Determination of uranium concentration in phosphate rocks using SSNTDs

The objective of this work is to determine the Uranium concentration in the Phosphate rock samples using Fission Track Radiography and Neutron Activation Analyses. In Fission Track Radiography Technique samples of Phosphate rocks in the form of Solid slabs. Pellet and Solution were placed in contact with, Lexan, a Solid State Nuclear Track detector along with standard reference material SRM-612 and NBS-120b respectively. The detectors were exposed to a beam of thermal neutron of known flux in the Pakistan Research Reactor (PARR-1) at PINSTECH. The fission tracks in the detectors were revealed by etching and counted. From the tracks densities Uranium concentrations were determined. The concentration of Uranium in samples ranges from 21 to 71ppm. In Instrumental Neutron Activation Analysis technique the fine powder samples along with their standard NBS-120b were sealed in plastic vials and were exposed to thermal neutrons in the Pakistan Research Reactor (PARR-2) at Patchiness for one hour. High Purity Germanium detector was used and number of gammas were counted. The number of counts were converted into uranium concentration. The concentration of uranium ranges from 24 to 79ppm. The results obtained show that Fission radiography technique is an excellent technique to determine the Uranium concentrations in the Phosphate rocks. (author)