Nuclear Energy and Safety Research Division
The Paul Scherrer Institute has a long tradition in energy research. With respect to nuclear energy, PSI has a unique position in Switzerland. This is due to its heavy infrastructure, namely the Hot Laboratory with so-called hot cells, well equipped and shielded zones for work and research on radioactive material. In addition, the nuclear energy division takes advantage of PSI's large facilities like the Swiss Light Source (SLS) and the Swiss Spallation Neutron Source (SINQ).
Based on this infrastructure and the know-how of its collaborators the Division is involved in three main topics of research: Safety of currently operating light-water reactors, safety characteristics of future reactor concepts and related fuel cycles, and long-term safety of deep geological repositories for nuclear wastes of all kind.
The work is being done on behalf of the Federal Government and in close cooperation with the Swiss nuclear utilities, the national waste management organization, Nagra, and the national regulatory authority, ENSI. It also includes scientific services for the nuclear power plants. Most of the research is connected with international projects on a multi- or bi-national cooperation basis.
Recent News from NES
An international group of researchers led by the Paul Scherrer Institute has carried out in-depth analyses of the climate impact of blue hydrogen. This is produced from natural gas, with the CO2 resulting from the process captured and permanently stored. The study concludes that blue hydrogen can play a positive role in the energy transition – under certain conditions.
This highlight presents a successful, in-house developed integration of an Electron Beam Ion Source (EBIS) able to ionize gases to high charge states with a customized commercial MC-ICP-MS. The successful joining of the two ion flight paths is a milestone towards comprehensive routine analyses of solids, liquids, and gases using THE SAME MASS SPECTROMETER, the latter analyses free from atmospheric contamination. After implementation of an introduction system for gas mass spectrometry, routine analyses will comprise isotope ratio and relative abundance determinations of fission gases in used nuclear fuel. In addition to the unique versatility of the MC-EBIS-ICP-MS, inclusion of the EBIS furthers opens the little-studied field of mass spectrometry of highly charged ions.
Water boiling control evolution of natural geothermal systems is widely exploited in industrial processes due to the unique non-linear thermophysical behavior. Even though the properties of water both in the liquid and gas state have been extensively studied experimentally and by numerical simulations, there is still a fundamental knowledge gap in understanding the mechanism of the heterogeneous nucleate boiling controlling evaporation and condensation. In this study, the molecular mechanism of bubble nucleation at the hydrophilic and hydrophobic solid–water interface was determined by performing unbiased molecular dynamics simulations using the transition path sampling scheme. Analyzing the liquid to vapor transition path, the initiation of small void cavities (vapor bubbles nuclei) and their subsequent merging mechanism, leading to successively growing vacuum domains (vapor phase), has been elucidated. The simulations reveal the impact of the surface functionality on the adsorbed thin water molecules film structuring and the location of high probability nucleation sites.
As of February 1st 2022, Russell McKenna joins the Paul Scherrer Institute’s Laboratory for Energy Systems Analysis (LEA) as head of the Laboratory. The position at PSI and the full professorship at ETHZ will enable him to combine his research with teaching activities. This optimally reinforces the cooperation between ETH Zurich and the two energy sectors, ENE and NES, of the PSI.
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.
Sustainable, synthetic fuels, so-called e-fuels, can help reduce CO₂ emissions. For their production, electricity from renewable sources is required in order to allow for a close to CO₂-neutral balance. The availability of electricity from renewable sources, which ensures the climate benefits of e-fuels, is currently still limited. “Especially in order to produce on a larger scale, a lot of renewable electricity is needed,” explains Christian Bauer, researcher at the Laboratory for Energy Systems Analysis (LEA) at PSI.
NZZ am Sonntag has picked up this highlight in its issue on March 7th, 2021: The highlight refers to the analysis performed in SCCER Joint Activity Scenarios and Modelling, where PSI-LEA performed the analysis of the energy transition pathways.
The entire study is an investigation into the self-similarity behavior  of first and second order statistical quantities derived from a large-scale jet flow taken from one of the experiments in the PANDA facility using the Proper Orthogonal Decomposition (POD).
What is presented, are the merits, the potential and the characteristics of the corresponding underlying POD analysis. Proper Orthogonal Decomposition (POD) is a mathematical framework to extract large-scale structures which are otherwise eventually masked by the complexity of the fully turbulent flow; example: the meandering of a jet which is not so obvious for the original data.