[en] One of the primary objectives of the LOFT (Loss-of-Fluid Test) Program is to provide data required to evaluate and improve the analytical methods currently used to predict the LOCA (Loss-of-Coolant Accident) response of large pressurized water reactors. The purpose of the paper is to describe the computer modeling methods used in predicting the fluid conditions in the LOFT core during the blowdown and refill phases of a nuclear LOCE (Loss-of-Coolant Experiment). Prediction results for a LOFT nonnuclear isothermal LOCE are compared to the experimental data to illustrate the validity of the modeling choices