The flow diagram of the TOPFLOW facility is given in Fig. 14; a front and a side view is shown in Fig. 15.

The main additional test sections are the steam drum (L = 5m, D=1.5m, V = 8 m3) and two vertical pipes (D = 50 and 200 mm, L = 10 m) to be used for the instrumentation development, evaluation of flow profiles, WWER steam generator behaviour during small break LOCA and the investigation of heat up, local steam production and temperature stratification in large water pools and turbulence. Additionally several junctions are foreseen for the connection of further test sections like a PWR hot leg model [4]. The pressure vessel has been removed but is still available if needed.

The data acquisition systems will be replaced and extended, e. g. the number of the measurements as well as the acquisition rate are increased. Additionally the balance of plant system will be replaced and is now computer controlled.