SPACE3.0 and RELAP5/MOD3.3 Simulations of Siphon Break Experiments

The system codes used for the safety analysis of reactor facilities should accurately and reliably predict the transient phenomena for the facility. Therefore, it is necessary to have appropriate model and analysis capabilities for the purpose, the range, and the major thermal hydraulic phenomena of the facility. Many experiments were carried out to understand the thermal hydraulic characteristics of siphon break. Full-scale experiments have been performed by POSTECH in various sizes of pipe rupture and siphon breaker line. A series of experiments has been conducted by Idaho state university in an experimental facility consisting of relatively small size pipe. In this paper, SPACE3.0 and RELAP5/MOD3.3 were used to simulate the experimental data. Their calculation results were compared with the experimental data. The simulations of siphon break experiments were performed using SPACE3.0 and RELAP5/MOD3.3. In the 14-inch LOCA with a 4-inch siphon breaker, both SPACE3.0 and RELAP5/MOD3.3 calculate the pool level lower than the experiment when the siphon phenomenon is finished, and SPACE3.0 predicts much lower pool level than RELAP5/MOD3.3. Both SPACE3.0 and RELAP5/MOD3.3 well predict the POSTECH experiment with the 14-inch break size and 6-inch siphon breaker and the Idaho state university experiment.