Physics study of deep-burning of spent fuel transuranics using commercial LWR cores

Abstract

This paper describes a physics study of the utilization and destruction of the transuranic (TRU) nuclides contained in spent fuel through a high burnup irradiation (Deep Burn) in commercial light water reactors (LWR). The TRU nuclides are contained in the Fully Ceramic Micro-encapsulated (FCM) fuel, comprising of TRISO particles dispersed in a matrix of silicon carbide and manufactured in fuel pellets and fuel pins. This study is performed by using the traditional two-step core design procedure, which consists of fuel assembly calculations and core analysis. The main focus is on the core physics characteristics including safety-related parameters. The target reference core is the YongGwang unit 3, cycle 6 reload core. New fuel assemblies consisting of the conventional UO2 pins and new FCM TRU fuel pins are charged into the cores from cycle 6 to an equilibrium cycle. The results show that the reload cores can be designed to achieve the deep-burning (∼60% burnup) of TRU without adverse changes to the safety-related parameters and the core performance parameters. The equilibrium core has TRU self-recycling capabilities, being able to “deep burn” as much TRU nuclides as it generates.