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Putting Nuclear Plants Out to Sea

March 3, 2016

Nuclear power presents a conundrum to many environmentalists. It’s practically the only way to supply the U.S. (or the world) with large, industrial amounts of electricity...

Stephen Mraz Blog

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Researchers at MIT are looking into the possibility of building nuclear power plants at sea, and away from population concerns. Above, the Gundremmingen nuclear power plant in Germany. (Courtesy of Wikimedia Commons)

Nuclear power presents a conundrum to many environmentalists. It’s practically the only way to supply the U.S. (or the world) with large, industrial amounts of electricity without pumping more CO₂ into the atmosphere. But many people (NIMBYs) strongly resist having a nuclear plant built near them for fear of radiation or meltdowns.

One possible solution being put forth by an engineering team at the Massachusetts Institute of Technology envisions large-scale nuclear plants mounted on floating platforms, much like today’s deep-sea drilling platforms, and anchoring them about 10 miles off shore. This makes engineering sense to me on several levels.

It combines proven technologies and each has its own industrial base: deep-sea platforms and nuclear plants.

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They would be built in shipyards already accustomed to building deep-sea platforms and nuclear-powered ships and boats (think aircraft carriers and submarines). This means power plants could be built and decommissioned safely in shipyards already experienced at handling similar tasks. That also means there is no site preparation before “building” the plant or cleanup when it’s no longer operational, or at least a minimal amount.

If marine engineers ensure it is anchored in water of the proper depth (about 300 ft. deep), it should be able to ride out any earthquakes or tsunamis, the Achilles’ heel of the Japanese Fukushima Daiichi plant.

The plant owner no longer has to find a site near a good supply of cooling water, which is usually expensive land. Instead, the plant will be floating in cooling water.

The cooling water would be pumped up from the ocean depths where the water is always relatively cold. After doing its job, the water, now warmed, can be discharged near the surface, so there’s no thermal disruption of the immediate surroundings.

The MIT plan estimates a 300 MW plant would have a cylindrical main structure about 140 ft. in diameter. A 1,100 MW plant would have a 240-ft. diameter.

There might be challenges in building an underwater transmission line that could handle all that power, but it should be possible. (Or they could use all that electricity to extract hydrogen from seawater.) And plant technicians and engineers would have to live and work at sea for a few months at a time, but oil and gas workers do it, as well as sailors.

I would, however, like the team to run the numbers to see what kind of output they could get from an even cleaner and safer thorium plant.