Multispectral remote sensing for determination the Ultra-mafic complexes distribution and their applications in reducing the equivalent dose from the radioactive wastes

Evaluating the radiation shielding behavior of rocks is significant because the rocks are the pivot materials used for construction purposes. The validation of radiation shielding properties of mafic and ultramafic rocks is inadequate. Here we investigate the Neoarchean mafic and ultramafic complex from the Bhavani Shear Zone in southern India through an integrated approach of lithological mapping using VNIR and SWIR bands of ASTER data along with laboratory-derived reflectance spectral data (0.4 to 2.5 µm). The complex occurs as structurally concordant lenses and sheets within supracrustal gneisses and is composed of a suite of Peridotite, Pyroxenite, and meta-gabbro. We obtained different band combinations, ratioed band composites, PCA, MNF, PPI, MF, and LSU. The bulk chemical data of these rocks analyzed by XRF shows a tholeiitic to a calc-alkaline composition for these rocks. The laboratory spectra were interpreted and resampled to ASTER VNIR and SWIR bands and characterized along with the geochemical data. Among the various band combinations, PCA 428, MNF 321, and band ratios 8/9, 2/1, 5/4 yielded robust results in discriminating the mafic–ultramafic complex. The PPI, MF, and LSU techniques also yielded good results to map the distribution and abundance of the ultramafic rocks. Moreover, using the Monte Carlo simulation, containers with various wall thicknesses, wall materials, and different volumes were suggested, and to dispose of the radioactive wastes with an intermediate level. The dose rate from radioisotopes Cs-137 and Co-60 with a specific activity of 1.058E+9 Bq/L are 30221µSv/h, 51,007 µSv/h, and 12,633 µSv/h without using the containers. The mentioned dose rate decreases to 1.993, 9291, and 11,099 µSv/h when the container walls are made of 20 cm thickness Gabbro formations. The mentioned containers are cheap and effective variants for disposing of the radioisotopes produced from nuclear power stations and nuclear medicine.