Integral passive containment cooling tests were performed for AP600 to examine the overall containment performance at large scale. At the time, there were no other water distribution tests to provide a demonstration of water distribution over the steel containment dome outer surface and the top of the containment side walls. Wind tunnel tests were conducted to confirm the structural performance of the containment shield building air inlet and outlet.

A large-scale integral system behaviour test facility PANDA (Coddington et al., 1993), is present at the PSI in Switzerland. This was originally built to understand better, long­term decay heat removal by natural circulation in passive boiling water reactors. However, since the latter is a generic phenomenon, many of the data from many of the tests are of relevance to more general light water reactor applications.

The LINX facility (Coddington et al., 1993), is another facility at PSI that was used to investigate the thermal-hydraulics of natural convection and mixing in pools and large water volumes. In the past, aerosol transport was studied in the AIDA facility. This is a separate-effects facility for the investigation of aerosol transport and the associated deposition in plena and tubes.

A European Thematic network has been established for the Consolidation of the Integral System Test Experimental Databases for Reactor Thermal-Hydraulic Safety

Analysis (CERTA-TN) (FISA 2003, to be published). The objective is to preserve for the future, the reactor safety thermal-hydraulic databases acquired in various integral system test facilities. A database will be produced that has up-to-date data access and retrieval capabilities and uses modern web-based information technologies.

In the final part of this chapter some of the research requirements for future innovative reactors are addressed. Some of these also relate to work that will be needed to realise nearer term evolutionary and prototype reactor systems that will also be required to confirm the technologies of the longer term Generation IV reactors before they are built.