New reactors and nuclear fuels

Accelerator driven nuclear installations
> New generation fuels

Accelerator driven nuclear installations

A nuclear installation driven by a particle accelerator has a subcritical core. A subcritical reactor does not contain sufficient fissile material to maintain a chain reaction. To prevent the reactor from stopping it needs to be "fed" continually with neutrons produced via a particle accelerator.

When the latter is disconnected the chain reaction stops within a fraction of a second (one hundred thousandth) and the reactor stops. This is referred to as an accelerator driven system: ADS. Because of its high safety factor this innovative technology has a promising future.


Transmutation refers to the fission of long-lived elements in radioactive waste into short-lived elements. The technology can shorten the lifespan of waste by a factor of 1000. Waste that would remain radioactive for hundreds of thousands of years would in that case only pose a risk for a couple of thousand years. This transmutation can be achieved safely in a subcritical nuclear system driven by a particle accelerator. An ADS makes it possible to load up to half the core with high-level radioactive waste, which facilitates concentrated processing. MYRRHA enables us to test this concept and collate vital information for future industrial scale transmutation.

Fourth generation reactors

SCK•CEN contributes significantly to the development of a new generation of safer and more efficient nuclear reactors. We are already testing innovative materials and fuels that will be part of these installations. MYRRHA is set to take over this role in about ten years' time. MYRRHA can be considered one of the leading test rigs for these future nuclear systems.


Discover more about MYRRHA

New generation fuels

Many research reactors throughout the world are still operating on highly enriched uranium. Because they facilitate research into the interaction between radiation and matter, they play a vital part in the process of making nuclear energy safe. To this end a reactor requires a compact core. If highly enriched uranium were to fall into the wrong hands it could be used for the production of nuclear weapons.

It is important, therefore, to switch to low enriched fuels wherever possible, without it affecting the strength of the reactor.To do so a fuel needs to be developed with an extremely high density, preferably six times higher than enriched uranium.

This compensates for the low enrichment but ensures that the reactor maintains the same performance level. In recent years we have played a pioneering role in this type of research by testing these low enriched fuels.

More info: Monitoring safety of nuclear power plants

More information on our Science Platform