Thermohydraulic investigations for PWR and BWR type reactors

A model calculation is developed in this work, in order to make the design, optimisation and improvement of systems possible, which work in light water reactor conditions. Differing from the usual solutions, the computer program has a double task. First, the whole plant is simulated, in order to determine the flow, temperature and pressure at various planes of measurement, which is called circuit simulation in this work. The individual components are also taken into account, i.e. it is possible to describe the water level in the condenser, the steam content of the test section etc. precisely. Some measurements on the IPEN water circuit were used for comparison and for the assessment of the theoretical model for calculations. These measurements were done in various thermo-hydraulic conditions and in as diverse circuit configurations as possible. There is good agreement between calculation and measurement, but the small deviations depend on the configuration used and the measuring position. Temperature measurements in a fixed configuration give good repeatability and also show good agreement with the calculations. One should note the short calculation time, which is due to the process of calculation developed. The disadvantage of the modular process is that the calculation of a component depends greatly on its internal construction. It is, however, possible to achieve wide applicability by the flexible input data representation. The applicability for other systems was confirmed by calculation of the FRoeJA experiments and the bundle of a commercial nuclear powerstation and by comparison with the wellknown COBRA IV-1 computer model. (orig./GL)