Speeding up radioactive decay through transmutation

Even as the debate on the advantages and disadvantages of nuclear power rages on in many countries, about 30 new nuclear power plants are being built around the world, including in Europe. Some
countries such as Germany or Sweden are committed to a nuclear phase-out, but are their commitments definite?

Whatever the answer may be, it is more than likely that nuclear waste disposal will continue to be a burning issue in the future. An EU-funded project is trying to find alternatives to storing
the radiating waste underground by developing methods for transforming it and speeding up radioactive decay. The key word is transmutation, a concept that has been in the minds of scientists
for decades.

The integrated project EUROTRANS (‘European research programme for the transmutation of high level nuclear waste in an accelerator driven system’) investigates the feasibility of a
transmutation plant. Such a plant could help to turn about 2,600 tonnes of long-lived, highly toxic radioactive waste – the weight of all nuclear fuel rods used in the European Union in a year
– into more short-lived or stable fission products.

Before transmutation can take place, the long-lived radionuclides have to be separated from the radioactive waste. In order to achieve that, so called spallation has to take place: the nuclei
of heavy metal atoms are hit with high-energy protons via an accelerator, knocking out pieces of the nuclei and nucleons. Those ‘spallation neutrons’ react with the radioactive core of the
fission products, so that they are transformed into other nuclides, gradually reducing radioactivity in the process.

About 50 partners from 14 countries are involved in the EUROTRANS project, which is coordinated by the Research Centre Karlsruhe and is linked to similar projects in the USA, Japan and South
Korea. Research teams in five domains are involved in the project:
– development and accelerator optimisation;
– coupling of the components;
– fuel development;
– heavy-liquid metal technologies;
– material data.

Researchers at the Ruhr University Bochum, Germany, for instance, are modelling heat transfer mechanisms. ‘We are addressing this part of the puzzle by simulating heat transfer from a
high-performance heating rod onto the coolant used here, a lead-bismuth melt,’ Professor Marco Koch of Ruhr University Bochum, whose team cooperates with ten further groups in this domain,
explains. ‘From this, we want to infer parameters for the turbulence modelling of the flow.’

‘Then you know how to design the flow channels and with which flow speed and temperature difference the cooling set-up will be ideal,’ adds engineer Tilman Drath, also of Ruhr University
Bochum.

While research into transmutation has already benefited from the EU’s Fifth Framework Programme, EUROTRANS now receives ?23 million under the Sixth Framework Programme (FP6). The study will be
completed in spring 2009, after which an experimental transmutation plant could go online, the researchers hope.

For further information, please visit:

EUROTRANS:

Ruhr University Bochum:
https://www.ruhr-uni-bochum.de/

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