Criticality evaluation of PWR1000 core at optimized power reactor type

Criticality evaluation of the PWR1000 core at optimized power reactor been done using (Monte Carlo N-Particle) MCNP4C computer code. The aim of calculation is to know the characteristic one of the cores of PWR1000 MWe namely OPR1000 core. The OPR1000 reactor is one of PWR types NPP with passive safety condition. One of the important parameter to understand the design characteristic is a core criticality. Evaluation of the design calculation was done for the OPR core which used solid fuels UO₂ with power thermal 2825 MWt. The enrichment fuel compositions were 1.60 %, 3.28 % and 2,78 % with gadolinia as a burnable poison. The OPR core used 16x16 grids of fuel assemblies with 236 pin rods, 4 guide tubes and 1 instrument tube. The OPR reactor has 177 fuel assemblies in the core in matrix of 15x15. MCNP4C code is one of the core calculation code used Monte Carlo method which has good validation. The result of calculation showed that the value of k_eff for OPR1000 core is 1,17912 it is lower than other k_eff value of PWR cores. So the core of OPR1000 reactor is a low boron concentration that means the reactor need low boron concentration become the core subcritical condition. (author)