Russia's floating nuclear plants to power remote Arctic regions
These reactors, mounted on huge, 140m by 30m barges, are being built in the Baltic shipyard in St Petersburg and will be floated through the Norwegian and Barents Seas to where they will generate heat and electrical power in the Arctic.
The first, Academician Lomonosov, has been built and its two 35MWe KLT-40S reactors are now being installed. Lomonosov is destined for Vilyuchinsk, on the Kamchatka Peninsula in the Russian Far East where she will be operating by 2016. Up to ten similar plants are destined for similarly remote and unpopulated areas.
Power where it’s needed
Russia is building these reactors to help extract its most valuable asset: Siberian oil and gas. This requires huge quantities of energy and large amounts of heat for the operators living in subzero temperatures. Relatively small, self-contained nuclear power units such as these are a way of providing energy in this inhospitable, isolated region far from the grid. Nuclear power is seen as both dependable and relatively simple to operate.
The concept is not new. The US mounted a submarine nuclear power plant on the Liberty ship, Sturgis, in 1966 to power the Panama Canal Zone from 1968 to 1975.
The Russian concept shares a similar heritage, using two small, military reactors designed for nuclear powered icebreakers. Instead of driving a ship’s propeller, it drives electricity generators and has facilities to provide heating. Larger barge-mounted reactors up to 600MWe are planned – a similar size to a civil nuclear, gas- or coal-fired power station on land.
Cheaper to run?
Such plants are ideal for remote regions and these reactors are a direct application of military industries. Can they tell us anything about the economics and safety of small power reactors?
The KLT-40S reactor is fuelled by 30-40% enriched uranium, which falls outside what would be allowed for civil use (concern about weapons proliferation limits enrichment to very low levels). The reactors are built in factories and assembled in shipyards, where productivity is much higher and quality standards easier to police than on construction sites. But military reactors are designed with little thought for costs and because of their small power output it’s very likely that their lifetime generating costs will be several times that of large, grid-connected reactors, and many more times higher that of a gas power station.
Mixed safety record
Modern nuclear safety practice focuses on the “three Cs”: control of reactivity, cooling of the core, and containment of radioactivity. Each of these has to be completely effective and reliable, so designers employ multiple system redundancy with backups and layers of protection.
Just how safe Russian military reactors are is clouded in secrecy; we just don’t know how safe the KLT-40S is. Russia has successfully operated nine nuclear icebreakers over the past 50 years. On the other hand we know that seven Russian nuclear submarines have sunk, some due to reactor problems and others due to weapons explosion onboard, and a further ten reported reactor accidents. So this reactor’s pedigree is not unblemished.
Cooling systems for civil reactors have become very complex and this is a prime cause of soaring construction costs. It is difficult to install in a naval vessel the number of systems and separate them so that they provide redundancy should one fail. New ideas are needed, such as the natural circulation cooling used in some small reactor designs in the US. They provide cooling through largely passive systems, which are inherently less complex and therefore cheaper.
Providing containment is difficult in a small plant. The usual approach is to construct a very large, almost cathedral-like, box around the reactor to ensure that even in the worst case a radioactive release is kept inside the plant. The result of poor containment design can be seen from the disaster at Fukushima in 2011, where radioactivity had to be vented into the atmosphere to ensure the structure did not burst from built up pressure.
As with many other aspects, we do not know whether the containment structure of the Russian reactors will be effective. Though the Russians are being imaginative in developing barge-mounted reactors to address a problem specific to their geography and their needs, the lack of openness makes it hard to see how useful their nuclear technology can be in the West.
Britain still has a similar nuclear capability and a nuclear-powered naval fleet, but one more attuned to civil safety standards. But, unlike Russia and the US, Britain is making little attempt to develop such small, factory-built reactors as a counter to the huge costs of civil reactors – such as the multi-billion pound planned power station at Hinkley Point in Somerset.