Theoretical physical investigation of 50 MW heavy water reactor core

One hundred samples from Oligocene Qatrani sediments representing carbonaceous clays, sandstones and limestones are analysed radiometrically for eU, eRa and the equilibrium factor P. The equilibrium beta-gamma method of De Lange (1957) is used, besides some autoradiographic studies are made. Results showed that 66% of the analysed samples have their U content below 100 ppm. This reflects that U mineralization in the Oligocene Qutrani rocks is generally weak. About 67% of the clay samples have their U content below 50 ppm. The distribution of U in the sandstone shows a different pattern in a sense that its distribution has a wider range than in clays and shows more scatter. Thus the maximum U mineralization is associated with the sandstones. The equilibrium factor P shows almost normal distribution and has a mode ranging between 0.9-1.1 which indicates the presence of equilibrium in the U series. However, some mobility for U has occurred by means of which U or Ra and daughters were leached from some parts of the area and were redeposited again in other parts causing certain variations in the P factor Nuclear plates of alpha tracks revealed even distribution of the tracks in both clays and sandstones. This means either that U is not concentrated in single mineral grains but is rather diffused or that the radioactive mineral is extremely fine