Analys av nivåproblematik i dränagetank på Ringhals 1
The focus of this project has been on the drainage tank of the reheater on Ringhals 1. This tank has on two previous occasions received such a high water level that the system automatically emergency stopped. For this reason, events and various readings from these two occasions has been specifically studied and analyzed. In order to prove theories about what causes these problems a model of the system was created in the program Dymola. Using simulation results from the model, we have been able to demonstrate how the system's measured values should look likeunder normal conditions with respect to flows, pressures, temperatures, valve positions and water level in the drainage tank. The project has provided a basis for the parameters that should be investigated further and to facilitate this we have given suggestions on some new measure points in the system. Analysis results also gave a clearer picture of how the high levels in the tank have emerged. The previous theory that the high levels occurred due to vaporization in the tank has more or less been disproved. Analyses of the measurements indicate that the high level is not only caused by steam, but to an unusually large amount of water in the tank at the high-profile occasions.