VEERA facility for studies of nuclear safety in VVER type reactors

The VEERA facility was built in 1987 for experiments that simulate soluble neutron poison (boric acid) behaviour in a pressurized water reactor (PWR) during the long-term cooling period of loss-of-coolant accidents (LOCAs). The experiments provided insight especially into the processes of concentration, mixing and possible crystallization of boric acid in the core region of a PWR. In 1993 the facility was modified in order to use it for studies of the reflooding phenomenon. The results of the reflood experiments will be used as a data base for testing the capability of the reflood models of different computer codes. The VEERA facility in its original and modified forms is described in this report. Details of the geometry and dimensions of the components are given. This data is needed as a geometrical boundary condition in input deck preparation for thermal hydraulic analysis. The instrumentation and the data acquisition system are described so that the applicability of the facility and the accuracy of the measurements for different types of experiments can be evaluated. Initial and boundary conditions of the experiments and the principal test procedures are also summarized.