Disposal of low-level radioactive wastes on the Oak Ridge Reservation. II. Proposed classification of wastes for management and disposal

This paper discusses a proposed strategy for classification and disposal of low-level radioactive wastes on the Oak Ridge Reservation (ORR). The strategy is based on the results of a preliminary screening analysis, described in the preceding paper, which identified the principal radionuclides of concern for limiting radiation doses to off-site individuals and inadvertent intruders. Low-level wastes would be segregated into four classes. Class-I wastes would have such low concentrations of any radionuclides that disposal using industrial landfill technology would result in acceptable doses to the public at any time after disposal. Class-II wastes would have higher concentrations of shorter-lived radionuclides, pricipially 90Sr, 137Cs, 152Eu, and 154Eu, and would be placed in above-grade tumuli with engineered barriers to permit radioactive decay to acceptable levels before exposures of the public likely could occur. Class-III wastes would have higher concentrations of long-lived radionuclides, principially 99Tc and isotopes of uranium, and would be treated to remove the soluble fraction of contaminants and then placed in below-grade disposal units designed to inhibit access by inadvertent intruders. Class-IV wastes would have such high concentrations of any radionuclides that they are unacceptable for disposal on the ORR. These materials would be treated to remove the fractions that are Class-I, -II, or -III wastes, and the remaining wastes would be stored for shipment and disposal at another site. The concentration limits of radionuclides in each waste class would be based on limits on annual effective dose equivalent to off-site individuals or inadvertent intruders of 10 mrem (0.1 mSv) from all exposure pathways or 4 mrem (0.=4 mSv) from the drinking water pathway only in conjunction with site-specific performance assessments. (author) 1 tab., 10 refs