Introduction to the session Reactor Models 3rd Technical Workshop On Fuel Cycle Simulation 3rd Technical Workshop On Fuel Cycle Simulation 9-11/07/2018 - Paris

Reactor models : a key issue in fuel cycle simulation Fuel cycle studies : a way to assess possible futur nuclear fuel cycle « Economy » driven studies Nuclear/renewable energy interation GENIII / GNE IV synergy (fuel cycle costs) Cf 10/07 « Nuclear » driven studies Material recycling (waste vs natural ressources) Material diversion Cf 11/07 Most of the observables of interest are function of isotopic quantities (both front end and back end) Uranium enrichement for nuclear fuel cost Gamma and neutron dose rate for fuel transportation … The purpose of a reactor model is to predict : The fuel quantity needed for the loading The spent fuel composition Etudes dynamiques du cycle Etudier les contraintes et avantages de certaines options du cycle Réacteurs Observables du cycle sont dépendantes des quantités de matières Prédiction des quantités de matières ! Couplage entre Boltzman et Bateman Exemple de scénario de transition cf autre session… 3rd Technical Workshop On Fuel Cycle Simulation 9-11/07/2018 - Paris

Reactor models : a key issue in fuel cycle simulation One model : a recipee based on external depletion calculation Uox spent fuel PWR Uenr Fuel cycle simulator Data used by the fuel cycle simulator without (almost) no treatment A change in the reactor parameter implies another recipee All reactor configurations shall be anticipated by the user it may be difficult to anticipate isotopic compositions that may encounter the reactor  Multi-recycling It may be more efficient to develop an algorithm for reactor modeling inside the fuel cycle simulator  Computational power  Convenience Modèle le plus simple : Recepee Pas besoin de plus tant qu’on ne recycle pas les matières Après – on tabule… mais on se limite Ou on créer des modèles plus compliqués Evolution de la puissance Evolution du fissile et de la compo FIT Benchmark !! Et incertitudes -> Notion de la confiance… 3rd Technical Workshop On Fuel Cycle Simulation 9-11/07/2018 - Paris

Given BU ; specific power, … Reactor models : a key issue in fuel cycle simulation Reactor model requirements  Fuel Loading Model : Calculation of the fresh composition function of: Reactor parameters Fissile isotopic compositions (coming from spent fuel)  Irradiation Model : Calculation spent fuel composition Resolution of Bateman’s equations :  Others ?? Fissile ?? %𝑭𝒊𝒔𝒔𝒊𝒍𝒆 ?? Fresh Fuel Fertile Given BU ; specific power, … Modèle le plus simple : Recepee Pas besoin de plus tant qu’on ne recycle pas les matières Après – on tabule… mais on se limite Ou on créer des modèles plus compliqués Evolution de la puissance Evolution du fissile et de la compo FIT Benchmark !! Et incertitudes -> Notion de la confiance… 3rd Technical Workshop On Fuel Cycle Simulation 9-11/07/2018 - Paris

Reactor models : a key issue in fuel cycle simulation Models should be representative of the physics : Example of a PWR UOX : the reactor must be critical at all time :  Modeling of the criticality is base on cell calculations ! Modèle le plus simple : Recepee Pas besoin de plus tant qu’on ne recycle pas les matières Après – on tabule… mais on se limite Ou on créer des modèles plus compliqués Evolution de la puissance Evolution du fissile et de la compo FIT Benchmark !! Et incertitudes -> Notion de la confiance… How to considered core effect ? (Ex : for RNR) Which criteria must be consider when the reactivity is not evolving ? (ex : MSR) 3rd Technical Workshop On Fuel Cycle Simulation 9-11/07/2018 - Paris

Reprocessing unit = Fabrication plant Reactor models : a key issue in fuel cycle simulation A particular focus on MSR :  How those reactor interacts with other reactors ? Reactors models are also indispensible for studying reactor synergies.  Ex : plutonium from RNR fertile blankets in PWR ? Some open questions : How to model blankets (for breeding or for transmutations) ? What about SMR, ADS ? How much shall we increase the complexity ? (ex : core loading models?) Are those models really necessary ? Cf. Nicolas’ presentation FIT Benchmark (Functionality Isolation Test) Reactor Reprocessing unit = Fabrication plant Strong coupling between the reactor and the chemical control unit Each reactor is a « mini » fuel cycle 3rd Technical Workshop On Fuel Cycle Simulation 9-11/07/2018 - Paris

The presentations of the session : FITXS : A fast burn-up scheme based on the fitting of one-group cross-section Maté Halasz Multi-zoned fuel irradiation model for ASTRID-like SFR with the CLASS code Léa Tillard Modeling MSRs in DYMOND  Ed Hoffman for Bo Feng Modeling a fast MSR with ORION Eva Davidson Molten salt reactor modeling and simulation  Eva Davidson for Benjamin Betzler 3rd Technical Workshop On Fuel Cycle Simulation 9-11/07/2018 - Paris