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Concept

Nuclear reactor physics

Publications associées (31)

Gamma-ray Spectroscopy in Low-Power Nuclear Research Reactors

Andreas Pautz, Vincent Pierre Lamirand, Oskari Ville Pakari

Gamma-ray spectroscopy is an effective technique for radioactive material characterization, routine inventory verification, nuclear safeguards, health physics, and source search scenarios. Gamma-ray spectrometers typically cannot be operated in the immedia ...

MDPI2024

Neutron-Gamma Noise Measurements in a Zero-Power Reactor Using Organic Scintillators

Andreas Pautz, Vincent Pierre Lamirand, Oskari Ville Pakari

Noise measurements in light water reactor systems aid in generating validation data for integral point kinetic parameter predictions and generating monitoring parameters for reactor safety and safeguards. The CROCUS zero-power reactor has been used to supp ...

Ieee-Inst Electrical Electronics Engineers Inc2024

Gamma noise to non-invasively monitor nuclear research reactors

Andreas Pautz, Vincent Pierre Lamirand, Oskari Ville Pakari, Pavel Frajtag, Tom Mager

Autonomous nuclear reactor monitoring is a key aspect of the International Atomic Energy Agency’s strategy to ensure nonproliferation treaty compliance. From the rise of small modular reactor technology, decentralized nuclear reactor fleets may strain the ...

Nature Research2024

High brightness neutron source optimized for very high pulsed magnetic field experiments

Mina Akhyani

Conducting neutron scattering experiments in the presence of high pulsed magnetic fields, namely above 40 T, provides valuable information about the magnetic structures of materials. However, these experiments are challenging and time-consuming because the ...

EPFL2024

Atomic level insight into irradiation effects in nuclear fuel materials

Shaileyee Bhattacharya

Microstructural evolution during in-pile irradiation, radiation damage effects and fission products behavior in UO2 nuclear fuel are key issues in understanding and for the modeling of the performance as well as safety characteristics of nuclear fuels in t ...

EPFL2024

Design of an Instrumented Fuel Rod for Intra-pin Neutron Flux Measurements in the CROCUS Experimental Reactor

Andreas Pautz, Vincent Pierre Lamirand, Mathieu Hursin, Thomas Jean-François Ligonnet, Tom Mager, Won Dong Shin

In response to the need for validating high-fidelity deterministic neutronics solvers capable of pin-resolved neutron flux distributions, an instrumented fuel rod was designed for the experimental reactor CROCUS, operated by EPFL’s Laboratory for Reactor P ...

2023

Down-conversion of a single photon as a probe of many-body localization

Cristiano Ciuti

Decay of a particle into more particles is a ubiquitous phenomenon to interacting quantum systems, taking place in colliders, nuclear reactors or solids. In a nonlinear medium, even a single photon would decay by down-converting (splitting) into lower-freq ...

NATURE PORTFOLIO2023

A holistic investigation of photocatalytic hydrogen generation

Sangram Ashok Savant

Photocatalytic (PC) solar hydrogen production is a promising way to provide green hydrogen using only sunlight and abundant reactants such as water. PC approaches use catalytically active semiconductor particles suspended in liquid electrolytes. The partic ...

EPFL2023

Extension of the OFFBEAT fuel performance code to finite strains and validation against LOCA experiments

Andreas Pautz, Alessandro Scolaro, Carlo Fiorina, Edoardo Luciano Brunetto

The mechanical analysis of nuclear fuel behavior under base-irradiation conditions has traditionally been performed adopting the small-strain approximation. However, many cases of interest for fuel behavior involve the occurrence of large rod deformations ...

ELSEVIER SCIENCE SA2023

Recent progress in calcium looping integrated with chemical looping combustion (CaL-CLC) using bifunctional CaO/CuO composites for CO2 capture: A state-of-the-art review

Oliver Kröcher, Muhammad Awais Naeem

Calcium looping integrated with chemical looping combustion (CaL-CLC) process is an efficient and cost-effective CO2 capture technology. In this technique, the heat generated by chemical looping combustion of CuO is used insitu to calcine CaCO3, thus avoid ...

ELSEVIER SCI LTD2023

High accuracy measurement of the prompt neutron decay constant in CROCUS using Gamma Noise and bootstrapped uncertainties

Andreas Pautz, Vincent Pierre Lamirand, Oskari Ville Pakari, Pavel Frajtag, Tom Mager

We experimentally demonstrate the advantages of gamma detection for noise measurements to deter-mine the prompt neutron decay constant a of a nuclear reactor using the power spectral density (PSD) method, coupled to a new uncertainty estimation scheme base ...

PERGAMON-ELSEVIER SCIENCE LTD2022

Miniature and Minimalistic Neutron Detectors for Online High-Resolution Experiments in the Zero-Power Reactor CROCUS

Fanny Vitullo

The continuous strive for more efficient and reliable nuclear power plants is leading to increasing complexity in the design and operations of reactors. As a consequence, comprehensive analyses are required to assess the reactor's safety during normal and ...

EPFL2022

On the Capability of Wall-Modeled Large Eddy Simulations to Predict Particle Dispersion in Complex Turbulent Flows

Mohamed Aly Hashem Mohamed Sayed

Predicting particle transport in turbulent flows has a plethora of applications, some of which are: the transport of atmospheric aerosols, the deposition of blood cells in the arteries of human bodies and the atomization of fuel droplets in combustion cham ...

EPFL2022

Advanced methodologies for modeling and assessment of SFR safety functions

Janos Bodi

The present doctoral work was performed to contribute to the conceptual design development and safety assessment of a Generation IV Sodium Fast Reactor (SFR) in the frame of the European Sodium Fast Reactor Safety Measures Assessment and Research Tools (ES ...

EPFL2022

Development of a novel two-phase flow solver for nuclear reactor analysis: algorithms, verification and implementation in OpenFOAM

Andreas Pautz, Carlo Fiorina, Stefan Radman

A porous medium-based representation of nuclear reactors and complex engineering systems more in general can significantly reduce simulation and modelling costs, while preserving a reasonable degree of accuracy via regime map-based correlations for modelli ...

2021

Analysis of the first COLIBRI fuel rods oscillation campaign in the CROCUS reactor for the European project CORTEX

Andreas Pautz, Vincent Pierre Lamirand, Mathieu Hursin, Carlo Fiorina, Oskari Ville Pakari, Pavel Frajtag, Axel Guy Marie Laureau, Adolfo Rais, Daniel Godat

The Horizon2020 European project CORTEX aims at developing an innovative core monitoring technique that allows detecting anomalies in nuclear reactors, such as excessive vibrations of core internals, flow blockage, or coolant inlet perturbations. The techn ...

2021

A Hybrid Approach to Neutron Transport with Thermal-hydraulic Feedback for Reactor Transient Analysis

Alexander Aures

Understanding the time-dependent behaviour of a nuclear reactor following an intended or unintended change of the reactor conditions is of crucial importance to the safe operation of nuclear reactors. Safety evaluations of nuclear reactors involve the anal ...

EPFL2021

Delayed gamma fraction determination in the zero power reactor CROCUS

Andreas Pautz, Vincent Pierre Lamirand, Oskari Ville Pakari, Pavel Frajtag, Tom Mager

Gamma rays are an inextricable part of a nuclear reactor's radiation field, and as such require characterization for dose rate estimations required for the radiation protection of personnel, material choices, and the design of nuclear facilities. Most comm ...

EDP SCIENCES S A2021

A Coarse-mesh Methodology for the Analysis of One and Two-phase Nuclear Reactor Thermal-hydraulics in a Multi-physics Context

Stefan Radman

The analysis of nuclear reactors for performance and safety assessment benefits from the use of computational tools. In this context, this work aims at the development and application of a thermal-hydraulics methodology and related software that respond to ...

EPFL2021

Development of a Novel Finite Volume Methodology for Multi-Dimensional Fuel Performance Applications

Alessandro Scolaro

Fuel performance codes are an essential tool for ensuring the safe and economic opera-tion of nuclear reactors. Traditionally, these codes have been developed following a simple 1.5-D modelling approach, where the fuel behavior is simplified by assuming ax ...

EPFL2021