Natural Circulation of Lead-Bismuth in a One-Dimensional Loop: Experiments and Code Predictions

Abstract

The paper summarizes the results obtained by an experimental and computational study jointly performed by ENEA and University of Pisa. The study is aimed at assessing the capabilities of an available thermal-hydraulic system code in simulating natural circulation in a loop in which the working fluid is the eutectic lead-bismuth alloy as in the Italian proposal for Accelerator Driven System (ADS) reactor concepts. Experiments were performed in the CHEOPE facility installed at the ENEA Brasimone Research Centre and pre- and post-test calculations were run using a version of the RELAP5/Mod.3.2, purposely modified to account for Pb-Bi liquid alloy properties and behavior. The main results obtained by the experimental tests and by the code analyses are presented in the paper providing material to discuss the present predictive capabilities of transient and steady-state behavior in liquid Pb-Bi systems.

Decay Heat Removal and Transient Analysis in Accidental Conditions in the EFIT Reactor

“…The so modified RELAP5 code has been applied in previous ADS plant transient analysis such as PDS-XADS [7], and the results have been successfully compared with other codes. Furthermore, the code has been validated against experimental data from tests conducted on the CHEOPE and CIRCE facilities at ENEA/Brasimone Centre [8,9]; a new experimental program to be conducted on the large-scale integral facility CIRCE will provide further valuable data for code validation and verification. This modified version of RELAP5 code is used in the framework of a collaboration between ENEA Centre and the Department of Nuclear Engineering (DIN) of the University of Palermo for T/H transient analysis of EFIT.…”