Advanced technologies offer ways of reducing the quantity of nuclear waste. “New types of nuclear power plants can switch to a closed fuel cycle. It means that nuclear waste wouldn’t be buried as such; instead, it would be chemically dissolved and the recyclable component re-processed into new fuel. As a result, many of the most long-lived radioactive substances could be used at new types of facilities,” says Professor Riitta Kyrki-Rajamäki of Lappeenranta University of Technology.

Professor Kyrki-Rajamäki heads the New Type Nuclear Reactors project which is part of the Sustainable Energy Research Programme launched by the Academy of Finland. Very much different from the existing light water reactors, the new types of reactors have already attracted worldwide interest.

The New Type Nuclear Reactors project studies what is known as ‘fourth-generation nuclear reactors’. The purpose of the project is to improve the analysis capabilities in view of these Gen IV reactors – in other words, the development and application of new computational and experimental methodologies for studying the reactors. The main fields of science involved are reactor physics, reactor dynamics, materials technology, thermal hydraulics, and computational fluid dynamics.

While the use of nuclear energy does not generate significant emissions of greenhouse gases or fine particles, the inexpensive uranium resources required for light water reactors will only last for the next 200 years. If the number of nuclear power plants increases, the resources will be depleted even faster. Currently, there are some 450 units in operation with around 50 more being built. “The transition to new types of reactors over the next few decades would guarantee that the existing reserves of raw material for nuclear fuel last for thousands of years to come,” explains Professor Kyrki-Rajamäki.

Professor Kyrki-Rajamäki also emphasises that the new reactor concepts would present many challenges because no compromise must be made on reactor safety. It is important to prepare safety standards for these reactor types that differ from the existing facilities to a considerable degree. For one thing, the new plants would make use of new materials that would have to be tested to ensure safety. For example, the new graphite-moderated reactors would have a fuel cooling system based on heat radiation which is easier to control; however, a new safety-critical issue would be the prevention of atmospheric interaction.

According to Professor Kyrki-Rajamäki, Finland should be actively involved in international activities in order to influence and benefit from the development of new types of nuclear reactors. Through the New Type Nuclear Reactors project, Finland is contributing to the international cooperation through research and by training new scientists for the nuclear sector.

The other parties involved in the project in addition to Lappeenranta University of Technology are Helsinki University of Technology and the Technical Research Centre of Finland VTT.