Validation of an advanced APOLLO3® deterministic scheme for characterizing of the Jules Horowitz irradiation reactor core

International audienceJHR is a new material testing reactor under construction at CEA Cadarache. Currently, the neutronic characteristics of the core are calculated thanks to the HORUS3D/N deterministic scheme. The industrial route of this scheme follows a two steps approachwith first the APOLLO2 MOC lattice calculation and then the CRONOS2 core calculation based on diffusion theory. APOLLO3®is the new deterministic calculation platform at CEA, which incorporates advanced computation methods. In this paper, a new reference calculation scheme for JHR is being set up using the new methods brought by APOLLO3®. The calculation scheme is validated against reference stochastic simulations performed by TRIPOLI4®. Improvements at the lattice step allow a significant reduction of biases on absorption rates for fuel elements and Hf control rods when compared to results of a scheme that mimics, within APOLLO3®, the HORUS3D/N scheme. The main changes in the new scheme are coming from the use of the subgroup self-shielding method instead of the Fine-structure equivalence method. These changes are associated to refined geometrymeshes and to the 383 energy group structure. Condensed cross-sections from the lattice step are used to compute the neutron balance of a 2D JHR core configuration with five Hf control rods inserted. Core-reflector super cell has been added in the new calculation scheme to produce refined reflector cross sections. The MOC 2D core calculation performed with a coarser 41-group structure preserves the lattice calculation improvements and gives better predictions on reactivity and reactions rates. Next steps will use a 3D Sn MINARET full-core calculation with depletion including in-core experimental devices

A Deterministic against Monte-Carlo Depletion Calculation Benchmark for JHR Core Configurations

International audienceThe Jules Horowitz Reactor (JHR) is the next international Material-Testing Reactor (MTR) under construction in the south of France at CEA Cadarache research center. Its first criticality is foreseen by the end of the decade. The innovative character of the JHR led to the development of a specific neutronic calculation scheme called HORUS3D/N for performing design and safety studies. HORUS3D/N is based on the deterministic codes APOLLO2 and CRONOS2 and on the European nuclear data library JEFF-3.1.1. Up to now, the biases and uncertainties due to the HORUS3D/N calculation scheme in depletion have been assessed by comparing HORUS3D/N deterministic calculations with 2D APOLLO2-MOC reference route calculations. The recent development of the Monte-Carlo code TRIPOLI-4 in its depletion mode (TRIPOLI-4D) offers the opportunity to study the JHR 3D core configurations under fuel depletion conditions. This paper presents the first CRONOS2/TRIPOLI-4D benchmark results obtained for 3 core configurations of interest including control rods and experimental devices up to a burnup value of 60 GWd/t$_{HM}$. The main parameters of interest are the reactivity and the isotopic concentrations as functions of burnup. This first study of actual JHR configurations in depletion demonstrates the reliability of TRIPOLI-4D to calculate a complex geometry using a large number of depleting regions. In particular, a good agreement between the two codes is observed concerning the $^{235}$U consumption with discrepancies values less than -0.5% at 60 GWd/tHM. Nevertheless, a global CRONOS2 overestimation of the plutonium inventory can be noticed. Compared with 3D assembly calculation in an infinite lattice, this overestimation was tracked down to the condensation of the nuclear constants provided by APOLLO2, showing the limits of a two steps calculation

HORUS3D/N neutron calculation tool, a deterministic scheme dedicated to JHR design and safety studies: development, validation, biases and uncertainties quantification

International audienceThe international Jules Horowitz Material Testing Reactor (JHR) is under construction at the CEA Cadarache research center in southern France. Its first criticality is foreseen by the beginning of the next decade. In order to perform JHR neutron simulations, a specific calculation scheme, named Horowitz Reactor simulation Unified System 3-Dimention/Neutron (HORUS3D/N), has been developed since the 2000s for the very first JHR definition studies. Then it was improved and modified in parallel with the JHR design evolution, integrating the most accurate neutron codes and nuclear data libraries. This paper describes the very latest version of HORUS3D/N, named HORUS3D/N v4.2. The industrial route is based on the APOLLO2.8–4 and CRONOS2.10 deterministic codes and the European nuclear data library JEFF3.1.1. Besides, HORUS3D/N v4.2 includes the APOLLO2.8/REL2005/CEA2005 package recommendations applied for light reactor studies. This paper also provides the performance quantification of HORUS3D/N v4.2 as a result of the Verification & Validation—Uncertainty Quantification (V&V–UQ) process. This reference calculation scheme is now a basis for the development of the neutron calculation tool dedicated to JHR operation and loading studies

Validation of horus3d/n against tripoli-4R^Rd for core depletion calculation of the jules horowitz reactor

ISBN: 978-0-89448-726-2International audienceThe international Jules Horowitz material testing Reactor (JHR) is under construction at CEA Cadarache research center, in southern France. Its first criticality is foreseen by the end of the decade. In order to perform JHR design and safety studies, a specific neutronics calculation tool, HORUS3D/N, based on the deterministic codes APOLLO2 and CRONOS2 and on the European nuclear data library JEFF3.1.1, was developed to calculate JHR neutronics parameters taking into account fuel depletion reactivity, power distribution, control rod reactivity worth, etc. Up to now, the biases and uncertainties on the different neutronics parameters computed with HORUS3D/N were assessed, in particular, by comparing HORUS3D/N deterministic calculations with reference route calculations based on APOLLO2-MOC and TRIPOLI-4$^R$. The use for JHR of the recent Monte-Carlo TRIPOLI-4 in its new Depletion mode (TRIPOLI-4$^R$D) will also allow providing biases for the main neutronics parameters under fuel depletion conditions. These biases will give a quantitative estimation of the impact of the approximations of the flux calculation in the deterministic route. This paper presents a contribution to the validation of HORUS3D/N based on the first comparisons between the calculations performed with APOLLO2-MOC and CRONOS2, and the ones from TRIPOLI-4$^R$D. The study is performed on 2-D calculations for two different clusters in an infinite lattice configuration. It focuses on the main parameters of interest isotopic concentrations, plate power distributions, reactivity, as functions of burnup. The results obtained show reasonable discrepancies with APOLLO2 calculation and allow to be confident on the APOLLO2.8/REL2005/CEA2005 package recommendations developed by CEA for light water reactor studies used in HORUS-3D/N. In particular, the main fuel isotopes are well predicted with TRIPOLI-4$^R$D with discrepancies values lower than -1.5 percent

JHR neutron deterministic calculation scheme improvement thanks to monte carlo analysis in depletion

International audienceThe international Jules Horowitz Material Testing Reactor (JHR) is under construction at CEA Cadarache research center, in southern France. In order to perform JHR design and safety studies, a specific neutron calculation tool, HORUS3DN, was developed. It is based on APOLLO2 and CRONOS2 deterministic codes and the European nuclear data library JEFF3.1.1. The validation step aims at quantifying the computation tool performances, i.e. the biases and uncertainties associated with HORUS3DN computations. These biases and uncertainties were in particular assessed by comparing HORUS3DN deterministic calculations with a reference computation route using a heterogeneous geometry in 2D and 3D.The recent development of the new CEA's Monte Carlo burn-up code, TRIPOLI-4 version 10, offers the opportunity to study JHR configurations during depletion with a probabilistic computation code.This paper presents, as a complement to the validation step, comparisons performed between HORUS3DN and TRIPOLI-4 code with its new depletion capability. The study is performed on 2D and 3D computations for different JHR core configurations. It focuses on the reactivity discrepancies as functions of burnup and neutron leakage.Finally, these comparisons will contribute to improve the computation options of the HORUS3DN calculation scheme. It has been used in order to upgrade the depletion of the boron insert in the reflector and the axial neutron leakage. Improvements consist in an increased number of energy groups (in the homogenized cross section calculations), the removal of transportdiffusion equivalence factors, and a refined geometric modeling