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Transient fission matrix approach for assessing complex kinetics behavior in the ZEPHYR ZPR coupled core configurations

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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

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

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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 ...

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

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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 ...

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Gamma noise to non-invasively monitor nuclear research reactors

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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 ...

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A hybrid photothermal catalytic system, which combines both the photochemical (light) and thermal (heat) activation pathways over a bifunctional catalyst, has demonstrated remarkable levels of reaction activity and selectivity when compared with individual ...

Cell Press2024

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

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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

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

A holistic investigation of photocatalytic hydrogen generation

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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 ...

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Extension, validation, and optimization of Serpent/DYN3D/ATHLET code system for SFR applications

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The sequence of codes Serpent/DYN3D has been developed by the Helmholtz-Zentrum Dresden-Rossendorf and successfully applied to core static and transient analyses of sodium-cooled fast reactors (SFRs). The successful application of the sequence to SFRs was ...

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Nuclear fusion reactor plasmas will need to exhaust a significant proportion of energy flux through radiative processes, to enable acceptable divertor loads. This can be obtained by line radiation from impurities, injected from the plasma edge. There are h ...

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Gamma-Blind Fast Neutron Detection for Spent Nuclear Fuel Characterization

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In this thesis, the development and testing of a system for measuring the axial distribution of fast neutron emission of spent nuclear fuel rods is presented. Emphasis is placed on the novel fast neutron detector used which can reliably work in extremely h ...

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Regressive Tomography and Direct Regressive Reconstruction: A Research Note

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Two related methods for inverting line-integrated measurements are presented in this research paper in the context of the recent deuterium-tritium experiments in the JET tokamak. Unlike traditional methods of tomography, these methods rely on making use of ...

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Investigation and Validation of Unstructured Mesh Methodologies for Modeling Experimental Reactors

Andreas Pautz, Mathieu Hursin, Carlo Fiorina, Tom Mager

This paper summarizes a methodology developed at Ecole Polytechnique Federale de Lausanne for the neutronic modeling of the CROCUS experimental reactor and proposes solutions to the challenges one may face while modeling a research reactor with a complex g ...

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

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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 ...

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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 ...

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On the development of multi-physics tools for nuclear reactor analysis based on OpenFOAM (R): state of the art, lessons learned and perspectives

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In the last two decades, the use of OpenFOAM as a multi-physics library for nuclear applications has grown from a sporadic use for exploratory studies to a widespread application for the analysis of innovative reactor concepts and highly complex problems. ...

ELSEVIER SCIENCE SA2022

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

Multi-physics modeling of VVERs with high fidelity high-resolution codes

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The calculations performed for the design and operation of a Nuclear Power Plant (NPP) are a key factor for their safety analyses. The standard for the computational analysis of NPPs is the so called conventional approach, which relies on coarse mesh diffu ...

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An Efficient Sampling Algorithm for Non-smooth Composite Potentials

Nicolas Henri Bernard Flammarion

We consider the problem of sampling from a density of the form p(x) ? exp(-f (x) - g(x)), where f : Rd-+ R is a smooth function and g : R-d-+ R is a convex and Lipschitz function. We propose a new algorithm based on the Metropolis-Hastings framework. Under ...

Microtome Publishing2022