Publications de Axel Guy Marie Laureau

CORTEX experiments – Part I: Modulation campaigns in AKR-2 & CROCUS for the validation of neutron noise codes

Nicolas Weiss, Daniel Godat, Pavel Frajtag, Andreas Pautz, Adolfo Rais, Oskari Ville Pakari, Vincent Pierre Lamirand, Mathieu Hursin, Fanny Vitullo, Thomas Jean-François Ligonnet, Axel Guy Marie Laureau

We present the experimental campaigns – namely, three per facility – carried out between 2018 and 2021 in the AKR–2 and CROCUS zero power reactors within the framework of the Horizon 2020 European project CORTEX. Their purpose was to produce high-quality a ...

2025

Tool Developments in the OpenMC Code: Correlated Sampling and Transient Fission Matrix Approach Coupled to OpenFOAM

Thomas Jean-François Ligonnet, Axel Guy Marie Laureau, Elsa Merle

This article outlines the advancements made in broadening the application scope of the OpenMC neutron transport code to include thermohydraulic coupling and nuclear data uncertainty propagation. These developments primarily involve the incorporation of the ...

Taylor & Francis Inc2024

Design of an Open-Loop Pile-Oscillation Program in the CROCUS Reactor

Andreas Pautz, Vincent Pierre Lamirand, Thomas Jean-François Ligonnet, Axel Guy Marie Laureau

As a follow-up to the CEA-EPFL PETALE experimental program on stainless steel nuclear data, the EPFL initiated an open-loop pile-oscillation experimental program in the CROCUS reactor: BLOOM. A reproduction of the critical experiments of PETALE, the progra ...

2024

CORTEX experiments, Part II: Postprocessing of neutron noise time series to determine reliable mean and uncertainties

Andreas Pautz, Adolfo Rais, Oskari Ville Pakari, Vincent Pierre Lamirand, Mathieu Hursin, Axel Guy Marie Laureau

In this paper we present the methodology developed to analyze the detector response of neutron noise experiments performed at EPFL CROCUS and TUD AKR-2 reactors in the framework of the H2020 CORTEX project. The noise, or modulation, is induced by controlle ...

2024

Revision of PSI calculation capabilities and validation experience on the BEPU-type reactor dosimetry applications

Vincent Pierre Lamirand, Axel Guy Marie Laureau

The present paper summarizes the experience accumulated at the Laboratory for Reactor Physics and Thermal-Hydraulics (LRT) of the Paul Scherrer Institute in the field of reactor dosimetry, as well as outlines the recent progress achieved in relation to the ...

EDP Sciences2024

High-Resolution Modeling Without Computation Slowdown for PETALE in CROCUS

Andreas Pautz, Vincent Pierre Lamirand, Thomas Jean-François Ligonnet, Axel Guy Marie Laureau

In a collaboration between Ecole Polytechnique Fédérale de Lausanne (EPFL) and CEA, in the fall of 2020, the experimental Programme d’Étude en Transmission de l’Acier Lourd et ses Eléments (PETALE) was successfully carried out in the CROCUS reactor of EPFL ...

2024

Analysis of the preliminary campaign for the PETALE program

Andreas Pautz, Vincent Pierre Lamirand, Thomas Jean-François Ligonnet, Axel Guy Marie Laureau

The PETALE program aims to provide new experimental data to constrain the stainless steel nuclear data. In this frame, a preliminary measurement campaign has been performed to characterize the neutron flux in key positions of the CROCUS reactor and to deve ...

EDP SCIENCES S A2023

Unmoderated molten salt reactors design optimisation for power stability

Andreas Pautz, Axel Guy Marie Laureau, Andrea Bellè

The critical region of unmoderated molten salt reactors consists in a cavity filled with a liquid fuel. The lack of internal structure implies a complex flow structure of the circulating fuel salt. A preliminary core shape optimization has been performed d ...

PERGAMON-ELSEVIER SCIENCE LTD2022

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

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

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

Dosimetry modeling and experimental validation for the PETALE program in the CROCUS reactor

Pavel Frajtag, Andreas Pautz, Vincent Pierre Lamirand, Axel Guy Marie Laureau

The PETALE experimental program in the CROCUS reactor intends to provide integral measurements on reactivity worth and dosimetry measurement to constrain nuclear data relative to stainless steel heavy reflectors. The experimental setup consists in eight su ...

2021

CORE SIM+ simulations of COLIBRI fuel rods oscillation experiments and comparison with measurements

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

At EPFL, the CROCUS reactor has been used to carry out experiments with vibrating fuel rods. The paper presents a first attempt to employ the measured data to validate CORE SIM+, a neutron noise solver developed at Chalmers University of Technology. For th ...

2021

First in-core gamma spectroscopy experiments in a zero power reactor

Pavel Frajtag, Andreas Pautz, Oskari Ville Pakari, Vincent Pierre Lamirand, Axel Guy Marie Laureau

Gamma rays in nuclear reactors, arising either from nuclear reactions or decay processes, significantly contribute to the heating and dose of the reactor components. Zero power research reactors offer the possibility to measure gamma rays in a purely neutr ...

E D P SCIENCES2021

The COLIBRI experimental program in the CROCUS reactor: characterization of the fuel rods oscillator

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

The present article presents the mechanical characterization of the fuel rods oscillator developed for the purposes of the COLIBRI experimental program in CROCUS. COLIBRI aims at investigating the radiation noise related to fuel vibrations. The main motiva ...

2020

In-core dosimetry for the validation of neutron spectra in the CROCUS reactor

Pavel Frajtag, Andreas Pautz, Vincent Pierre Lamirand, Axel Guy Marie Laureau, Yifeng Jiang

The present article describes the preliminary validation study of simulated in-core and reflector n eutron spectra in preparation of oncoming experimental programs in the zero-power reactor CROCUS at EPFL. For this purpose, a set of activation foils were i ...

E D P SCIENCES2020

Bayesian Monte Carlo assimilation for the PETALE experimental programme using inter-dosimeter correlation

Andreas Pautz, Vincent Pierre Lamirand, Axel Guy Marie Laureau, Dimitri Rochman

This article presents the methodology developed to generate and use dosimeter covariances and to estimate nuisance parameters for the PETALE experimental programme. In anticipation of the final experimental results, this work investigates the consideration ...

2020

Power calibration methodology at the CROCUS reactor

Pavel Frajtag, Andreas Pautz, Oskari Ville Pakari, Vincent Pierre Lamirand, Axel Guy Marie Laureau

In the present article, we detail the method used to experimentally determine the power of the CROCUS zero-power reactor, and to subsequently calibrate its ex-core monitor fission chambers. Knowledge of the reactor power is a mandatory quantity for a safe ...

E D P SCIENCES2020

Assessment of representativity of the PETALE experiments for validation of Swiss LWRs ex-core dosimetry calculations

Hakim Ferroukhi, Andreas Pautz, Alexander Vasiliev, Vincent Pierre Lamirand, Axel Guy Marie Laureau, Dimitri Rochman

The international experimental program PETALE will be carried out at the CROCUS research reactor of EPFL. The program aims at measuring neutron penetration in slabs made of materials composing typical LWR reactor pressure vessel. The measurements will be u ...

E D P SCIENCES2020

Neutron noise experiments in the AKR-2 and CROCUS reactors for the European project CORTEX

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

The present article gives an overview of the first experimental campaigns carried out in the AKR-2 and CROCUS reactors within the framework of the Horizon 2020 European project CORTEX. CORTEX aims at developing innovative core monitoring techniques that al ...

E D P SCIENCES2020

Uncertainty propagation based on correlated sampling technique for nuclear data applications

Andreas Pautz, Vincent Pierre Lamirand, Axel Guy Marie Laureau, Dimitri Rochman

A correlated sampling technique has been implemented to estimate the impact of cross section modifications on the neutron transport and in Monte Carlo simulations in one single calculation. This implementation has been coupled to a Total Monte Carlo approa ...

2020

Uncertainty propagation for the design study of the PETALE experimental programme in the CROCUS reactor

Andreas Pautz, Vincent Pierre Lamirand, Axel Guy Marie Laureau, Dimitri Rochman

The PETALE experimental programme in the CROCUS reactor intends to provide integral measurements to constrain stainless steel nuclear data. This article presents the tools and the methodology developed to design and optimize the experiments, and its operat ...

2020