Jacopo Buongiorno, MIT

Researchers at the Massachusetts Institute of Technology (MIT) have proposed a tsunami-proof nuclear concept that combines current reactor technology with a rig similar to those used in oil and gas. MIT’s Jacopo Buongiorno outlines the benefits.

MIT Professor Jacopo Buongiorno; background image shows a dispersion of nanoparticles in water that accelerates quenching of a hot rodlet (simulating a nuclear fuel rod), a feature that may be used to improve the thermal performance of nuclear reactors.

By Jason Deign

Jacopo Buongiorno is the lead author of a paper on the offshore small modular reactor (OSMR), in which reactors can be sited in deep water using an oil rig-like platform.

Q: What is unique about the OSMR concept?

The first thing to say is that even though our paper discusses an offshore floating SMR, the concept is not limited to SMRs. In principle, you could have a 1,000MW reactor. The platform would be bigger, that’s all.

It is unique compared to Russian floating reactors because those are floating plants but they are not really offshore.

By putting our concept a few miles off the coast, should there be an accident you would have more distance from habitation; say up to 10 miles, which is the current mandated evacuation zone in the US. The other difference has to do with tsunamis.

If you have a plant on the coast, it could still be damaged by a tsunami wave. But at 100 metres of depth they are of no concern; the plant rides the wave. Tsunamis are eliminated as a security concern. That makes our concept different to the Russian concept.

There are two other concepts that might be compared to ours. One is the French submerged concept, Flexblue, but that is essentially designed to be operated remotely. The other is the old Atlantic generating station idea that progressed to a contract with Westinghouse.

However, that was a large terrestrial plant mounted on a barge, which did not take advantage of any of the intrinsic advantages of being offshore, like putting the reactor below the water level for cooling purposes.

Q: Where do you expect to commercialise this?

Currently in the US the appetite for new reactors is very low, as we have extremely low prices for natural gas. Nuclear is clearly not the preferred choice. But the situation could change very quickly if we start exporting gas.

Western Europe is heavily dependent on Russian gas and one thing the US could do is start selling American liquefied natural gas to Europe.

That could push domestic gas prices up again, and then this reactor would make sense on the West Coast because you have deep water, up to around 100 metres, fairly close to shore.

Even today, it would still make sense in any country with deep water next to the shore and any country that is highly seismic, because it eliminates the tsunami problem.

So in Japan, Chile, Peru, China, the Philippines and Indonesia, all countries that are highly seismic, it would make a lot of sense.

Q: How would you deal with operations and maintenance?

As far as operations are concerned, what we have in mind is the oil and gas platform model, having people on the rig for two or three-week shifts.

Minor maintenance would be done by the crew on board and for major maintenance you would move the rig back to a centralised facility, say every 10 to 15 years.

Q: Are there safety considerations with being so far offshore?

The basic safety question with nuclear reactors is how to ensure cooling under any circumstances. Our reactor is in a containment structure that is of the order of 15 to 20 metres underwater, so we have easy access to ocean water.

We are using the ocean as our ultimate heat sink. Even if you have a meltdown, which is very unlikely, the fuel and radioactivity are retained in the reactor.