Reducing radon exhalation from covered tailings: optimization or cost effectiveness?

Reduction of radon exhalation from uranium tailings as a function of the number of radon diffusion lengths in cover materials is discussed, based on dimensionless mathematical functions. Cost effectiveness is examined to determine the least expensive cover with a preselected number of radon diffusion lengths (i.e., a preselected level of radiation protection), and to find the maximum attainable reduction in radon flux with a predetermined cost (i.e., a fixed amount of money). Cost effectiveness rather than optimization through cost benefit analysis can be used advantageously in these cases.