Modélisation du phénomène d'autoprotection dans le code de transport multigroupe APOLLO2

Ce document décrit les avancées réalisées dans le cadre de la modélisation du phénomène d'autoprotection dans le code de transport multigroupe APOLLO2. Elles concernent le traitement en espace et en énergie de l'équation de ralentissement, l'établissement de formules de quadrature pour calculer les taux de réaction, l'établissement d'une méthode traitant directement un mélange de noyaux résonnants et le développement d'une méthode de type "sous-groupes". Nous validons ensuite, de façon élémentaire puis de façon plus globale ces nouvelles modélisations. Nous avons obtenu un gain en précision très significatif sur le calcul des taux de réaction dans le cadre de calculs multigroupes sur un maillage énergétique relativement grossier et avons offert la possibilité de réaliser un calcul d'autoprotection "de référence" dans le cadre de calculs multigroupes sur un maillage énergétique fin. Ce document se termine par une conclusion et par des perspectives sur le travail restant à faire.This document describes the improvements carried out for modelling the shelf-shielding phenomenon in the multigroup transport code APOLLO2. They concern the space and energy treatment of the slowing-down equation, the setting-up of quadrature formulas to calculate reaction rates, the setting-up of a method that treats directly a resonant mixture and the development of a "sub-group" method. We validate these improvements either in an elementary or in a global way. Now, we obtain, more accurate multigroup reaction rates and we are able to carry out a reference self-shielding calculation on a very fine multigroup mesh. To end, we draw a conclusion and give some prospects on the remaining work.PARIS-CNAM (751032301) / SudocSudocFranceF

Current status of the verification and processing system GALILÉE-1 for Evaluated Data

This paper describes the current status of GALILÉE-1 [1], the new verification and processing system for evaluated data, developed at CEA. It consists of various components respectively dedicated to read/write the evaluated data independently of the format, to diagnose inconsistencies in the evaluated data and to provide continuous-energy and multigroup data as well as probability tables for particle transport and depletion codes. All these components are written in C++ language and share the same objects. In this paper, we detail themain advances made in GALILÉE-1 : Unresolved Resonance Range (URR) treatment, Thermal Scattering Law (TSL) processing and anisotropy calculations from resonance parameters

Current status of the verification and processing system GALILÉE-1 for evaluated data

This paper describes the current status of GALILÉE-1 that is the new verification and processing system for evaluated data, developed at CEA. It consists of various components respectively dedicated to read/write the evaluated data whatever the format is, to diagnose inconsistencies in the evaluated data and to provide continuous-energy and multigroup data as well as probability tables for transport and depletion codes. All these components are written in C++ language and share the same objects. Cross-comparisons with other processing systems (NJOY, CALENDF or PREPRO) are systematically carried out at each step in order to fully master possible discrepancies. Some results of such comparisons are provided

GALILÉE-1: a validation and processing system for ENDF-6 and GND evaluations

GALILÉE-1 is the new validation and processing system for evaluated data, developed at CEA. This system can handle evaluations stored either in the ENDF-6 format or in the new General Nuclear Data (GND) format. It consists of various components respectively dedicated to read/write the evaluated data whatever the format is, to diagnose inconsistencies in the evaluated data and to provide continuous-energy and multigroup data as well as probability tables for transport and depletion codes. All these components are written in C++ language and share the same objects. This paper describes the state of progress of the various parts of the system and gives some illustrations

Neutronique

International audienceLa neutronique est l'étude du cheminement des neutrons dans la matière, celle des conditions d'une réaction en chaîne et celle des modifications de la composition de la matière dues aux réactions nucléaires. Elle rend possibles la conception et l'exploitation des réacteurs nucléaires et des installations du cycle du combustible.En utilisant des données issues du monde quantique (les interactions entre les neutrons et les noyaux atomiques) pour calculer des grandeurs comme la puissance d'un réacteur, la neutronique jette un pont entre le monde microscopique et le monde macroscopique. Son caractère multi-échelle la conduit à travailler sur des échelles de temps, d'espace et d'énergie s'étendant sur plus d'une dizaine d'ordres de grandeur.Née en 1932 avec la découverte du neutron, la neutronique est une science arrivée à maturité qui, pourtant, continue d'évoluer : l'augmentation régulière de la puissance des ordinateurs bouleverse les méthodes de calcul, bouscule le statut de l'expérience et élargit les perspectives de la simulation numérique. L'un des défis actuels est de coupler la neutronique à la thermohydraulique et à la thermomécanique pour simuler le comportement d'un réacteur.Cette monographie fait une présentation globale de la neutronique sous le double éclairage de la recherche et des applications, et présente quelques résultats marquants obtenus récemment

Current status of the verification and processing system GALILÉE-1 for evaluated data

This paper describes the current status of GALILÉE-1 that is the new verification and processing system for evaluated data, developed at CEA. It consists of various components respectively dedicated to read/write the evaluated data whatever the format is, to diagnose inconsistencies in the evaluated data and to provide continuous-energy and multigroup data as well as probability tables for transport and depletion codes. All these components are written in C+ + language and share the same objects. Cross-comparisons with other processing systems (NJOY, CALENDF or PREPRO) are systematically carried out at each step in order to fully master possible discrepancies. Some results of such comparisons are provided

Current status of the verification and processing system GALILÉE-1 for Evaluated Data

This paper describes the current status of GALILÉE-1 that is the new verification and processing system for evaluated data, developed at CEA. It consists of various components respectively dedicated to read/write the evaluated data whatever the format is, to diagnose inconsistencies in the evaluated data and to provide continuous-energy and multigroup data as well as probability tables for transport and depletion codes. All these components are written in C++ language and share the same objects. Cross-comparisons with other processing systems (NJOY, CALENDF or PREPRO) are systematically carried out at each step in order to fully master possible discrepancies. Some results of such comparisons are provided