The VERCORS programme, which involves tests with short fuel-rod samples, has proved to be a rich source of information regarding FP release and tranport.

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

Passive Containment Cooling System (PCCS) removes residual heat from upper drywell of the containment to the liquid pool surrounding the PCCS heat exchanger. It also has an important role in mitigating the offsite dose by retention of a fission product release in the containment. The operation of the PCCS is based on density differences between the containment and water pool

The QUEOS facility serves to study premixing phenomena with solid spheres, i.e. without the danger of a steam explosion and the complication of melt fragmentation. Emphasis was put on high sphere temperatures (up to 2600 K) and the use of large numbers of comparatively small spheres so that intensive multiphase interactions with strong coupling of the phases (collective motion of the spheres) are observed. In order to simulate melt jets as closely as possible, the spheres are released as a cylindrical jet into a three-dimensional test vessel.

The test section of the facility consists of a scaled-down model of VVER-440 steam generator, which has a bundle of 38 tubes with inlet and outlet chambers (hot and cold chamber, respectively), and a secondary side with the steam outlet line but without droplet separators and steam dryers.

VITI (‘‘VIscosity Temperature Installation’’) facility has been developed to measure viscosity, density and surface tension on corium up to 2600 C by aerodynamic levitation. But it is also used as small crucibles heating for material interactions tests. Samples of less than 100 g can be studied in VITI.

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 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).

The aim of the DEFOR (Debris Bed Formation) program is clarification of the phenomena that govern formation of the debris bed in different scenarios of corium melt release into a deep water pool and quantification of the debris bed properties related to coolability.

The OECD-IAEA Paks Fuel Project aimed to support the understanding of fuel behaviour in accident conditions on the basis of analyses of the Paks-2 event. Numerical simulation of the most relevant aspects of the event and comparison of the calculation results with the available information was carried out between 2006 and 2007.

The STORM (Simplified Test On Resuspension Mechanism) facility was designed and operated by JRC-Ispra to work with high concentration of soluble and insoluble aerosol materials (up to 25 g/m3), a wide range of aerosol compositions, size distribution and density and high carrier gas and steam flow rate (about 1kg/s).

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.