Handling of nuclear waste and waste transmutation

A satisfactory solution for the disposal of waste from nuclear power plants is a key issue for the future of nuclear energy production. The research in this field focuses on the partitioning (i.e. chemical separation) of long-lived radioactive isotopes in the nuclear waste and subsequent transmutation into short-lived or stable isotopes. Transmutation occurs via neutron capture or fission reactions by exposing the materials to high neutron fluxes. The goal is to burn the so-called long-lived fission products (LLFP) such as ⁹⁹ Tc, ¹²⁹I, and ¹³⁵Cs, and minor actinides (MA) such as Np, Am, and Cm isotopes.

There are three options for the reduction of long-lived radiotoxicity of nuclear waste:

1. using high fluxes of fast neutrons from a dedicated fast reactor or a spallation source using an accelerator driven system

2. recycling actinides and fission products in a molten salt reactor

3. using very high burn-up fuels in pressurised light-water reactors (PWR).

In all cases the knowledge of the associated nuclear data is not complete, and especially so in case of the relevant reaction cross-sections in fast reactor systems and accelerator-driven systems.

Total and capture cross sections on ⁹⁹Tc and ¹²⁹I have been measured with high energy resolution at IRMM. Several reaction cross sections for these isotopes were also determined with the activation technique and total and capture cross-section measurements on ²³⁷Np have been carried out. Measuring ²⁴¹Am is planned.