Allison Macfarlane, who was Chair of the US Nuclear Regulatory Commission (NRC) from 2012-2014, has been looking at Small Modular Reactors in the USA and elsewhere. She thinks they are likely to be uneconomic, much like the their larger brethren, which, as she describes, have recently been doing very poorly in the USA.
Indeed, just like the EPR story in the EU, it makes for a sorry saga: ‘The two units under construction in South Carolina were abandoned in 2017, after an investment of US$9 billion. The two AP-1000 units in Georgia were to start in 2016/2017 for a price of US$14 billion. One unit started in April, 2023, the second unit promises to start later in 2023. The total cost is now over US$30 billion.’
Big reactors do look increasingly hard to fund and build on time and budget, while it is argued that smaller ones could be mass produced in factories at lower unit costs and finished units installed on site more rapidly. However, that would mean foregoing conventional economies of (large) scale, and, overall, Macfarlane claims that SMRs may end up being worse that large plants in operational and economic terms. For example, she says ‘one of the reasons SMRs will cost more has to do with fuel costs’ with some designs requiring ‘high-assay low enriched uranium fuel (HALEU), in other words, fuel enriched in the isotope uranium-235 between 10-19.99%, just below the level of what is termed “highly enriched uranium,” suitable for nuclear bombs.’ She notes that ‘currently, there are no enrichment companies outside of Russia that can produce HALEU, and thus the chicken-and-egg problem: an enrichment company wants assurance from reactor vendors to invest in developing HALEU production. But since commercial-scale SMRs are likely decades away, if they are at all viable, there is risk to doing so.’
She also notes that the use of HALEU, so as to offset the smaller size of the reactor core, will ‘result in increased security and safeguards requirements that will add to the price tag’. As she has explored in a PNAS paper with others, smaller cores mean more neutron escapes and so a need for more shielding, which will become activated, adding to the waste burden to be dealt with. Indeed she says, overall, some SMRs may produce ‘significantly more high-level waste by volume that current light water reactors.’ That view did not go down well with SMR promoters, who sometimes portray SMRs as being cleaner than standard reactors.
Some advanced SMRs may use molten salt fluids as a reactant and also coolant, and the waste chemistry then is different, although there will still be wastes to deal with. But for the moment, the focus is on simpler technology - just scaled down versions of the standard Pressurised Water Reactor (PWR). Macfarlane notes that one of these, NuScale, is the only SMR design to received ‘design certification’ for its 50MW unit from the NRC. However, the company has now decided to submit a new application to the NRC to build a larger version, presumably in the expectation that this would be more economic. It’s also proposed to have multiple units on one site, sharing some common services. That might offset some of the extra costs of small systems, but not much. Macfarlane says ‘cost estimates for the reactor have risen from US$55/megawatt electric (MWe) in 2016 to $89/MWe in 2023, according to the Institute for Energy Economics and Financial Analysis.’
Arguably, to be economic, they need to be bigger. That seems to have been the logic behind another mini-PWR, the Rolls Royce SMR being developed in the UK by Rolls Royce. Although at 470MW, that one is hardly ‘small’. By contrast, Oklo, another US company, is going in the opposite direction. It has been developing Auora, an advanced micro-nuclear power plant. It’s a tiny (1.5 MW) liquid sodium cooled fast neutron reactor. However, it was outright rejected by the NRC. Macfarlane says that ‘the NRC rarely outright rejects an application, instead working with licensees until they either get the application right or decide to walk away. In this case, Oklo refused to fill “information gaps” related to “safety systems and components.’ But Oklo persevered. And she notes it has gone for public finance via a merger with AltC Acquisition Corporation.
It all fits into what see she see as an emerging pro-SMR mind set, with there being a lot of speculative investment venture cash still around- and a lot of press support. She says that though ‘very few of the proposed SMRs have been demonstrated and none are commercially available, let alone licensed by a nuclear regulator’, the media has been promoting them as the way ahead. Even usually sane US outlets like the Atlantic Policy journal seem to have joined in. She says we now have ‘an echo chamber, with each outlet clambering over the next to crow about the great benefits of nuclear power in misleading language that suggests this technology is already entirely proven out’. So she concludes, a bit pessimistically, that, in the USA, ‘in the nuclear celebratory mood of the moment, there is little patience or political will for sober voices to discuss the reality that new nuclear power is actually many decades away from having any measurable impact on climate change – if at all’.
The situation in Europe is a bit different. Although nuclear is also being supported in some countries, like the UK and France, anti-nuclear views are also apparent. For example a recent academic paper in Joule claims that ‘relying on nuclear new-builds to achieve the EU climate targets is virtually impossible.’ And overall it concludes ‘in solving the climate crisis, new nuclear is a costly and dangerous distraction.’ Whereas SMRs will be any better is unclear. There are quite a few speculative SMR ventures around the world, as a UK review noted, but a recent study of 19 proposed SMR designs found that they were likely to be generally more expensive than conventional nuclear, and even more so than renewables. So, why bother?
As Macfarlane says, the battle lines are drawn on this issue around the world, with much of it being a PR battle - there is no real hardware yet. While the likes of Forbes magazine are pushing SMRs as the ‘go-to energy source’, in a hard hitting article in Fortune, Stephanie Cookes says ‘the billions currently being spent on nuclear are crowding out viable, less costly solutions for decarbonizing the power sector.’
Place your bets…but, for some, the outcome already looks clear. As David Schlissel said in US trade journal Utility Drive, ‘an old adage is that anything that sounds too good to be true probably is. Given the history of the nuclear power industry, everyone - utilities, ratepayers, legislators, federal officials and the general public - should be very skeptical about the industry’s current claim the new SMRs will cost less and be built faster than previous designs.’
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