(LWR OFF-NORMAL BEHAVIOUR INVESTIGATION) A Reactor Thermal-Hydraulic Safety Research Programme carried out by the Commission of the European Communities at the Ispra Site of the Joint Research Centre.

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

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 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.

The Institute for Nuclear Research Pitesti was founded in 1971 as a unit of strategic importance, having as field of activity the scientific research, design, technological development and scientific and technical responsibility for the development of nuclear energy in Romania.

The experimental programme named KAJET is being performed to investigate features of a pressurized melt jet and the interaction with substratum material. Compact melt jets, rather than a spray-type melt release, are simulated using iron and aluminium oxide instead of corium. The melt is generated by a thermite reaction. The experiments provide general information about erosion processes and data for the validation of computer codes (or, if possible, simplified correlations) which then are able to transfer the results to reactor conditions.

Complex measurements were performed at the integral high temperature test facility CODEX (COre Degradation Experiment) between 1995-2002 with electrically heated UO2 fuel rod bundles. The main advantages of the CODEX facility are the use of real UO2 pellets, the sophisticated data acquisition technique including aerosol measurements and the large flexibility in the selection of test conditions. The most imporant limitations are the use of fresh – non-irradited - fuel pellets and the application of electrical heating burdened with positive temperature feed-back effect.

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).

SIMECO program at KTH was performed to investigate the heat transfer of natural convection in an internal heated liquid pool, simulating a molten corium pool which may be formed in the reactor lower plenum during a severe accident.

The REKO-3 test facility allows the investigation of catalyst samples inside a vertical flow channel under well defined conditions comprising gas mixture, flow rate and inlet temperature.

The objective of the EMAIC (Emission AIC) facility is to characterise the physico-chemical nature of the aerosol source term resulting from the vaporisation of control rod material made of the metals Silver (Ag), indium (In), Cadmium (Cd) after their cladding rupture during a PWR severe accident.