Small break loch experiments and verification of CANAC-II code

Scaled experiments on small break, loss-of-coolant accidents have been conducted. The tests simulated loss-of-coolant accidents (LOCAs) resulting from a 0.53% and a 0.13% communicative break in the cold leg and the pressurizer power operated relief valve (PORV). The thermal-hydraulic behavior such as natural circulation and reflux condensation cooling during a small break LOCA has been investigated.

A new computer program CANAC-II (a Computer Analysis Program of Natural Circulation for multi-loop systems) has been developed and verified based upon comprehensive tests. A drift flux model was applied for two-phase flow in CANAC-II. It also has a shorter computer running time than the real time.