The accident at Fukushima has not plunged the atomic energy industry into crisis. On the contrary, the number of nuclear plants under construction around the world is reaching never-before-seen levels. The nuclear deal only recently struck between the US and India shows a renewed interest in this form of energy supply. The events in Japan, however, still raise questions about safety in the event of major natural disasters. This is in part why an MIT team, led by Jacopo Buongiorno, is studying the possibility of putting reactors on offshore platforms. Placing them on the high seas, he explains, would not only simplify the construction process, but also increase their resilience against earthquakes and tsunamis.
Did Fukushima sound the death knell for the nuclear industry in Europe?
The outlook for the nuclear industry in Europe is more positive than negative. Sure, Switzerland reacted to Fukushima by deciding not to build any new plants and to shut down the current ones when they reach the end of their useful life. Germany too has taken a similar approach, but the phase-out had already been announced during the days of the Schröder government, and was only postponed by Angela Merkel. With the exception of these two countries, however, there have been important developments in Europe, especially in the United Kingdom, which already has quite a significant fleet of reactors and reckons on expanding it further.
Another country that is building new plants is Finland, nor should we forget that France is 75%-powered through nuclear energy, Belgium and Sweden are at 40-50%, and substantial levels are found throughout Eastern Europe. This is despite the great emphasis that several European countries have placed on renewables. But while photovoltaics and wind power are definitely important, they create problems in managing the energy grid when they account for more than 20% of power generation, since their intermittent nature makes it necessary to install backup generators which are generally gas-fueled.
In any case, notwithstanding the advances made in Europe, it is elsewhere in the world that the real gamble on nuclear power is being taken. From this perspective, we are at never-before-seen levels in terms of the number of new plants under construction.
So where are most of these being built?
The spread of nuclear energy is concentrated in the Far East and the Persian Gulf: India and Vietnam definitely, but China – which alone accounts for about 40% of the new plants – is the most important market by virtue of its vast energy needs, currently 80% met by coal as regards electricity generation.
Next there’s the Middle East. Strange as it might seem that such oil-rich nations would invest in nuclear power, the Gulf countries prefer to sell their oil on the international market and use atomic energy to meet domestic needs. It is for this reason that the Emirates are building new reactors with a capacity of 5 Gigawatt, while Saudi Arabia plans to construct 17 GW of nuclear capacity.
Finally, despite the great success of shale gas, there has also been progress on the nuclear front in the United States, especially in those states where the energy market is regulated and offers security to investors. The fact that new reactors are being built in America is in itself a historical step forward, given that the most recent US nuclear installation was completed in 1996.
What advantages could be offered by the offshore reactors your team is studying at MIT?
We started looking into the possibility of building offshore reactors a year and a half ago, and we’re still at a conceptual stage. However, since it involves combining two existing and well-established technologies – water-cooled nuclear reactors and oil rigs – the technological risk is very low. The advantages are significant, both from a financial point of view and from a safety perspective. In fact, the idea is to directly build the reactor in a shipyard and transport it as a single unit, a process capable of ensuring greater speed and certainty of construction compared to building a land-based reactor.
From a safety standpoint, there are three important points: a floating unit is not susceptible to earthquakes, and, since it is moored 10 to 20 km offshore, can count on water depths of at least 100 meters, which eliminates the danger associated with tsunamis. In addition, there is direct access to seawater, with heat exchangers that enable the reactor to be cooled indefinitely without the need for any external intervention. This way, the chances of accidents are reduced to a minimum.
So does the offshore option resolve the safety issue?
At the moment, the project’s greatest Achilles’ heel is that of safety in the event of external attack. Unlike a land-based facility, an offshore reactor is also exposed to possible underwater attack. The problem is not resolved simply by installing underwater barriers to prevent intrusions. The most difficult risk to deal with is an attack carried out by a large ship headed on a collision course with the rig. To obviate this danger also, we are designing the reactor in such a way as to protect the unit in case of impact. The idea is to place the unit, along with its containment structure, at such a depth as to put it out of reach of even the largest ships in circulation.
In addition to the safety problem, there is also a need to put in place the necessary reactor-building infrastructure, even though there are many shipyards in the United States that already have expertise in constructing and decommissioning aircraft carriers and nuclear submarines. Another factor is the social acceptability of offshore nuclear facilities. Although accidents are not likely, the fact that there is still a risk of sea contamination raises a lot of objections. In reality, studies tell us that small leaks of radioactivity in the ocean are diluted and disperse very quickly.
Jacopo Buongiorno has been an Associate Professor of Nuclear Science and Engineering at the Massachusetts Institute of Technology (MIT) since 2004. After obtaining a degree in Nuclear Engineering from the Polytechnic of Milan and a PhD in Nuclear Engineering from MIT, he worked at the Idaho National Laboratory (INL), where he led the Generation-IV program for the development of the supercritical water-cooled reactor in the United States.
