Thu. Oct 17th, 2019

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The new, safer nuclear reactors that might help stop climate change

3 min read

From sodium-cooled fission to advanced fusion, a fresh generation of projects hopes to rekindle trust in nuclear energy.

BP might not be the first source you go to for environmental news, but its annual energy review is highly regarded by climate watchers. And its 2018 message was stark: despite the angst over global warming, coal was responsible for 38% of the world’s power in 2017—precisely the same level as when the first global climate treaty was signed 20 years ago. Worse still, greenhouse-gas emissions rose by 2.7% last year, the largest increase in seven years.

Such stagnation has led many policymakers and environmental groups to conclude that we need more nuclear energy. Even United Nations researchers, not enthusiastic in the past, now say every plan to keep the planet’s temperature rise under 1.5 °C will rely on a substantial jump in nuclear energy.

But we’re headed in the other direction. Germany is scheduled to shut down all its nuclear plants by 2022; Italy voted by referendum to block any future projects back in 2011. And even if nuclear had broad public support (which it doesn’t), it’s expensive: several nuclear plants in the US closed recently because they can’t compete with cheap shale gas.

“If the current situation continues, more nuclear power plants will likely close and be replaced primarily by natural gas, causing emissions to rise,” argued the Union of Concerned Scientists—historically nuclear skeptics—in 2018. If all those plants shut down, estimates suggest, carbon emissions would increase by 6%.

At this point, the critical debate is not whether to support existing systems, says Edwin Lyman, acting director of the UCS’s nuclear safety project. “A more practical question is whether it is realistic that new nuclear plants can be deployed over the next several decades at the pace needed.”

As of early 2018 there were 75 separate advanced fission projectstrying to answer that question in North America alone, according to the think tank Third Way. These projects employ the same type of reaction used in the conventional nuclear reactors that have been used for decades—fission, or splitting atoms.

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One of the leading technologies is the small modular reactor, or SMR: a slimmed-down version of conventional fission systems that promises to be cheaper and safer. NuScale Power, based in Portland, Oregon, has a 60-megawatt design that’s close to being deployed. (A typical high-cost conventional fission plant might produce around 1,000 MW of power.)

NuScale has a deal to install 12 small reactors to supply energy to a coalition of 46 utilities across the western US, but the project can go ahead only if the group’s members agree to finance it by the end of this year. History suggests that won’t be easy. In 2011, Generation mPower, another SMR developer, had a deal to construct up to six reactors similar to NuScale’s. It had the backing of corporate owners Babcock & Wilcox, one of the world’s largest energy builders, but the pact was shelved after less than three years because no new customers had emerged. No orders meant prices wouldn’t come down, which made the deal unsustainable.

While NuScale’s approach takes traditional light-water-cooled nuclear reactors and shrinks them, so-called generation IV systems use alternative coolants. China is building a large scale sodium-cooled reactor in Fujian province that’s expected to begin operation by 2023, and Washington-based TerraPower has been developing a sodium-cooled system that can be powered with spent fuel, depleted uranium, or uranium straight out of the ground. TerraPower—Bill Gates is an investor—forged an agreement with Beijing to construct a demonstration plant by 2022, but the Trump administration’s restrictions on Chinese trade make its future questionable.

Another generation IV variant, the molten-salt reactor, is safer than earlier designs because it can cool itself even if the system loses power completely. Canadian company Terrestrial Energy plans to build a 190 MW plant in Ontario, with its first reactors producing power before 2030 at a cost it says can compete with natural gas.

One generation IV reactor could go into operation soon. Helium-cooled, very-high-temperature reactors can run at up to 1,000 °C, and the state-owned China National Nuclear Corporation has a 210 MW prototype in the eastern Shandong province set to be connected to the grid this year.

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