It promises to fix all the problems with traditional nuclear power, making it cheaper, faster, and easier to build.

Smaller, safer, modular units.

A game changer for nuclear going forward.

It's called a small modular reactor, and over the past few decades, more than 80 start-ups and projects have been working on this futuristic vision.

But there's one big problem. So far, only one has actually been built.

There are reasons why small modular reactors are not being built, even though many people are talking about them.

Nuclear power is in the spotlight again, as the world rushes to find clean energy alternatives.

SMRs could be a really useful tool for doing things that big nuclear plants can't do yet.

And they have a leg up from renewables because they could provide constant power everywhere.

But after decades of nuclear decline,

Western countries are really struggling to make this technology work.

And developing countries like China, Russia, and India seem to be pulling ahead fast.

So, do SMRs deserve all this hype? And how can we actually make them happen?

Nuclear power is a very divisive topic, with a lot of strong arguments for and against the technology.

It's a powerful low-carbon alternative to fossil fuels, and unlike renewables like solar and wind, which fluctuate based on the weather, nuclear has a consistent output.

The IEA, an international body that advises governments on the transition to clean energy, says nuclear has to more than double by 2050 if we want any chance at reaching net zero.

The problem with nuclear is that it's really big and expensive, takes too long to build, and could cause civilization-ending disaster.

In the 70s and leading up to the 80s, there was high public support.

Dr. Kuhika Gupta researches public support for nuclear energy in the United States and India.

That momentum really crashed through the 80s and 90s with the Chernobyl Three Mile Island incidents that happened.

We made a video on the rise and fall of nuclear energy as a tool to fight climate change, which you can watch here.

Nuclear energy really struggled to bounce back from those big disasters.

And when the Fukushima nuclear accident happened in 2011, the industry's credibility took another massive hit.

But things are starting to look up again.

Public support has maybe started trickling back to pre-Fukushima levels, and support is even higher for small modular or other type of advanced reactor technologies.

That might be because a lot of these SMRs have some very flashy advertising.

While there are lots of different SMRs being developed, there's currently four main types, each using a different coolant to manage the extreme heat of a nuclear fission reaction.

They are light water, high temperature gas, liquid metal, and molten salt SMRs.

The most common type, though, is light water reactors.

They're very similar to traditional nuclear power plants, which are almost all water-cooled.

That makes them much easier to design and get approved, as today's nuclear regulations are mostly based on water-cooled reactors.

For light water reactors, the idea is to take a big traditional nuclear power plant, shrink it down, and mass-produce it.

It would work very much like airliners.

Dr. Adam Stein is an engineer, researcher, and consultant who focuses on nuclear energy.

Instead of how we've typically built most nuclear power plants in the past, which is completely from scratch, usually mostly at the power plant site.

If you think of a large jumbo jet, it's built in a factory, in a consistent manner, with the same parts every time, with rigorous quality control.

Dr. Stein says making it in a factory means you can keep the same specialized workforce, the same supply chain, and the same standards, and just ship the already-made power plant to wherever it needs to go.

These small plants would have a much smaller output than a full-size nuclear reactor.

Most definitions of SMRs put them anywhere up to 300 megawatts, which means today's average full-size nuclear reactors output more than triple the biggest SMRs.

But in exchange, they take up very little space.

Nuclear already uses the least amount of land amongst low-carbon energy sources by far, and SMRs could take that to the next level.

NuScale, one of the biggest SMR developers, claims that this power plant, the Voyager 12, would take up 0.13 square kilometers of land, output the equivalent of 18.6 square kilometers of solar panels.

So that could get nuclear power online in more places much faster.

But what about the risk of nuclear accidents?

Well, SMRs have an answer for that too, and it's called passive safety.

In nearly all of today's nuclear power plants, the biggest safety task is keeping the core of the reactor cool enough if the plant suddenly shuts down and stops making power.

If the coolant stops circulating for long enough, the fuel will get too hot and melt down.

That creates the risk of leaking radioactive material into the surrounding area if all the material doesn't stay contained in the core.

That's what happened at the Fukushima Daiichi plant in 2011 after an earthquake triggered a safety shutdown.

The plant automatically switched to its backup generators to keep the coolant circulating through pumps.

But an hour later, a massive tsunami triggered by the earthquake wiped out the plant's backup systems, and three reactors melted down.

So to avoid this type of scenario, many newer generation power plants use passive and self-contained safety systems that don't rely on human operators or external power.

This approach is seen as safer than previous models.

And many SMR safety designs claim to be completely passively cooled without the need for any external water either.

To do that, they would use a natural force called convection, which is basically the same thing that happens in a kettle.

When liquids and gases get hot, they rise to the top, and when they cool, they sink to the bottom, creating a loop.

To take advantage of convection, these SMRs have a series of chambers that can allow for passive circulation of water.

The reactor core is placed inside a larger shell, which is submerged in water in a containment structure underground.

In an emergency, the nuclear reaction which generates heat would shut down, and the reactor would close itself off, not letting anything in or out.

So to get rid of the remaining heat inside the core, convection comes in.

As the water inside the core heats up, it rises to the top, turns into steam, and gets pushed out into the larger shell, which is kept cool from the water it's submerged in.

That steam hits the larger shell, condenses back into water, and pools at the bottom, ready to flow back into the reactor and continue the cycle.

In theory, that cycle can just keep going until the reactor cools down enough to no longer be a threat.

But while there's a lot of hype around these innovative designs, the likelihood of SMRs ever actually working out depends a lot on how you look at them.

Are they like any other type of energy source, standing on their own feet and making a profit in the free market?

Or are they a strategic asset that governments can use to fill the gaps while they phase out of fossil fuels, even if they lose money building them?

Analysts say that first way is the approach in the US and EU, and so far, it hasn't worked out too well.

It was just too expensive.

That's Dr. Friederike Fries, a physicist and nuclear energy researcher.

She says that despite a surge of SMR startups and projects in the US and Europe over the past decade, small nuclear has run into the same problems as big nuclear, with heavy regulations, project delays and cost blowouts.

And because it's smaller, it also makes less money.

SMRs lose the economy of scale in energy production.

The smaller the output, the less revenue you can make.

So you have to have really tailored applications.

This is a really, really small market.

When you add to that rising inflation and the increasing costs of essential materials to make these plants, like steel, you get a recipe for financial meltdown.

That happened last November to NuScale, one of the first and most promising SMR startups and the only one with US regulatory approval.

After decades of planning, the company cancelled its first ever deployment of reactors in Idaho.

NuScale says the project, called the CFPP, faced unique challenges and ended due to a lack of subscriptions.

But many analysts say increasing costs played a big part.

NuScale was supposed to be built in the United States, which has a long history in nuclear power plants.

It has the biggest civil nuclear fleet, and still it did not work out.

There was support from the government, support from the regulatory authority, and still it did not work out. It was just too expensive.

The price tag was like, per kilowatt hour,

I think in the end about four times than what they usually have at conventional nuclear power plants right now.

NuScale's president says the company is continuing with its other domestic and international customers to bring American SMRs to market, including a project to replace a decommissioned coal plant in Romania with a Voyager SMR plant.

But NuScale is an example of how tough it is for private companies and startups in the West to get small modular reactors going.

So what about that second approach?

Looking at SMRs as a strategic national investment that might not necessarily make a lot of money.

That's the approach taken by countries like China and Russia, where SMR projects are almost entirely state-run, operated by national companies like China's CNNC and Russia's Rosatom.

In the past, countries that were able to build nuclear power successfully and have those be successful industrial investments were ones that were able to control their costs by avoiding unnecessary regulatory burdens and then also control revenue by allowing them to make sure they could compete effectively on the downstream, that they could sell into a market and be assured of a reasonable rate of return for selling power.

That's David Fishman, an economics and policy analyst who specialises in China's energy sector.

Countries like China right now, they do a great job controlling costs upstream and they do an excellent job ensuring revenue for the power sales downstream.

That's because even if you have a great design for an SMR, experts say quite a few different steps have to come together to make it all happen.

There's the materials needed to build the facility, which all have to be certified as nuclear safe.

Then there's the workforce to build the plant and the workforce to operate it.

Then there's getting the fuel needed to run the reactor.

So rather than all of these steps being done by different private companies who all need to make a profit, countries like China and Russia package up all of these steps and sell them as a bundle.

It's not just the technology you're getting, it's also coming with the entire supply chain solution, it's coming with the low-interest loans that are provided by the exporting companies' banks, maybe the import-export bank of China is getting a big low-interest loan, something like that.

And for the current environment, it feels like that's just much more competitive.

And Fishman says that approach has allowed SMR projects in China to keep moving, even when they run into challenges.

In 2019, China's National Nuclear Corporation began work on a 125-megawatt SMR project on Hainan Island called Linglong-1.

It's scheduled to be finished by the end of 2026, which would make it the first commercial land-based SMR in the world.

And that strategic national investment approach could also make some SMRs that have really niche uses more likely to work out too, like high-temperature gas-cooled or molten-salt reactors, which are currently some of the only alternatives to coal for industrial processes that need a lot of heat, like making food, cement or chemicals.

We made a video on molten-salt reactors and thorium, which you can watch here.

So that's the end of the story, right?

State-run projects are the solution that will finally get SMRs happening, and soon there'll be hundreds of reactors being built and shipped all over the world.

Not quite.

There are still a lot of questions hanging over SMRs that need to be answered before the dream of factory-built nuclear can come true.

The world's energy needs are increasing rapidly, and we're still a long way away from net-zero emissions.

So while SMRs do have their uses, some experts say countries that decide to invest more in nuclear are more likely to need bigger, not smaller, plants.

China is going to do better than everybody else, and it's still only going to have this kind of impact on the decarbonisation journey and on the offsetting of coal journey.

And while public opinion on nuclear is improving, the idea of having thousands of small nuclear plants all over the world raises concerns for some about how all that waste is going to be managed.

Some SMR designs have closed fuel cycles that could theoretically last up to 30 years, but the science is still out on that, and some studies have shown SMRs using more, not less, nuclear fuel overall.

Still, many advocates point out that we're probably going to need nuclear for a lot longer than 2050, or whenever we manage to reach net-zero.

The world's population and energy needs are going to keep rising, and the strategy of using nuclear alongside renewables looks like it's here to stay.

So what do you think of these small nuclear reactors?

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