The claims made by advocates of these Generation IV concepts simply don't stack up.
Dr James Hansen is rightly admired for his scientific and political work drawing attention to climate change. His advocacy of nuclear power ‒ and in particular novel Generation IV nuclear concepts ‒ deserves serious scrutiny.
In a nutshell, Dr Hansen (among others) claims that some Generation IV reactors are a triple threat: they can convert weapons-usable (fissile) material and long-lived nuclear waste into low-carbon electricity. Let's take the weapons and waste issues in turn.
Dr Hansen says Generation IV reactors can be made "more resistant to weapons proliferation than today's reactors" and he claims that "modern nuclear technology can reduce proliferation risks".
But are new reactors being made more resistant to weapons proliferation and are they reducing proliferation risks? In a word: No.
Fast neutron reactors have been used for weapons production in the past (e.g. by France) and will likely be used for weapons production in future (e.g. by India).
India plans to produce weapons-grade plutonium in fast breeder reactors for use as driver fuel in thorium reactors. Compared to conventional uranium reactors, India's plan is far worse on both proliferation and security grounds. To make matters worse, India refuses to place its fast breeder / thorium program under IAEA safeguards.
Dr Hansen claims that thorium-based fuel cycles are "inherently proliferation-resistant". But in fact, thorium has been used to produce fissile material (uranium-233) for nuclear weapons tests. Again, India's plans provide a striking real-world refutation of Hansen's claims.
Dr Hansen claims that integral fast reactors (IFR) ‒ a non-existent variant of fast neutron reactors ‒ "could be inherently free from the risk of proliferation". Unfortunately, that isn't true. Dr George Stanford, who worked on an IFR R&D program in the US, notes that proliferators "could do [with IFRs] what they could do with any other reactor − operate it on a special cycle to produce good quality weapons material."
Dr Hansen acknowledges that "nuclear does pose unique safety and proliferation concerns that must be addressed with strong and binding international standards and safeguards."
There's no doubting that the safeguards systems needs strengthening ‒ even some nuclear advocates acknowledge the problem. Dr Hansen says he was converted to the cause of Generation IV nuclear technology by Tom Blees, whose 2008 book 'Prescription for the Planet' argues the case for IFRs.
But Dr Hansen doesn't seem to have paid much attention to those sections of the book where Blees argues for radically strengthened safeguards including the creation of an international strike-force on standby to attend promptly to any detected attempts to misuse or to divert nuclear materials.
Dr Hansen claims that "modern nuclear technology can ... solve the waste disposal problem by burning current waste and using fuel more efficiently" and he states that nuclear waste "is not waste, it is fuel for 4th generation reactors!"
But even if IFRs ‒ Dr Hansen's favoured Generation IV concept ‒ worked as hoped, they would still leave residual actinides, and long-lived fission products, and long-lived intermediate-level waste in the form of reactor and reprocessing components ... all of it requiring deep geological disposal.
UC Berkeley nuclear engineer Prof. Per Peterson states: "Even integral fast reactors (IFRs), which recycle most of their waste, leave behind materials that have been contaminated by transuranic elements and so cannot avoid the need to develop deep geologic disposal."
So if IFRs don't obviate the need for deep geological repositories, what problem do they solve? They don't solve the WMD proliferation problem associated with nuclear power. They would make more efficient use of uranium ... but uranium is plentiful.
In theory, IFRs would gobble up nuclear waste and convert it into low-carbon electricity. In practice, the EBR-II reactor in Idaho ‒ an IFR prototype, shut down in 1994 ‒ has left a legacy of troublesome waste. This saga is detailed in a recent article and a longer report by the Union of Concerned Scientists' senior scientist Ed Lyman.
Dr Lyman states that attempts to treat IFR spent fuel with pyroprocessing have not made management and disposal of the spent fuel simpler and safer, they have "created an even bigger mess".
Dr Lyman concludes: "Everyone with an interest in pyroprocessing should reassess their views given the real-world problems experienced in implementing the technology over the last 20 years at [Idaho National Laboratory].
"They should also note that the variant of the process being used to treat the EBR-II spent fuel is less complex than the process that would be needed to extract plutonium and other actinides to produce fresh fuel for fast reactors. In other words, the technology is a long way from being demonstrated as a practical approach for electricity production."
Generation IV economics
Dr Hansen claimed in 2012 that IFRs could generate electricity "at a cost per kW less than coal." A complex, novel reactor coupled to a complex, novel reprocessing system will be cheaper than shovelling coal into a burner? Not likely.
The US Government Accountability Office's 2015 report noted that technical challenges facing SMRs and advanced reactors may result in higher-cost reactors than anticipated, making them less competitive with large light-water reactors or power plants using other fuels.
A 2015 report by the International Energy Agency (IEA) and the OECD's Nuclear Energy Agency (NEA) said that "generation IV technologies aim to be at least as competitive as generation III technologies ... though the additional complexity of these designs, the need to develop a specific supply chain for these reactors and the development of the associated fuel cycles will make this a challenging task."
The late Michael Mariotte commented on the IEA/NEA report: "So, at best the Generation IV reactors are aiming to be as competitive as the current − and economically failing − Generation III reactors. And even realizing that inadequate goal will be "challenging." The report might as well have recommended to Generation IV developers not to bother."
The idea of reactors converting weapons material and nuclear waste into low-carbon power is attractive to even the most hardened nuclear critics. But unfortunately, the claims made by advocates of these Generation IV concepts simply don't stack up.
Dr Jim Green is the national nuclear campaigner with Friends of the Earth Australia and editor of the Nuclear Monitor newsletter, where a longer and fully referenced version of this article can be found.