Uranium assay in mineral samples by means of neutron detection of uranium-238 spontaneous fission

An “in situ” method to determine uranium content in mineral samples by means of detecting neutrons from 238U spontaneous fission is presented. The method is simple, exact, reliable and passive (it does not need any external excitation source). The technique was experimentally validated, and those experiments were also modeled by a Monte Carlo neutron transport code (MCNP), to check the concordance between experimental results and simulations. Relying on this concordance, calculation ability to describe hypothetical situations was established. The influence of many factors (multiplicative medium, electronic noise, etc.) was estimated. The results obtained allow us to affirm that, with this method it is possible to determine concentrations of 0.05 wt% of uranium (detection limit).The technique has the advantage of sampling very considerable mineral volumes (≈0.2 m3).