An Overall Investigation of Cold Leg Pipe Break Accidents of the ATLAS Facility

A previous parametric study of the direct vessel injection (DVI) line breaks was re-evaluated to see their applicability to the cold leg (CL) pipe breaks in ATLAS (Advanced Thermal-hydraulic test Loop for Accident Simulation). Evaluation results of the tests and analyses for the major parameters, i.e., the pressurizer (PZR) pressure, downcomer water level, collapsed core water level, and clad temperature, were compared for four different CL pipe break scenarios. The overall trends of the major parameters showed reasonable behaviors between the tests and analyses. The clad temperature showed conservative behaviors in the analyses using the suggested options. The suggested counter-current flow limit (CCFL) options for the fuel alignment plate (FAP) and cross-over legs (COLs) can be applicable to any small-break loss-of-coolant accident (SBLOCA) scenario for the CL pipe and DVI line breaks in the ATLAS tests. In this paper, a previous parametric study of the DVI line breaks was re-evaluated to see its applicability to that of the CL pipe breaks in ATLAS. The evaluation results of the tests and analyses for the major parameters, i.e., the PZR pressure, downcomer water level, core water level, and clad temperature, were compared for four different CL pipe break scenarios. The overall trends of the major parameters showed reasonable behaviors between the tests and analyses