Offshore nuclear plants, anchored in deep water, could be the answer to preventing catastrophic tsunami and earthquake damage like that inflicted on the Japan's Fukushima Daiichi complex in 2011, according to research underway at MIT.

A team led by the university's Dr. Jacopo Buongiorno is developing a design for a nuclear reactor that he says has the potential "of revolutionizing the nuclear industry, both in terms of economics and safety."

The facility could be built entirely in a shipyard, then towed several miles offshore and linked to the electric grid with a transmission line, Buongiorno says in a video presentation of his research.

Although the concept of a floating nuclear plant is not new— Russia is now building one on a barge moored at the shore—none have been located far enough offshore to be able to ride out a tsunami, says Buongiorno, an associate professor of nuclear science and engineering.

He and his team presented the concept last week at the Small Modular Reactors Symposium, hosted by the American Society of Mechanical Engineers.

Safety Offshore

For this new design, Buongiorno says, “the biggest selling point is the enhanced safety.”

With the facility far offshore, moored in about 100 meters of water, "the biggest issue that faces most nuclear plants under emergency conditions—overheating and potential meltdown, as happened at Fukushima, Chernobyl, and Three Mile Island—would be virtually impossible at sea," MIT said in a research announcement.

Such a complex would be immune to the effects of tsunamis and earthquakes, Buongiorno contends. Like offshore oil drilling platforms, the facility would include living quarters and a helipad for transportation to the site.

Illustration courtesy of Jake Jurewicz/MIT-NSE

A cutaway view of the proposed plant shows that the reactor vessel itself is located deep underwater, with its containment vessel surrounded by a compartment flooded with seawater, allowing for passive cooling even in the event of an accident.

“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," he says. "The reactor containment itself is essentially underwater.”

Other Advantages

Buongiorno sees other advantages in his plan.

For one thing, he says, it is increasingly difficult and expensive to find suitable sites for new nuclear plants. They usually need to be next to an ocean, lake, or river to provide cooling water, but shorefront real estate consumes much of the available land.

Plants offshore, but out of sight from land, could be located close to the markets they serve.

“The ocean is inexpensive real estate,” Buongiorno says.

Second, if an accident occurs at an offshore facility, he said, it should not require widespread evacuations, as is currently the case.

In addition, decommissioning the plant at the end of its life could be accomplished by simply towing it away to a central facility, as is done now for the Navy’s carrier and submarine reactors. The ocean site would remain pristine, according to MIT.

Construction and Security

Meanwhile, shipyard construction allows for better standardization of facilities, and the steel design eliminates the use of concrete, which Buongiorno says is often responsible for construction delays and cost overruns.

Screen grab / Christopher Sherrill, MIT Department of Nuclear Science and Engineering

Offshore nuclear plants have several advantages, including cost and construction standards, says Dr. Jacopo Buongiorno, but “the biggest selling point is the enhanced safety.”

The design is flexible, allowing for plants of any size, up to today's largest facilities. Once in operation, the plant would operate like an on-shore facility and under the same regulatory security requirements.

“Project work has confirmed the feasibility of achieving this goal, including satisfaction of the extra concern of protection against underwater attack,” says Professor Neil Todreas, MIT's KEPCO Professor of Nuclear Science and Engineering and Mechanical Engineering, a member of the research team

'Very Feasible'

Buongiorno sees a market for such plants in Asia, which has both high tsunami risks and a rapidly growing need for new power sources. “It would make a lot of sense for Japan,” as well as Indonesia, Chile, and Africa, he says.

MIT professor Michael Golay and others from MIT and the University of Wisconsin are also involved in the project. Another key partner is Chicago Bridge and Iron, of Canton, MA, a major nuclear plant and offshore platform construction company.

One Japanese nuclear scientist who is not involved in the project calls it "very attractive and promising."

“I think this is technically very feasible," says Toru Obara, a professor at the Research Laboratory for Nuclear Reactors at the Tokyo Institute of Technology. "...Of course, further study is needed to realize the concept, but the authors have the answers to each question —and the answers are realistic.”