Determination of Physicochemical Forms of Iodine-131 in Ejector Gases during Operation of the Industrial Reactor Facility at FSUE Mayak Production Association

On the basis of the recommendations of the IAEA and the requirements of domestic regulatory documents, a study is conducted to determine the activity of aerosol and gaseous forms of 131 I compounds in a gas-aerosol mixture of emission from an industrial reactor facility (hereinafter referred to as IRF). Three types of packs of analytical filters are used as an adsorption-filter material. Under normal operating conditions, a series of sampling procedures is performed at a point in front of the gas cleaning system. The investigations have made it possible to determine the dominant physical form of 131 I in the high-pressure gas holder. It is shown that, in a gas-aerosol mixture prior to the IRF gas cleaning system, the volumetric activity of iodine is determined mainly by hardly adsorbed gaseous compounds. The ejector gases contain iodine-131 compounds, which are hardly adsorbed on silver nitrate impregnate. The obtained data will be used in designing the cleaning systems for new IRFs of a similar type.