Preliminary results of aerosol deposition experiments in an engineering-scale ice condenser

Initial data are reported from engineering-scale tests of aerosol deposition in a small section of an ice condenser typical of that used in certain pressurized water reactors (PWRs). The data will be used to validate a computer code (ICEDF) that predicts aerosol deposition in PWR ice condensers. The code was developed to assess the effectiveness of one type of engineered safety feature (ESR). Results of the three tests completed show that decontamination factors (DF = aerosol mass flux entering divided by aerosol mass flux leaving) from 1 to 3 are achieved in the test section depending on aerosol, gas flow, and ice conditions. A measured DF of 1.0 was obtained when no ice was present in the test section, the aerosol aerodynamic mass median diameter (AMMD) was 6 μm, and gas flow rate was low, 0.03 m3/s. The computer code, ICEDF, calculated a DF of 1.4 for similar conditions. When ice was present in the system and the same aerosol and gas flow conditions were used, the measured DF increased to 2.1 while the ICEDF computed DF ranged from 2.6 to 1.9. The DF increased dramatically when the gas flow rate was increased to 0.23 m3/s and had a steam mole fraction of 0.44. Including the zone upstream of the test section where considerable cooling occurs, a measured DF of 10 or more was observed. The test section DF declined during this test from 3.6 to less than 1.0, as ice was melted out. Particle growth from 2.4 μm (AMMD) to 9.1 μm (AMMD) was observed in the test section during this test, probably due to steam condensation. Test temperature data and flow visualization studies indicate complex gas flow with stable large-scale flow recirculation