Impacts of short-lived radionuclides on 10CFR61 classification and dose-to-curie methodologies

Procedures for dose-to-curie calculation and 10CFR61 classification must account for radwaste containing significant quantities of radionuclides with half-lives of weeks to months. The contributions from shorter-lived nuclides may be significant in waste from plants early in operational history. At the Palo Verde Nuclear Generating Station, the reactor coolant pumps contain antimony, and 60-day Sb-124 is the major nuclide in the radwaste. Computer calculations are presented that show how containers with a one-R/h dose rate but containing waste of different ages and with Co-60 and Sb-124 in varying ratios have very different total curie contents and compositions. Three approaches are described for accurately determining the curie compositions and 10CFR classification of such waste