Neutronic analysis of the LVR-15 research reactor using the PARCS code

Abstract

Research reactors, together with the computational codes, represent a valuable tool combination to investigate over phenomena which can take place in nuclear power plants. In this framework, the Research Centre Řež (CVŘ), which owns two research reactors, Lehkovodní Reaktor 0 (LR-0) and Lehkovodní Reaktor 15 (LVR-15), is moving towards the creation of a code portfolio to be used to relicense them in front of the State Office of Nuclear Safety (SUJB).LVR-15 is a light water tank type research reactor, adopting a sandwich tube type fuel (IRT4M). The first step of this research activity is the preparation of a working model of LVR-15 using SCALE and PARCS codes: SCALE is used to estimate the Cross Sections (XS) based on the real geometry of the reactor and PARCS is used to perform calculation of transients. The results obtained show that the model is adequately accurate for steady state, as soon as the calculation reaches the criticality. The power calculated during the transient calculations, instead, stabilize after about 1000 s and become comparable, within a 2% bias, with the experimental data, extrapolated from the reactor operation. In conclusion, this demonstrates that PARCS code is capable of modelling our research reactor fuel assemblies geometry in a satisfactory way, although further developments would improve the accuracy of the adopted methodology.