Neutronic analysis of comparation UN-PuN fuel and ThN fuel for 300MWth Gas Cooled Fast Reactor long life without refueling

Abstract

Neutronic analysis of comparation UN-PuN fuel and ThN fuel for 300MWth Gas Cooled Fast Reactor long life without refueling has been done. Gas Cooled Fast Reactor is a Generation IV reactor with gas coolant (i.e. helium) and using fast spectrum neutron. The neutronic calculation was carried out using SRAC (Standard Reactor Analysis Code) version 2006 under the Linux Operating System with nuclear data library JENDL4.0. The first calculation is fuel pin cell calculation (PIJ-method) by using a hexagonal cell and then followed by the calculation of the core reactor (CITATION-method). The calculation of the core reactor used homogeneous and heterogeneous core configuration. The UN-PuN fuel use plutonium as a fissile material and natural uranium as a fertile material and the ThN fuel use U233 as a fissile material and natural thorium as a fertile material. The percentages of fissile material are varied in heterogeneous core configuration. It is used to decrease the peaking power in the center of the core. The heterogeneous core configuration contains of Fuel 1 (F1) 8% fissile materials, Fuel 2 (F2) 10% fissile materials, and Fuel 3 (F3) 12% fissile materials. F1 is located in the central core, F2 middle core and F3 outer core. The diameter and height active core are 240 cm and 100 cm. The reflector radial-axial width is 50 cm. All of the calculations can reach burn up time more than 20 years with excess reactivity less than 1 percent (Δk/k <1%) both UN-PuN fuel and ThN fuel. It means that the reactor stable in 20 years. The average of power density both of UN-PuN fuel and ThN fuel are around 66 Watt/cc. The maximum power density of UN-PuN fuel is 94Watt/cc and ThN fule is 129Watt/cc. The UN-PuN fuel has lower maximum power density value than ThN fuel. So, for fast neutron spectrum reactor especially Gas Cooled Fast Reactor type, it is better used UN-PuN fuel than ThN fuel.