Radiation dose estimates from timepieces containing tritium or promethium-147 in radioluminous paints

Potential radiation doses from the distribution, use, repair, and disposal of timepieces containing tritium (H-3) or promethium-147 (Pm-147) in radioluminous paint were estimated for the United States population. Under typical conditions, a maximum annual whole-body dose from H-3 of 0.9 mrem/year was estimated for repairmen, while a maximum of 0.3 mrem/ year was estimated for watch wearers from Pm-147. The total population dose from an annual distribution of 8.3 x 106 timepieces containing H-3 in luminous paint was estimated to be 2200 man-rem/year; from an annual distribution of 2.0 x 106 timepieces containing Pm-147, 390 man-rem/year. Greater than 90 percent of these doses, for both nuclides, may be derived during use of the products in accordance with the exposure scenarios developed in this assessment. Under atypical conditions, where it was assumed that either a large number of timepieces were destroyed in fires and all isotope containment lost or radioluminous paint was accidentally ingested, the maximum individual whole-body dose was estimated to be 59 mrem from ingestion of 1 mCi of H-3, assuming complete solubility of the isotope in the body