Comparing Analysis of Loss of Coolant Accident on Bethsy Facility with Apros 6.05 and 6.06.

Abstract

In this paper, the comparison of analysis of international standardized problem ISP 27 using two versions of APROS process simulation software 6.05 and 6.06 is presented. Numerical simulation of experiment Bethsy 9.1b, also known as ISP 27 was performed on a scaled down model of a three loop, 900 MWe Framatome PWR. In the test a small LOCA, with 2-inch cold leg break, combined with High pressure Injection System (HPIS) failure is simulated. State oriented approach, which requires operators to start an Ultimate Procedure were used. Model was first built in APROS 6.05 using standard modules in order to describe the volumes, heat structures and regulation of the test facility and was then exported to APROS 6.06. The results from both versions showed all the processes such as loop seal clearing, core uncover and rise of cladding temperature and other processes taking place in the experiment were in a good agreement with experimental data. However even though results were similar some differences were noticeable. The differences in core cladding temperature, time integrated break mass flow, core liquid level and pressurized pressure were analysed in more detail in this paper.