The European Journal of Physics N (EPJ-N)
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Latest FLUKA developments
No full textThe FLUKA Monte Carlo code has recently undergone significant enhancements, driven by needs from its user community. Key improvements are discussed, such as a new point-wise treatment for the interactions of low-energy neutrons, the incorporation of a new model for nuclear elastic scattering of protons below 250 MeV, explicit generation of synchrotron radiation photons during charged particle tracking, a revised modeling approach for coherent effects in bent crystals, and the addition of arc-DPA scoring. While improving and extending FLUKA physics performance is essential, it is equally important to ensure the long-term maintainability of the codebase. This paper also outlines the strategy and substantial progress in evolving FLUKA to meet this objective. The FLUKA features are being translated into a new codebase, fulfilling essential criteria such as continuity in the user experience and compatibility with existing inputs, thus laying the foundation for a new FLUKA generation. The codebase makes use of the Geant4 toolkit when appropriate. Additionally, the enhanced collaboration with Geant4 has resulted in the development of an interface, detailed in this paper, that enables access to the FLUKA hadronic models from any Geant4 application
Overview of TRIPOLI-5, a Monte Carlo code for HPC
No full textCEA, IRSN and EDF have joined forces and started the development of the TRIPOLI-5® Monte Carlo particle transport code in 2022, with the goal of performing massively parallel simulations on hybrid computing architectures. TRIPOLI-5 benefits from the experience gained from previous investigations conducted on the PATMOS mini-app, concerning the portability of particle-transport algorithms in High Performance Computing environments. Currently, the main focus of TRIPOLI-5 is on reactor physics applications, including multi-physics feedback for stationary and non-stationary configurations. In the long run, TRIPOLI-5 will eventually cover a broader range of applications (encompassing radiation shielding and nuclear instrumentation) and thus supersede the current-generation Monte Carlo codes TRIPOLI-4®, developed at CEA, and MORET6, developed at IRSN. In this paper, we provide an overview of the current status of TRIPOLI-5 and highlight the trends for future developments
Recent Developments to the ANSWERS
No full textMONK® and MCBEND® are two advanced Monte Carlo codes developed by the ANSWERS® Software Service, which have been used in over 30 countries worldwide for a range of applications, and have been well-established in the UK criticality and shielding communities respectively over the course of several decades. These codes continue to be actively developed to meet the needs of their users. We introduce a number of new developments which have been implemented in recent releases of these codes, or will be implemented in the next release. As MONK and MCBEND share a significant amount of source code, some of these new developments are in common between the two codes and some are specific to each. Improvements to the physics include stochastic mixing of bound thermal scattering data, Doppler broadening rejection correction, improved support for low temperature analyses in MONK, and modelling of photonuclear reactions in MCBEND. A novel approach for transferring irradiated geometry components between models has been developed for burn-up credit applications in MONK. A list mode facility has been added for subcritical analyses, including a model for the full distribution of neutron multiplicity. The geometry capabilities have been enhanced by the addition of novel stochastic geometry algorithms for modelling highly disordered heterogeneous mixtures and random distributions of shapes. IGES-formatted CAD geometries may be imported into MONK and MCBEND and approximated as a set of triangular surface polygons in a new Fractal Geometry body. The new IGES import feature additionally offers dedicated particle tracking routines that process the model geometry within the IGES file exactly, allowing the geometry to be used in MONK and MCBEND with no approximation. New estimators of the adjoint flux in both codes and adjoint-weighted kinetics parameters in MONK have been implemented, in addition to a pulse height distribution detector resolution model in MCBEND. A brief discussion of parallel processing in both codes is presented. New developments to the tools available in the accompanying Visual Workshop integrated development environment are also described
Karlsruhe Nuclide Chart – a tradition in progress for nuclear data
No full textThe Karlsruhe Nuclide Chart is a well-known nuclear data collection used in education and research institutions worldwide. This paper summarises its content from 1958, with data on 1517 experimentally observed nuclides, to the latest 2022/23 edition with data on 4122 nuclides. The paper also provides an overview of the data content of the latest edition with emphasis on the data sources. The unique features of this nuclide chart are the compact presentation of the most essential and up-to-date nuclide data in small, 1.5 × 1.5 cm nuclide boxes and the availability in different printed formats. This compact data presentation allows the Chart to supplement educational and research materials in the last 65 years. In the past eleven years, the Chart’s booklet has been extended by 100 simplified decay schemes for nuclides of particular interest to understand the decay processes in more detail
Life cycle assessment of nuclear power in France: EDF case study
No full textThe French electricity mix is dominated by nuclear power, representing 69% of the power generation in 2021, and further development of nuclear power for electricity is expected. This study applied Life Cycle Assessment (LCA) to evaluate the potential environmental impact of nuclear power generated by EDF SA., the world’s largest nuclear operator and electric utility company operating all the nuclear reactors in France. The study’s main objective was to assess the potential environmental impacts of nuclear power, from raw material extraction to end-of-life, according to several indicators, while focusing on the climate change indicator. The total impact of nuclear power on climate change (3.7 gCO2eq/kWh) is found to be in the lower range of LCA studies on nuclear power conducted so far. Mining and milling of uranium are the most contributing stages, while EDF’s electricity generation is the second largest contributor. The key output of this LCA is the extensive data collected, resulting in a detailed LCA model covering the entire French nuclear fleet. Future studies should focus on (1) collecting more specific data on uranium mining and processing, as these are so far based on database data, and (2) addressing other LCA indicators, such as water use, land use, and ecotoxicity
Overview of PHITS Ver.3.34 with particular focus on track-structure calculation
No full textThis paper presents the latest updates on PHITS, a versatile radiation transport code, focusing specifically on track-structure models. Track structure calculations are methods used to simulate the movement of charged particles while explicitly considering each atomic reaction. Initially developed for radiation biology, these calculation methods aimed to analyze the radiation-induced damage to DNA and chromosomes. Several track-structure calculation models, including PHITS-ETS, PHITS-ETS for Si, PHITS-KURBUC, ETSART, and ITSART, have been developed and implemented for PHITS. These models allow users to study the behavior of various particles at the nano-scale across a wide range of materials. Furthermore, potential applications of track-structure calculations have also been proposed so far. This collection of track-structure calculation models, which encompasses diverse conditions, opens up new avenues for research in the field of radiation effects
Generation of particle self-shielded neutron cross-sections for the Monte-Carlo code TRIPOLI-4
No full textSelf-shielding effects of micrometric particles randomly distributed in nuclear materials were the subject of extensive studies. These effects are known as a double-heterogeneity problem due to “microscopic” heterogeneities, involving the decrease of the neutron flux inside the particles, and “macroscopic” heterogeneities, affecting the neutron flux distribution over the entire volume containing those particles. The present study aims to take advantage of the capabilities of the GELINA facility (JRC-Geel, Belgium) in terms of non-destructive analysis of materials to validate experimentally any models developed to solve the double heterogeneity problem. In order to complement past experiments carried out at the GELINA facility, new transmission experiments were carried out on long cylindrical samples containing microspheres of Gd2O3 with diameters of 195 and 380 μm dispersed in UO2 pellets. The analysis of the experimental transmission spectra with the resonance shape analysis code REFIT and Monte-Carlo neutron transport code TRIPOLI-4® demonstrates that the particle self-shielding model proposed by Doub can reproduce the huge attenuation of the neutron absorption in the Gd resonances by reducing significantly the computational cost of Monte-Carlo simulations
High-fidelity models for the online control of power ramps in fuel displacement systems – Revisiting the ISABELLE experiment in the OSIRIS Material Testing Reactor
No full textThe Jules Horowitz Reactor (JHR) is an MTR under construction at the CEA Cadarache, France. Its design and future operation build upon the lessons learned from the OSIRIS MTR. The CEA intends to transfer the knowledge accumulated with the ISABELLE1 loop of OSIRIS to the ADELINE loop of the JHR, both dedicated to power-ramp-type irradiation experiments, the purpose of which is to test the resistance of PWR fuel rod cladding under extreme levels of stress. In this article, we revisit the ETALISA experiment, a heat balance measurement experiment performed in 1992 for calibrating power ramps in ISABELLE1. We use high-fidelity modelling and simulation tools, especially the neutron-gamma TRIPOLI-4® Monte Carlo transport code, to calculate the detailed components of the heat balance, correction terms, and uncertainties. Comparisons between the simulations and the experiments show a very good agreement in the total linear heat generation rate of 400 W/cm at high power. The computed 2σ uncertainty is found to be 5%, a value essentially identical to the estimate derived in 1993 from an engineering approach. The use of modern simulation tools does not make it possible to improve upon this value, but provides a better understanding of the various components and corrections introduced in the total heat balance. The main limitations come from the ISABELLE1 online instrumentation, thermocouples and self-power neutron detectors, which set a limit on our very knowledge of the actual power ramp experimental conditions
Turbulent induced vibration of a guide tube in experimental reactor
No full textThe design of advanced experimental nuclear reactors consists in integrating safety and operational requirements as well as reaching targets in terms of thermal power and neutron spectrum. In order to meet theses constraints, slender structures with little supports and crossing the entire reactor vessel are implemented in the reactor and are subjected to an axial flow that generates flow-induced vibration (FIV). From the industrial point of view, the mastering of the occurrence of FIV and its associated wear in case of contacts is requested. The stationary fluid forces applying on slender tubular structure in response to its motion are of primary interest since they can significantly affect the vibration amplitudes and even the stability of the system, especially in case of confined axial flow with high velocities (typically higher than 10 m/s). In this study it proposed to compare two approaches to estimate the vibration induced by turbulent excitation of an industrial device encountered in a research nuclear reactor. The control-rod guide-tube mock-up of the Jules Horowitz Reactor, previously tested in an hydraulic channel at the Technical Center from Le Creusot in France, is retained for this benchmark. Two models are proposed, one based on derivation of leakage flow theory and the other one was based on potential flow theory with adjusted coefficients given by CFD simulations. The flow induced vibration amplitude is consistent with the experimental data. Also, the calculation and experiment provide similar trends when the boundary conditions are changed