Neutronic evaluation of a PWR with fully ceramic microencapsulated fuel. Part II: Nodal core calculations and preliminary study of thermal hydraulic feedback

The present paper focuses on two of the issues associated with this proposed implementation: specifically the development of a reasonable reference full-core model of an advanced PWR with FCM fuel and the response of the PWR to a reactivity insertion accident (RIA). This work addresses the issues of the increased power density and transients that occur on short time-scales in a PWR. In this case, the RIA takes the form of a control rod ejection for a typical PWR reactor. This results in a sudden increase in power and a corresponding increase in fuel kernel temperature. In the case of a PWR, this response is more demanding than in the case of a gas-cooled reactor, because the kinetic parameters and feedback coefficients of the two reactors are quite different. The parameters for the fuel and matrix material in the PARCS thermal-hydraulic module were modified to reflect the different geometry and materials. Preliminary data for both un-irradiated and irradiated SiC were obtained from the literature and included in the analyses. A super prompt critical RIA produces an average energy deposition (<124.6 J/g) that is estimated for different simplified thermal representations of the FCM fuel pin.