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Vincent Pierre Lamirand

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Related publications (62)

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, Won Dong Shin, Tom Mager

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

Modeling noise experiments performed at AKR-2 and CROCUS zero-power reactors

Vincent Pierre Lamirand, Mathieu Hursin

CORTEX is a EU H2020 project (2017-2021) devoted to the analysis of 'reactor neutron noise' in nuclear reactors, i.e. the small fluctuations occurring around the stationary state due to external or internal disturbances in the core. One important aspect of ...

2023

Millimetric fuel rod displacements: an experimental study of the impact on local thermal neutron flux in the CROCUS reactor

Daniel Godat, Pavel Frajtag, Andreas Pautz, Oskari Ville Pakari, Vincent Pierre Lamirand, Fanny Vitullo, Thomas Jean-François Ligonnet

The impact on the thermal neutron flux due to a few mm displacement of a single fuel rod in the periphery lattice of the CROCUS zero-power reactor was measured. These high-resolution experiments were carried out using a miniature neutron detector positione ...

American Nuclear Society2022

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

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

Characterization of High Harmonic Frequencies in Reactor Noise Experiments Within the CORTEX Project

Andreas Pautz, Vincent Pierre Lamirand

We present a novel technique of neutron noise detection and experimental data interpretation developed during the EU H2020 project CORTEX aiming to improve the capabilities for identification and localization of neutron noise sources. The experimental data ...

2022

Towards the Validation of Noise Experiments in the CROCUS Reactor Using the TRIPOLI-4 Monte Carlo Code in Analog Mode

Andreas Pautz, Oskari Ville Pakari, Vincent Pierre Lamirand

Intrinsic neutron noise experiments offer a non-invasive manner to measure the prompt decay constant or reactivity of fissile systems. Using the fluctuations in the density of fission chains, one can infer the kinetics parameters via correlation analysis s ...

2021

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

Validation of axial void profile measured by neutron noise techniques in CROCUS

Pavel Frajtag, Andreas Pautz, Oskari Ville Pakari, Vincent Pierre Lamirand, Mathieu Hursin

Recently a joint project has been carried out between the Paul Scherrer Institut, the Ecole Polytechnique Federale de Lausanne and swissnuclear, an industrial partner, in order to determine the axial void distribution in a channel installed in the reflecto ...

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

Highly localized azimuthal measurements in the CROCUS reactor towards the validaiton of high-fidelity neutronics codes

Pavel Frajtag, Andreas Pautz, Vincent Pierre Lamirand, Fanny Vitullo

Highly localized in-core measurements are necessary for the validation of neutron transport calculations with high spatial resolution. In the present work, a miniature neutron detector developed at EPFL in collaboration with PSI was used to carry out a set ...

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

High resolution measurements with miniature neutron scintillators in the SUR-100 zero power reactor

Andreas Pautz, Vincent Pierre Lamirand, Fanny Vitullo

Three 1-mm(3) miniature fiber-coupled scintillators have been used to perform cm-wise resolution measurements of the thermal neutron flux within experimental channels of the SUR-100 facility, a zero power thermal reactor operated by the Institute of Nuclea ...

E D P SCIENCES2021

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

PISTIL, a reactivity modulation device to probe the transfer function of the nuclear reactor CROCUS

Pavel Frajtag, Andreas Pautz, Vincent Pierre Lamirand

The present article summarizes the development and testing of a reactivity modulation device developed by the French Atomic and Alternative Energies Commission (CEA). It was installed in the CROCUS reactor of the Swiss Federal Institute of Technology in La ...

E D P SCIENCES2021

Design of a 150-miniature detectors 3D core-mapping system for the CROCUS reactor

Pavel Frajtag, Andreas Pautz, Vincent Pierre Lamirand, Fanny Vitullo

The present article provides an overview of the design of a three-dimensional (3D) full-core mapping system for the CROCUS reactor, operated at the Ecole polytechnique federale de Lausanne (EPFL), Switzerland. The system is composed of 149 miniature neutro ...

E D P SCIENCES2021

Local and high distance neutron and gamma measurements of fuel rods oscillation experiments

Pavel Frajtag, Andreas Pautz, Oskari Ville Pakari, Vincent Pierre Lamirand, Fanny Vitullo

We report in the present article on the successful observation using noise analysis of the lateral oscillation of one fuel rod by +/- 2.5 mm around nominal at 0.1 Hz frequency, using an mm(3) miniature neutron scintillator at the rod level, and a BGO gamma ...

E D P SCIENCES2021

Modeling the response of a diamond detector in the zero power reactor CROCUS

Pavel Frajtag, Andreas Pautz, Vincent Pierre Lamirand, Mathieu Hursin, DongHyuk Lee

The present manuscript documents the development of a practical calculation scheme to model the response of a diamond detector in the mixed (neutron and gamma) radiation field of the CROCUS experimental reactor at EPFL. The model is shown to perform reason ...

SPRINGER HEIDELBERG2021

Delayed gamma fraction determination in the zero power reactor CROCUS

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

Design and Simulation of Gamma Spectrometry Experiments in the CROCUS Reactor

Andreas Pautz, Oskari Ville Pakari, Vincent Pierre Lamirand, Mathieu Hursin, Fanny Vitullo

Gamma rays in nuclear reactors, arising either from fission 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 neutronic envir ...

E D P SCIENCES2020

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

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