17 Feb 2022 by James McKenzie
James McKenzie thinks that small modular nuclear reactors could help many countries to meet their “net-zero” emissions targets
Mention “nuclear power” and attention almost immediately turns to safety. Despite huge advances in nuclear technology in recent decades, everyone still thinks about the accidents that occurred at older reactors like Chernobyl, Three Mile Island or Fukushima. Safety – and the politics surrounding it – remains the single biggest issue influencing the development of nuclear power around the world.
Dozens of countries don’t even have – or don’t want – nuclear power. Some have nuclear but are phasing it out. Germany, for example, closed three of its six remaining nuclear plants on 31 December 2021, which together accounted for 6% of the country’s electricity. The other three will shut down later this year, with much of the shortfall in the short term being made up by burning natural gas.
A lot of attention is turning to smaller and potentially safer “modular” reactors that are, in principle, quicker and cheaper to build.
For many, however, nuclear power is starting to look like an acceptable solution to reach net zero. According to the International Atomic Energy Agency (IAEA), there are currently 443 nuclear fission plants operating around the world, with a further 50 under construction in 19 countries. Most of these reactors are “big nuclear” plants producing more than 1 gigawatt of electricity (GWe), each taking decades and billions of dollars to build.
However, fission is a very scalable technology and a lot of attention is turning to smaller and potentially safer “modular” reactors that are, in principle, quicker and cheaper to build. So could these reactors, which are defined as having a typical output of 300 MWe, be part of the answer to delivering carbon-free energy to meet the doubling of demand that is predicted in coming years?
A burgeoning market
According to market-research firm Allied Market Research, the world-wide market for small modular reactors (SMRs) was worth $3.5bn in 2020 and is projected to reach $18.8bn by the end of the decade. Apart from being small and cheap, the big advantage of SMRs is that they are designed to be built in factories and then transported in modules to sites for installation. Here in the UK, the government has already earmarked up to £215m for SMRs as part of a larger Advanced Nuclear Fund to invest in the next generation of nuclear.
One firm getting in on the act is Rolls-Royce, which last November said it was setting up the Rolls-Royce Small Modular Reactor (RR-SMR) business unit, following a £195m cash injection from private firms and a £210m government grant. Costing about £2bn, each of its 470 MWe SMRs would be able to power a million homes. Rolls-Royce sees the approach as low risk as light-water reactors are a mature technology with a proven track record.
In fact, SMRs have a decent and predictable LCOE (levelized cost of electricity) value, which is a measure of the average net cost, in today’s money, of generating electricity from a plant over its entire lifetime. LCOEs are used for investment-planning purposes to compare different methods of electricity generation on a consistent basis. If approved for use in the UK, Rolls-Royce could build up to 16 reactors, generating £250bn in export sales. The programme could create 40,000 new jobs by 2050.
In addition to providing a stable, base load of power, SMRs would give us the energy to make “green” hydrogen.
In addition to providing a stable, base load of power, SMRs would give us the energy to make “green” hydrogen, thereby supporting the path to net-zero and the decarbonization of transport. But SMRs are just one part of a wider programme of advanced nuclear reactors. Indeed, the IAEA has a database of 72 different designs. Some are hugely innovative using advanced fuels, breeder technology and various cooling strategies to slash construction and operation costs, while addressing safety and non-proliferation issues.
Powerful stuff
Over in the US, TerraPower, a start-up co-founded in 2008 by Bill Gates, has chosen Kemmerer – a former coal town in Wyoming – as the preferred site for its new “Natrium” fission reactor. It would use liquid sodium both to cool the reactor and store energy. With a power output of 345 MWe that can be boosted during peak demand to 500 MWe, a prototype could be complete by 2028. The company ultimately hopes to sell its reactors for $1bn a pop.
TerraPower is also working on “travelling wave reactor” (TWR) technology. This proposed fission reactor would convert fertile material (in the reactor) into usable fissile fuel, while at the same time burning up any unwanted fissile material. TWRs use fuel efficiently without high levels of uranium enrichment or reprocessing, instead directly using depleted uranium, natural uranium or even, potentially, spent fuel.
There are even ultra-compact, “micro-reactors”, some of which could be transported on a truck.
The concept is still being developed – no TWRs have ever been built. But to me it’s an exciting prospect. TerraPower claims its TWR could use mined uranium 30 times more efficiently. And with all the fuel staying in the reactor until it’s used up, the firm says its technology has none of the safety and proliferation concerns that arise with reprocessing used fuel. Given existing global stockpiles of depleted uranium, TerraPower reckons that its TWRs could power the planet for at least a thousand years.READ MORESmall modular nuclear reactors are a crucial technology, says report
There are even ultra-compact, “micro-reactors” being designed with outputs of 1–20 MWe, some of which could be transported on a truck. These new designs include the U-Battery from Urenco and partners as well as the eVinci by Westinghouse. They could be used, say, to produce heat (for industrial applications like steel making), to power remote communities, to serve as back-up for the main electricity grid or even to help disaster-relief efforts.
The speed at which any of these technologies are developed will, of course, be slowed by essential safety regulations and uncertain market demand. The usual approach taken by start-up companies – build your best prototype and then see what happens – isn’t feasible with nuclear as mistakes are likely to be expensive, long-lasting and damaging for the environment. But with the right regulatory approach, SMRs could be a key part of the global net-zero plan, delivering the carbon-free power we so desperately need.
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