A FULL REFERENCE APOLLO3^® DETERMINISTIC SCHEME FOR THE JHR MATERIAL TESTING REACTOR

Abstract

JHR is a new material testing reactor under construction at CEA Cadarache. Its high flux core contains 37 fuel assemblies loaded along concentric rings into alveolus of an aluminum matrix. For the operation of the reactor, twenty-seven of these fuel assemblies hovnst hafnium rods in their center while the other ones but also the beryllium radial reflector can accommodate experimental devices. In order to accurately predict its operating core characteristics but also its irradiation performance, a recently developed scheme based on the APOLLO3® platform is being developed which uses the sub-group method for spatial self-shielding, the 2D method of characteristics and the 3D unstructured conform MINARET Sn transport solver. A 2D model of JHR has been built and optimized for calculating, at the lattice step, the self-shielded and condensed cross sections thanks to the sub-group method and the method of characteristics. Results are benchmarked against a TRIPOLI-4® stochastic reference calculation. A more refined spatial mesh gives better results on fission rates and reactivity compared to the ones of the former APOLLO2 scheme. The classical 2-step calculations use the hypothesis of infinite lattice configuration, which is reasonable for the assemblies close to the center but not for peripheral ones. Hence, a new approach is being set up taking into account the surrounding of each assembly. The newly 3-step scheme uses the Sn solver MINARET and gives better results than the traditional 2-step scheme. This approach will be applied to a 3D modelling of the heterogeneous JHR core configurations incorporating experimental devices and enabling burn up calculations.

Overview of SERMA’s Graphical User Interfaces for Lattice Transport Calculations

“…Many experimental facilities, such as material test reactors, show very complex geometry patterns that can be efficiently drawn by our GUIs, thanks to the many functionalities available for unstructured geometries. A radial cut of the Jules Horowitz Reactor (JHR) [11] produced by ALAMOS is illustrated in Figure 6, together with a particular detail of the unit cell, showing broad use of element overlap and automatic mesh recalculation by the method intersector2d.…”

“…In order, the model is first built by components in (a), the basket and the water gap next to the reflector are added by APIs in (b), a triangle mesh is applied in the reflector Many experimental facilities, such as material test reactors, show very complex geometry patterns that can be efficiently drawn by our GUIs, thanks to the many functionalities available for unstructured geometries. A radial cut of the Jules Horowitz Reactor (JHR) [11] produced by ALAMOS is illustrated in Figure 6, together with a particular detail of the unit cell, showing broad use of element overlap and automatic mesh recalculation by the method intersector2d. The core layout of the SPERT-III facility [12] is illustrated in Figure 7, with a colored map for the properties identifying the resonant nuclides used in the self-shielding calculations over the full north-east quadrant.…”