NEW YORK – Much of the world has been turning away from nuclear power, with its ageing plants, legacy of meltdowns and radioactive waste.
But some governments, big companies and billionaires including Mr Bill Gates and Mr Warren Buffett are convinced the technology can help save the planet.
Unlike wind and solar sources, nuclear power can be switched on and off at any time, and without the planet-warming emissions produced by gas and coal.
Billions of dollars in investments are going towards a new generation of so-called small modular reactors (SMRs), which ultimately could provide a safe and nimble source of carbon-free energy – if they can overcome challenges related to economics, safety and public opinion.
1. How small is small?
Of the more than 70 such reactors that the International Atomic Energy Agency lists as being in some stage of design or development, the smallest are less than 5m in diameter and 10m in height. (The plant that would be built to operate the reactor would be bigger, of course.) SMRs typically have less than 300 megawatts of generating capacity, about a third of existing reactors’. The “M” in SMR – modular – means these reactors can largely be built in factories and shipped in standardised parts for assembly on-site. That means shorter construction times and greater flexibility to expand to meet demand.
2. Why rethink reactor designs?
Since the Fukushima Daiichi meltdown in Japan in 2011, there has been a dearth of investor interest in building expensive new plants, with China, Russia and India as notable exceptions. Instead, utilities have gravitated towards carbon-intensive coal and gas plants to fill in the gaps of intermittent solar and wind resources. That has led climate advocates such as Dr James Hansen, one of the first scientists to publicly warn about the danger of global warming, to call for more nuclear energy.
3. Do SMRs already exist?
The only ones currently in commercial operation are a pair of 35-megawatt units on a floating power plant deployed by Russia in the Arctic in 2020. China expects to begin trials in 2026 on an SMR being built near an existing power plant on Hainan island. The first commercial SMR project in the United States, planned for the site of the Idaho National Laboratory, was supposed to consist of six reactors capable of producing a combined 462 megawatts and be ready by the end of this decade. But NuScale Power Corp, the only company with a licensed US design, cancelled that project in late 2023 because of rising costs.
4. Why are economics a challenge?
Cost competitiveness is an uphill climb. NuScale was aiming for an SMR that could sell power for US$55 (S$74) per megawatt-hour (MWh). But the cost of its first project ballooned to the point where a price of almost US$120/MWh would have been necessary to be viable, and the company was forced to fire more than a quarter of its workers. Wind and solar power has dropped well below US$50/MWh in many regions and could fall below US$20/MWh by the end of the decade, according to BloombergNEF. A 2020 study by professors at the University of British Columbia found that on a lifetime basis, the cost of electricity produced by SMRs could be 10 times greater than the cost of electricity produced by diesel fuel. The economics might be more favourable when considering SMRs as alternatives to large-scale batteries to serve as at-the-ready backups for solar and wind power when the sun isn’t shining or the wind isn’t blowing.
5. Who’s investing in SMRs?
Companies pushing SMR design, in addition to NuScale, include Electricite de France, China National Nuclear, Japan’s Toshiba and Russia’s Rosatom. Mr Gates and Mr Buffett have teamed up to build and test a reactor at an abandoned coal plant in Wyoming. Rolls-Royce Holdings raised £455 million (S$773.4 million) to fund the development of SMRs, with almost half of the financing coming from the British government. The Canadian and US governments have also offered hundreds of millions of dollars in subsidies to kick-start the SMR industry. India’s state-controlled nuclear power industry was considering allowing greater participation of private firms in developing SMR reactors to help curb the country’s reliance on coal. The European Commission is encouraging industry collaboration to roll out SMRs in the next decade to help meet net-zero targets.
6. Are SMRs safe?
Proponents say SMRs will be safer than earlier generations of nuclear power plants. The basic idea remains the same – splitting atoms to release energy, a process known as nuclear fission, that heats water to produce steam that spins turbines to make electricity. About half of the SMR models under development use water as a coolant, as most currently operating reactors do. Explosions at Fukushima and at Three Mile Island in the US in 1979 were caused by heat from exposed fuel rods splitting the hydrogen from the steam used to cool the reactor. Some SMR designs, by contrast, use molten salt and metals as coolants. SMR designs also integrate new kinds of fuel and backup emergency systems that should reduce the likelihood of meltdowns. On the other hand, smaller reactors would ideally be located closer to population centres, increasing the possible danger from an accident. And like their larger brethren, SMRs produce radioactive waste that must be stored safely for centuries. BLOOMBERG
