SMRs offer a great opportunity for new nuclear development, but the industry will not be served well by over promising on price and development timeframes.

The new generation of small modular reactors (SMRs) are anticipated to provide enhanced safety, lower cost, easier financing, better grid compatibility and reduced project risks (which can improve social acceptance and attract private investment). Because of this, the nuclear community and even the public media are increasingly looking to SMRs to herald in a long-awaited but never yet observed “nuclear renaissance”. But this will not happen if SMR developers repeat past mistakes. Over promising on low costs is a major issue – one remembers early claims that nuclear electricity would be “too cheap to meter”.

It is yet to be shown that the economies of scale which led to nuclear power plants becoming ever larger can be outweighed by the economies of multiples which are expected from factory line production – assuming that full order books can keep these lines busy. But for how many of the over 80 SMR designs being developed will there be a large enough market to feed a factory production line?

Already 50 years ago, physicists and engineers designing large nuclear power plants were focused on the interesting challenges of proposing ever more reactor variants that looked – on paper – to be more efficient, safer or cheaper. But even the comparatively limited variety of designs proposed back then proved to be more an obstacle than an advantage. The UK, for example, dithered for years in making hard choices, while building and operating expensive first-of-a-kind units of many different types. The most successful large reactor programme was in France where an early decision was taken to narrow in to a standardised PWR design. Today, the clear lesson is that only a handful of SMR designs can hope to benefit from economics of multiples and thus reach commercial success.

A further mistake from the past which also affects the economics is the long timescales required for implementation of nuclear power plants. Many of the delays have been due to technical or project management weaknesses but a large contributor has often been the time needed by regulators to license a new design. The way to overcome this obstacle is to develop a set of risk-informed regulations tailored to smaller SMR designs and then to harmonise licensing regulations across potential user countries. A useful precedent is the US Federal Aviation Administration whose aircraft regulations are accepted globally as the technical basis for all national regulations.

But getting the economics of SMRs right and shortening licensing and construction times will not on their own solve the problem. There are other challenges which large reactor designers ignored until too late. The clearest example here is neglecting to address the issue of safe disposal of spent fuel and/or highly radioactive wastes. Even today, although safe geological disposal facilities are being implemented, for example in Finland, the “unsolved waste problem” is still put forward by many as an objection to expanding nuclear power. SMR developers should, already at the design stage be considering what wastes will be produced and at the tendering stage should be offering specific help and advice to their potential customers, most especially if these are small or new nuclear nations.

In addition to these potential impediments to wide deployment of SMRs, there are some novel issues to be addressed. One of these is related to the nuclear proliferation and security concerns which might arise in a scenario where hundreds of SMRs are distributed around the globe in many countries with no nuclear experience and, in some cases, in remote regions within these countries. In the end, because of their smaller fissile inventories and compact designs, the nuclear security concerns with widespread SMR deployment may be less than with current nuclear-power plants with their much larger inventories of fissile materials. However, the issue should be discussed now by the nuclear community and not ignored until it is brought up as an impediment by nuclear opponents in potential SMR user countries.

If we want to learn from the bitter lessons of past hoped-for nuclear renaissances, then we should learn from the mistakes made back then and also anticipate any new and novel issues that will arise with widespread SMR deployment.

Image: Over promising on low costs is a major issue for SMR development and is reminiscent of early claims that nuclear electricity would be “too cheap to meter” The most successful approach has been to focus on a standard PWR design (Source: WNA)

Author: Dr Charles McCombie, Independent nuclear advisor