[en] Reactor accidents may cause releases of radionuclides from containment. The active material would cause exposure to man through inhalation of gases or aerosols or through consumption of food products containing deposited radioactive particles. Certain aspects of internal exposure are considered. They are field assessment of the exposure potential of milk, and predictions of human thyroid dose commitment based on direct measurements of radioiodine incorporated within the human thyroid. Radioiodine in milk may be inferred by measurements of radioiodine in cow thyroids, and by measuring deposited radioiodine on pasture grasses consumed by cows. Direct radioiodine measurements on milk were also considered