Modeling of the LOFT facility with use of RELAP5 code

A LOFT (Loss Of Fluid Test) facility has buils as an installation to provide necessary data for thermo-hydraulic system of Nuclear Power Plant during occurrence of abnormal operating conditions (Fig [1]). The LOFT facility has been dedicated to simulate loss of coolant accident (LOCA) in large, commercial pressurized water reactors (PWR). The LOFT facility has used fuel bundles with nuclear fuels with total power of 50 MWt, instead of commonly used electrically heated rods, which is an unique feature in case of installations assigned to simulate various thermo-hydraulic conditions during Design Basic Accident (DBA). During the lifetime of the facility over a dozen of tests have been performed, with severe damage experiment as last one. For the modelling purpose test L2-5 has been chosen, in which facility was configured to simulate a double-ended cold leg break.

The main objective of the work is to gain experience in modelling, functioning of the nuclear facility and to extend knowledge on possible thermodynamic phenomena which may occur during postulated transient. These goals was achieved by creation of full, detailed model of LOFT facility form the scratch.

Autor: Kacper Samul