Lace-Espaa experimental programme on the retention of aerosols in water pools. (Programa experimental Lace-Espaa sobre retencion de aerosoles en lechos acuosos)

摘要

A matrix of eleven experiments on aerosol retention behaviour in submerged beds and supresion pools in water-cooled reactors under severe accident conditions has been performed, for these experiments, an intermediate scale, multi-purpose facility was set up at CIEMAT (Madrid). The facility includes various systems: aerosol ageneration (CsI), mixing section, injection line and pool-vessel (8 m''3), as well as the corresponding aerosol instrumentation and a process control and data adquisition system. Some parameters have been varied in order to study their influence in the DF: steam/noncondensable ratio in the accidental mixture (0.1 to 0.9) particle size, flow rate (two regimes: bubble and jet) and injector geometry (mono-orifice and multi-orifice). On the other hand, some parameters have been kept constant along the experiments; pool geometry (diameter, water level), water temperature, pressure in the atmosphere above the water, submergence, injection temperature and injection time. A rapid decrease in the DF is observed as the proportion of particles measuring less than 1 micrometer increases. Retention decreases in the case of smaller particles and considerably higher in the case of larger particles. It has been also possible to observe the influence of the injected steam fraction. Experiments with greater fraction than the saturation fraction have greater DF than those ones with smaller fractions. The jet regime with horizontal injection and the multi-orifice geometry would appear to show a somewhat higher capacity of retention than those in the bubble regime under similar conditions. It would be necessary to confirm this greater capacity for retention by means of additional experimental data. This work, performed by the LACE-Espaa Consortium, has been carried out in the frame of the European Commission's Shared Cost Action Programme on Reactor Safety 1988-91 on a contractual basis. (ERA citation 20:005733)