Study of D2O/H2O-cooled thorium-fueled PWR-like SMR cores using the KNACK toolbox: conversion and safety assessment

International audienceBased on SMURE (Serpent2/MCNP Utility) and NDM (Nodal Drift Method for time-dependent diffusion), a full set of academic methods named KNACK (Knack of Nodal Approach to Core Kinetics) has been used for the design of 600 MWth D2O/H2O-cooled thorium-fueled SMR (Small Modular Reactor) cores. Three types of lattice, with 17x17, 19x19 or 21x21 PWR-like FAs (Fuel Assemblies), have been considered. After initial fissile zoning for power flattening, full core burnup calculations with D2O/H2O Spectral Shift Control have been performed at HFP (Hot Full Power) for the comparison of conversion performance. Temperature dependences of diffusion data have been implemented within a thermal lumped model for safety. A simple criterion, on coolant temperatures only, has finally been used for the comparative analysis of Rod Ejection Accidents (REA) from HZP (Hot Zero Power)