A Small Modular PWR Core Design Using Nitride Fcm Fuels With Fecral Cladding for Natural Circulation

Abstract

In this work, a SMR (Small Modular Reactor) core based on the current PWR technology is neutronically designed and analyzed from view point of core physics. The core rates 160 MWt and it consists of 37 rectangular fuel assemblies in which 13×13 rods are located. The each 13×13 rod fuel assembly contains 9 larger water holes for control rod and instrumentations while the assembly pitch is the same as that of the typical Westinghouse type 17×17 fuel assembly. The fat fuel rods are employed for long cycle operation of 768 EFPDs for equilibrium cycle coupled with the accident tolerant FCM (Fully Ceramic Micro-encapsulated) fuels having nitride kernels. In particular, we considered new BP (Burnable Poison) rods in which the Er₂O₃ BP material is admixed with the SiC matrix of FCM fuel rather than the BISO particle type BP. The reload core analysis from the initial to equilibrium cycles shows that the reload cores have cycle lengths range from 675 EFPDs for initial core to 768 EFPDs for equilibrium cycle, sufficient shutdown margins, and the desirable safety-related parameters. But the smaller average discharge burnup of ~74 MWD/kg for the equilibrium cycle than the forced convection core given in the accompanying paper was achieved due to the smaller core size.