Regulatory Assessment of the Use, Subsequent Dose and Health Risks posed by Tritium in Canada

摘要

A number of licensees of the Canadian Nuclear Safety Commission (CNSC) either produce tritium oruse it as part of laboratory studies or commercial processes. Most notably are the CANDU (CANada DeuteriumUranium) nuclear power reactors, which use heavy water (deuterium oxide) as part of their moderator and heattransport systems and, as a consequence, produce more tritium than any other commercial power reactor. Inaddition, there are a number of auxiliary uses of tritium in Canada including the production of self-illuminatinglights frequently used in exit signs, tracers in laboratory studies, and for reserve estimation in oil and gasexploration, all of which release tritium into the environment. As a consequence, the health risks attributed totritium are an important consideration in Canada and are frequently raised during public hearings of the Tribunalof the CNSC and as a result, the Tribunal has charged CNSC staff to report on a number of issues related to theuse, resultant dose, drinking water standards, health risk and environmental consequences of tritium. Some ofthese studies are already complete and so this discussion will provide an overview of the use of and doses due totritium in Canada, a review of international drinking water standards, and a preliminary overview of the CNSC’sassessment of the health risks posed by tritium.