.

There is also some US work on high temperature / fast neutron reactors, which could use thorium, with a degree of waste burn up possibly being achieved. Some novel mini-reactors are also being developed. But in terms of utility scale projects, it seems that the US programme is some decades away from a practical commercial reactor. That will surely also be true of the Chinese programme- although small prototypes may emerge before then, a 20 year timeframe was mentioned. But a 10MW Japanese Fuju project is claimed to be likely to be ready within 5 years.
[http://nextbigfuture.com/2011/02/chinas-thorium-reactor-and-japans.html
](http://nextbigfuture.com/2011/02/chinas-thorium-reactor-and-japans.html)

Basically, possible fast track break throughs like this aside, for the moment we are stuck with what we have got- uranium pressurised water reactors.

For more optimistic views, see:
www.itheo.org(http://www.itheo.org) and www.thoriumenergy.org
Also http://pubs.acs.org/cen/science/87/8746sci2.html
And www.telegraph.co.uk/finance/comment/7970619/Obama-could-kill-fossil-fuels-overnight-with-a-nuclear-dash-for-thorium.html

There is clearly a significant lobby in the USA, including, notably, US climate scientist Dr. James Hansen, and there has been some positive UK media coverage, including from the Guardian: http://www.guardian.co.uk/environment/2009/jul/13/manchester-report-nuclear

But it probably didn’t help the case for thorium that British National Party leader Nick Griffin MEP, backed the liquid fluoride thorium concept strongly in a recent speech to the Europarliament. http://www.eutimes.net/2011/04/nick-griffin-leaves-climate-change-eurocrats-speechless/

Posted in Renew your energy | Tagged , | Leave a comment | Permalink
View all posts by this author  | View this author's profile