Small Modular Reactors and Advanced Modular Reactors – State of Play

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.



IAEA Technology Roadmap for Small Modular Reactor Deployment

IAEA Nuclear Energy Series, No. NR‑T‑1.1

Technology Roadmap for Small Modular Reactor Deployment

We hear a lot about the potential for Small Modular Reactors, Advanced Modular Reactors and microreactors to provide reliable, affordable, low carbon energy to produce electricity, district heat, industrial heat and hydrogen, including in places where grids cannot reach but, other than in China and Russia where they are getting on with the job, generally the discussion is about getting to the demonstrator (or First of a Kind (FOAK)) rather than beyond.

The stated objective of this paper by the IAEA, drafted by an international group over a series of meetings, “is to present several model technology roadmaps to Member States which can be adapted to their specific projects”. The guidance “describing good practices, represents expert opinion but does not constitute recommendations made on the basis of a consensus of Member States”. It is notable that no one from RR, ONR or BEIS was on this group.

The authors keep interrupting the narrative about how to plan for the deployment of SMRs with seemingly random sections reviewing the state of play with various designs across the world and the history of the field.

The paper is apparently aimed at:

  • owners/operating organizations, who drive the demand and requirements for reactor designs;
  • designers, who develop the technologies; and
  • regulators, who establish and maintain the regulatory requirements that need to be met by owners/operating organizations.

Technology roadmaps, we are told, “are part of a methodology that guarantees the alignment of investments in technology and the development of new capabilities. A proven management tool, technology roadmaps are used for identifying, evaluating, communicating and promoting the development of complex technology projects”. One aim is to increase the chances of passing well known pitfalls where failure is more likely (Figure from IAEA NR-T-1.18).

The first pitfall is the potential failure of the R&D to satisfactorily addressed all technology gaps to enable the construction of a reliable prototype or the performance of an important proof of concept test. (I think that technically competent reactor designs fail at this stage due to a lack of funds to continue). The second is commercial; is the technology reliable, accepted by the regulator and cost competitive against its alternatives?

The operation of an SMR or a fleet of SMRs requires national soft and hard infrastructure such as:

  • Physical facilities for the delivery of electricity [or heat];
  • Site and supporting facilities for handling and disposing of radioactive waste;
  • Legal, regulatory and policy framework;
  • Financial resources necessary to implement the required activities;
  • Trained human resources.

In fact, the paper recognises 19 infrastructure issues (Table 2 of report). This is a useful list. Civil servants looking at government support for this technology should review this list to see if it identifies any expensive or difficult hurdles.

One of the issues with SMRs is the potential for them to be built rapidly – several a year – with the potential for deployment in countries other than those in which they were designed and built. These two factors present a challenge to site licencing which is much discussed.

For countries that already have a nuclear industry the hosting of a SMR or fleet of SMRs should not pose great legal, regulatory or infrastructure issues although the siting requirements may need further consideration as with potentially reduced emergency planning zones and less cooling water requirements these plants can go on a wider range of sites. It would also be necessary to consider the county’s ability to manage the fuel cycle and waste produced by the SMRs if they differ from the existing fleet. The paper gives an update on progress in several countries.

For countries without an existing nuclear industry the IAEA has outlined an approach in an earlier paper (Milestones in the Development of a National Infrastructure for Nuclear Power, IAEA Nuclear Energy Series No. NG‑G‑3.1 (Rev.1)). This involves stages before a knowledgeable commitment can be made to nuclear power; before they are ready to invite bids from suppliers and before they are ready to commission and operate the first power station. Each of these stages are discussed.

It is interesting to consider how this might apply to the Russian concept of floating power stations where the extreme view could be that the licensing, safety and fuel cycle issues are all managed by the Russian company to their national standards and the host country has an electric cable running into from offshore. How different is this to a French PWR providing power to the UK via a cable running under the English Channel?

Section 3 of the report is a review of the prospects for SMR technology which the IAEA rate as promising. Section 3.2.4 seems to suggest that public are certain to accept the technology because it is the only way to hit the IPCC’s decarbonisation target. I am not convinced!

Section 4 identifies stakeholders of which the keys ones are the designer/supplier, the owner/operating organisation, the technical support organisation, the investors, the regulatory bodies, the government and the public. It then discusses regulatory frameworks including the IAEA and OECD/NEA and WENRA and discusses goal setting and prescription as the two major licensing approaches before introducing the SMR Regulators’ Forum.

Section 5 concentrates on near term deployable SMR technology and provides a road map in three sections: owner or operating organisation, designer/vendor of the technology, regulatory bodies. This section is very disjointed and hard to read.

Section 6 looks at more innovative reactors designs which are further from market and highlights technical areas and R&D activities that are likely to absorb effort and funds on the pathway to deployment. This section also reviews six technologies that are being considered and takes a speculative look at the potential integration of renewable energy sources with nuclear sources.

An annex to the report reviews three designs of SMR in operation or under construction.

This could be a very interesting report but the drafting is poor making it hard to read from beginning to end. It does however give an impression of the breadth and depth of work that is required to support a nuclear power plant. I’m sure that it could be useful to a civil service providing government funding and support to the SMR industry. What would be useful is a map showing the development path for SMR and AMR reactors with a series of gates through which they have to pass, a discussion about what needs to be achieved before a reactor design can pass each gate and the technological and financial risks implied, who is responsible for the risks and an estimated cost and time for reaching each gate.

Streamlining the licensing of Small Modular Reactors, WNA Webinar


WNA webinar

I watched the World Nuclear Association webinar about streamlining the licensing of Small Modular Reactors on July 28th. This was an interesting event with some good speakers. It is currently available on-line here.

The grumble behind the event is that, while companies want to sell their reactors around the world the pesky regulators in each country they want to build in want their say on the suitability of the design and this is tiresome, time consuming, expensive and may lead to country-specific design changes. The speakers made a good case that their jobs would be easier and that SMRs could start generating energy sooner if the regulatory barriers were at least lowered. We were also told that this is important for decarbonising the world energy market which is a relatively new way the SMR companies are trying to lean on Governments.

The audience was challenged by Tom Bergman, Vice President of Regulatory Affairs, NuScale (a leading SMR design/build Company from the USA) with the question “Do you believe that a design approved in the USA is not fit for somewhere else?”. Maybe we could ask him if he would be happy for a British designed reactor, approved by the British regulators and built in Britain to be operated in his backyard without US inspection of the safety case, design, build and operation? We also heard from Sol Pedre, Manager of CAREM project, the National Atomic Energy Commission, Argentina (CAREM is a simplified PWR being built in Buenos Aires province) who, rather naively in my opinion, thought that if they could build and operate a reactor in Argentina then that should go a long way to convincing other regulators that the design is safe enough for worldwide deployment.

Nadezhda Salnikova, Head of Business Development Department of Afrikantov OKBM, JSC, ROSATOM (this is the company that designs and builds Russia’s nuclear propulsion projects such as submarines, icebreakers and floating nuclear power plant) commented that they produce plant for use within Russia under Russian regulatory supervision but the floating power stations can go anywhere. A lack of global licensing means extra work for the Company and work for the local regulators that may be beyond their capabilities.

It was suggested that new nuclear nations could simply accept the regulatory approval of the country selling the reactor. I suspect that this runs counter to IAEA expectations but might be acceptable if a floating plant was to be temporarily positioned following some crisis and operated by experienced staff. This is little different to a nuclear-powered submarine or ice breaker visiting a foreign port.

I have some sympathy for the potential loss of design stability caused by local requirements. This potentially makes the design chain and build more complex but we are talking about an industry that, according to the IAEA had more than 70 SMR designs running in 2020  (Ref. here) while NuScale have designed 50, 60 and 77 MWe versions of their reactor before building any. Design updates do not seem to be a particular problem. Meanwhile modern flexible manufacturing systems should enable slightly different builds to be accommodated on the production lines without reducing shareholder value too far.

The problem with attempts to produce global standards is that most countries agree with the concept providing that the world adopts their existing standards (hence my question to Tom Bergman above).

This event did not really explore the barriers to closer working of the regulators across the world and the advantages that might accrue from converging regulation. I would be interested to see a  comparison of the regulators. What do they do in a similar fashion? what do they do differently? How much scope do their national laws and guidance give them to meet in the middle? Why would they want to do this? How much of the licensing effort is based on design and how much on siting, building and operating? Knowing this, we might then be in a better position to move partial streamlining of international licensing from an aspiration to a realistic target. (This information may be available in the WNA report “Design Maturity and Regulatory Expectations for Small Modular Reactors” which I haven’t yet read in full).

Small Modular Reactors are often based on evolutions of proven technology with enhanced levels of safety built in. Much of the additional safety comes from the small size and layout of the plant greatly reducing vulnerable pipework and reducing dependency on active systems for layers of safety. They have reduced the number of systems (valves, pumps, filters, tanks, chemicals, switches etc) that need to be considered. It seems logical to assume that their safety cases are simpler and fewer systems means fewer things to understand and approve. Design approval should be quicker.

Importantly the construction takes place in factories, possibly in a foreign country. What expectations will the regulator have for quality control and will they require to inspect the reactor during build?

If governments wish to see SMRs contributing to low carbon electricity, district heating, process heating and hydrogen production in the not-too-distant future then they do need to encourage regulators to do their bit to hasten the process without compromising safety. Generic Design Assessment (GDA), which takes about 4 years and is not mandatory, is far from the only issue. They also need to consider how the licensing of sites and operators will be undertaken if the market penetration talked about comes to pass.

What will the siting requirements be? Currently the UK process spends a lot of time and effort considering if a particular site is suitable for a reactor. That may be acceptable if you are only going to build one or two sites a decade but we cannot expect, for example, a foundry to spend years of effort to get permission to use a small (or even micro) reactor to melt metal. What siting processes do we need if, for example, six reactors are going to built and deployed each year?

In the UK the ONR has recently announced new guidance for parties requesting Generic Design Assessment of SMRs and AMRs (Advanced Modular Reactors). It would have been interesting to hear a discussion of this guidance, and the strategy behind it, to see if it goes someway to meeting the aspirations of the reactor manufacturers.

The UK 10 point plan calls for demonstrator SMR and AMR deployment in the early 2030s. But what is the strategy to deploy them, including siting them, in the following years?

I started listening to this webinar thinking about the issue of using one design of reactor in several different countries but ended up thinking that a more difficult issue (in the UK) may be that of gaining public and regulator acceptance of many more nuclear reactors doing a wider range of jobs requiring them to leave their large, well-protected sites, in the countryside with their hundreds of well qualified workers and instead sit in one corner of an industrial site or in the outskirts of a town and with a much smaller staff. This is  a national, rather than an international, issue.

I’m grateful to the WNA for organising this webinar and for the speakers who gave their time. It is an interesting topic and was well presented. A good case was made that life for a reactor vendor would be easier if some of the regulatory barriers were streamlined. It was not made obvious that this was likely or even possible. The question in the webinar title was not answered.