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Topics: Education, Existentialism, History, Medicine, Nuclear Power

21st-century weather models show how radioactive fallout from atmospheric nuclear tests spread more widely than thought across the US

The Trinity Nuclear Test on 16 July 1945 is a key incident in the blockbuster Oppenheimer movie and in the history of humankind. Many scientists think it marks the beginning of the Anthropocene, a new geological era characterized by humanity’s influence on the Earth. That’s because Trinity’s radioactive fallout will forever appear in the geological record, creating a unique signature of human activity that can be precisely dated.

But there’s a problem. In 1945, radioactive monitoring techniques were in their infancy, so there are few direct measurements of fallout beyond the test site. What’s more, weather patterns were also less well understood, so the spread of fallout could not be easily determined.

As a result, nobody really knows how widely Trinity’s fallout spread across the U.S. or, indeed, how the fallout dispersed from other atmospheric nuclear tests on the U.S. mainland.

Nuclear Mystery

Today, that changes thanks to the work of Sébastien Philippe at Princeton University and colleagues. This team used a state-of-the-art weather simulation for the 5 days after each nuclear test to simulate how the fallout would have dispersed.

The result is the highest resolution estimate ever made of the spread of radioactive fallout across the U.S. It marks the start of the Anthropocene with extraordinary precision, and it throws up some significant surprises. Some parts of the U.S. are known to have received high levels of fallout, and the new work is consistent with this. But the research also reveals some parts of the US that received significant fallout without anybody realizing it.

The findings “provide an opportunity for re-evaluating the public health and environmental implications from atmospheric nuclear testing,” said Philippe and co.

Between 1945 and 1962, the U.S. conducted 94 atmospheric nuclear tests that generated yields of up to 74 kilotons of TNT. (Seven other tests were damp squibs.) 93 of these tests took place in Nevada, but the first, the Trinity test in the Oppenheimer film, took place in New Mexico.

How The Trinity Nuclear Test Spread Radioactive Fallout Across America, the Physics arXiv Blog, Discover Magazine

The underground Onkalo repository in Finland is designed to safely and permanently store hazardous, radioactive waste. Credit: Posiva

Topics: Environment, High Energy Physics, Nuclear Power

Finland and the former Yugoslavia adopted nuclear energy only four years apart. In 1971 Finland began construction of its first nuclear plant, Loviisa, and the first of two planned reactors went into commercial operation in 1977. Yugoslavia started building the Krško plant in 1975. In the 1980s, both countries acknowledged the need for a long-term nuclear waste management strategy and started making plans for permanent disposal repositories.

Fast-forward four decades, and Finland is on the verge of becoming the world’s first country to achieve permanent deep geological disposal for spent nuclear fuel, the highly radioactive waste that contains uranium, plutonium, fission products, and other heavy elements. Meanwhile, the fate of the spent fuel generated at Krško, which is jointly owned by former Yugoslavian republics Croatia and Slovenia, is still very much unknown. Both countries have yet to get a handle on even low-level radioactive waste, including contaminated clothes and water filters, which is slowly overwhelming storage facilities and threatening to halt plant operations.

The US has long struggled to find a final resting place for its nuclear waste, to the point that it is now spending billions of dollars to reimburse plant operators for the costs of storing spent fuel. The dramatically different outcomes of Finland and Croatia’s lengthy searches for permanent nuclear waste solutions are reflections of the varied ways in which this long-standing worldwide problem is being tackled by the nations of the European Union. Whereas Finland, Sweden, and France are expected to open permanent underground spent-fuel repositories by the early 2030s, 12 other nuclear EU countries are far behind, planning to open deep geological disposal facilities sometime between the 2040s and the 2100s. According to a 2019 European Commission report on the implementation of its nuclear waste directive, only a few of those nations have made progress in selecting a site.

European Union nations grapple with nuclear waste storage, Vedrana Simičević, Physics Today.

The design concept of BWXT Advanced Nuclear Reactor. BWX Technologies

Topics: Applied Physics, Alternate Energy, Climate Change, Nuclear Power

According to the US Energy Information Administration, the US uses a mixture of 60.8% fossil fuel sources to generate 2,504 billion kilowatt hours of energy. Our nuclear expenditure is a paltry 18.9%. The totality of renewable sources (wind, hydropower, solar, biomass, and geothermal) is a little higher: 20.1%. This is the crux of the "Green New Deal."

Though I long for the cleaner, neater version of nuclear power in fusion, it's kind of hard to mimic the pressures and magnetic fields necessary to spark essentially a mini sun on the planet. I think the resistance to nuclear fission is cultural: from the atomic bomb, Oppenheimer quoting the Bhagavad-Gita at the first successful testing, a classic "what have we done" trope. Popular fiction emphasizes doomsday scenarios and radioactive zombies. Honorable mention: Space 1999, which like zombies I doubt could ever happen, but it kept my attention in my youth. There are also genuine concerns about Chernobyl (still in Ukraine), Three-Mile Island, and Fukushima Daichi that come to the public's mind.

The reason the percentages on fossil fuels are so high is that they release extreme amounts of energy to superheat water for turbines to turn magnets superfast in copper coils. That is how most of the electricity we consume is made.

France currently generates 70% of its energy from nuclear power plants, with plans to reduce this to 50% as they mix in renewables. This is proportional to the percentage the US already has in renewables. My only caveat is an obsolescence plan for solar panels (they have to be implanted with caustic impurities to MAKE them conductive, and after twenty years, could end up in a landfill near humans). Battery-operated vehicles are fine, but Lithium has to be mined, it requires a lot of water, typically the indigenous peoples near the mines don't make a profit, and their land and resources are spoiled.

If we truly are going to transition from fossil fuels to "cleaner energy," I think we should realize that power plant designs have improved greatly since the aforementioned disasters.

As an engineer, I always tried to follow this edict from my father: "Experience isn't the best teacher: other people's experiences are the best teacher." In short, learn from others' mistakes, and try to not repeat them. It works in other nontechnical areas of life as well.

I (fingers crossed) assume nuclear power plant design engineers follow something similar to improve on future designs for safety, and as we've been exposed to with the war in Ukraine, global energy security.

I'm proposing an "everything on the table strategy," not Pollyanna. By the way, our "carbon footprint" appears to be a boondoggle by the industries that caused our current malaise.

The U.S. Department of Energy's Advanced Reactor Demonstration Program commonly referred to as ARDP, is designed to help our domestic nuclear industry demonstrate its advanced reactor designs on accelerated timelines. This will ultimately help us build a competitive portfolio of new U.S. reactors that offer significant improvements over today’s technology.

The advanced reactors selected for risk-reduction awards are an excellent representation of the diverse designs currently under development in the United States. They range from advanced light-water-cooled small modular reactors to new designs that use molten salts and high-temperature gases to flexibly operate at even higher temperatures and lower pressures.

All of them have the potential to compete globally once deployed. They will offer consumers more access to a reliable, clean power source that can be depended on in the near future to flexibly generate electricity, drive industrial processes, and even provide potable drinking water to communities in water-scarce locations.

5 Advanced Reactor Designs to Watch in 2030, Alice Caponiti, Deputy Assistant Secretary for Reactor Fleet and Advanced Reactor Deployment, Office of Nuclear Energy

Topics: Alternate Energy, Climate Change, Nuclear Power, Thorium

The Royal Society of Chemistry: Thorium (named for a certain Marvel character).

If China’s experimental reactor is a success it could lead to commercialization and help the nation meet its climate goals.

Scientists are excited about an experimental nuclear reactor using thorium as fuel, which is about to begin tests in China. Although this radioactive element has been trialed in reactors before, experts say that China is the first to have a shot at commercializing the technology.

The reactor is unusual in that it has molten salts circulating inside it instead of water. It has the potential to produce nuclear energy that is relatively safe and cheap, while also generating a much smaller amount of very long-lived radioactive waste than conventional reactors.

Construction of the experimental thorium reactor in Wuwei, on the outskirts of the Gobi Desert, was due to be completed by the end of August — with trial runs scheduled for this month, according to the government of Gansu province.

Thorium is a weakly radioactive, silvery metal found naturally in rocks, and currently has little industrial use. It is a waste product of the growing rare-earth mining industry in China and is, therefore, an attractive alternative to imported uranium, say researchers.

China prepares to test thorium-fueled nuclear reactor, Smriti Mallapaty, Nature

LAWRENCE LIVERMORE NATIONAL LABORATORY

Topics: Energy, Environment, Modern Physics, Nuclear Fusion, Nuclear Power

More than a decade ago, the world’s most energetic laser started to unleash its blasts on tiny capsules of hydrogen isotopes, with managers promising it would soon demonstrate a route to limitless fusion energy. Now, the National Ignition Facility (NIF) has taken a major leap toward that goal. Last week, a single laser shot sparked a fusion explosion from a peppercorn-size fuel capsule that produced eight times more energy than the facility had ever achieved: 1.35 megajoules (MJ)—roughly the kinetic energy of a car traveling at 160 kilometers per hour. That was also 70% of the energy of the laser pulse that triggered it, making it tantalizingly close to “ignition”: a fusion shot producing an excess of energy.

 “After many years at 3% of ignition, this is super exciting,” says Mark Herrmann, head of the fusion program at Lawrence Livermore National Laboratory, which operates NIF.

NIF’s latest shot “proves that a small amount of energy, imploding a small amount of mass, can get fusion. It’s a wonderful result for the field,” says physicist Michael Campbell, director of the Laboratory for Laser Energetics (LLE) at the University of Rochester.

“It’s a remarkable achievement,” adds plasma physicist Steven Rose, co-director of the Centre for Inertial Fusion Studies at Imperial College London. “It’s made me feel very cheerful. … It feels like a breakthrough.”

And it is none too soon, as years of slow progress have raised questions about whether laser-powered fusion has a practical future. Now, according to LLE Chief Scientist Riccardo Betti, researchers need to ask: “What is the maximum fusion yield you can get out of NIF? That’s the real question.”

Fusion, which powers stars, forces small atomic nuclei to meld together into larger ones, releasing large amounts of energy. Extremely hard to achieve on Earth because of the heat and pressure required to join nuclei, fusion continues to attract scientific and commercial interest because it promises copious energy, with little environmental impact.

With explosive new result, laser-powered fusion effort nears ‘ignition’, Daniel Clery, Science Magazine