Evaluation of the ground-water contamination hazard from underground nuclear explosions

Abstract

Radioactivities in ground water collected at Nevada Test Site since the underground nuclear explosions in Operations Plumbbob and Hardtack Phase II have not been significantly above background, due to the formation of silica glass by the explosion, and the ion-exchange properties of fission products in normal earth minerals and water. The glass formed by the high shock pressures releases less than 10 per cent of its radioactivity when leached with water, and the rock minerals crushed by the explosive-forces adsorb several tens of milliequivalents of fission products per 100 g. The distribution coefficients for adsorption range from 50 to 500,000, depending on the particular fission product and mineral. A theory pertaining to the flow of activity in an ion-exchange medium is developed, and equations for application of laboratory data to field experiments are included. Some of the available distribution coefficients are tabulated from the literature on waste disposal. It is concluded from existing information that hazards arising from underground explosions in other media will not give rise to serious contamination problems. Until more experience is gained, measurements of aquifer properties should be made prior to planned explosions to determine that safe conditions exist in each particular case.