Removing method for volatile ruthenium off-gases

Purpose: To efficiently remove the volatile ruthenium contained in off-gases generated in nuclear fuel cycle facilities. Method: In the case of removing volatile ruthenium containing in off-gases, the volatile ruthenium has been adsorbed to remove by passing the off-gases in silica gel layers in an adsorption column. However, other ingredients contained in the off-gases are also adsorbed to the silica gel and, as a result, the adsorption ratio of the volatile ruthenium is worsened to necessitate the frequent exchange of the adsorption column. Based on the finding that the adsorption efficiency for the volatile ruthenium is increased by mixing the off-gases with NOx, the off-gases are at first mixed with NOx and then the mixed gas is passed through the silica gel layers in this invention, by which the ruthenium can be adsorbed to remove efficiently. (Kamimura, M.)