Getting bigger but not safer or cheaper – the myth of Rolls Royce and its very big non-modular reactor

Rolls Royce’s so-called small modular reactor (SMR) is getting bigger, but is likely to have fewer special safety features compared to EDF’s increasingly pricey design for Hinkley C.

In 2017 Rolls Royce said that its small modular reactor would be between 220 and 440 MW, but the latest design is bigger, at 470 MW. It is strange to call this small. Reactors in service at the moment (the so-called AGR reactors) were around the 600 MW size for each unit and, strange as it might seem, most of the first generation of so-called ‘Magnox’ nuclear reactors built in the UK were actually smaller than 470 MW. They were not called ‘small’. So why is Rolls Royce calling this a SMR? There’s no reason for this other than public relations.

Rolls Royce claim that the parts will be mainly built in factories. Well, of course they will, that’s always the case with nuclear power plant. The difference with building a relatively smaller plant of course is that you get less of the economies of scale in doing this. That is why nuclear power plant have got bigger.

So the fact that the Rolls Royce unit will be about a third the size of the EPR is likely to make them cost more. But there is one way that Rolls Royce will be able to economise compared to the European Pressurised Reactor (EPR) being built at Hinkley C, and that is because I have seen no sign that Rolls Royce will include some special safety features that have been included in the EPR.

The best known of these safety features are a) a ‘double containment’ feature that is designed to stop material from the inside getting out (as well as another external shell to shield from aircraft) and b) a ‘core catcher’ to stop a melting core eating its way into the ground and potentially contaminating water courses. I am assuming Rolls Royce will not be including either of these features, although it will have to satisfy the Office for Nuclear Regulation (ONR) that it has other ways of stopping radioactive releases from accidents.

Rolls Royce are now starting a ‘Generic Design Assessment’ (GDA) process with the ONR which will take around 5 years. After then they will be asking the UK Government for a blank cheque for a project.

Of course there is another factor and that is that EDF have some experience (admittedly not very successful of late) of building nuclear power plant. Rolls Royce  do not have experience of building large nuclear power plant (which is what they are really hoping to do). Producing small (and, it must be said extremely expensive) genuinely small reactors for nuclear submarines is not the same thing at all! So Rolls Royce are likely not to have the skills to build large nuclear power plant. That is a bad sign!

The so-called SMRs proferred by Rolls Royce will just be the latest in a long line of very expensive, very lately delivered nuclear power stations in the UK. It is unlikely to be any cheaper than the reactor that EDF is building at Hinkley C  (becoming more expensive as time goes on). But it will have fewer safety features.

By David Toke

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