Der folgende Beitrag ist zwar vor der Erdebeben-/Tsunami-/Kernkraftwerkkatastrophe in Japan erschienen, aber das Thema ist mit Sicherheit noch nicht zu den Akten gelegt.

Could underwater nuclear stations be headed for the English channel?
lans for undersea nuclear reactors around the coast of France could see a boom in uptake of the technology – but serious questions about costs and waste remain unanswered

There are now 58 nuclear reactors in France, which provide nearly 80 per cent of the country’s electricity supply. Now, in a bid to bring dependable energy to remote coastal communities, the French government has decided to give the green light to a different kind of nuclear power programme – smaller nuclear reactors to be based on the ocean floor.

In January, France’s naval construction firm DCNS agreed on a joint two-year study of a concept for submerged nuclear power plants together with French company Areva, Electricité de France and the French Atomic Energy Commission (CEA). Promoters say these could provide energy for millions of people in coastal locations worldwide.

The concept for the nuclear submarine, known as FlexBlue, involves a cylindrical vessel about 100 meters long and 15 meters in diameter that would encase a complete nuclear power plant with an electrical capacity of between 50 MW and 250 MW. By comparison Sizewell B power station in Suffolk has an output of almost 1200MW.

Flexblue would comprise a small nuclear reactor, a steam turbine-alternator set, an electrical plant and associated electrical equipment. Submarine power cables would carry electricity from the Flexblue plant to the coast.

With costs significantly cheaper than traditional onshore reactors – estimated at several hundred million Euros compared to about 5 billion Euros for a full-sized reactor – French engineers believe it could lead to a boom in the uptake of nuclear power.

The French are not the only ones interested in offshore nuclear power. The Russians have already developed the design for a floating nuclear power plant which uses two 70-MW reactors derived from those used in Russian submarines and icebreakers and launched a prototype last year.

Cores would be protected by three barriers: fuel cladding, reactor vessel and hull. The designers argue that immersion in sea water would ensure an infinite natural means of passive cooling and permit inherent safety and security. In addition, each plant would also be protected against potential intruders. The French argue that a submerged power plant would be less vulnerable to earthquakes, tsunamis, or floods, and would be far less vulnerable to terrorist attack.

Sceptics are concerned that warmer water released from the reactors could be dangerous for local ecosystem. And, should there be a nuclear accident ‚the sea will be destroyed,‘ according to the President of Anti-nuclear organisation Crilan, based in Cherbourg. ‚The fierce warming-up of the water will cause a massive thermal shock that will destroy sea life.‘

However, supporters of Flexblue have attempted to downplay concerns suggesting the undersea reactors would be based entirely on proven technologies, simply combined in a new way. They say with two-thirds of the world’s population currently living within 80 kilometres of the sea the new technology could make nuclear power more attractive to countries. For more remote locations, the nuclear reactors could allow for a fast and efficient way to add electrical supply to the region without needing any surface-based infrastructure, including the kind of supply systems needed for coal or oil-powered stations.