FUEL AND FUEL CYCLE | FAST BREEDERS What waste?
By utiliising nuclear waste a new generation of fast breeder reactors could power the world for centuries. What’s stopping us?
EXISTING NUCLEAR MATERIALS STOCKPILES CURRENTLY considered ‘waste’ can instead be repurposed to provide low-carbon energy, supporting wind and solar in achieving a net zero economy in Europe. This is according to a new analysis from RePlanet, a network of charitable organisations that explores science-based solutions to climate change. In their report, titled ‘What a waste: How fast-fission
power can provide clean energy from nuclear waste’ and authored by Mark Lynas with contributions from Joris van Dorp and Rauli Partanen, the group is proposing fast- tracking an urgent programme of fast breeder reactor construction that will allow the use of these nuclear waste materials to provide a previously untapped source of low- carbon energy. All current nuclear power reactors used in Europe – with
the exception of the gas-cooled reactors In the UK and the heavy water reactors in Romania – are light-water reactors using enriched uranium as their fuel. Light-water reactors using enriched uranium utilise less than 1% of the actual energy potential in the natural uranium used to make their fuel and irradiated fuel assemblies removed from reactors are considered nuclear waste. Using current inventories of spent fuel, the authors
argue that there is sufficient energy in nuclear waste to run Europe at current electrical power consumption for up to a thousand years if it were to be used as fuel in closed-cycle fast reactors. If unconventional uranium and thorium resources are also considered in the global picture, nuclear fuel is essentially limitless, they say – sufficient to supply a growing human civilisation with carbon-free energy for tens of thousands of years, and likely far longer.
Vast energy resources The author’s analysis finds that Europe – the UK and the EU combined – has a total inventory of nearly 580,000 tonnes of potential nuclear fuel for fast reactors. This compares with about 470,000 tonnes of uranium in depleted uranium (mostly stored as 700,000 metric tonnes of uranium hexafluoride (UF6) in the United States, and a worldwide stock of about 1.6 million tonnes of depleted uranium only, not including spent fuel. This global stock of DU increases by about 50,000 tonnes per year due to new uranium enrichment and fuel fabrication, they add. There are significant uncertainties in exactly how much
more efficiently fast reactors using a closed fuel cycle can use uranium when compared with current-generation light-water reactors. These uncertainties largely concern assumptions about the retrieval efficiency of the cycle reprocessing and refabricating fuel, but efficiency estimates vary from a factor of 60 to a factor of 100. The factor of 100 is based on assuming fully efficient retrieval and return of all fissionable and fertile materials from spent fuels to the fuel cycle.
Nonetheless, even using the lower estimate current
global inventories add up to over 11 million TWh of electrical energy, the report concludes, while current world total electricity consumption is about 23,000 TWh a year. The report adds that including uranium still in the ground in economically proven reserves, gives another 6.2 million tonnes, enough for about 2,000 years of clean power globally. There are even larger amounts of uranium in unconventional resources, such as dissolved in seawater, or even the discarded ashe from coal power plants which contain uranium and thorium traces and thus an energy content 10 times that of the original coal, the authors state. Uranium is not the only potential nuclear fuel in fast
reactors either. They can also use the thorium fuel cycle pioneered in India. Thorium-232 breeds into uranium-233 and thorium is three to four times more abundant than uranium making it a source of power which could support human civilisation for tens of thousands of years. In other words, the report concludes, if uranium or thorium are used in breeder reactors with a closed fuel cycle, the supply of nuclear fuel for fission is essentially limitless on any timescale meaningful to human civilisation.
Above: Dounreay in Scotland was the location of a test site for the development of prototype fast breeder reactor that was part of the west’s now abandoned fast breeder programme Photo credit: Steve Allen/
Shutterstock.com
38 | June 2023 |
www.neimagazine.com
The economic case for fast breeders While the report concedes that the economics of fast reactors are currently unproven, it notes that many countries in the past have run fast reactor prototypes. These include the EBRII in the United States, Phénix in France, Monju in Japan and the on-going Russian BN fast reactor programme. The Western programmes were closed down prematurely for a combination of political and technical reasons, with only the Russian effort currently continuing. The authors argue that fast breeder technology has not been more actively pursued in part because economically,
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