Small Modular Reactors – a real prospect? by Gordon MacKerron

Despite ongoing and major delays in financing Hinkley Point C, which would be the first new nuclear power station in the UK for over 25 years, enthusiasm for new nuclear power remains high in several quarters.  This includes the Energy Technologies Institute (ETI), a public-private partnership between the UK Government and energy and engineering companies.  It has just produced an ‘insights’ report on the future UK role of nuclear power.[1]

Although the report is about all potential future nuclear technologies, it gives little attention to the large scale reactors that are the only currently feasible technology choice for nuclear.  But in considering such reactors, it now believes that in its ‘optimistic’ scenario for the future (‘Clockwork’) the possible feasible total capacity by 2050 of large reactors is 35 GWe, down from a previous maximum of 40 GWe.  Given that the UK Government gave the green light for nuclear power back in 2008 and the earliest we are now likely to get any power from new reactors is around 2025, this would still be going some.

What the report is really interested in exploring is the potential for Small Modular Reactors (SMRs), which ETI sees as potentially complementary to large reactors.[2]  SMRs are reactors of below 300 MWe, (some 4 or more times smaller than current designs), none of which yet exists, though there are many possibilities.  ETI argues that 21 GWe of these SMRs might be in place by 2050, an apparently modest total compared to the 63 GWe of ‘theoretical capacity’ of SMRs for the same year.  All this is in the context of the ETI’s optimistic, high-growth scenario – its more pessimistic scenario (‘Patchwork’) is not considered, so we are in an exclusively nuclear–positive world.  In this scenario, ETI seems to suggest that SMRs are a good prospect.

However there are at least two serious problems – according to ETI’s own account – that could prove destructive to the SMR ambition.

The first is that ETI only expects that SMRs might be economically viable if there were a pre-existing district heating network at city-scale.  SMRs could feed otherwise wasted heat from the nuclear reaction into this network – in addition to feeding electricity into the grid.  But this network would already have to exist and have been paid for.  The costs of adding this network to the costs of SMRs is, implicitly but clearly, enough to render SMRs economically unviable.  There is no obvious reason to expect these multiple heating networks to be so conveniently available as a ‘free good’ to SMRs on so large a scale, if at all.

Second there is the economic appraisal itself.  Given that the construction costs of SMRs are yet entirely unknown, but will be dominant in overall costs, ETI is in a difficult position in trying to make a stab at what these costs might be.  Its report says that its estimates are ‘independent of any specific vendor estimates’ and ‘are not derived from the traditional bottom up application of established power plant cost breakdown structures’.  Unfortunately ETI does not say exactly how its cost estimates are derived, nor show any intermediate steps in this process.  Given that there cannot be any commercial confidentiality issues involved because of the ‘independence’ of the estimates.  This omission is unfortunate, especially in the light of chronic historic optimism in previous nuclear cost estimates, even when designs are well established.

There are three further issues with the ETI report.  The first is the assertion, muted but clear, that a major objective is for the UK to acquire full IPRs in any SMRs that might be deployed.  While development of indigenous technology capabilities is generally desirable, the UK has no serious capabilities in SMRs at present.  The acquisition of intellectual property rights (IPRs) would be a long and costly process and ETI do not clarify how this might be done.  It would also seriously extend timescales and highlights tensions between climate change-derived urgency and other worthwhile objectives.  Given that the UK has no ambitions to acquire IPRs for the three reactor types currently being pursued, it is not at all clear why this becomes so important for SMRs if low carbon is the dominant objective.

Second there is the almost total neglect of the need for public engagement and consent for SMRs, especially as they would need to be sited relatively close to cities (so that the district heating systems would be viable).  This might or might not be a show-stopper but it certainly constitutes a major public acceptance risk and at the very least suggests that major delays are likely.

Finally there is the unsupported assertion that ‘action needs to be taken now if the option to deploy SMRs …is not to be closed off’, echoing similar remarks by the Select Committee on Energy and Climate Change a few months ago. [3]  This makes no sense at all.  It would be much more prudent to wait and see whether other countries’ proposed deployment of SMRs proves successful before premature commitments are made to a technology that is economically and socially high-risk.  And if, as seems probable in a time of continuing reductions in public expenditure, no such supportive public action will be taken now,[4] this kind of rhetoric may easily backfire.

Gordon smilingSo what can we conclude from this report?  It may reflect growing disillusion within the nuclear community with the large reactors currently proving so hard to finance and deploy.  Whether this is the case or not, ETI – while advocating early development of SMRs in the UK – have in practice demonstrated quite how thin the current case for SMR pursuit really is.

Gordon MacKerron

[1] Energy Technologies Institute Nuclear – the role for nuclear within a low carbon energy system An insights report, October 2015

[2] Small Modular Reactors are a topic of recurring current interest.  See ‘Small modular reactors – the future of nuclear power?’ – A blog by Gordon MacKerron and Phil Johnstone, 2 March 2015

[3]  House of Commons Energy and Climate Change Committee Small nuclear power 4th report, Session 2014-2015, HC 347, 17 December 2014

[4] The Government’s response to the Energy and Climate Change Committee cited above makes no commitment to significant expenditure, instead concentrating on further studies.  House of Commons Energy and Climate Change Committee Small nuclear power – Government response to the Committee’s 4th report,  Session 2014-2015, HC 1105 5 March 2015

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  1. […] design and build it in the 2020s. This timetable looks tight but could be technically feasible. But even if it is, one of the main advantages claimed for SMRs – proximity to urban areas to allow….  Shale may fare a bit better but this is not clear either. Government is taking powers to […]

  2. […] However, some types of small nuclear plants can very output more easily- the small reactors used in submarines are designed to do this. And in theory, if new small units are also designed so that the heat output can be used direct, rather than just being used to generate power, then that would add more flexibility- assuming there was a nearby heat load. ETI see 30 km as a maximum distance for heat transmission without too much heat loss, so that defines a potential role for mini-nukes. Most large nuclear plant are located well away form centres of population for safeties sake, and to get access to cooling water, and so could not supply heat to cities, but it’s claimed that mini-nukes will be safer, and so more acceptable near cities, so they could meet heat loads, and be flexible grid balancing plants too. A big set of assumptions! The economics also depend crucially on whether heat grids are available- if not, then the cost of building heat networks has to be added to the cost of SMRs:… […]

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