Experimental and Analytical Investigations of Aerosol Processes—Wash-Out and Wash-Down

AbstractTimely evolution of radioactive airborne aerosols, the mass of particles deposited on structures or transported with condensing water into the sump, and any influence of safety systems on the aerosol distribution will have a crucial influence on the potential aerosol source term into the environment. Different phenomena affect the main aerosol processes, and important ones besides gravimetrical and diffusive settling require experimental investigations to improve and validate modeling assumptions. Experimental investigations in the THAI (Thermal-hydraulics, Hydrogen, Aerosol, Iodine) test facility have been performed to investigate (a) insoluble silver aerosol wash-down behavior from vertical steel and horizontal decontamination paint-coated surfaces by condensing steam (test AW-3, supported by a laboratory-scale wash-down test series), and (b) the depletion of the airborne aerosol concentration by wash-out due to the use of a nuclear power plant typical water spray system (test AW-4). The paper d...