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By Glenn Harlan Reynolds : BIO| 27 Sep 2020
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Whether or not you believe that we're in the midst of an episode of anthropogenic global warming, it seems to me that burning fossil fuels when there are alternatives is obviously a bad idea. Leaving aside greenhouse gases, burning coal and oil releases all sorts of nasty substances into the air, ranging from the obvious -- like hydrocarbons and soot -- to the not-so-obvious, like the surprising amount of radioactivity released into the atmosphere by burning coal.

Furthermore, hydrocarbons like coal and oil have many other valuable non-fuel applications. If we can avoid setting them on fire, it seems like we should.

But that leaves the question of where the energy is to come from. Solar and wind power are nice, but not likely to provide anywhere near enough power barring some dramatic advance. Nuclear power is the obvious alternative, but until recently it's gotten such bad press as to be a non-starter.

Now some environmentalists are beginning to argue that nuclear power is valuable, and maybe even essential if we are to prevent a global environmental catastrophe. One of them is James Lovelock, who argues that the risks of nuclear power are far smaller than the risks from burning coal and oil:

"We live in a nuclear-powered universe. We're the oddballs by getting energy from burning carbon.

"My justification of nuclear power is that we've reached a stage now where the dire things that threaten us are so great that even the results of an all-out nuclear war pale into insignificance as unimportant compared to what's going to happen."

I think -- and hope -- that Lovelock's greenhouse disaster scenario is overly pessimistic. But I could be wrong, and as I've suggested, there are lots of reasons to make the shift from hydrocarbons to nuclear power anyway. To borrow a phrase from Carl Sagan, it's just good planetary hygiene.

What's more, we're fortunate that the choice isn't between continuing to burn fossil fuels or shifting to nuclear power as we've known it over the past several decades. Although nuclear power plants to date have been safer and more economical than is generally appreciated, the current generation of operational nuclear plants is obsolescent and results have been, in many ways, disappointing.

Fortunately, the technology hasn't been standing still. Partly as a result of recent Congressional efforts to fund reactor research, and partly as a result of ongoing work in national laboratories and the nuclear power industry, things in the field are looking up. As a recent survey article in Popular Mechanics magazine makes clear, there are new approaches to nuclear power in the offing that promise cleaner and more efficient power production with far less risk of "all-out" (or even minor) nuclear war in the process. Of these, perhaps the most promising technology is the pebble bed reactor:

"A typical pebble-bed reactor would function somewhat like a giant gumball machine. The design calls for a core filled with about 360,000 of these fuel pebbles -- "kernels" of uranium oxide wrapped in two layers of silicon carbide and one layer of pyrolytic carbon, and embedded in a graphite shell. Each day about 3000 pebbles are removed from the bottom as fuel becomes spent. Fresh pebbles are added to the top, eliminating the need to shut down the reactor for refueling. Helium gas flows through the spaces between the spheres, carrying away the heat of the reacting fuel. This hot gas -- which is inert, so a leak wouldn't be radioactive -- can then be used to spin a turbine to generate electricity, or serve more exotic uses such as produce hydrogen, refine shale oil or desalinate water.

"The pebbles are fireproof and almost impossible to use for weapons production. The spent fuel is easy to transport and store, though there still remains the long-term problem of where to store it. And the design of the nuclear reactor is inherently meltdown-proof. If the fuel gets too hot, it begins absorbing neutrons, shutting down the chain reaction. In 2004, the cooling gas and secondary safety controls were shut off at an experimental pebble-bed reactor in China -- and no calamity followed, says MIT professor Andrew Kadak, who witnessed the test."

China, with a booming economy, a huge population, and air pollution problems that are already absolutely dreadful, is very interested in pebble bed reactors. And they would seem to promise a lot for the United States, too -- plus a way to promote nuclear power in the Third World without the kinds of nuclear-weapons proliferation threats we face today.

As the Popular Mechanics article notes, boosters of new nuclear technology sport bumper stickers reading "split an atom, save a tree." Perhaps they should read "split an atom, save the world."

Glenn Harlan Reynolds is a TCS Daily contributing editor.

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