Climate Change Emissions Nuclear

Hansen to Obama Pt III – Fast nuclear reactors are integral

Nuclear energy? Pah! Too dangerous (risk of meltdown or weapons proliferation), too expensive, too slow to come on line, insufficient uranium reserves to power more than a small fraction of the world’s energy demand, blah di blah blah blah blah. There is certainly plenty of opposition out there to nuclear energy in any way, shape or form. Nuclear is bad news, it’s a distraction, it’s a carry over from the cold war, it’s old school thinking. And so on.

Well, the above is what the majority of environmentalists and pacifists would tell you. And there is some very solid reason for scepticism about the widespread use of nuclear power, especially Generation II nuclear fission reactors (I suggest we keep the ones we’ve got, but don’t bother with any more of them). But in the brave new world of the Sustainability Emergency (climate crisis + energy crisis + water crisis + mineral crisis + biodiversity crisis, etc.), we simply haven’t got time or scope for such hard-line negativity. We need every solution we can lay our hands on — and more for good measure.

Hansen is willing to talk about nuclear energy. I am too – given chronic intermittency issues with large-scale renewables and the need for plenty of extra energy to fix huge looming problems with hanging together a sophisticated civilisation on a habitable planet, it’s got to be in the mix. Indeed, in the long run, it, in the form of fusion power, could well be the only form of energy that matters to humanity (if we manage to get through the post-industrial crunch, that is). There are plenty of tantilising prospects for safe, effective, long-term baseload power from 4th+ generation nuclear fission power. But for now, there is just nowhere near enough action ($$ and willpower) on the R&D and roll out front.

Hansen explains this in part III. He also goes into more detail on this issue in his earlier Trip Report, which I also quote below…


Tell Barack Obama the Truth – The Whole Truth (Part III of IV)

Dr James E. Hansen

Nuclear Power. Some discussion about nuclear power is needed. Fourth generation nuclear power has the potential to provide safe base-load electric power with negligible CO2 emissions.

There is about a million times more energy available in the nucleus, compared with the chemical energy of molecules exploited in fossil fuel burning. In today’s nuclear (fission) reactors neutrons cause a nucleus to fission, releasing energy as well as additional neutrons that sustain the reaction. The additional neutrons are ‘born’ with a great deal of energy and are called ‘fast’ neutrons. Further reactions are more likely if these neutrons are slowed by collisions with non-absorbing materials, thus becoming ‘thermal’ or slow neutrons.

All nuclear plants in the United States today are Light Water Reactors (LWRs), using ordinary water (as opposed to ‘heavy water’) to slow the neutrons and cool the reactor. Uranium is the fuel in all of these power plants. One basic problem with this approach is that more than 99% of the uranium fuel ends up ‘unburned’ (not fissioned). In addition to ‘throwing away’ most of the potential energy, the long-lived nuclear wastes (plutonium, americium, curium, etc.) require geologic isolation in repositories such as Yucca Mountain.

There are two compelling alternatives to address these issues, both of which will be needed in the future. The first is to build reactors that keep the neutrons ‘fast’ during the fission reactions. These fast reactors can completely burn the uranium. Moreover, they can burn existing long-lived nuclear waste, producing a small volume of waste with half-life of only sever decades, thus largely solving the nuclear waste problem. The other compelling alternative is to use thorium as the fuel in thermal reactors. Thorium can be used in ways that practically eliminate buildup of long-lived nuclear waste.

The United States chose the LWR development path in the 1950s for civilian nuclear power because research and development had already been done by the Navy, and it thus presented the shortest time-to-market of reactor concepts then under consideration. Little emphasis was given to the issues of nuclear waste. The situation today is very different. If nuclear energy is to be used widely to replace coal, in the United States and/or the developing world, issues of waste, safety, and proliferation become paramount.

Nuclear power plants being built today, or in advanced stages of planning, in the United States, Europe, China and other places, are just improved LWRs. They have simplified operations and added safety features, but they are still fundamentally the same type, produce copious nuclear waste, and continue to be costly. It seems likely that they will only permit nuclear power to continue to play a role comparable to that which it plays now.

Both fast and thorium reactors were discussed at our 3 November workshop. The Integral Fast Reactor (IFR) concept was developed at the Argonne National Laboratory and it has been built and tested at the Idaho National Laboratory. IFR keeps neutrons “fast” by using liquid sodium metal as a coolant instead of water. It also makes fuel processing easier by using a metallic solid fuel form. IFR can burn existing nuclear waste, making electrical power in the process. All fuel reprocessing is done within the reactor facility (hence the name “integral”) and many enhanced safety features are included and have been tested, such as the ability to shutdown safely under even severe accident scenarios.

The Liquid-Fluoride Thorium Reactor (LFTR) is a thorium reactor concept that uses a chemically-stable fluoride salt for the medium in which nuclear reactions take place. This fuel form yields flexibility of operation and eliminates the need to fabricate fuel elements. This feature solves most concerns that have prevented thorium from being used in solid fueled reactors. The fluid fuel in LFTR is also easy to process and to separate useful fission products, both stable and radioactive. LFTR also has the potential to destroy existing nuclear waste, albeit with less efficiency than in a fast reactor such as IFR.

Both IFR and LFTR operate at low pressure and high temperatures, unlike today’s LWR’s. Operation at low pressures alleviates much of the accident risk with LWR. Higher temperatures enable more of the reactor heat to be converted to electricity (40% in IFR, 50% in LFTR vs 35% in LWR). Both IFR and LFTR have the potential to be air-cooled and to use waste heat for desalinating water.

Both IFR and LFTR are 100-300 times more fuel efficient than LWRs. In addition to solving the nuclear waste problem, they can operate for several centuries using only uranium and thorium that has already been mined. Thus they eliminate the criticism that mining for nuclear fuel will use fossil fuels and add to the greenhouse effect.

The Obama campaign, properly in my opinion, opposed the Yucca Mountain nuclear repository. Indeed, there is a far more effective way to use the $25 billion collected from utilities over the past 40 years to deal with waste disposal. This fund should be used to develop fast reactors that eat nuclear waste and thorium reactors to prevent the creation of new long-lived nuclear waste. By law the federal government must take responsibility for existing spent nuclear fuel, so inaction is not an option. Accelerated development of fast and thorium reactors will allow the US to fulfill its obligations to dispose of the nuclear waste, and open up a source of carbon-free energy that can last centuries, even millennia.

The common presumption that 4th generation nuclear power will not be ready until 2030 is based on assumption of ‘business-as-usual”. Given high priority, this technology could be ready for deployment in the 2015-2020 time frame, thus contributing to the phase-out of coal plants. Even if the United States finds that it can satisfy its electrical energy needs via efficiency and renewable energies, 4th generation nuclear power is probably essential for China and India to achieve clear skies with carbon-free power.


MORE by Hansen on the same topic, with some extra details and a book recommendation for further reading…

Trip Report – Nuclear Power

On one of my trips I read a draft of “Prescription for the Planet” by Tom Blees, which I highly recommend. Let me note two of its topics that are especially relevant to global warming. Blees makes a powerful case for 4th generation nuclear power, the Integral Fast Reactor (IFR). IFR reactors (a.k.a. fast or breeder reactors) eliminate moderating materials used in thermal reactors, allowing the neutrons to move faster. More energetic splitting of nuclei releases more neutrons. Instead of using up less than 1% of the fissionable material in the ore, a fast reactor burns practically all of the uranium. Primary claimed advantages are:

a) The fuel is recycled on-site, incorporating radioactive elements into new fuel rods. The eventual ‘ashes’ are not usable as fuel or weapons. The radioactive half-life of the ashes is short, their radioactivity becoming less than that of naturally occurring ore within a few hundred years. The volume of this waste is relatively small and can be stored easily either on-site or off-site.

b) The IFR can burn the nuclear ‘waste’ of current thermal reactors. So we have a supply of fuel that is better than free – we have been struggling with what to do with that ‘waste’ for years. We have enough fuel for IFR reactors to last several centuries without further uranium mining. So the argument that nuclear power uses a lot of fossil fuels during uranium mining becomes moot.

c) IFR design can be practically failsafe, relying on physical properties of reactor components to shut down in even the most adverse situations, thus avoiding coolant problems of Chernobyl and Three Mile Island, as well as the earthquake problem. The terrorist threat can be minimized by building the reactor below grade and covering it with reinforced concrete and earth.

Wait a minute! If it’s that good, why aren’t we doing it? Well, according to Blees, it’s because, in 1994, just when we were ready to build a demonstration plant, the Clinton Administration cancelled the IFR program. Blees offers a partial explanation, noting that Clinton had used the phrase “You’re pro-nuclear!” to demonize rivals during his campaign, suggesting that Clinton had a debt to the anti-nuclear people. Hmm. The matter warrants further investigation and discussion. It’s not as if we didn’t know about global warming in 1994.

Even more curious is the assertion that Argonne scientists, distraught about the cancellation, were told they could not talk about it (why do I find this easy to believe?). Here too there is no explanation in depth, although Blees notes that the Secretary of Energy, Hazel O.Leary, was previously a lobbyist for fossil fuel companies (my gosh, is everybody in Washington an ex-lobbyist – alligators will go extinct!).

I have always been agnostic on nuclear power. I like to hope that, if our next President gives high priority to a low-loss national electric grid, renewables will be able to take over most of the power generation load4. Wind and solar-thermal are poised to become big players. IEA’s estimate that renewables will only grow from 1% to 2% (by 2030!) can be dismissed due to IEA’s incestuous relation with fossil industries – nevertheless, one must have healthy skepticism about whether renewables can take over completely. Maybe an understatement – I’m not certain.

Blees argues that it made no sense to terminate research and development of 4th generation nuclear power. Was it thought that nuclear technology would be eliminated from Earth, and thus the world would become a safer place?? Not very plausible – as Blees points out, several other countries are building or making plans to build fast reactors. By opting out of the technology, the U.S. loses the ability to influence IFR standards and controls, with no realistic hope of getting the rest of the world to eschew breeder reactors. Blees suggests, probably rightly, that this was a political calculation for domestic purposes, a case of dangerous self-deception.

Bottom line: I can’t seem to agree fully with either the anti-nukes or Blees. Some of the anti-nukes are friends, concerned about climate change, and clearly good people. Yet I suspect that their ‘success’ (in blocking nuclear R&D) is actually making things more dangerous for all of us and for the planet. It seems that, instead of knee-jerk reaction against anything nuclear, we need hard-headed evaluation of how to get rid of long-lived nuclear waste and minimize dangers of proliferation and nuclear accidents. Fourth generation nuclear power seems to have the potential to solve the waste problem and minimize the others. In any case, we should not have bailed out of research on fast reactors. (BTW, Blees points out that coal-fired power plants are exposing the population to more than 100 times more radioactive material than nuclear power plants – some of it spewed out the smokestacks, but much of it in slag heaps of coal ash. See re the effect of this waste on Native Americans in the Southwest, as well as ‘Burning the Future’, above, re the Appalachians.)

I don’t agree with Blees’ dismissal of the conclusion of most energy experts that there is no ‘silver bullet’; they argue that we need a mix of technologies. Blees sees a ‘depleted uranium bullet’ that could easily provide all of our needs for electrical energy for hundreds of years. His argument is fine for pointing out that existing nuclear material contains an enormous amount of energy (if we extract it all, rather than leaving >99% in a very long-lived waste heap), but I still think that we need a range of energy sources. Renewable energies and nuclear power are compatible: they both need, or benefit from, a low-loss grid, as it is more acceptable to site nuclear plants away from population centers, and nuclear energy provides base-load power, complementing intermittent renewables.

BTW, nuclear plants being proposed for construction now in the U.S. are 3rd generation (the ones in operation are mostly 2nd generation). The 3rd generation reactors are simplified (fewer valves, pumps and tanks), but they are still thermal pressurized reactors that require (multiple) emergency cooling systems. France is about to replace its aging 2nd generation reactors with the European Pressurized Reactor (EPR); a prototype is now being built in Finland. According to Blees, OECD ranks EPR as the cheapest electric energy source, cheaper than pulverized coal – that evaluation doubtless presumes use of a standard design, a la the French procedure for its 2nd generation reactors. The prototype in Finland, according to reports, is running behind schedule and over budget – that was also true in the prior generation, yet the eventual standard French reactors have been economical. Current efforts to start construction of 3rd generation nuclear plants in the U.S., so far, do not seem to have achieved a standard design or to have avoided project delays (partly due to public opposition) that drive up costs.

Blees argues that the 4th generation technology basically exists, that the design will be simplified, especially due to the absence of a need for emergency cooling systems. He foresees a standard modular construction of the reactor per se, smaller than earlier generations, which can be built at the factory, shipped to the site, and dropped in the prepared excavation. His cost estimates have this nuclear power yielding cheaper electricity than any of the competition. The system is designed to eliminate long-lived nuclear ‘waste’ and minimize proliferation dangers. There is enough fuel available without further uranium mining to handle electricity needs for several centuries, for whatever fraction of electricity needs cannot be covered by renewable energies. If these claims are anywhere close to being correct, we could phase out use of fossil fuels for electricity generation over the next few decades.

I do not have the expertise or insight to evaluate the cost and technology readiness estimates. The overwhelming impression that I get, reinforced by the ‘boron’ topic below, is that Blees is a great optimist. But we need some good ideas and optimism. The book contains a lot of interesting insights and tidbits, e.g., there is more energy available in the nuclear material spewn out as waste by coal plants than the amount of energy produced by the coal burning. The book will be available in about a month; see his web site


Well, that’s sure to stir the pot. But he’s got a point, hasn’t he? Part IV wraps this up, and closes with some strong statements about what we should and shouldn’t be willing to do.

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By Barry Brook

Barry Brook is an ARC Laureate Fellow and Chair of Environmental Sustainability at the University of Tasmania. He researches global change, ecology and energy.

44 replies on “Hansen to Obama Pt III – Fast nuclear reactors are integral”

The problem I have with Hansen is that he is discussing three areas – climatology, economics, and technology – without being as clear as I would like that his only field of academic expertise is climatology. The danger is that he might dilute his authority on climate by his amateur pronouncements in other fields. I don’t mind that he uses his prominence to offer advice on what to do, but I wish he would be clearer in delineating his area of specialization. After all, we are plagued by retired televison weather presenters claiming to be climate scientists, so it might help if genuine climate scientists were clearer about their qualifications.

Even a generalist like Barry Brook has some limits on his fields of expertise, after all.


Molnar@3: Yes, I can see the risk (dilution of authority), but Hansen is a physicist a 30 year background of scientific research behind him, so has more expertise on this matter than 99.99% of the wider population. I wish the nuclear physicists were more broadly engaged with the public on this topic. But they’re not – or they’re not listened to like Hansen is. I applaud him for speaking out on this matter. At present, public debate is far too dominated by the idiotic minority who take pride in knowing nothing.


So far I haven’t heard a squeak from our in-denial friends about Hansen’s interest in Gen IV nuclear energy.

It’s going to be a real problem for them (if they ever get their heads around the differences in reactor technologies) because of the way they’ve demonised his name.

They can hardly embrace Hansen’s “conversion” (as they will see it) because it comes packaged with the unpalatable message about their worst fears.

It will also be a test for the true believers some of whom’s understanding of the science is on a par with the true deniers.


John, yes, the old “Fusion is 50 years away – and always will be”. That pessimism could be right, but those I’ve spoken to in the know suggest that the 50 is more like 30 now, and the shifting baseline has finally anchored. Of course a tech that is 30 years off is still way too distant to save us from the climate+energy crisis, but it’s worth pursuing in the long-term as the rewards for success are boundless. 4th gen nuclear could be delivering much sooner.


I’d love to see fusion happen-when I was in high school&undergrad (starting ~1960), I was seriously considering fusion physics for a career, having read the book “Project Sherwood” that thought with luck it might be commercial within 30 years :-)

Burton’s slide 25 says: Fusion: Not for at least 50 years, but then, that was in 2004, but on the third hand, I don’t casually ignore high-energy/particle Nobel physicists when they speak of fusion :-)

If there’s something substantial that’s changed, I’d be pleased to see it, but certainly, for now, I consider it still in the “Pure R” category it’s been in for 50+ years.


It’s a harsh unpalatable truth for many conservationists that nuclear power is clearly part of the answer.

Much of the cost of setting up nuclear plants in Australia would be in legal challenges, excess red tape etc, such that it genuinely would be too expensive and too slow to start here. These aren’t engineering challenges, they’re social policy ones, which are typically far harder to solve.

My objection to nuclear power is that it’d be too expensive compared even to the ridiculously expensive PV option, at least for Australia. We’re dictated to by cretins…


I agree with all the comments in the 1st blah-di-blah paragraph to be honest. The technology talked about as the holy grail is to me no different to clean coal geosequestration… pie in the sky dreams compared to the reality of solar and wind and the suite of clean renewables.

But what I always say in this debate is that I’m more than happy for nuclear to be considered part of the mix in a global economy that commits to the kinds of carbon emission cuts that are required, and places a true price on carbon in the marketplace. I’m less worried about side effects of nuclear reactors than I am about the realities of climate change.

What I won’t consider, however, is adopting nuclear technology as pushed by people who are climate skeptics, and refuse to price carbon or reduce emissions.


At the moment we have, I believe, a large supply of potentially baseline power that is only used for peak demand. That is hydroelectric. Why no use hydro for the baseline power and renewables for the peak (which tends to happen when its hottest (aircon) and thus when solar is most effective)? This doesn’t involve building more dams, just using the ones we have constantly.


Simply not enough installed hydro. The problem is consecutive days where the sun isn’t shining and the wind isn’t blowing – at that point you need full system backup, or a renewable installed capacity of 4 (optimistic) to 10 (realistic) the installed capacity to be able to have sufficient ‘spare’ generating capacity to make enough non-thermal backup (e.g. ammonium hydrates, hydrogen, compressed air, gravity fed storage etc). I’m going to do a post on this issue soon as I’d be interested in comments.


James @ 11

I think this is an over-simplification, as can be seen in The Economics of Hydro Power.

Unlike nuclear and coal, which are truly baseload (i.e., one doesn’t casually shut them off), hydro:

– can do baseload and does
– can do peak, i.e., is dispatchable

– but not arbitarily, because not only are there usually environmental rules, but one cannot usefully let a reservoir drain, and letting the water flow without generating electricity is a waste. Put another way, big dams on reliable rivers are doing baseload anyway.

According to this, 87% of the electricity in Washington state is hydro, which means that most of their baseload is hydro…


I recommend the Archer+Jacobson paper on distributed windfarms for baseload.


This is why I dislike technology debates – they are a smokescreen to the climate challenge. We need to reduce carbon emissions, and we need to do it using whatever technology is available. Nuclear, wind, solar, whatever…

But you can’t dismiss the potential of hydro, or solar, or wind to provide baseload power, while backing a non-existent nuclear technology that may never be. Just as we can’t assume solar will one day be cheap and have options to provide baseloads.

It is ludicrous to be picking technologies now, but the emissions targets, and the cap and trade, well those clear price incentives will at least drive the investment in research that is needed to get us to whatever technology ends up dominating the energy future.


Fair point about assumptions MattB.

I guess the rationale of the above advocation of research into Gen IV is about fundamental technology bounds – we know large-scale nuclear is axiomatically baseload since it is not affected by weather. We also know that sun and wind power will be limited at times when it is cloudy or calm. This is a core underpinning of these relevant techs. The only way the latter can change is if storage methods improve or the renewable grid becomes massively distributed and enlarged. Of course if Gen IV nuclear is not invested in and developed, it will be as ‘intermittent’ as any renewable – as you rightly point out, it won’t exist.

My argument above is that we need to be aggressively pushing all alternatives and probably do need to pick some focal targets, at least early on. As you know from the site content, I’m no renewable basher and I want the problem addressed any way that is feasible.

JohnM, thanks for the distributed wind paper – useful. I would classify it as ‘mostly baseload’. But there is still a snag, as I’ll detail the post-after-next (right after Hansen to Obama IV).


Barry @ 15
Needless to say, the distributed windfarm study is hardly a panacea, and the grid requirements are serious, but the main clarification is that for wind:

– the peak power varies
– the peak *cannot* be treated as baseload
– but with adequate size, geographic dispersion, and grid, some useful fraction of peak *can* be treated as baseload

I.e., wind is *not* all-or-none, unlike the common idea “wind is intermittent, so needs 100% backup”.

Of course, even intermittent supplies play OK with charging electric vehicles overnight.


By the way, there are several companies actively pursuing new nuclear designs that do (assuming they complete their designs and achieve regulatory approval) overcome some of the “too slow and the costs are too unpredictable” arguments, by reducing the size and moving most of the construction to a factory.

The longest-standing and arguably most credible is the PBMR, based in South Africa.

The second is Nuscale Power. Their proposed design is a scaled-down version of the standard light water reactor that’s been used for 50 years; their innovations are that their design is small enough to make in a factory and transport it by truck. However, because it’s familiar technology, it should be reasonably easy to get the design approved. They appear to have considerable management expertise involved.

The final one is Hyperion Power Generation. Their design is the most technically interesting of the lot. Basically, their reactor is a tub full of uranium hydride, which has rather interesting properties. The moderator in their design is the hydrogen in the uranium hydride. However, if the reaction results in the reactor getting too hot, the hydrogen comes out of the hydride. Voila, reaction slows down. If it cools down again, hydrogen is re-absorbed. Reaction speeds up. No control systems and whatnot required, just run a heat exchanger on the wall. Very cool, but Hyperion seem to spend lots of time spruiking their technology (which appears to be genuine) and considerably less time actually engineering prototypes and discussing their plans for regulatory approval than the others.

None of these solves the waste problem (which is IMO a beatup) or the fuel availability problem (again, a beatup), but they might well be available and deployable in a lot shorter timeframes than the Gen IV reactors.


Robert @18: I agree with most of what you say – indeed, this is the Gen III and Gen III+ tech shown in the leading diagram of the blog post.

But I’d be interested in hearing your reasoning for considering the fuel availability problem a beatup – yes, there will be more uranium reserves discovered in the future — but why do you think the EROEI of these will be positive?

John @17: There are enough times when 100% backup is needed to make it a least a serious issue – around 2-3 days per month in even high resource areas. But I need to explain where I get this from, so will have to blog on it soon – you tempt me, sir!


Barry @19, an answer to your question: Most U exploration taking place in Australia right now is in Tertiary paleochannels and similar supergene mineralisation environments. These are always going to be shallow and therefore not take a great deal of energy to extract, physically or otherwise. Peak oil may be upon us within the decade, but we’ve still got a long way to go up on the U production curve – we’ve literally barely scratched the surface. Geoscience Australia, the authority on this subject, stated in their submission to Switkowski’s Uranium Mining, Processing and Nuclear Energy Review: “…it is our considered opinion that there will be adequate nuclear fuel resources to support steady growth of the nuclear power sector throughout the 21st century.” In the context of technological development (of the renewables that we undoubtedly also need), a hundred years is a lot of time to buy.

As you might gather, I’m still of the opinion that of all the arguments against nuclear power, fuel availability is the weakest by some margin.


“adequate nuclear fuel resources to support steady growth of the nuclear power sector throughout the 21st century.”

To me the key words are “Steady Growth”. Much much more than steady growth is required were current nuclear energy technologies to take over global base energy demand. Phenomenal or exponential growth would be needed, and they don’t say they have resources to support such growth throughout the 21st century.

And Robert @18 – unfortunately most people who think the nuclear fuel supply issue is a beat up, and that the nuclear waste issue is a beat up, probably think that climate change is a beat-up too;)


Mark Duffett has covered one part of the response to your question, Barry; we haven’t looked for uranium very hard yet. Even the lowest-grade ores currently mined have enormous EROIs – see here, so we’d have to mine much, much lower grade ores before we’d have to worry about EROI too much.

The second part is that uranium has been so cheap we haven’t really bothered using it efficiently. There are a number of ways that we could stretch existing fuel supplies substantially if we chose.

The first option is reprocessing, which is done for commercial reuse of fuel in France, the UK, and Japan, but not in the USA. It’s not economically rational at current uranium prices, but makes perfect sense if uranium got more expensive (but still well under the costs where EROI concerns can be discounted on the basis of a back-of-the-envelope calculation). There are proliferation concerns with reprocessing, but they are a very complex issue and some of the key data points remain classified (key amongst them whether spent power reactor fuel could plausibly be reprocessed and used in a nuclear weapon; the guesses in the public domain seem to vary between “with considerable difficulty, but yes” to “no”).

But there are other alternatives. The simplest is to use more efficient reactors. The new generation of conventional nuclear reactors (the first of which are under construction) will be more fuel-efficient, not only because of superior thermal efficiency (particularly the PBMR, as it uses a higher operating temperature than the water-based reactors) but because they have higher breeding ratios. All uranium-fuelled nuclear reactors breed plutonium, not just fast breeder reactors. A fair proportion of their energy comes from burning that plutonium, rather than the original uranium. If you increase the breeding ratio, you can get a lot more out of the fuel.

A related possibility is offered by the Canadian-designed CANDU reactor series. These reactors are of a different design to most of the power reactors out there; they use heavy water as their moderator rather than light water, which already makes them quite efficient – they apparently use about 30% less uranium than conventional light-water reactors. But they offer a further trick- you can use spent fuel from a conventional reactor as fuel for a CANDU in a more straightforward manner than recycling conventional reactor fuel for reuse in the same type of reactor. See this on the DUPIC fuel cycle.

There is also the possibility of using thorium as part of the fuel mix in conventional, existing reactors. There’s been work done in this area, but it’s unattractive at the moment, essentially because uranium is too cheap to make overcoming the difficulties worthwhile.

All of the above makes me pretty confident that uranium could be extracted at reasonable cost and at very attractive EROIs for at least the next century, even if it makes up a much larger part of the world’s energy use than it does today.


Simply not enough installed hydro.

I’d expect wind energy to work really well when there’s already plenty of hydro available but more energy in total is needed than the hydro can supply, e.g. in Tasmania. Wind energy could be considered to be like base load generation in the sense that it is inflexible. Hydrp is flexible so can deal with not just variations in demand but also variations in other forms of supply. We could supply all the power needs of, say, NSW, Victoria and Tasmania from just hydro generators at any one time, just not indefinitely.


Chris O’Neil: the trouble is that the amount of water you’d have to run through the turbines would be far, far in excess of current capacity. That means you’d need to construct a pile of new or expanded buffer weirs to moderate the outflow. And that will be hugely environmentally contentious, given the locations of the overwhelming majority of our dams.

Not to mention that if you tried to feed 10GW of generation capacity, you’d drain the country’s reservoirs in a week.


MattB @21, no one (at least not me) is arguing for “current nuclear energy technologies to take over global base energy demand”. All I am saying is that nuclear has to be a significant part of the mix. Not ‘phenomenal’ or ‘exponential’ growth, more of the order of triple the current capacity. As a wise man @14 said, “we need to reduce carbon emissions, and we need to do it using whatever technology is available. Nuclear, wind, solar, whatever…”


Ahh darn it I guess lesson one is never follow one of Mark’s links when you have 95% completed a genuis blog entry:)

Mark I don’t disagree – other than on the fuel supply contraints. Also that triple capacity is taking it to 60% of global electricity supply, which in my books is “taking over global base energy demand”.

I also have issue with the 2nd link – claiming that the increase in nuclear is much more feasible than in renewables…

In fact the entry itself shows that it only took a short amount of time for nuclear to go from zero to 20% of supply, so why would that be difficult for renewables. I’d suggest going from 20% to 40% is much more difficult, as evidenced in the failure of nuclear to progress past this point.


MattB @26: “I’d suggest going from 20% to 40% is much more difficult, as evidenced in the failure of nuclear to progress past this point.”

Hmmmm, I’d suggest the fundamental reasons for the slowing of nuclear progress have been much more political than technical or economic.


Of course they were political reasons, but they certainly stopped it in its tracks.

There are similarly only political reasons to not introduce renewables for a very healthy wedge. Economic arguments are out the window when you look at the kind of contraints on carbon proposed in today’s new blog. And politically it would be lapped up relative to nuclear.


This is why I don’t like technology debates – the mix is not something that should be determined by debate. Governments should ensure a sufficiently high price on carbon, apply minimal regulation and subsidy, then get out of the way and let the market decide.

Recent events notwithstanding – let’s not throw out the free market baby with the reckless lending bathwater.


Mark @20 and Robert @22: Thanks for that information. I’ve since spoken to some mining geologists here in South Australia and they say much the same thing about the potential for future U discoveries. Given that I’ve not seen anything close to a Hubbert linearization diagram for U, I’m willing to accept what you guys say about large +v EROI stocks of U remaining, and will pull my head in on the argument of ‘running out of fission fuel’. It seems an unproven scare tactic – at least unless further data to the contrary come to light.


Chris O’Neil: the trouble is that the amount of water you’d have to run through the turbines would be far, far in excess of current capacity.

Not true (current capacity 7 GW while baseload capacity of Vic (6.5 GW), NSW and Qld is probably around 20 GW) but my point is that even with current capacity, there is still enormous potential for the existing hydro to support variations in output from wind generators.

That means you’d need to construct a pile of new or expanded buffer weirs to moderate the outflow. And that will be hugely environmentally contentious, given the locations of the overwhelming majority of our dams.

They certainly wouldn’t need to be anywhere near as big as the existing supply dams which are in more environmentally contentious locations than downstream of the generators. Of course, wind generation will need to be vastly greater than it is now before this needs doing.

Not to mention that if you tried to feed 10GW of generation capacity, you’d drain the country’s reservoirs in a week.

It would probably take a few weeks (7.2 per cent of electrical energy comes from hydro)A week without wind generation would be uncommon. The objective is not necessarily to do away with fossil fuel generation entirely, it is to greatly reduce the need for it which would happen if it’s not needed very often.


What happens to the EROI for uranium when we dig the biggest hole in the world to get to it? The proposed expansion of Olympic dam will required the removal of an unprecedented tonnage of overburden to even get to the uranium ore. The real EROI requires factoring in the energy required to lift every tonne of overburden up a long spiral path half a km deep and 2km in diameter. Then in a decade the site must be reclaimed. This all will as usual be done using public subsidised diesel fuel.

This operation will also require suspension of the laws that apply to all other operations (through the indenture act).

When we are turning to such uranium sources this early it does not bode well for the Uranium optimist argument regarding supply continuity with at reasonable EROI).


Re Barry 30 “It seems an unproven scare tactic – at least unless further data to the contrary come to light.”

Barry, have you come across Storm Van Leeuwen? It’s hard to find a life-cycle analysis that are not tainted by the perceptions of the ubiquitous profit motive, hence I was interested in the Storm-Smith analysis ( They include a detail estimation of uranium reserves (


On the bright side of the claim made about Gen IV reactions, if the nuclear lobby say all this is achievable (fast and safely), then there is no excuse to build another single installation of Gen 2 design or even their much vaunted Gen 3 reactors. As these designs deplete fuel and create waste at a rate that is impractical to shift current energy generation.

(Current nuclear installations (approx 450 in number) produce in the order of ~15% of the world’s electricity (~5% of total power). Current Uranium reserves are in the order of ~60 years. Design life of a reactor is in the order of ~25-40 years. The Bush administration has granted permits to extend the life of current reactors to 60 years. Thus if we were to replace all current rectors with Gen 2 (or possibility unproven Gen 3 reactors) then the life of just the replacement rectors alone would see the depletion of the majority of feasible Uranium reserves (See Storm-Smith). Yet this leaves no scope for expansion of the nuclear energy share.

In short, the optimistic Gen 4 case (presented by Hansen) is essential for nuclear to further reduce greenhouse emissions. Current reactor designs are a drain and their multiplication will not reduce emissions over the century. Worse, expansion of current reactors will accelerate the depletion of fuel and reduce the energy return of energy investment (EREI) by producing reactors that will be stranded without a full lifetime supply of fuel.

I have continued fear for the suppression of support for renewables (on the relative scale required) and continued scepticism about optimistic assessment of the yet to be proved Generation four nuclear plant.


Mark – as I understand it, pebble bed reactors make the fuel unsuitable for Gen IV tech, but Gen II processes and non-pebble Gen III actually create the feedstock required for IFR power stations, so are supplying, not depleting, future supply. I need to post more on this in the near future – I’ve found a lot more relevant stuff recently that is worth making people aware of.

Thanks for the Storm-Smith analysis – I’ll look this up.


Mark @32, the copper and gold at Olympic Dam are worth more than the uranium. That’s what makes it economic to excavate a half-kilometre deep hole.

And I’ve never been quite convinced that not levying a component of tax on diesel amounts to a ‘subsidy’, but anyway…if I had my way, I’d be digging that sort of hole using shaped nuclear charges; I reckon that’d bump up the EROEI a bit ;-)


Hi Barry,

That is consistent with my understanding, that “spent fuel” from Gen II reactors’ can theoretically be used as fuel for Gen IV reactors. The trap would be building more Gen II reactors and leaving these costly (energy) investments stranded without a complete lifecycle of “good” (EROI) uranium.

Yet, the presentation notes which James Hansen reference re. Gen IV reactors were so optimistic as to be questionable. Some counter points can be found in a presentation by Michael Dittmar ( Dittmar observes that no public scientific document seems to exist which quantifies the achieved longer term useful Pu(239) breeding factor! Lacking this data, Dittmar asks, “were all [previous and existing] fast reactors operated without achieving efficient breeding?”

Dittmar also states, that despite promising 30 years ago a claimed a theoretical increase of fissile material by a factor of 60, fast reactors are still not really a success story. 11 (out of 13) fast reactors are closed or not operating. No commercially functioning fast breeder exists today!

Helen Caldicott highlights the dangers of the highly reactive sodium and potassium that are used as coolant in Gen IV reactors. This is likely associated with the reluctance to transition to this generation.


Hi Mark Duffet, Yes the copper and gold at Olympic dam do need to be factored into the economics and energy investment (which I believe Storm-Smith count 20% of energy investment towards the uranium, based on 20% of the income projected to be derived from Uranium).

The tax holiday on mining diesel makes it cheaper for BHP, and competition for scarce resources means more expensive for the rest (including low income families). Perhaps its subjective but I’d count these types of distortions as subsidies. Similarly I would count free pollution as a subsidee. Without such detailed full costing we keep getting economics that fails to count half the important stuff, and hence doesn’t properly do its job properly.


Mark @37, see my more recent post, linked above in comment #39.

Regarding reactive sodium:

Under neutron bombardment, sodium-24 is produced. This is highly radioactive, emitting an energetic gamma ray of 2.7 MeV followed by a beta decay to form magnesium-24. Half life is only 15 hours, so this isotope is not a long-term hazard – indeed it has medical applications. Nevertheless, the presence of sodium-24 further necessitates the use of the intermediate coolant loop between the reactor and the turbines.

To which George Stanford adds: “As you can see, the author had a hard time finding significant disadvantages. The overall safety of the IFR concept is remarkable. gss”


What concerns me here is the apparent acceptance of C)2 as the problem to be addressed. There is enough coal to keep us going for a very long time. Nuclear energy is dangerous and the AEC and similar bodies cannot be trusted to be open about past events. What makes you think they can be trusted about the future? Engineers specialise in certain fields so a generalist can be no better informed than a generalist in any other area. Hansen is no different. When the measure of safety is effectively an acceptable risk level where corporations cannot be sued because there is a chance the event is caused by background radiation we are skating on thin ice. But please remember there is no evidence that global warming is melting the ice and raising sea levels. In fact the volume of ice is increasing and the oceans should be falling by around 0.19mm per year. A more accurate assessment of the real ocean situation would be volume of water but that is possible too hard at the moment. So, we do not know what is happening with oceans. If we could accurately asses volume and then ‘tip it over a simulated geosphere’ we could see what is happening. We cannot. But, imagine, if all the rivers eroded all the land thereby filling in the trenches in the Earth’s crust, assuming crust stability – a big assumption. Then, with no additional water from ice, the oceans would cover more land. Note I did not say rise or fall because the erosion would actually cause plates to shift and other happenings. Hyperbole and political hype are meaningless in real terms; they serve to justify new taxes and a redistribution of funds and central government. Meanwhile a major proponent reaps huge economic benefits. LoL.


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