The trajectory taken by mainstream nuclear power reactors over the years has tended towards more powerful units with ever more layers of backup safety systems. These are complex and therefore difficult to build and eye-wateringly expensive (Hinkley Point C costs have risen from £18bn in 2016 to £22bn – £23bn in 2021). There have been several attempts to simplify nuclear power designs by introducing passive safety and reducing the lengths of pipes and number of systems.
The concept of the Small Modular Reactors (SMR) has a long history. In the UK the Safe Integral Reactor (SIR) proposed by Rolls Royce in the 1980s and 90s used PWR technology but with reduced size and the steam generator inside the main pressure vessel. This reduces the lengths of vulnerable primary circuit pipes and other external components which greatly reduces the chances of a loss of cooling accident. It also provides more effective decay heat removal by natural circulation leading to improved safety at reduced cost and complexity. Several other SMR designs were proposed at about this time (see ASME Symposium 2011).
Picking winners? In 2016 a report written for the UK government (SMR Techno-Economic Assessment Project 3 – SMRs: Emerging Technology) reviewed over 40 SMR concepts in 6 technology groups looking for those that could be deployed by around 2030 and contribute to the UK’s 2050 decarbonisation commitment. An important conclusion was that “A combination of a lack of technical maturity, together with the likely time and effort for licensing and deployment indicates that all Emerging Technologies except SM-HTGR are at least significantly challenged on ‘Time and Cost to Deployment’ relative to SM-PWRs”. This begs the question “is the UK in danger of missing a better long-term solution by placing undue emphasis on short deployment targets?”
At about the same time another report looked at Micro Nuclear Reactors (typically under 30 MW electrical) and concluded that there were no great technical barriers to their development and that the finances looked good. It suggested that two barriers existing were uncertainly in how the regulatory process will apply to such reactors and uncertainty in long term political commitment to manage a predictable nuclear industry environment.
It was concluded that Small Modular PWRs represent the least cost generation option for SMR technologies in the short or medium term. That these can provide low grade heat for district heating and some industrial processes was seen as an advantage despite no market penetration for UK nuclear in these areas. It was also concluded that emerging technologies, particularly the Small Modular – High Temperature Gas-cooled Reactor, could offer other advantages in UK energy futures where high temperature process heat is used directly to decarbonise industrial and/or transport activities. It appears that the government accepted these conclusions.
A RR SMR brochure (2017) claimed that “A Small Modular Reactor (SMR) programme represents a once in a lifetime opportunity for UK nuclear companies to design, manufacture and build next generation reactors to meet the UK’s energy needs”. They promised SMRs providing 220 MW to 440 MW, cheaper per MW than large scale reactors, low technical risk, high fraction of UK content, 1/10th the land requirement, running by 2028.
The brochure listed a several conditions that would be required:
| Condition | Apparent progress (my judgement!) |
| Selection of one preferred technology | HM Government have confirmed that they will support SM-PWR and SM-HTGR. |
| A UK industrial policy that supports UK intellectual property, advanced manufacturing and long-term high value jobs in the UK | Difficult to assess but the recent purchase by the Government of Sheffield Forgemasters is a good sign. |
| Match funding until the end of the Critical Design Review | It seems that funding has now been achieved to complete the GDA process. |
| A Generic Design Assessment (GDA) slot to ensure the process of licensing | GDA is now open to SMR and AMR designs. |
| A suitable site to develop a First of a Kind (FOAK) power station | There seems to be a view that the FOAK SM-PWR will be built on a previous nuclear power site which seems sensible. |
| A policy supporting a UK electricity market of at least 7 GWe for SMRs | Current declared strategy looks to demonstrator (FOAK) rather than fleet. We do not yet have a declared siting and policy framework. |
| Export support to reach international markets | Too soon to say |
They don’t seem to tackle the issue of who would pay for them to be built after the FOAK, who would own them, who would operate them and how they would all be paid. RR want to build and sell 7 GW electrical, they don’t want to own and operate them.
A World Nuclear Association (WNA) report (2021) discusses an aspiration for a worldwide nuclear environment where internationally accepted standardized reactor designs can be deployed without major design changes. It reports a range of different SMR designs and a wide variety of licensing processes and diversity of overall national regulatory structures. It concluded that a country’s regulatory framework is generally either heavily prescriptive and rule-driven (such as the USA) or goal- or risk-driven (such as the UK); some are a combination of both. The report seems to hold out little hope for international approval but it does provide advice on best practice on licensing reactor designs in other host countries.
A later WNA webinar about streamlining the licensing of Small Modular Reactors again spoke of the potential gains for vendors from an international approvals system but offered few ideas on how that might be achieved.
The UK Government Ten Point Plan for a Green Industrial Revolution (November 2020) suggested that the UK electricity system could double in size by 2050 as demand for low-carbon electricity in sectors such as heat and transport rises. It looked to large scale nuclear to contribute and promised to look at the future of SMR and AMRs and invest where appropriate.
A Government Energy White paper (December 2020) states that “Nuclear power provides a reliable source of low-carbon electricity. We are pursuing large-scale nuclear, whilst also looking to the future of nuclear power in the UK through further investment in Small Modular Reactors and Advanced Modular Reactors.” It reports an aim to bring at least one large-scale nuclear project to the point of Final Investment Decision by the end of this parliament (it seems to be running out of viable options with Sizewell C being based on the hard-to-build EPR, Wylfa Newydd and Moorside inactive and Bradwell B embroiled in international politics).
The White Paper also promised that “We will provide up to £385 million in an Advanced Nuclear Fund for the next generation of nuclear technology aiming, by the early 2030s, to develop a Small Modular Reactor (SMR) design and to build an Advanced Modular Reactor (AMR) demonstrator”.
The UK government has opened the Generic Design Assessment (GDA) to Advanced Nuclear Technologies and the ONR released new guidance on the process.
A public dialogue was held in early 2021 to “inform future policy development and engagement with the public”. The output does not seem to be available yet.
The UK Research and Innovation Low-cost nuclear challenge (24th May 2021) aims to develop a compact, standardised nuclear power station product based on the Rolls-Royce led SMR. It has ear-marked £215 million investment from the UK government, to be matched with £300 million investment from industry (19/11/20) with Tom Samson, the CEO of the UK SMR consortium promising “We will continue our current work and then move seamlessly into our next phase in May 2021 beyond which we can begin creating 40,000 high quality jobs, £52 billion of value to the UK economy; and targeting the £250 billion in exports”.
The government has also sought views on the potential of high temperature gas cooled reactors with the aim to have a demonstrator by the early 2030s asking if people think they have a role in the net zero CO2 target, if there is further evidence they are unaware of and how well the UK supply chain could support the programme.
A report written by the University of Manchester, Dalton Nuclear Institute supports the development of a demonstration HTGR and suggests adding hydrogen generation to the aspirations for the demonstrator. It also recommends a suitable body that is equipped and empowered to deliver the HTGR project be constituted. This, it suggests, should be complemented by an independent body “unconflicted by claims and lobbying by any particular system proposer” to maintain an ongoing UK view of developments in AMR systems, a broad-based advisory body offering the government advice on the nuclear programme.
Meanwhile Canada has a comprehensive Small Modular Reactor Action Plan resulting from a pan-Canadian effort bringing together key enablers from across Canada including the federal government, provinces and territories, Indigenous Peoples and communities, power utilities, industry, innovators, laboratories, academia, and civil society”. It comes with a statement of principles, 117 chapters written by participants and 513 tracked actions each linked back to the recommendations made in an earlier roadmap document. This is a credible programme.
In Russia Small Modular Reactors are being built for icebreakers, for floating power plant and for land-based systems. They have the KLT-40S Integral PWR which has been evolved into the RITM-200 which is smaller and lighter. This has several variants for land and floating applications (the floating applications include providing propulsion for icebreakers and providing electricity and heat for coastal communities). There are proposals for a land-based SMR at Yakutia in the Russian Far East.
China has started to build an ACP100 SMR demonstration project at the Changjiang nuclear power site in Hainan. Designed for electricity production, heating, steam production or seawater desalination the 125 MWe PWR. The plan envisages sites with 2 to 6 ACP100 reactors with a 60-year lifespan and 24-month refuelling. A floating version is also planned.
In the US NuScale power are planning to build a 6 unit site for the Utah Associated Municipal Power Systems (UAMPS) (down from the 12 units originally planned). The first module is scheduled to be operational in 2029, and the full plant in 2030. Meanwhile funding is being collected to build a demonstration Natrium reactor in Wyoming on the site of a retiring coal power station. This is a sodium cooled fast reactor with a thermal storage device allowing load following, including electrical outputs rates higher than the reactor’s power output for periods of time.
France has announced another new SM-PWR design, the “NUWARD”TM, while saying that they are “open to international cooperation, notably to foster the harmonisation of regulation, the standardisation of design and design optimisation”. (If that really was the case then why didn’t they join an existing project rather than develop their own?).
Japan is reported to be interested in developing and deploying SMR and AMR. Their aspiration is for a SMR demonstration site by 2030 and the establishment of the technology to use high temperature reactors to generate hydrogen.
This is clearly an interesting time for Small and Advanced Modular Reactors. They are being built in Russia and China, both of which see a good market. They are being developed in the USA, Canada, the UK and several other countries, seemingly with coherent government support. They are seen as an affordable route into the nuclear industry providing an opportunity to decarbonise the energy market and reduce dependence on imported fuels. We need to see continuing progress on the design and licensing of this technology, demonstrator sites for those that have not got there yet and a siting policy, financial model and operating regime that enables the full market potential to be realised. Meanwhile we can expect to see many of the systems currently under development to fall by the wayside.
The NEI Small and Advanced Reactors event (4th November 2021) will be a follow up to their virtual event held in February 2021. It will look at the development plans and licensing activities for a range of small and advanced reactor technologies from across the world. It will cover all aspects of industry, with insight from reactor developers, utilities, regulators, supply chain, academics and the financial community with sessions covering market development, manufacturing and construction, the utility view of the role of SMR/AMR, finance and economics, Fuel and progress towards demonstration plant and beyond. One to watch.