THE DEVELOPMENTS AND VERIFICATIONS OF TRACE MODEL FOR IIST LOCA EXPERIMENTS

摘要

The test facility IIST (INER Integral System Test) is a Reduced-Height and Reduced-Pressure (RHRP) integral test loop, which was constructed for the purposes of conducting thermal hydraulic and safety analysis of the Westinghouse three-loop PWR Nuclear Power Plants. The main purpose of this study is to develop and verify TRACE models of IIST through the IIST small break loss of coolant accident (SBLOCA) experiments. First, two different IIST TRACE models which include a pipe-vessel model and a 3-D vessel component model have been built. The steady state and transient calculation results show that both TRACE models have the ability to simulate the related IIST experiments. Comparing with IIST SBLOCA experiment data, the 3-D vessel component model has shown better simulation capabilities so that it has been chosen for all further thermal hydraulic studies. The second step is the sensitivity studies of two phase multiplier and subcooled liquid multiplier in choked flow model; and two correlation constants in CCFL model respectively. As a result, an appropriate set of multipliers and constants can be determined. In summary, a verified IIST TRACE model with 3D vessel component, and fine-tuned choked flow model and CCFL model is established for further studies on IIST experiments in the future.