A Study on Removal Mechanisms of Cesium Aerosol From Noble Gas Bubble in Sodium Pool (III) Measurement of Decontamination Factors in Water Simulation Test

Abstract

In a postulated accident of fuel pin failure of a sodium-cooled fast reactor, a fission product of cesium will be released from the failed pin as an aerosol such as cesium iodide and/or cesium oxide together with a fission product noble gas such as xenon and krypton. The xenon and krypton released with the cesium aerosols into the sodium coolant as bubbles have an influence on the removal of cesium aerosols by the sodium pool in a period of bubble rising to the sodium pool surface. Then, the cesium aerosols could transfer into the containment vessel as an initial inventory of a source term. To meet this target, we have developed the computer program AESOP that deals with the expansion and the deformation of the bubble together with the aerosol absorption and researched the sensitivities of the physical parameters on decontamination factor (DF) of cesium aerosols such as the initial bubble diameter, sodium pool depth, and temperature, aerosol particle diameter, and density, initial aerosol concentration in the bubble in previous our papers. In this study, we performed a water simulation test to measure the DFs of simulant aerosols with nitrogen gas bubbles rising through the water pool for the code validation. The experiments revealed that the DFs increased with the increase in the aerosol diameter and the water pool depth.