There’s a lot of talk about ‘small modular reactors’ (SMRs) by pro-nuclear advocates who recognise that the existing generation of large reactors has no future. However, SMRs are mostly imaginary: they are not commercially available anywhere in the world, they have been promised for decades and always seem to remain a decade away.

But because SMRs don’t exist, the nuclear industry is free to paint a completely hallucinatory picture of reactors that are fast, cheap, and pollution free. For a couple of years, the Australian Liberals and Nationals were trumpeting the NuScale SMR project in the United States, until the company cancelled the project over the open-ended costs and delays.

So join us for a deep-dive where we dig into the reality. There are some links for further resources at the bottom.

This short video looks at the realities of Small Modular Reactors the costs, current uses, the problems and why nuclear is no solution to the climate crisis.

1. What is a Small Modular Reactor?

Large reactors typically have a capacity of about 1,000 MW, whereas SMRs would have a capacity of under 300 megawatts (MW). Construction at reactor sites would be replaced with standardised factory production of reactor components (or modules) then installation at the reactor site. The term modular also refers to the option of building clusters of small reactors at the same site.

SMRs don’t have any meaningful existence. Some small reactors exist, and there are hopes and dreams of mass factory production of SMRs. But currently there is no such SMR mass manufacturing capacity, and no company, consortium, utility or national government is seriously considering betting billions building an SMR mass manufacturing capacity.

None of the operating or under-construction SMRs meet the ‘modular’ part of the SMR definition: there is no factory production of reactor components / modules. All of them are years behind schedule. The real-world experience to date strongly suggests that SMRs will replicate the experience with large reactors with regards to massive cost-escalations and lengthy delays.

2. Are a lot of SMRs being built?

No private-sector SMR projects have reached the construction stage. A handful of SMRs are under construction, by state nuclear agencies in Russia, China and Argentina. Most or all of them are over-budget and behind schedule. None are factory built (the essence of the concept of modular reactors). They could not even be called prototype SMRs since there are no plans to mass produce more of them.

Alarmingly, about half of the SMRs under construction are intended to facilitate the exploitation of fossil fuel reserves in the Arctic, the South China Sea and elsewhere. Moreover there are disturbing, multifaceted connections between SMR projects and nuclear weapons proliferation.

The Generation mPower SMR project in the US was abandoned in 2017 by Bechtel and Babcock & Wilcox after the expenditure of US$500 million ‒ including a US$111 million federal government grant.

Transatomic Power gave up on its molten salt reactor R&D in 2018.

Westinghouse sharply reduced its investment in SMRs after failing to secure US government funding. Westinghouse CEO Danny Roderick said: “The problem I have with SMRs is not the technology, it’s not the deployment − it’s that there’s no customers.”

Warren Buffet’s MidAmerican Energy gave up on its plans for SMRs in Iowa after failing to secure legislation that would force rate-payers to part-pay construction costs. Instead, MidAmerican has invested over US$10 billion in renewables in Iowa and is now working towards its vision “to generate renewable energy equal to 100 percent of its customers’ usage on an annual basis.”

In the UK, Rolls-Royce scaled back its SMR investment to “a handful of salaries” in 2018 and threatens to abandon its R&D altogether unless massive government funding is provided and a suite of demands are met.

TerraPower abandoned its plan for a prototype fast neutron reactor in China due to restrictions placed on nuclear trade with China by the Trump administration.

The UK government abandoned consideration of ‘integral fast reactors’ for plutonium disposition in 2019 and the US government did the same in 2015.

3. What does industry say about SMRs?

The 2017 Lloyd’s Register report based on the insights of almost 600 professionals and experts from utilities, distributors, operators and equipment manufacturers. They predict that SMRs have a “low likelihood of eventual take-up, and will have a minimal impact when they do arrive”.

Likewise, American Nuclear Society consultant Will Davis said in 2014 that the SMR “universe is rife with press releases, but devoid of new concrete.”

A 2014 report produced by Nuclear Energy Insider, drawing on interviews with more than 50 “leading specialists and decision makers”, noted a “pervasive sense of pessimism” resulting from abandoned and scaled-back SMR programs.

Dr. Ziggy Switkowski ‒ who headed the Howard Government’s nuclear review in 2006 ‒ noted in 2019 that “nobody’s putting their money up” to build SMRs and “it is largely a debate for intellects and advocates because neither generators nor investors are interested because of the risk.” Moreover “the window for gigawatt-scale nuclear has closed”, Dr. Switkowski said, and nuclear power is no longer cheaper than renewables with costs rapidly shifting in favour of renewables.

World Finance reported in October 2018 that “while SMRs are purported to be the key to transforming the nuclear sector, history has painted a troubling picture: SMR designs have been in the works for decades, but none have reached commercial success.”

Former World Nuclear Association executive Steve Kidd wrote about SMR “myths” in 2015:

“The jury is still out on SMRs, but unless the regulatory system in potential markets can be adapted to make their construction and operation much cheaper than for large LWRs [light-water reactors], they are unlikely to become more than a niche product. Even if the costs of construction can be cut with series production, the potential O&M [operating and maintenance] costs are a concern. A substantial part of these are fixed, irrespective of the size of reactor.”


4. Aren’t SMRs more efficient than large reactors?

SMRs would be less efficient than large reactors in every respect, and hence more costly.

A 2016 European Commission report notes that decommissioning and waste management costs of SMRs “will probably be higher than those of a large reactor (some analyses state that between two and three times higher).”

The 2016 South Australian Nuclear Fuel Cycle Royal Commission report stated: “SMRs have lower thermal efficiency than large reactors, which generally translates to higher fuel consumption and spent fuel volumes over the life of a reactor.”

Prof. M.V. Ramana notes that “a smaller reactor, at least the water-cooled reactors that are most likely to be built earliest, will produce more, not less, nuclear waste per unit of electricity they generate because of lower efficiencies.”


5. What about the costs of SMRs?

Estimated construction costs for Russia’s floating plant increased more than four-fold and amounted to over US$10.6 billion per gigawatt (GW) (US$740 million / 70 MW). An OECD Nuclear Energy Agency report said that electricity produced by the Russian floating plant is expected to cost about US$200 (A$258) per megawatt-hour (MWh), with the high cost due to large staffing requirements, high fuel costs, and resources required to maintain the barge and coastal infrastructure.

Cost estimates for the CAREM SMR under construction in Argentina have ballooned. In 2004, when the CAREM reactor was in the planning stage, Argentina’s Bariloche Atomic Center estimated an overnight cost of US$1 billion / GW for an integrated 300 MW plant. When construction began in 2014, the estimated cost was US$17.8 billion / GW (US$446 million for a 25-MW reactor). By April 2017, the cost estimate had increased to US$21.9 billion / GW (US$700 million with the capacity uprated from 25 MW to 32 MW). Construction of the CAREM reactor was suspended in 2019 due to a ‘financial breakdown’ but construction resumed in 2020. The CAREM project is years behind schedule and costs will likely increase further. In 2014, first fuel loading was expected in 2017 but the project remains incomplete as of March 2021.

The estimated construction cost of China’s 210 MW demonstration high-temperature gas-cooled reactor (HTGR) has nearly doubled, with increases due to higher material and component costs, increases in labour costs, and increased costs associated with project delays. Plans for additional HTGRs at the same site have been “dropped” according to the World Nuclear Association. China reportedly plans to upscale the design to 655 MW but China’s Institute of Nuclear and New Energy Technology at Tsinghua University expects the cost of a 655 MW HTGR to be 15-20 percent higher than the cost of a conventional 600 MW PWR.

6. Aren’t SMRs cheaper than large reactors?

The Minerals Council of Australia has acknowledged that there will be no market for SMRs unless costs can be reduced to A$60‒80 / MWh, but the cost for power from Russia’s so-called SMR is A$300 / MWh, the latest estimate from US company NuScale was A$189 / MWh, and research commissioned by the 2015/2016 South Australian Nuclear Fuel Cycle Royal Commission estimated a cost of A$225 / MWh for SMRs. There isn’t one chance in a million that costs could be reduced to A$60‒80 / MWh.

CSIRO’s GenCost 2023‒24 report provides the following levelised cost estimates:

Nuclear SMRA$382‒636 / MWhA$212‒353 / MWh
90% wind and solar supply to the National Electricity Market with integration costs included (energy storage and transmission)A$91‒130 / MWhA$69‒101 / MWh

SMRs will inevitably suffer diseconomies of scale: a 250 MW SMR will generate 25 percent as much power as a 1,000 MW reactor, but it will require more than 25 percent of the material inputs and staffing, and a number of other costs including waste management and decommissioning will be proportionally higher.

It is highly unlikely that potential savings arising from standardised factory production will make up for those diseconomies of scale. Cost reductions arising from mass production of SMRs are entirely speculative. Cost increases arising from diseconomies of scale are certain ‒ they are built into the very concept of SMRs.

A 2015 report by the International Energy Agency and the OECD Nuclear Energy Agency predicts that electricity costs from SMRs will typically be 50−100 percent higher than for current large reactors.

An article by four current and former researchers from Carnegie Mellon University’s Department of Engineering and Public Policy, published in 2018 in the Proceedings of the National Academy of Science, considered options for the development of an SMR market in the US. They concluded that it would not be viable unless the industry received “several hundred billion dollars of direct and indirect subsidies” over the next several decades “since present competitive energy markets will not induce their development and adoption.”

7. But other groups say SMRs are cheaper?

Nuclear companies and lobbyists spread misinformation about SMR economics.

The Minerals Council of Australia (MCA) claims “robust estimates” using “conservative assumptions” indicate SMRs will produce power at a cost of A$64‒77 / MWh by 2030. However, the “robust estimates” using “conservative assumptions” are from companies that haven’t built a single SMR between them. Describing estimates provided by sources with a direct interest in a project as “independent” is dishonest.

The MCA bolsters its SMR cost claims with reference to the Energy Information Reform Project (EIRP), which purports to have conducted a ‘standardized cost analysis of advanced nuclear technologies in commercial development.’ In fact, the EIRP study simply collates company estimates and presents them with this qualification: “There is inherent and significant uncertainty in projecting NOAK [nth-of-a-kind] costs from a group of companies that have not yet built a single commercial-scale demonstration reactor, let alone a first commercial plant.”

The MCA, in its submission to the 2019 federal parliamentary nuclear inquiry, claimed SMRs could generate electricity for as little as A$60 / MWh, based on a report by the Economic and Finance Working Group (EFWG) of the Canadian ‘SMR Roadmap’ initiative. However, the MCA is selective in its use of the EFWG estimates: among the many estimates it excludes is the C$162.67 (A$180) / MWh estimate for power from a first-of-a-kind 300 MW on-grid SMR or, at the upper end, the estimate of C$894.05 (A$987) / MWh for power from a first-of-a-kind 3 MW remote community SMR.

In April 2024, Rolls-Royce claimed it could build a 470-megawatt reactor in Australia for A$3.5‒5 billion, as reported in The Australian. That equates to A$7.4-10.6 billion / GW. For comparison, this table compares Rolls-Royce’s claim with NuScale’s latest SMR cost estimate, with Hinkley Point (the only construction project in the UK), and with the Vogtle project in the US (the only project to have begun and completed construction in the US this century):

Rolls-RoyceA$7.4-10.6 billion / GW
NuScale SMRA$30.3 billion / GW
Hinkley Point (UK)A$27.2 billion / GW
Vogtle (USA)A$23.4 billion / GW

It is implausible that Rolls-Royce could build an SMR for as little as one quarter of the cost (per gigawatt) of the NuScale SMR proposal or one third of the cost of large reactor projects in the UK or the US. At this stage, Rolls-Royce does not even have a licensed design, let alone an operating SMR. Its cost claims should be seen in that context. Rolls-Royce’s progress with SMRs in the UK is heavily dependent on taxpayer subsidies (as it would be in Australia) and it is far from certain to proceed to construction.

8. The Royal Commission’s final report identified numerous hurdles and uncertainties facing SMRs, including the following:

The Royal Commission further stated in its final report:

“Advanced fast reactors and other innovative reactor designs are unlikely to be feasible or viable in the foreseeable future. The development of such a first-of-a-kind project in South Australia would have high commercial and technical risk. Although prototype and demonstration reactors are operating, there is no licensed, commercially proven design. Development to that point would require substantial capital investment.”


9. Resources and articles: