PACTEL integral test facility - Description of versatile applications

Regardless of the large number of thermal hydraulic experiments conducted with many different facilities, the need for good quality data from integral test facilities has not yet reached saturation. The parallel channel test loop (PACTEL) facility is one of the largest facilities of its kind. It was originally designed to model the thermal-hydraulic behavior of VVER-440 type pressurized water reactors (PWRs) currently used in Finland. Nevertheless, the PACTEL facility has served also in many other purposes than for VVERs only. The facility has been modified on a case-by-case basis according to the needs in configuration and positioning of auxiliary equipment. The newest plan is to modify PACTEL to be the PWR PACTEL, a facility with vertical steam generators for EPR applications topical in Finland. This paper describes the versatile use of the PACTEL facility for a large spectrum of thermal hydraulic research. The PACTEL facility is ideal for investigating planned recovery procedures during accidents and operational transients. For this purpose experimental series among others on small break loss-of-coolant accidents (SBLOCA), primary-to-secondary leakages (PRISE), and on anticipated transients without scram (ATWS) have been carried out. The PACTEL natural circulation experiment with stepwise coolant inventory reduction formed the basis for the OECD International Standard Problem (ISP-33). In addition, many other one-phase and two-phase natural circulation tests have been executed.