ON THE UTILIZATION OF HEAVY CONCRETE FOR RADIATION SHIELDING

This work is concerned with the use of ilmenite concrete (density=3.5 g/cm(3)) prepared from local materials as a radiation shield. Comparis on with a previously investigated ilmenite concrete (density = 4.6g/cm (3)) including iron punching additions in its constituents have been c arried out as this type of concrete was chosen for the construction of the biological shield for the second experimental reactor in Egypt. T he study reveals that the ilmenite concrete under investigation is mor e effective for the attenuation of fast neutrons. In addition the prod uction of the hard capture secondary gamma rays have been greatly decr eased by eliminating the iron punchings from the constituents of the i lmenite concrete under investigation which is also preferable from the economical point of view. Total macroscopic cross section for fast ne utrons, linear attenuation coefficients for gamma rays and the relaxat ion lengths both for the whole energy range and at different energies have been obtained and comparison with other published data has been d one when it is available. Two empirical formulae have been derived whi ch calculate the total flux of fast neutrons and gamma rays for differ ent types of concrete at different thicknesses. Good agreement between measured and calculated values using the two formulae has been obtain ed.