Jean-Charles Jaboulay

DEMO reactor design using the new modular system code SYCOMORE

A demonstration power plant (DEMO) will be the next step for fusion energy following ITER. Some of the key design questions can be addressed by simulations using system codes. System codes aim to model the whole plant with all its subsystems and identify the impact of their interactions on the design choices. The SYCOMORE code is a modular system code developed to address key questions relevant to tokamak fusion reactor design. SYCOMORE is being developed within the European Integrated Tokamak Modelling framework and provides a global view (technology and physics) of the plant. It includes modules to address plasma physics, divertor physics, breeding blankets, shield design, magnet design and the power balance of plant. The code is coupled to an optimization framework which allows one to specify figures of merit and constraints to obtain optimized designs. Examples of pulsed and steady-state DEMO designs obtained using SYCOMORE are presented. Sensitivity to design assumptions is also studied, showing that the operational domain around working points can be narrow for some cases.

Coupling between a multi-physics workflow engine and an optimization framework

A generic coupling method between a multi-physics workflow engine and an optimization framework is presented in this paper. The coupling architecture has been developed in order to preserve the integrity of the two frameworks. The objective is to provide the possibility to replace a framework, a workflow or an optimizer by another one without changing the whole coupling procedure or modifying the main content in each framework. The coupling is achieved by using a socket-based communication library for exchanging data between the two frameworks. Among a number of algorithms provided by optimization frameworks, Genetic Algorithms (GAs) have demonstrated their efficiency on single and multiple criteria optimization. Additionally to their robustness, GAs can handle non-valid data which may appear during the optimization. Consequently GAs work on most general cases. A parallelized framework has been developed to reduce the time spent for optimizations and evaluation of large samples. A test has shown a good scaling efficiency of this parallelized framework. This coupling method has been applied to the case of SYCOMORE (System COde for MOdeling tokamak REactor) which is a system code developed in form of a modular workflow for designing magnetic fusion reactors. The coupling of SYCOMORE with the optimization platform URANIE enables design optimization along various figures of merit and constraints

Quand l’instrumentation de mesure déportée œuvre à l’amélioration de la surveillance du bâtiment réacteur des centrales nucléaires en cas d’accident grave

Cet article presente les travaux menes dans le cadre du projet DISCOMS, initie apres Fukushima, et dedie a la surveillance du corium en cas d’Accident Grave (AG) avec percement de la cuve du reacteur. Apres etablissement des objectifs et identification des localisations possibles pour les capteurs, la modelisation des rayonnements a ete menee pour deux generations de reacteurs (le parc en exploitation ‘Gen2’, et ‘Gen3’ soit le reacteur EPR), tant en fonctionnement normal qu’en AG. Eu egard aux conditions extremes de l’interaction corium-beton, une modelisation thermique a diverses profondeurs du radier a ete realisee, afin d’optimiser l’enfouissement des capteurs. Ceci a permis la conception des Collectrons et le choix des fibres optiques monomodes a meme de resister a la temperature et a la dose pendant les 60 ans de fonctionnement, suivis d’un AG. Grâce a des tests en irradiateur, plusieurs fibres optiques presentant une faible attenuation induite ont ete qualifiees pour leur mise en câble. Celles-ci seront interrogeables par plusieurs instruments (OTDR, DTS, BOTDA, OFDR), dont les performances ont ete etablies. Pour les Collectrons, les etudes ont montre que l’AG etait detectable via la mesure de leur courant auto-genere. S’en suivit le developpement d’une electronique multivoie a bas niveau de courant, et d’une perche mixte collectrons -thermocouple, de grande longueur, contenant un premier Collectron Rhodium pour flux neutronique (fonctionnement normal), un second de type Platine pour les neutrons et γ (Accident Grave), et un thermocouple de type K. Le projet va se poursuivre, jusqu’a la validation globale, et in fine par un essai ‘Vulcano’ de coulee de corium sur une dalle de beton. Une fois la faisabilite assuree, le deploiement de cette solution innovante pourrait etre envisage.