Floating Nuclear Reactors Might Make More Sense Than You'd Think

Illustration for article titled Floating Nuclear Reactors Might Make More Sense Than You'd Think

At a symposium held by the American Society of Mechanical Engineers this week, a team of MIT engineers will present an idea that seems to tempt fate: A floating nuclear reactor, anchored out at sea, that would be immune to tsunamis and earthquakes. Is it really that crazy of a plan?

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First, here's what they're proposing. MIT professors Jacopo Buongiorno, Michael Golay, and Neil Todreas are the authors of a paper that describes a massive reactor that's built in a shipyard, then towed out to sea like an oil platform. A few miles off the coast, the reactor would be anchored in a single spot, feeding the power it produces back to the cities on the shore.

Russia is already building a floating reactor, and as Paleofuture has pointed out before, this idea isn't actually new at all: Floating plants were envisioned as early as the 1970s. But Buongiorno points out, but there are some key differences between the Russian plan and MIT's, which he says gives their plan "crucial advantages." First, MIT's design isn't so much a ship that moves around but an anchored platform, which means it's never in a situation where a tsunami or earthquake could affect it.

Second, and most important, is the cold ocean water that would surround the reactor. All those billions of tons of seawater will act as an endless source of cooling for the internal rods, ensuring that they never, ever overheat.

"The ocean itself can be used as an infinite heatsink," says Buongiorno. "It's possible to do cooling passively, with no intervention. The reactor containment itself is essentially underwater."

Illustration for article titled Floating Nuclear Reactors Might Make More Sense Than You'd Think

Another important part of the design is how it would lessen the dangers of decommissioning the plant in fifty years: Rather than undertaking the long, slow process of removing the rods and demolishing the plant, it would be towed "to a central facility, as is done now for the Navy's carrier and submarine reactors." If a meltdown occurred, the plant could "vent radioactive gasses underwater" rather than releasing them into the atmosphere and forcing millions to evacuate.

Wouldn't releasing radioactive gasses underwater also be pretty terrible, environmentally? Why not just stop building nuclear power plants altogether? That's not really the question these engineers set out to answer. This is about making the plants, whether or not countries chose to build them, safer.

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But it's hard to ignore the extraordinary moral implications of that particular detail. Given the choice between spraying humans with radioactive fumes and spraying the ocean floor, most of us would probably choose the latter. It's tough to argue with that, but it's also tough to endorse it. [MIT]

DISCUSSION

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Wouldn't releasing radioactive gasses underwater also be pretty terrible, environmentally?

It depends on the quantity of radioactive materials released.

If it's on the scale of Three Mile Island or Fukushima, which is a fairly worst-case scenario for western designed civilian plants... nah. It would be low enough in quantity, and scattered widely enough that it would be lost in background radiation pretty quickly.

As long as it's reported (Unfortunately, a big 'if') and seafood from the area is avoided for a few months, the human impact would be pretty low, limited to the workers on site. Even if it's not reported, the human impact would still be pretty low, likely on the order of single digit additional cases of thyroid cancer.


Why not just stop building nuclear power plants altogether?

There are three options we have for baseload power generation. Nuclear, Coal, and Hydroelectric.

Hydroelectric has huge environmental impact, but only the one time. And there isn't much in the way of hydroelectric generation possibilities that aren't already tapped.

Coal releases massive, massive quantities of particulates, and stuff like mercury and radioactive isotopes (Surprise!) into the atmosphere. Even with good scrubbers (Which reduce the efficiency of the plant, but I think we can all agree the payoff is worth that price), they are inherently dirty. Oh, and they have that CO2 stuff we keep saying we want to reduce.

Nuclear releases nothing to the atmosphere while operating within normal conditions, including zero CO2. It releases less radiation into the environment than a coal plant does, thanks to the trace radioactive elements in coal ash. It doesn't cause lung problems like coal plants do. There's a massive stockpile of viable fuel, even for our current inefficient and wasteful fuel cycles. The current waste can be used as viable fuels in alternate reactors, should we decide to get serious about that. And the only downside to civilian nuclear power generation is a small risk of catastrophic failure which has resulted in fatalities once in the sixty-plus years of civilian nuclear power generation.

Coal, meanwhile has had its share of massive environmental contamination disasters as well, but 'nuclear' scares people. "Fly ash" doesn't.