Dr Jim Green dissects the hype surrounding Small ”Modular” Nuclear Reactors.

 Nuclear power’s economic failure, Ecologist, Dr Jim Green, 13th December 2021     Small modular reactors

Small modular reactors (SMRs) are heavily promoted but construction projects are few and far between and have exhibited disastrous cost overruns and multi-year delays.

It should be noted that none of the projects discussed below meet the ‘modular’ definition of serial factory production of reactor components, which could potentially drive down costs.

Using that definition, no SMRs have ever been built and no country, company or utility is building the infrastructure for SMR construction.

In 2004, when the CAREM SMR in Argentina was in the planning stage, Argentina’s Bariloche Atomic Center estimated a cost of US$1 billion / GW for an integrated 300 MW plant (while acknowledging that to achieve such a cost would be a “very difficult task”).

Now, the cost estimate for the CAREM reactor is a mind-boggling US$23.4 billion / GW (US$750 million / 32 MW). That’s a truckload of money for a reactor with the capacity of two large wind turbines. The project is seven years behind schedule and costs will likely increase further.

Russia’s floating plant

Russia’s floating nuclear power plant (with two 35 MW reactors) is said to be the only operating SMR anywhere in the world (although it doesn’t fit the ‘modular’ definition of serial factory production).

The construction cost increased six-fold from 6 billion rubles to 37 billion rubles (US$502 million).

According to the OECD’s Nuclear Energy Agency, electricity produced by the Russian floating plant costs an estimated US$200 / MWh, with the high cost due to large staffing requirements, high fuel costs, and resources required to maintain the barge and coastal infrastructure.

The cost of electricity produced by the Russian plant exceeds costs from large reactors (US$131-204) even though SMRs are being promoted as the solution to the exorbitant costs of large nuclear plants.

Climate solution?

SMRs are being promoted as important potential contributors to climate change abatement but the primary purpose of the Russian plant is to power fossil fuel mining operations in the Arctic.

A 2016 report said that the estimated construction cost of China’s demonstration 210 MW high-temperature gas-cooled reactor (HTGR) is about US$5 billion / GW, about twice the initial cost estimates, and that cost increases have arisen from higher material and component costs, increases in labour costs, and project delays.

The World Nuclear Association states that the cost is US$6 billion / GW.

Those figures are 2-3 times higher than the US$2 billion / GW estimate in a 2009 paper by Tsinghua University researchers.

China reportedly plans to upscale the HTGR design to 655 MW but the Institute of Nuclear and New Energy Technology at Tsinghua University expects the cost of a 655 MW HTGR will be 15-20 percent higher than the cost of a conventional 600 MW pressurised water reactor.

HTGR plans dropped

NucNet reported in 2020 that China’s State Nuclear Power Technology Corp dropped plans to manufacture 20 HTGR units after levelised cost of electricity estimates rose to levels higher than a conventional pressurised water reactor such as China’s indigenous Hualong One.

Likewise, the World Nuclear Association states that plans for 18 additional HTGRs at the same site as the demonstration plant have been “dropped”.

In addition to the CAREM reactor in Argentina and the HTGR in China, the World Nuclear Association lists just two other SMR construction projects.

In July 2021, China National Nuclear Corporation (CNNC) New Energy Corporation began construction of the 125 MW pressurised water reactor ACP100.

According to CNNC, construction costs per kilowatt will be twice the cost of large reactors, and the levelised cost of electricity will be 50 percent higher than large reactors.

Fast reactor

In June 2021, construction of the 300 MW demonstration lead-cooled BREST fast reactor began in Russia.

In 2012, the estimated cost for the reactor and associated facilities was 42 billion rubles; now, the estimate is 100 billion rubles (US$1.36 billion).

Much more could be said about the proliferation of SMRs in the ‘planning’ stage, and the accompanying hype.

For example a recent review asserts that more than 30 demonstrations of different ‘advanced’ reactor designs are in progress across the globe.

In fact, few have progressed beyond the planning stage, and few will. Private-sector funding has been scant and taxpayer funding has generally been well short of that required for SMR construction projects to proceed.


Large taxpayer subsidies might get some projects, such as the NuScale project in the US or the Rolls-Royce mid-sized reactor project in the UK, to the construction stage.

Or they may join the growing list of abandoned SMR projects:

* The French government abandoned the planned 100-200 MW ASTRID demonstration fast reactor in 2019.

* Babcock & Wilcox abandoned its Generation mPower SMR project in the US despite receiving government funding of US$111 million.

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

* MidAmerican Energy gave up on its plans for SMRs in Iowa in 2013 after failing to secure legislation that would require rate-payers to partially fund construction costs.

* 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.


So we have a history of failed small reactor projects.

And a handful of recent construction projects, most subject to major cost overruns and multi-year delays.

And the possibility of a small number of SMR construction projects over the next decade.

Clearly the hype surrounding SMRs lacks justification.

Moreover, there are disturbing, multifaceted connections between SMR projects and nuclear weapons proliferation, and between SMRs and fossil fuel mining.

Hype cycle

Dr Mark Cooper connects the current SMR hype to the hype surrounding the ‘nuclear renaissance’ in the late 2000s:

“The vendors and academic institutions that were among the most avid enthusiasts in propagating the early, extremely optimistic cost estimates of the “nuclear renaissance” are the same entities now producing extremely optimistic cost estimates for the next nuclear technology. We are now in the midst of the SMR hype cycle.

* Vendors produce low-cost estimates.

* Advocates offer theoretical explanations as to why the new nuclear technology will be cost competitive.

* Government authorities then bless the estimates by funding studies from friendly academics.”  ………………. https://theecologist.org/2021/dec/13/nuclear-powers-economic-failure

One Response to “Dr Jim Green dissects the hype surrounding Small ”Modular” Nuclear Reactors.”

  1. Sebastian Geske Says:

    Very well written. I like it very much.

    I wrote a review myself: https://bit.ly/3sRxXWZ

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