Neutronics evaluation of a super-deep-burn with TRU Fully Ceramic Microencapsulated (FCM) fuel in CANDU

• The FCM fuel was introduced to transmute the LWR TRUs in CANDU.
• The neutronics analysis was performed in a 2-D lattice with a Monte Carlo code.
• A super-deep-burn of over 70% burnup can be achieved by the TRU FCM fuel.
• Safety parameters of TRU FCM fuel are more favourable than those of natural U case.

One of the potential approaches for dealing with spent nuclear fuel in order to ensure the sustainable development of the nuclear energy is to fully utilize (transmute) the transuranics (TRU) in nuclear reactors. The CANDU reactor has an extremely high neutron economy which is necessary for an efficient TRU burning. The current CANDU fuel elements are unable to achieve the high burnup required to transmute the TRUs. In this paper, a special nuclear fuel called FCM (Fully Ceramic Microencapsulated) is introduced to achieve a super-deep-burn of the TRUs and to tackle the issue of fuel element integrity. In the FCM fuel, the conventional TRISO fuel particles are randomly dispersed in a fully dense SiC matrix and the FCM fuel is expected to be able to accommodate an extremely high burnup. The core performances and characteristics were analysed from the neutronics perspective through the fuel lattice analysis. The fuel depletion calculations were conducted using the Serpent Monte Carlo code and the fuel discharge burnup was determined based on the non-linear reactivity theory. Kinetic and major safety parameters including the fuel temperature coefficient, void reactivity, and coolant temperature coefficient were also evaluated.