Partner: SNC-Lavalin

On the first of January 2021, European natural gas prices sat at a sedate 23 Euros per Megawatt hour. By June, the price had passed 30 Euros, by October it was 110 Euros… and then, finally, just before Christmas, the Dutch TTF benchmark recorded a spike of over 200 Euros per Megawatt hour.

A unique set of circumstances threw energy markets into turmoil, the effects of which some analysts say will be felt for years to come.

Global supply of fossil fuels could not keep up with demand as economies recovered from Covid-19. Added to this, the worst Chinese energy crisis for decades, power outages across India, drought in Brazil and environmental disasters in North America all put strain on the global energy web.

Added to this, a cold winter in Europe meant that gas storage levels were at legal minimums, and one of the least windy years in the UK for sixty years saw turbines standing idle and officials of a country formerly described as the ‘Saudi Arabia of wind’ turning to the remaining coal power stations to keep the lights on.

Reliance on fossil fuel imports, and a lack of domestic energy supply brought many developed nations to the brink and saw record amounts of coal being burned to balance global grids. Promises made to cut carbon emissions and reach net zero is one thing, but creating a really resilient energy system is another – one that can generate enough power to match demand as well as hit tough decarbonisation targets.

And a high penetration of renewables in energy generation is only one half of the solution.

The ongoing energy crisis is complicated. But what if there was a way to generate firm power, to do roll it out quickly, and to do it without increasing carbon emissions? A robust, green grid is the best defence against future crises.

The small modular revolution

The nuclear industry has been undergoing something of a resurgence in recent years, as governments look to reduce dependence on fossil fuels. Within this pivot back to nuclear, there is also a growing interest in the use of modern methods of construction to lower costs and improve schedule predictability.

Engineering Matters has covered modern methods of construction before for house, see episode #64 EDAROTH for more information. But the use of factory, modular construction to construct something as complicated as a nuclear power plant is even more revolutionary.

All current nuclear power relies on a process called fission to create energy. The reactor fires a neutron at a large, unstable particle such as Uranium. The collision splits the atom in two, releasing two lighter elements, and some more neutrons.

However, the resulting particles weight slightly less than the original particle. This unaccounted-for mass is converted into heat energy – and we get a lot of energy for very little mass – which is then used to heat water, creating steam, and turning a generator turbine.

So like most power plants, it creates electricity through steam, but there is no burning of fossil fuels, and no carbon released into the atmosphere. However, historically for grid generation we have built enormous, bespoke nuclear plants. With the Small Modular Reactor, there are advantages of reduced cost and a more consistent supply chain.

James Goodenough, New Nuclear Technologies Lead for Atkins says, “There’s definitely been a resurgence within the industry, within society in terms of SMRs. And I think what has driven it is the realisation worldwide that we need to do something, we need to act quickly. With the UK’s commitment to being carbon net zero by 2050. It’s really focused the mind of everyone that this is a serious problem.

Goodenough says that SMRs are attractive because they offer lower construction risk than their large-scale counterparts.

“Because the whole concept behind an SMR is that they’re factory built. So you don’t have the major construction project that we see down at Hinkley, for example. It’s all modularised, built in factories then shipped to site so it’s much more of a commodity, a production line type approach is the concept behind them.”

The two major nuclear projects in the UK at the moment are the under-construction Hinkley Point C and proposed Sizewell C, each costing over £20 billion and each with a capacity of 3.2GW, representing a little under 10% of 2014 electricity demand in the UK.

The design of Sizewell can be such that it benefits from the experience on Hinkley, but the SMR concept advocates going beyond this.

“If you’re continually trying to reinvent the wheel, then obviously the cost is going to remain high,” says Goodenough. “When you’re talking about SMRs. For it to really gain the benefit, you’re talking about a fleet [of these reactors]. You are churning them out of the factory.”

This could mean a dozen units, or even more, bringing the cost down as volume manufacturing benefits increase.

Julianne den Decker is Vice President of Project Delivery for SNC-Lavalin’s Canadian nuclear division. She thinks that there are some misconceptions about the nature of SMRs, because they tend to all get grouped together.

“Small modular reactors really encompass everything from what we would call the micro reactors. So some of these are as small as a shipping container,” says den Decker. “They’re designed for a remote application, some of them are as small as one megawatt, even, all the way up to what we would call grid scale applications. So as a, for example, the Rolls Royce reactor is over 400 megawatts. So that’s the size of a natural gas station.”

And a footprint of around two football pitches is a good approximation of the footprint of such a site. There will be more about the Rolls Royce consortium later.

“So they are very much an actual industrial facility, and they’re an installation. But the promise of them is to try to maximise the number of components that you can fabricate in modules, as the name suggests. The oil and gas industry has done this with offshore oil rigs and things like that. It standardises the design and gives you that repeatability.”

A final thing to understand about nuclear power is the concept of reactor generations. Modern reactors are described as third generation, or “Gen III”. The first of these began operation in the mid-to-late 1990s. Gen II reactors comprise the majority of reactors of the nuclear age, and Gen I were the prototype reactors built in the 1950s and 60s.

Each generation was made safer and more efficient, with Gen III reactors bringing in standardisation of design and passive safety features (which force the reactor to default to a safe shutdown state in the absence of human control).

The Generations were defined as Gen IV reactors entered the discussion. These are a little different, and are sometimes called ‘Advanced Reactors’ (or Advanced Modular Reactors/AMR’s, if modular construction is involved).

“Most of those are either high temperature, or they rely on some, some sort of inherent physical properties that allow them to shut down safely without a lot of human intervention,” says den Decker. “Those are the molten salt [reactors] and some of the high temperature gas reactors and things like that.”

A lot of these Gen IV designs are based on experimental reactors and new designs, but there has not yet been widescale deployment yet, and probably will not be seen before the 2030s, but they have some interesting features that have not been seen before.

“A lot of those do bring a lot of promise in terms of closing the fuel cycle, meaning they would be able to burn recycled fuels, and in some cases, their own fuel, to try to minimise the amount of spent fuel that you have to deal with. And in some cases, even being able to disposition the spent fuel that we already have today.”

That is, reusing spent nuclear fuel from older reactors, that has previously been classed as waste. A company in Canada called Moltex Energy is developing a molten salt reactor that is specifically designed to use the spent nuclear fuel that is currently stored in Canada.

“In the traditional recycling of fuel, as is done in France, you have to separate the plutonium that’s generated as you burn up your uranium. Then you have to be able to extract that from the spent fuel, which is a relatively expensive process, so that you can put it back and use it in a reactor.

“The molten salt types would allow you to not have to separate that plutonium and would allow you to just burn it along with all the other actinides and radioactive waste products. To just burn it all at once. So it’s proposing to be a much cheaper way to recycle your spent fuel and then still get carbon free electricity out the back-end of that plan.”

The UK’s approach to modern nuclear

Back in the UK, Goodenough says that the government has adopted a three-pronged approach to nuclear. Large scale nuclear, such as Hinkley and Sizewell, SMRs, and AMR studies. And although future technology is fun to think about, we need to be working on solutions now.

“If we really want something to be part of the energy mix that is going to help us decarbonize this world, we need to be promoting pushing and designing with existing known technology,” says Goodenough.

This leaves us with SMRs as a modern vision for nuclear to supplement the large-scale reactors, and the most promising project in the UK at the moment is led by Rolls Royce.

Back in about 2015, Rolls Royce were looking to enter the nuclear energy market. The company has a history of designing small reactors for nuclear-powered submarines and it was looking for a way to use its reactor for grid generation purposes. However, it realised that it was very unlikely that any companies would be designing a plant with a gap in it for a reactor.

“So then quickly decided, actually, this is something we’re going to have to design – a plant. They then set up by some gate getting interest within the industry and getting backing from the government.”

In 2019 it was granted funding of £18 million by UK Research and Innovation to develop the idea. They formed a consortium of the main UK nuclear players within that area: Atkins, Assystem, Jacobs, the National Nuclear Labs, Laing O’Rourke, Bam Nuttall, the Advanced Manufacturing and the Welding Institute. The consortium worked to design the pre-concept definition of what the plant might be.

This first phase lasted a year and a half to prove the concept and attract external investment. Phase 2 began in November 2021, and that is Rolls Royce SMR as a business entity. The current goal is that we will have an operating plan on the grid in the early 2030s, assuming an initial order within the coming year or so.

The 470MW capacity of this design is larger than the 300MW upper limit for what would typically be considered a small reactor, but the decision was made to go for the largest reactor (16m high and 4m in diameter) that could be transported by either truck, train or barge.

In fact, all of the modules can be transported in this way, and from the start of construction of the modules, it could take as little as five years before the generation of the first electricity, although each unit would have an on-site construction time of 500 days, with an operational life of 60 years.

This is a Gen III reactor that could be rolled out more rapidly than other nuclear plants, at a target cost of £1.8 billion per unit once five have been built.

Traditional obstacles to nuclear adoption

But there are obstacles to nuclear. Financing is a often huge one, and the RAB model whereby the costs of a future project are spread out among bill-payers over many years, and can even begin before construction. This has already been used on major infrastructure such as the Thames Tideway sewer tunnel, and takes a lot of the risk off developers, making nuclear a more comfortable investment.

However, for the lower cost SMRs, the RAB model is not necessary and financing is not an obstacle.

Another factor is the public perception of nuclear safety. And a way that safety can be measured in energy production, is fatality rates per terawatt hour. For brown coal and coal, this is 32.7 and 24.6 deaths respectively, for oil it is 18.4, for biomass 4.6, for gas 2.8… and for nuclear 0.07.This puts nuclear in the same order of magnitude as the renewables – wind, hydropower and solar, which are 0.04, 0.02 and 0.02 respectively.

The website OurWorldInData.org illustrated this wonderfully with an imaginary average town of 187,090 people in Europe, the amount of people needed to consume 1TWh of energy. If it were fuelled entirely by coal, some 25 people would die prematurely each year. If it were nuclear, it would take 14 years before a single person would die.

Things are still improving, and not just due to advancing technology, says den Decker.

“The Gen III’s are safer, but also the concept of regulation has, has really permeated across the world. And some of that was an outfall of Chernobyl and incidents like that. The mandates and requirements to have accident scenarios all written down, postulated out to a very, very high level of detail for the regulators to see.

“And with climate change taking its toll around the world, we continue to see increased requirements for the types of accidents that we have to postulate, and how many different concurrent events.”

Taking the Fukushima incident as an example, the entire nuclear industry is undertaking so-called ‘Fukushima upgrades’ to handle multiple concurrent events. They need to have a plan for losing off-site power at the same time as a natural disaster, at the same time as being unable to call emergency services.

The other major issue raised in discussion about nuclear is the waste. Although spent nuclear fuel and nuclear waste is not accumulated in great volumes, it can remain toxic for thousands of years.

The Rolls Royce SMR is capable of storing all of its material on-site, and final disposal options are re-use as fuel in Gen IV reactors, reprocessing at Sellafield, or being interred deep Geological Disposal Facility. The most advanced of these is the Onkalo project in Finland by Posiva, although the UK government is currently working to identify a domestic site.

“That’s sort of the industry sort of gold standard of how you how you would deal with spent nuclear fuel, and where you would store it, how you would store it,” says den Decker. “The question of the recycling of waste, I think is something that does need to be sorted out, because you don’t want to bury all the waste products and then figure out later that they could have been useful input material for [a Gen IV reactor].

However, it doesn’t completely eliminate the need for that deep geological repository, because every reactor type is going to have some level of waste product that it can’t possibly recycle. But it is a question of volume.

The Rolls Royce plant itself would produce one Olympic-sized swimming pool of material in its own 60-year lifetime.

“So, it’s manageable,” says Goodenough. “And one of the one of the facts that I really like is that if you live to the age of 80, and all of your electricity demand came from an SMR, the waste that you would personally have generated would fit into a coke can.

“But when we talk about waste in nuclear, I don’t know what image it conjures up in the general public’s mind. Whether they think of, the Simpsons with nuclear waste all littered around… but actually, we know about the waste, we know that all industries generate waste, but we know exactly how much we generate and we know what we are going to do with it, and how we are going to store it safely. I think that is important to grasp.”

Advocating for itself is not something that the nuclear industry has always been the best at, but the public perception has been changing.

Den Decker adds, “I think what’s what I see going on in the public space is that a lot of activists and in some cases, people who were previously sort of anti-nuclear, are becoming more educated about the other full lifecycle impacts on the environment from other electricity generation types.

“The facts are certainly in our favour in terms of it being the lowest overall carbon footprint and environmental impact from a total environmental cost per megawatt output.”

Industry is in a race against time with climate change, and it is essential to rapidly decarbonise energy with all of the tools available… but on the horizon there is a technology that is expected to supplant fission, even the Gen IV reactors, entirely.

That is fusion, and you can find out more about it in episode #96 Fusion: Britain Builds a Star, which we produced with help from the UK Atomic Energy Authority.

Fusion is another nuclear technology that will be a watershed moment for humanity, in terms of its safety (it does not involve a self-sustaining reaction or highly radioactive material) and its use of abundant hydrogen as fuel.

“It sends shivers down my spine just thinking about it,” says Goodenough. “It feels like we’re getting closer and with some of the recent experiments that that have concluded at the UKAEA in terms of their MAST project and how they can get the heat out of the exhaust is really kind of cemented that yeah, we It really feels like we’re getting somewhere now. And it’s certainly an extremely exciting time.”

As the lead of Atkins’ new nuclear technology business, James looks after small-scale fission and also fusion. His team is delivering multiple projects in support of the UKAEA’s STEP programme, which we cover in detail in episode 96, as well as undertaking the Architect Engineer role (as part of a joint venture) on the famous ITER project in southern France.

But here and now, we need to focus on known technologies that can decarbonise energy. And the only carbon-free source of energy that is classified as ‘firm power’, and not affected by variable climate conditions, is nuclear fission.

For the episode of Engineering Matters this Long Read is based on, click here