Evaluación experimental de las características del enfriamiento pasivo de la cámara de combustible del Reactor Nuclear de Lecho Fijo (FBNR)

Abstract

The Fixed Bed Nuclear Reactor (FBNR) is a Generation IV small reactor concept that incorporates passive safety features. The main objective of the present work has been to evaluate the feasibility and limiting parameters of the passive cooling process. The fuel in the FBNR is enclosed in spheres which contain UO2 as the nuclear source. In case of any flow interruption of the liquid coolant, the pebbles descend into the helical fuel chamber and the resulting decay heat is dissipated to the water reservoir. A mathematical model for the fuel chamber was developed based on homogenization techniques to derive effective expressions for the thermophysical properties of an idealized continuum, representative of the chamber and fuel elements. A mathematical simulation of the passive energy transfer was conducted in Solidworks. The maximum temperature reached was 901,5 °C, which falls under the 1204,4 °C recommended as a safety parameter. It will be possible to control said temperature for 29 days and 18 hours before the total evaporation of the water. Moreover, an experimental setting was built where electricity circulated through an immersion resistance. The results of the simulation of the cooling of the emitter were verified through the corresponding thermal experimentation.