Proposal by Nuclear Information and Resources Service
The goal in radioactive waste management must be to isolate human-made radioactive materials from the environment for their entire hazardous life. Since there is no safe threshold of exposure to ionizing radiation, all unnecessary exposures should be avoided.
The material must decay to radioactive levels indistinguishable from (not in addition to) original background, as determined by using appropriate sampling techniques and the best available, appropriate detection instrumentation properly calibrated and set at the most sensitive setting.
The general rule is that 10 to 20 half-lives is the hazardous life of radioactive materials, because in that time the material decays to about a thousandth to a millionth of the original amount [of radioactivity]. In some cases, depending upon the original amount of radioactivity in the material, 20 or more half-lives may be required for the material to reach levels that are indistinguishable from original background. The need for 20 half-lives or more generally will apply to highly concentrated wastes such a those from nuclear power plants and not to medical waste.
For information contact: Nuclear Information and Resources Service (NIRS), 1424 16th St. NW, Suite 404, Washington, DC 20036 USA. tel: 202/328-0002, fax: 202/462-2193.