Small modular reactors (SMR) are defined as reactors with a capacity of 300 megawatts or less. “Modular” refers to the serial factory production of reactor components, which could drive down costs.
By that definition, no SMR has ever been built, none are being built now and, in all likelihood, none will ever be built because of the prohibitive costs.
But dozens of small (less than 300 MW) reactors have been built, without factory production of components.
The United States Army built and operated eight small reactors from the 1950s, but they proved unreliable and expensive and the program was shut down in 1977.
Seventeen small civilian reactors were built in the US in the 1950s and ’60s, but all have since shut down.
Twenty-six small Magnox reactors were built in Britain, but all have shut down and no more will be built.
The only operating Magnox is a mini-Magnox in North Korea: the design was made public at an Atoms for Peace conference. North Korea uses its 5 MW Magnox to produce plutonium for nuclear weapons.
India operates 14 small pressurised heavy water reactors, each with a capacity of about 200 MW.
Professor MV Ramana noted in his 2012 book, The Power of Promise: Examining Nuclear Energy in India, that despite a standardised approach to designing, constructing, and operating these reactors, many suffered cost overruns and lengthy delays.
There are no plans to build more of these small reactors in India.
Elsewhere, the history of small reactors is just as underwhelming.
This includes three small reactors in Canada (all shut down), six in France (all shut down) and four in Japan (all shut down).
Ramana concluded his history of small reactors with this downbeat assessment: “Without exception, small reactors cost too much for the little electricity they produced, the result of both their low output and their poor performance.”
Cost blow-outs
Just four SMRs are said to be operating – none meet the “modular” definition of serial factory production.
These SMRs — one twin-reactor plant in Russia and another in China — exhibit familiar problems of massive cost blowouts and multi-year delays.
The construction cost of Russia’s floating nuclear power plant rose six-fold and the Organisation for Economic Co-operation and Development’s Nuclear Energy Agency estimates that the electricity it produces costs US$200 (A$302) a megawatt-hour.
The reactor is used to power fossil fuel mining operations in the Arctic.
The other operating SMR (loosely defined) is China’s demonstration 210 MW high-temperature gas-cooled reactor (HTGR).
The World Nuclear Association said the demonstration HTGR cost $6000 (A$9060) per kilowatt, three times higher than early cost estimates and 2–3 times higher than China’s larger Hualong reactors.
NucNet reported in 2020 that China dropped plans to manufacture 20 HTGRs after levelised cost estimates rose higher than conventional large reactors.
Likewise, the World Nuclear Association said that plans for 18 additional HTGRs at the same site as the demonstration HTGR have been “dropped”.
Yet again, we have evidence that the economics of small reactors does not stack up.
SMRs under construction
Three SMRs are under construction — again with the qualification that there is nothing “modular” about these projects.
Argentina’s CAREM reactor has been a disaster. Construction began in 2014 and the National Atomic Energy Commission now hopes to complete the reactor in 2027 — nearly 50 years after the project was conceived.
The cost estimate in 2021 was $750 million for a reactor with a capacity of just 32 MW. That’s A$1.1 billion for a plant with the capacity of a handful of large wind turbines.
China began construction in 2021 of a 125 MW pressurised water reactor. According to China National Nuclear Corporation, construction costs per kilowatt will be twice that of large reactors, and levelised costs will be 50% higher than large reactors.
Russia also began building the 300 MW demonstration lead-cooled BREST fast neutron reactor in 2021. The cost estimate has more than doubled to ₽100 billion (A$1.7 billion) and no doubt it will continue to climb.
NuScale Power
The US Department of Energy (DOE) in 2012 offered up to US$452 million to cover “the engineering, design, certification and licensing costs for up to two US SMR designs”. The two SMR designs that were selected by the DOE for funding were NuScale Power and Generation mPower.
Taking its cue from the US government, the South Australian Nuclear Fuel Cycle Royal Commission in 2015 commissioned research by WSP Parsons Brinckerhoff (now WSP) on the economic potential of the same two designs.
However, NuScale recently abandoned its flagship project in Idaho. NuScale secured subsidies amounting to about $4 billion (A$6.1 billion) from the US government, comprising a $1.4 billion subsidy from the DOE and an estimated $30 per MWh subsidy in the Inflation Reduction Act.
Despite that government largesse, NuScale did not come close to securing sufficient funding to get the project off the ground.
NuScale’s most recent cost estimates were through the roof: $9.3 billion (A$14.2 billion) for a 462 MW plant comprising six 77 MW reactors. That equates to $20,100 (A$30,700) per kilowatt and a levelised cost of $89 (A$135)/MWh. Without the Inflation Reduction Act subsidy, the figure would be $119 (A$180)/MWh. That is not far short of WSP’s estimate of A$225/MWh.
To put those estimates in perspective, the Minerals Council of Australia states that SMRs will not find a market in Australia unless they can produce power at a cost of A$60–80/MWh, which is 2–3 times lower than the WSP and NuScale estimates.
NuScale still hopes to build SMRs, but the company is burning cash and heading towards bankruptcy.
Generation mPower
Generation mPower — a collaboration between Babcock & Wilcox and Bechtel — was the other SMR design prioritised by the US DOE and the South Australian royal commission. mPower was to be a 195 MW pressurised light water reactor.
The DOE announced in 2012 that it would subsidise mPower in a five-year cost-share agreement. The DOE’s contribution would be capped at $226 million, of which $111 million was subsequently paid. The following year, Babcock & Wilcox said it intended to sell a majority stake in the joint venture, but was unable to find a buyer.
Babcock & Wilcox announced in 2014 it was sharply reducing investment in mPower to US$15 million annually, citing the inability “to secure significant additional investors or customer engineering, procurement and construction contracts to provide the financial support necessary to develop and deploy mPower reactors”.
The mPower project was abandoned in 2017. The joint venture companies spent more than $375 million on the project, in addition to the DOE’s $111 million contribution.
NuScale and mPower had everything going for them: large, experienced companies; conventional light-water reactor designs; and generous government subsidies.
But they struggled to secure funding other than government subsidies.
Needless to say, non-government funding is even more difficult to secure for projects without the involvement of large companies; for projects that envisage unconventional reactors (molten salt reactors, fast neutron reactors, etc.); and for projects that haven’t secured generous government subsidies.
Other failures
Many other plans to build small reactors have been abandoned.
US company Transatomic Power was promising in 2013 that its Waste-Annihilating Molten-Salt Reactor would deliver safer nuclear power at half the price of power from conventional, large reactors.
By the end of 2018, the company had given up on its bogus “waste-annihilating” claims, run out of money and gone bust.
MidAmerican Energy gave up on its plans for SMRs in Iowa in 2013 after failing to secure legislation that would require ratepayers to partially fund construction costs.
TerraPower abandoned its plan in 2018 for a prototype fast neutron reactor in China due to restrictions placed on nuclear trade with China by the Trump administration.
The French government abandoned the planned 100–200 MW ASTRID demonstration fast reactor in 2019.
The US government abandoned consideration of “integral fast reactors” for plutonium disposition in 2015 and the British government did the same in 2019. (Plutonium disposition means destroying weapons-useable plutonium through irradiation, or treating plutonium in such a way as to render it useless in nuclear weapons.)
Given that the technical and extreme cost challenges of SMRs have been known and widely reported on for years, why does the hype continue?
[Dr Jim Green is Friends of the Earth Australia’s national nuclear campaigner.]