Scientific Highlights LRS

13 November 2017

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Signal Noise Analysis in Nuclear Reactors: when the disturbing role of noise becomes valuable

Noise appears in many areas of science, and commonly has an unwanted and disturbing nature by deteriorating signals’ quality. Therefore, various techniques have been developed over the years for separating noise from pure signals. However, noise has a key role in signal analysis of nuclear reactors as its’ appropriate assessment can be used not only for exploring the normal and dynamic behaviour of nuclear cores, but also for identifying and detecting possible anomalies of reactor systems. State of the art methods have been recently implemented within the well-established signal analysis methodology of the STARS program, at the Laboratory for Reactor Physics and Systems Behaviour (LRS), for investigating nuclear reactor noise and getting a better insight on analysing reactors’ operation.

22 May 2017

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Spent Fuel Neutron Emission Work Receives Awards at ANS Conference

Spent fuel characterization is necessary to improve nuclear fuel design, optimize core refueling patterns and manage the handling, transport and storage of spent fuel assemblies. The experimental characterization of spent fuels includes measuring their gamma and neutron emissions typically with high-purity Germanium and He-3 detectors. In the past few years, however, efforts to develop efficient and low-cost, fast and thermal, neutron detectors have guided the research to the development of new scintillation detectors. These scintillators offer good efficiency, fast-timing properties, and good pulse shape discrimination capabilities for dual gamma and neutron detection. As collaboration between the Laboratory for Reactor Physics and Systems Behaviour (LRS) and Laboratory for Thermal-Hydraulics (LTH), a preliminary analysis was performed through Monte Carlo simulations to design a measurement unit at the HOTLAB based on new scintillators for the detection of fast neutrons emitted by spent fuel. This semester work of Marianna Papadionysiou was presented at the ANS Student conference in April and received two awards for "Best Detection and Measurement" and "Best Overall Research".

14 February 2017

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PERFORM-60: Modelling the Ageing of Reactor Vessel Steels

The main threat to the reactor pressure vessel (RPV) operational safety is certainly the radiation damage that hardens and embrittles the steel it is made of. Four decades of research worldwide have allowed understanding and monitoring the phenomena that come into play. At the computational level, a simulation platform, PERFORM-60, has the ambitious aim of predicting the steel evolution for most RPV and operational conditions. It was initially elaborated in the frame of the EU project of the same acronym and is currently further developed to be the end-product of the on-going H2020 EU project SOTERIA. As a contribution of the Laboratory for Reactor Physics and Systems Behaviour (LRS) to SOTERIA, the platform has been rigorously assessed for the first time since its release on a real case study of a Swiss RPV. This critical assessment has been acknowledged by the community and serves as basis for improvements and future developments of the platform within SOTERIA.

20 December 2016

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The Dynamics of Nuclear Reactors

Nuclear reactor dynamics deals with the transient behaviour of nuclear reactors which mostly refers to time changes of the imbalance between heat production and removal. Since the prediction of the dynamic behaviour is crucial for the safety of a reactor, computational models and methodologies have been developed in the framework of the STARS project, at the Laboratory for Reactor Physics and Systems Behaviour (LRS), with the main goal to simulate the complex behaviours of reactors under various conditions with a high level of fidelity.

10 October 2016

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Molten salt reactors – exploring an alternative

Energy and Environment Nuclear Power Plant Safety

At the Paul Scherrer Institute PSI, a small group of scientists is using theoretical models to explore an alternative for future nuclear reactors: so-called molten salt reactors. This helps to secure Switzerland’s expertise regarding globally relevant questions in the area of nuclear energy and reactor safety, for today and tomorrow.

22. February 2016

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Decommissioning of the research reactor Proteus

Miscellaneous Energy and Environment Nuclear Power Plant Safety

Start of the public examination period for decommissioning of the nuclear facility Proteus at the Paul Scherrer Institute PSI
The nuclear research facility Proteus is a so-called zero-power reactor. In service, the thermal output of the reactor was limited to a maximum of 1 kW. That means this is an experimental reactor that was run at a power level so low that it did not require cooling. Proteus went into service in 1968. The PSI would like to decommission the facility. The decommissioning project is now being publicly announced in the legally prescribed, official publications.

8. October 2015

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More robust thanks to imperfections

Energy and Environment Nuclear Power Plant Safety

Microscopic deviations from the ideal structure render uranium dioxide, the fuel commonly used in nuclear power plants, more resistant to radiation damage.

19. September 2013

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Computer simulations: a cornerstone of nuclear power station safety

Energy and Environment Nuclear Power Plant Safety

Without computer simulations, the operation of nuclear power stations would be very difficult. Whether it is a question of installing new components or conducting safety tests, virtually everything has to be calculated and analysed on the computer first. At the Laboratory for Reactor Physics and Systems Behaviour of the Paul Scherrer Institute PSI, computational models and methodologies are developed with precisely this in mind. Through this, PSI researchers also act as an independent partner to the national regulatory authority ENSI and contribute thereby to support safe operation of the Swiss nuclear power plants.