Bill bets on nuclear

by Laura Chevrot, GLOBUS Correspondent

The topic of cleaner energy is becoming increasingly relevant. As of today, over 113 countries including the United Kingdom have committed to carbon neutrality by 2030. Attention has turned towards alternative energies such as wind, solar and electric power to achieve net zero emissions. But these technologies have their downsides as well. Wind power is expensive, can cause aesthetic pollution and impact local wildlife.  Solar panels are costly, weather dependant, and are produced using toxic products and key minerals, simultaneously raising concerns about human rights in mining supply chains. Both solar and wind energy require vast amounts of land to operate.

As the climate crisis escalates, a well-renown entrepreneur and philanthropist has committed to solving issues of sustainability and poverty-reduction. Bill Gates, the co-founder and former CEO of Microsoft, has now embarked on a mission to find the most efficient form of carbon-free energy. His conclusion that nuclear technology is one, if not the only way to tackle the climate crisis is surprising to most. Yet it is reasoned. Since 2006, Bill Gates has been working to revive enthusiasm regarding nuclear power. He founded Terrapower, a company aiming to develop safe, clean and affordable nuclear powerplants.

The result of many years of research is a powerplant equipped with an innovative technology: a Travelling Wave Reactor. This reactor is designed to ‘consume uranium resources in a more efficient, cleaner, and safe manner than current nuclear technology’. The idea behind the Travelling Wave Reactor is to drastically reduce the amount of uranium waste derived from nuclear fission. Traditional reactors burn U235, which represents 0.7% of the uranium mined and used for nuclear fission. The remaining 99% of uranium (U238) mined, which isn’t fissile, is stored as radioactive waste underground. Terrapower’s reactor is capable of converting U238 into Pu-239 (Plutonium 239) which is fissile. The plutonium is then burnt, meaning that all the uranium mined is used in fission. The reactor could be fuelled by uranium currently stored underground, and then would continually reuse the waste it creates. To advocate for his project, Gates emphasises the fact that there is enough radioactive waste in Paducah, Kentucky to power the United States for two centuries using Travelling Wave Reactors. The design would also minimise costs, since reactors are usually powered by expensive fuel.

The cost of fuel also has impacts on the way in which traditional reactors are operated. In traditional powerplants, fuel is pumped into the reactor in little amounts because it is expensive. This mobilises many operators at once and is a delicate operation which can easily go wrong. Terrapower’s technology only requires the reactor to be refuelled every 60 years.  The conversion of U238 would also avoid transporting large amounts of waste across the globe. Gates is convinced that the Travelling Wave Reactor, if implemented correctly, could produce an entirely safe form of nuclear power.

Other efforts have been made at producing nuclear power safely. NuScale, a company based in Portland, Oregon, has opted for a Small Modular Reactor. Twelve reactors, taking up 1% of the space of a conventional reactor each, are stacked side by side to generate 60 megawatts of power as opposed to the traditional gigawatt provided by traditional reactors. This would lower costs, since each reactor could be built in a factory, and is safer, because reactors would be placed in separate pools of water and reinforced by separate security systems. Water is used in two ways in most nuclear reactors. It is brought to boil through heat produced by nuclear fission and converted into energy, but it is also used to cool the radioactive core. In the NuScale design, having reactors in separate pools ensures that the amount of heat generated by each core isn’t excessive. NuScale has also simplified the design of the reactors, meaning that accidents are less likely to occur. 

Although NuScale’s a design decreases the chance of accidents, it still relies on traditional technology, which has been proven dangerous. At Fukushima, in 2011, a tsunami cut the power supply enabling the cooling of three reactors, which melted in three days. It took two weeks to stabilise the reactors with water and four months for cooling to resume. Evidence points to the fact that Fukushima still houses radioactive debris, nine years after the catastrophe. This is where Terrapower’s plan is unique. The Travelling Wave Reactor could be combined with another one of their technical innovations, the Molten Chloride Reactor, which uses molten chloride instead of water to cool the radioactive cores. We all know that when water is heated at very high temperatures, it evaporates. The same goes for traditional reactors. As the water cooling the core evaporates due to the heat radiated from the core, operators need to keep pumping water into the cooling pools. During an incident like Fukushima, power supply is shut off and water stops being pumped into the pools, meaning that the water gradually heats up and stops cooling the core. Molten chloride, however, operates at very high temperatures, so it is safer than a water coolant. In the case of a power cut, the molten chloride still cools the reactor. Before the molten chloride reaches a critical heating point, the reactor shuts off without operator intervention, the process is halted, and heat from the core is disseminated through the air naturally. In Gates’ words, “the worst case is that the reactor stops generating electricity, not that any of the radioactive materials get out”.

Terrapower’s design has been tested using super-computers and although it seems like a plausible alternative to traditional reactors, the company has run into some technical issues, and is failing to mobilise enthusiasm for the project. Deteriorating state relations with China have also cut Terrapower’s plans for a joint venture with China National Nuclear Corp. short.

In an age where many believe “nuclear energy has no place in a safe, clean, sustainable future”, Terrapower has rebranded nuclear as potential solution to the energy crisis. However, the debate remains open. Would we be ready to risk another nuclear catastrophe in the hope that Terrapower’s reactor really is the game changer Gates wants it to be? Is focus on the “new nuclear” simply deterring our attention from much needed research in renewables? More than that, would promoting a technological miracle as a solution to the climate crisis distract us from a much-needed global effort to reduce emissions? Bill Gates focuses on what he does best; he invents. Yet are we to achieve sustainability through invention, or through a systematic change of our current lifestyles?

For more about Bill Gates and Terrapower see Episode 3 of the Netflix original series, Inside Bill’s Brain (2019).

Header image by Mick Truyts, via Unsplash

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