Investigation of clay bricks for storage facilities of radioactive-wastage

Abstract

Shielding is an integral part of any radiation facility, it is the method used for radiation protection. Safe storage of nuclear waste materials has become an important issue after Fukushima event. In Japan and France surface facilities are being considered for the storage of low-activity radioactive wastes. At these surface facilities, compacted clay liner obtained from clayey soil has been used as a cap barrier. The purpose of clay liner is to minimize the permeation of moisture, especially due to rainfall, through the barrier up to the radioactive material. Thereby it also reduces the emanation probability of undesirable radon gas and gamma-rays into the atmosphere. The brainchild behind the present investigation is to find the possibility of the burnt clay bricks to be used in these surface storage facilities. The present study aims to evaluate the gamma-ray shielding behaviour of burnt clay bricks in energy range 0.001–15MeV. The samples of bricks were collected from four local brick-factories located near Bathinda-Ferozpur road, Punjab (India). An existing computer programme, Gamma Ray Interaction Coefficients (GRIC)-toolkit was modified for theoretical calculations of some interaction parameters for selected sample. Mineralogical study using X-Ray Diffraction (XRD) followed by Rietveld refinement (XRD-R) has been found in good agreement with Wavelength Dispersive X-Ray Fluorescence (WDXRF) investigation of samples for chemical compositions. XRD-R could be an interesting tool to recognize the radiation attenuation characteristics of materials. It has been concluded that local burnt clay bricks own the moderate gamma-ray shielding abilities while brick of clay (M-0) shows comparatively superior shielding behaviour. Thus brick of clay is the suitable candidate in the construction of environmentally-safe storage facilities for radioactive waste.