Two-phase flow test facility was constructed to study the applicability of Particle Image Velocimetry (PIV) and Wire-Mesh Sensors (WMS) for different types of single- and two-phase flows

The PREMIX experiments have been performed to study the premixing of sizable amounts of very hot oxidic melts with water when being released as a jet in a reasonably characterized way and with full optical access. Alumina at 2600 K from a thermite reaction was used to simulate the corium melt. A technique has been developed to retain the molten iron in the source so that the contribution of iron to the melt is well below 10 %. PREMIX involves the full physics of the mixing process including jet break-up and melt drop fragmentation. But, of course, on the other hand, the initial and boundary conditions are more difficult to control and to vary compared to experiments with solid spheres such as QUEOS.

The DISCO-H test facility was set up to perform scaled experiments that simulate melt ejection scenarios under low system pressure in Severe Accidents in Pressurized Water Reactors (PWR). These experiments are designed to investigate the fluid-dynamic, thermal and chemical processes during melt ejection out of a breach in the lower head of a PWR pressure vessel at pressures below 2 MPa with an iron-alumina melt and steam.

The Epicur programme (physicochemical studies on confined iodine under irradiation) aims at providing experimental data to validate the chemical models for iodine in the reactor containment under accident conditions. These models are integrated into the Iode model of the Astec computer code, jointly developed by IRSN and GRS. They are used to predict the behaviour of different types of possible accidents and related releases of radioactive products.

The TOSQAN experimental vessel is a large stainless steel cylindrical enclosure (volume 7m3, height 4m, internal diameter 1.5m) with double walls. A coolant circulates in between the walls to regulate the wall temperature from 60 °C to 160 °C. Non radioactive aerosols, steam and non explosive gases can be injected at different controlled flow rates via diverse injection pipes located at different locations of the enclosure. Different instrumentation is used, namely PIV (particle image velocimetry), LDV (laser doppler velocimetry), rainbow refractometry, out of focus imaging and SRD (spontaneous Raman diffusion) spectrometry.

The VULCANO facility is mainly composed of a furnace and a test section, which is thoroughly instrumented. In the experiments with prototypic material the furnace has the following characteristics:

• Capability to melt oxidic mixtures of various compositions (UO2, ZrO2, SiO2, FeOx) with the possible addition of metals.
• Liquidus temperature of the load between 1700 and 2900 °C.
• Capacity to melt & pour 100 kg. •Continuous low pouring rates (0.1–1 l/s).

The DISCO-C facility serves to investigate melt dispersal from the reactor pit when the reactor pressure vessel lower head fails at low system pressure of less than 2 MPa. The fluid dynamics of the dispersion process is studied using model fluids, water or bismuth alloy instead of corium, and nitrogen or helium instead of steam. The effects of different breach sizes and locations, and different failure pressures on the dispersion can be studied.

A research program on reflood of an overheated core and corresponding topics is running at KIT, including large scale bundle tests at IAM-WPT , various kinds of separate-effects tests at IAM-AWP , model development and code application.

The KROTOS test facility is a relatively small scale experimental installation dedicated to the study of:

• (a) molten fuel-coolant pre-mixing either with prototypic reactor melts or simulants such as alumina up to 5 kg;
• (b) progression and energetics of spontaneous and triggered fuel-coolant interactions (vapor explosions).

FARO (Furnace And Release Oven) experimental facility began the experiments of the LWR-MFCI phenomena in 1990 in collaboration with several reactor safety research organizations from European Union member countries and with the participation of the United States Nuclear Regulatory Commission.

Condensation studies at LUT started with an open pool test facility (POOLEX) modeling the suppression pool of the BWR containment. During the years 2002-2006, the facility had several modifications and enhancements as well as improvements of instrumentation before it was replaced with a more versatile PPOOLEX facility in the end of 2006

This facility comprises a water supply pipe, a quartz test section (110, 180 or 290 mm diameter) in which the debris bed is placed, together with its instrumentation, and a steam relief pipe. It is used to conduct refl ooding tests by means of injecting water onto a bed of metal particles heated by induction. The instrumentation measures the different temperatures and pressures in the debris bed, the fl ow of injected water and the fl ow of generated steam.