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US researchers have proposed the idea of building floating nuclear power plants far out at sea to increase their safety and security.
Engineers from MIT, the University of Wisconsin, and US nuclear and offshore platform construction firm Chicago Bridge and Iron, have presented a study to the American Society of Mechanical Engineers that says plants built on floating platforms like those used for offshore oil drilling, would avoid disasters such as the earthquake and tsunami that struck the Fukushima plant in Japan in 2011.
The nuclear platforms would be built in shipyards and house reactors up to 1000MW in size. They would then be towed five to seven miles out at sea, moored to the sea floor and connected to the grid on land via an underwater transmission line. At such a distance the platform would not be affected by tsunamis. In event of a cooling failure, such as happened at Fukushima after the tsunami, it would use seawater for cooling fuel rods, preventing a meltdown and the escape of radioactive material.
Associate Professors Jacopo Buongiorno of nuclear science and engineering at MIT said the platform would use the mature technologies such as light-water nuclear reactors and offshore oil and gas drilling platforms to minimise risk.
He said: "The biggest selling point is the enhanced safety. It's very close to the ocean, which is essentially an infinite heat sink, so it's possible to do cooling passively, with no intervention. The reactor containment itself is essentially underwater."
Although the concept of a floating nuclear plant is not unique Russia is in the process of building one on a barge moored at the shore — none have been located far enough offshore to be able to ride out a tsunami, Buongiorno added.
Other advantages include the remoteness of the site combined with the availability of cooling water. Decommissioning would also be simplified — the platform would be towed to a central facility, as is done now with the US Navy’s carrier and submarine reactors. In addition shipyard construction also allows for better standardisation, and an all steel design would eliminate the use of concrete, which is often a cause of construction delays and overruns in nuclear plant construction.
Buongiorno said the most suitable market would be Asia, which has a combination of high tsunami risks and a rapidly growing need for new power sources. "It would make a lot of sense for Japan, as well as places such as Indonesia, Chile, and Africa.”