Subcooled decompression analysis of the ROSA and the LOFT semiscale blowdown test data with the digital computer code DEPCO-MULTI

In the ROSA (Rig of Safety Assessment) program, the digital computer code DEPCO-SINGLE and DEPCO-MULTI (Subcooled Decompression Process in Loss-of-Coolant Accident - Single Pipe and - Multiple Pipe Network) were prepared to study thermo-hydraulic behavior of the primary coolant in subcooled decompression of the PWR LOCA. The analytical results with DEPCO-MULTI on the subcooled decompression phenomena are presented for ROSA-I, ROSA-II and LOFT 500, 600, 700 and 800 series experiments. The effects of space mesh length, elasticity of pressure boundary materials and simplification for computational piping system on the computed result are described. This will be the final work on the study of the subcooled decompression analysis as for the ROSA program, and the authors wish that the present code shall further be examined with the data of much advanced experiments. (auth.)