The following test series related to natural convection are under consideration:

— boiling in large water pools

— WWER steam generator behaviour with out/with non-condensables

— two phase flows in typical reactor geometries (e. g. hot leg, downcomer)

— operational mode and effectiveness of passive safety systems.

A first feasibility study has been performed regarding a reactor with internal circulation flows. The Argentinean CAREM PWR Project has been used as a model. In Fig. 16 a comparison between the CAREM Reactor and its modelling in TOPFLOW is shown.

5. CONCLUSIONS

With the NOKO facility high quality data have been produced. They were used to study phenomena and used as a basis for comparison with code calculations.

Based on the experience gained with the NOKO facility the TOPFLOW facility will be improved and its test spectrum extended. Especially the development of two-phase instrumentation will be a major goal.