‘The EPR is safe, very safe’ said Tony Roulstone at a lecture in Oxford on Tuesday 21^st October. But the complexity of the design means it is extraordinarily difficult to build. This type of reactor is, he said, perhaps in an unguarded moment, ‘unconstructable’. Roulstone, who runs the Master’s programme in nuclear engineering in Cambridge, described the proposed EPR nuclear power station at Hinkley Point as similar in concept to ‘a cathedral within a cathedral’ which would stretch the ability of any business to build it. With two sets of 6 metre thick concrete walls towering 70 metres above Somerset, the building would survive a direct hit from an airliner but at a very high price in terms of construction timetable and cost.

He went on to say that Areva, the French company that owns the EPR design, is no longer actively selling power stations of this type. In those countries still looking to expand nuclear power, such as Saudi Arabia, China and Turkey, Areva is now pushing an alternative reactor. In China, where several EPRs are currently being constructed, the authorities have indicated that they will not use the design for future power plants. In other words, the Hinkley Point design is already regarded as a failure by those with most knowledge of it. In Finland and in Normandy, where the EPR is already under construction, delays of several years and enormous cost overruns are crippling the projects.

The latest estimates for the cost of Hinkley Point are still rising. The EU recently indicated it thought the total bill might be higher than £24bn, although EdF, the site owner, still says that its figure is about £16bn. Using the lower number, the cost per kilowatt of capacity is almost £5,000. Gas-fired power stations could be built for about an eighth of this price.

EdF, the most experienced operator of nuclear power stations in the world, is expecting to pay about four times as much for Hinkley Point as it did for the last nuclear power stations to be constructed in France fifteen years ago. But larger nuclear plants were supposed to be cheaper to build per unit of generating capacity. This theory, said Roulstone, underlies the political decision to support the EPR in the UK over the course of the last ten years. Actually, he went on to say, unlike any other energy technology in the world, global power station builders are seeing very little benefit from constructing larger nuclear power stations. And, crucially, the cost reductions derived from building multiple power stations of a single type (the so-called ‘learning’ effect) are turning out to be small or non-existent.

Roulstone mused on why this might be. He said that learning effects are usually observed for goods made in factories. The fact that nuclear power stations are almost entirely constructed on individual sites meant that the expertise gathered in one place are not transferred to the next construction project. Recent experience, such as at the Finnish EPR construction site, shows that management is particularly difficult when large bands of workers, sometimes speaking different languages, try to work productively together in a relatively small and cramped area. The workforce is unused to the extremely demanding construction quality requirements imposed by the safety engineers.

Interestingly, he spoke of building nuclear stations, the largest civil engineering projects in the world as requiring ‘craft’ skills that are usually associated with tiny factories. And craft learning is extremely difficult to transfer from place. The Chinese are trying to encourage this by transferring workforces from one finished nuclear power station to the next construction project. I suspect this would be much more difficult in the UK.

Much of Tony Roulstone’s lecture was about other types of reactor which thought deserved much greater investigation. Small reactors have been opposed, he suggested, because they contravene the standard wisdom that bigger is always better in nuclear. But a much larger percentage of the plant can be constructed in factories away from the site and therefore might be able to capture the benefits of much greater ‘learning’ effects. He showed that for relatively small amounts of money – at least by comparison to the big nuclear programme - the UK and other countries could see if cost reductions in small reactors, possibly using thorium, could be attained that might match or beat the price of EPRs or other giant reactors.

This is unlikely to happen. Roulstone said the central assumption of the UK government now appears to be that the country will build about 16 gigawatts of large nuclear plants (providing about 25% of UK electricity) at a cost of around £100bn. EdF will bring in Chinese investors to help finance its share of this expenditure. Chinese companies will then get much of the business constructing other plants that will built after EdF’s EPRs at Hinkley and Sizewell. And, he concludes, future plants may be constructed using alternative technologies, including variations of the Westinghouse AP1000. By their actions, Tony Roulstone wrote to me in an email this morning, Chinese companies ‘appear to have rejected EPR as a staple of their future build programme’.

Most scenarios, though not all, show the UK needing a large nuclear programme to meet its power and decarbonisation needs. But by focussing on the increasingly unpopular EPR design, the country may have saddled itself with an unmanageable and hugely expensive construction project that will sour the prospects of all other nuclear technologies for another generation. Perhaps those of us who still believe in the value of nuclear power should pray that sceptical investors refuse to commit their funds to the Hinkley project.