Neutronic and burn up analysis of VVER 1000 benchmark using EXCEL and TRIHEX-FA code system

Abstract

Benchmarking and validation of the neutronic codes is an important aspect of the reactor design. This paper presents VVER-1000 X2 Benchmark steady state core physics analysis carried out using the lattice level burn-up code, EXCEL and core physics analysis using multi-group diffusion code, TRIHEXFA developed at BARC. These codes have been augmented with new features for modeling of LWR Cores. The VVER-1000 X2 Benchmark with modern fuel assembly (FA) design is a comprehensive benchmark proposed for validating and verifying package of codes and data libraries for reactor physics calculations of LWRs, which includes fuel assembly modeling, generation of homogenized cross section data base for all envisaged core conditions, and reactor core modeling. The trends of k∞ (k-inf) values as a function of various parametric variations and as a function of burn-up for all the fuel assemblies considered in benchmark are analyzed in detail and the deviations have been estimated.The VVER-1000 core follow-up simulations are done by using core diffusion code TRIHEXFA using the few group data generated by EXCEL code. Important core physical characteristics like critical soluble boron, 2-D radial power distribution, axial power distribution, radial peaking factors and volumetric power peaking factors, FA burn-up values obtained from the TRIHEXFA simulations are compared with the experimental core follow up data. All these parameters are found to be reasonably in good agreement with the values provided in benchmark.