After several years of loyal and reliable services during heavy duty operation in a reactor, nuclear fuel must be discharged and go into retirement. For Switzerland, the final place of retirement is planned to consist of a deep geological repository where the used nuclear fuel will be disposed. Before the repository is constructed, the used fuel will need to be stored in wet pools and/or dry storage casks.

During all this time, safe handling of the fuel will remain the top priority for operators and regulators. To gain better knowledge on the relevant phenomena which could potentially affect the fuel thermo-mechanics and safety characteristics during long storage periods as well as to allow predicting their evolution, simulation models are being developed at PSI within the DRYstars project.

A first milestone was recently achieved with the development of models coupled to state-of-the-art fuel performance codes for each of the three main categories of phenomena considered as having high safety relevance for storage, namely helium behaviour, creep behaviour and hydrogen behaviour.

Fission products from the PSI-SINQ gas-jet facility, as operated by LRC, were used to reveal the separation of relevant radionuclides from radioactively contaminated water.

At PSI, young scientists from experimental and modelling labs are working hand in hand in order to better understand the effect of hydrogen on the mechanical properties of zirconium alloys.

The Department of Radiation Safety and Security at PSI proposes an additional use to the common surgical face.

Switzerland plans to construct an underground repository for its radioactive waste by 2050. Three sites are under consideration. Researchers at PSI are providing data that will help in determining which is most suitable.

An issue of Chimia was published about the status of radiochemistry research in Switzerland.

What happens to the diffusive properties and the porosity when cement and clay come in contact? At PSI, scientists are studying cement and clay as sealing materials in underground repositories for radioactive waste.

Calculational evolution helps in bringing together different aspects of nuclear physics, namely “nuclear reaction theory” and “reactor physics”.

Combining IC’s capabilities for speciation analysis and the new ICP-OES for swift and reliable wastewater analysis, the PSI hotlab now offers a comprehensive set-up for routine wastewater examinations providing future autonomy from external contractors for wastewater management.

The recent stress corrosion cracking (SCC) in Alloy 182 in reactor pressure vessel nozzles, reactor internal attachment or penetrations dissimilar metal welds in boiling water reactors (BWRs) represent a serious potential safety concern.