Uranium Analysis in Natural Environment

Abstract

Nondestructive uranium analysis by epithermal neutron activation was confirmed to be utilized as a simple and reliable method for the determination of uranium in environmental materials such as surface soil and river sediment. In the case of surface soil, samples to be irradiated with neutrons are prepared in the following manner so that they may be satisfactorily represent the actual mean chemical compositions. From 2 to 3kg of surface soil having been passed through a sieve to remove particles larger than 1mm in diameter, about 5g are taken and pulverized in a mixer-mill. About 100mg of the pulverized soil are accurately weighed and sealed into a polyethylene bag. The samples thus prepared are wrapped in a cadmium foil and irradiated with reactor neutrons. Gamma-ray spectra of activated samples are collected 4 to 5 days after the neutron irradiation. The detection limit was found to be about 0.1ppm for usual soil samples.