Developing a fresh core neutronic model at 300K for a VVER-1000 reactor type using MCNP6

Abstract

A steady state neutronics model for a fresh core Voda Voda Energo Reaktor (VVER)-1000 reactor type is developed using an internationally recognised code, Monte Carlo N-Particle, version 6 (MCNP6). This research study is based on a VVER type of pressurized water reactor (PWR), which is of Russian design. The neutronics model is done at 300 K, assuming the use of fresh fuel. Major core operational parameters including the 𝑘𝑒𝑓𝑓 , power profiles, reactivity coefficients and control rod worth were evaluated for the reactor core. The present study looks at the ability of the VVER-1000 reactor system to provide appropriate neutronics behaviour of the fresh core at the start of the initial cycle from cold zero power. A convergence study on the MCNP6 results is the most crucial part of MCNP6 simulation in the study, hence a convergence study of the MCNP6 results was initially done to ensure accuracy. The primary objective of the study is to develop an MCNP input model for the VVER-1000 reactor core using the North-West University Reactor Code suite (NWURCS) developed at the North-West University, School of Mechanical and Nuclear Engineering. The verification of the NWURCS code also forms part of the study. The steady state results obtained from the different models for all the investigated cases are presented and compared to previous research. The calculated values support safe start-up of a reactor and also assist in predicting the behaviour of the system.