He jishu (Feb 2021)
Development and application of control limits of derived air concentration for tritium
Abstract
BackgroundTritium is one of the radionuclides released during the operation of nuclear facilities. The radiation hazard of tritium to human body is internal exposure, which is not only related to the activity of tritium, but also closely related to the chemical form and intake route of tritium. In view of the current standards involving tritium, there is an inconsistency in the control limit of tritiated water (HTO), as well as elemental tritium (HT).PurposeThis study aims to derive and standardize the concentration limits of HTO and HT, as well as the discharge activity concentration limits of HTO.MethodsThe development of tritium concentration control limits and the basis for the formulation of relevant standards were analyzed. According to the current radiation protection standards of China, combined with the latest biodosimetry parameters of tritium in publications of International Atomic Energy Agency (IAEA) and International Commission on Radiological Protection (ICRP), the control limits of derived air concentration (DAC) and water activity concentration for tritium were recalculated. When calculating the recommended limit of air concentration derived from HTO, the skin absorption was converted into the inhalation, and the complete skin absorption was set to half of the inhalation.ResultsSince the dose conversion coefficient used in the current standard is close to that in the new international publications, the recommended limits of HTO are slightly smaller than that specified in the standard, and the corresponding values are basically in the same order of magnitude.ConclusionsThe derived results can provide reference for the standard formulation of radiation protection management. The applicable objects of control limits are also clearly exhibited and distinguished. These objects are only available for people, not for facilities or equipment.
Keywords
