Scientific Highlights NES

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 ^[1] 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.

CeRh₂As₂, a nonsymmorphic heavy fermion material, was recently reported to host a remarkable temperature versus z-axis magnetic-field phase diagram with two superconducting phases. In this material, the two inequivalent Ce sites per unit cell, related by inversion symmetry, introduce a sublattice structure corresponding to an extra internal degree of freedom. In this work, we propose a classification of the possible superconducting states in CeRh₂As₂ from the two Ce-sites' perspective.

In December 2020, the Swiss Academy of Sciences (SCNAT) published its white book on radiochemical education in Switzerland. The report was authored under the lead of Prof. Dr. Roger Alberto (University of Zurich), Dr. Mario Burgener (Spiez Laboratory), and Prof. em. Dr. Heinz W. Gäggeler (University of Bern/Paul Scherrer Institute) and comprises contributions from many experts on the topic from various institutions throughout Switzerland. The white book highlights the imminent loss of experts in the field of radiochemistry and provides solutions to counteract this development.

As of December 10, 2020, the ETH Zurich appointed PSI’s Prof. Dr. Patrick Steinegger as assistant professor of radiochemistry  (tenure track). Thus, the ETH domain took first counter  measures against the imminent loss of radiochemical expertise  in Switzerland, emphasized in the “Weissbuch Radiochemie  Schweiz” by the Swiss Academy of Sciences (SCNAT).  Furthermore, the December issue of CHIMIA (Swiss Chemical  Society) invited to present the diverse radiochemical activities  throughout the country.

The December issue of CHIMIA of the Swiss Chemical Society (SCS) focused on the radiochemical activities throughout Switzerland. Scientists of the Laboratory of Radiochemistry contributed with a number of articles ranging from topics of fundamental sciences to applied research, thereby reflecting on the diverse projects carried out in our laboratory.

A safe, economical and environmental friendly disposal of used nuclear fuel represents an essential objective of relevance for all. This guides the approach under development at the laboratory for reactor physics and thermal-hydraulics. Establish higher resolution simulation methods to gain more detailed knowledge on the content of each single nuclear fuel rod ever irradiated in a reactor. Thereafter, use this knowledge to explore optimization approaches that could potentially enlarge the range of disposal options allowing to fulfill the highest level of safety standards while reducing economical costs and geological footprints at the same time.

All matter in the universe is made of atoms and all atoms are made of particles. Spontaneous changes within atoms as well as collisions between atoms and surrounding particles are nuclear reaction processes guided by nuclear physics laws. To simulate these processes using computer models, probabilities for the various involved nuclear reactions are required. This is precisely the role of nuclear data: supply the computational models with evaluated quantities representing these nuclear reaction probabilities.

Through this, nuclear data can effectively be seen as the fundamental link between nature and any computer simulation involving nuclear reactions. It is thus of primary importance to continuously improve knowledge on nuclear data. In that context, researchers at the laboratory for reactor physics and thermal-hydraulics have recently focused on the development and application of Bayesian frameworks combining both differential and integral experiments for the improvement of nuclear data. By considering the different experiments together, the aim is to achieve enhancements of the nuclear data evaluations while preserving the basic nuclear physics sum rules.

The Energy Economics Group quantified the new World Energy Scenarios 2019 in collaboration with the World Energy Council and Accenture Strategy. The three scenarios (named "Modern Jazz", "Unfinished Symphony", and "Hard Rock") depict possible future developments of the global energy systems until 2040 and were presented at the World Energy Congress 2019 in Dubai.

Nuclear reactors are complex systems with inherent stochastic behaviour. In simple words, the behaviour of various reactor processes are continuously fluctuating over their mean values, even under normal operation and steady-state conditions. The detailed and systematic analysis of this noisy behaviour can reveal valuable information about the operating status of the studied nuclear reactor. More importantly, designed modifications of the reactor’s operation or even unexpected deviations from the normal performance can be identified using advanced signal analysis techniques. The STARS program, at the Laboratory for Reactor Physics and Thermal-Hydraulics (LRT) in PSI, based on a tight collaboration with the Swiss nuclear industry, has developed a well-established signal analysis methodology, being continuously improved since more than two decades. The latest enhancements of the PSI signal analysis methodology allow a deeper understanding of the underlying mechanisms that drive the reactor’s operation, and can provide better insight on the root-cause of possible disturbances or malfunctions. Recently, the latest STARS activities in advanced signal analysis techniques were culminated by an international recognition through a special distinction from the AIP Chaos Journal.