Build Back Better: Making small modular reactors stack up

Government could be set to invest more in small modular reactors as part of the green recovery plan. They could provide the natural successors to large nuclear reactors, supplying baseload in a future where intermittent energy will play an increasing part. But only if there is commitment to the necessary volume to deliver progressive cost reduction, say Julianne Antrobus and Robbie Lyons.

It is widely recognised that while nuclear power can play a large part in the UK’s pursuit of net zero carbon emissions, this ambition is being held back by the seemingly inevitable high costs and long build times of nuclear power plants. The technical complexities of large reactor construction and huge capital requirements make financing such projects a risky proposition, further driving up the price of both the plant and the electricity it generates.

A key element of the Nuclear Sector Deal is to pursue significant cost reduction in nuclear new build projects. Small modular reactors (SMRs) seek to deliver lower costs by implementing three key principles. The first is standardisation of design across the whole plant, reducing recurrent engineering work; the second is to manufacture standardised modules off-site; the third is to adopt a building programme which delivers multiple standardised plants in series.

This approach can overcome the lack of economies of scale that have conventionally led to small reactors being written off as not commercially viable. However, this requires a nuclear supply chain that is willing and able to adapt to this new approach and use a model which has proved to be successful in the offshore wind sector and aircraft manufacture.

The UK Government clearly sees the potential. In December 2019 it announced it was investing £18m in a partnership with industry led by Rolls Royce to develop their SMR. In July 2020 the Government announced a further £40 million investment in the development of both advanced modular reactors (AMRs) and SMRs.

With the Financial Times reporting today that a further £2 billion investment may come as part of the Government’s “Build Back Greener” plan, how can the nuclear industry ensure it delivers on the potential of SMRs?

Vendors should engage suppliers for long term fleet build, not single projects

The experience of nuclear power plant construction in Western economies has been of tailored plant designs and specific supply chains for each project, partly driven by a desire to use local companies. This has led to a lack of standardisation and ability to learn, whereas the use of strategic partnerships in Korea’s nuclear programme and comparable industries shows that such a structure enables lessons to be learned and applied to subsequent projects.

The need to gain experience means that production must be consolidated with the same suppliers delivering across global markets, rather than pursuing technology transfer to local suppliers. Long-term relationships would enable suppliers to invest in their production capability and capacity, and a consolidated domestic programme could establish a competitive export proposition, supporting the UK’s global trade agenda.

Nuclear component manufacturers should be ready for change

Progressive cost reduction over an SMR programme will come primarily from the factory-made components. This means component manufacturers will need to engage in continuous review and revisions to production processes. For manufacturers of highly specialised, low volume components, this may call for a significant change to established ways of working. In addition, this would create the impetus to adopt manufacturing processes that may be novel to nuclear but well established in other sectors, such as the use of robotic systems.

Regulation must accelerate evolution to adapt to scaled up standardisation

To achieve the production volume required for significant cost reduction, a standardised SMR plant design must be deployable across multiple, multi-unit sites, in both the UK and international markets. Such design standardisation will also need to be supported by national regulators.

The Office for Nuclear Regulation (ONR) has demonstrated its commitment to be an enabling regulator for SMRs by reviewing its processes and guidance to ensure they are fit for purpose, while pursuing bilateral and multilateral engagement with foreign regulators. The refreshed Generic Design Assessment (GDA) allows for both flexible scope of the process and non-continuous assessment. This enhances the potential for early regulatory engagement by new reactor vendors, as well as the possibility of concurrent assessments by international regulatory bodies. However, could the ONR and other regulators go further?

Greater standardisation across a fleet of SMRs could enable more detailed design assessment within the GDA. This would then reduce individual site licensing costs and resource requirements because their common features would make it possible to make similar licence applications for deployments of the same design. Moreover, standardisation across global markets will require harmonisation of codes and standards. A focused effort is required to close existing divergences to reduce the regulatory costs of international developments. By reducing regulatory risk and increasing interoperability with foreign regulatory activities, this would encourage the development of both domestic and international SMRs in the UK.

Transforming the supply chain to deliver cost competitive SMRs would also serve the wider goals of the Nuclear Sector Deal. It would drive investment in advanced manufacturing and construction techniques, establish a production programme to provide a competitive export proposition, and ultimately establish a long-term new build programme that could excite, attract, and develop the next generation nuclear workforce.

The government has set a challenging and compelling target for net zero. SMRs can make a big contribution to that, but regulators and industry need a similar commitment from Government on demand in the forthcoming Energy White Paper. That will encourage the investment that will pave the way for SMRs.

This article was first published in Utility Week