Climate change

December 9, 2008

Hansen to Obama Pt III – Fast nuclear reactors are integral

Filed under: Climate Change, Uncategorized — Barry Brook @ 1:02 pm

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.


1 Comment »

  1. You can find more information about the Idaho National Laboratory’s Generation IV Systems at

    Comment by htomfields — December 11, 2008 @ 3:41 am

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