ENHANCEMENT IN GAMMA-RAY INDUCED DECOMPOSITION OF SODIUM AND POTASSIUM NITRATES BY BORATE AND CYANIDE ADDITIVES

Gamma - radiolytic decomposition of sodium and potassium nitrates and its admixtures with respective cyanide and berate additives has been s tudied over a wide absorbed dose range from 675 to 500 kGy. The decomp osition of nitrate increases with the nature and concentration of the additive in the admixture. The enhancement is more significant at >80 mol% of the additive. G(NO2-) values, calculated on the basis of elect ron fraction of the nitrate salt, decrease with increasing concentrati on of the nitrate. ESR spectral studies suggest the formation of radic al species such as BO4 and BO32- etc, in berates whereas in case of cy anide additive F-H centres are produced. The radical species and colou r centres so produced may then transfer their energy to nitrate and ca use enhancement in decomposition. A comparison with other oxyanion add itives shows that G(NO2-)values decrease in the order PO43- > B4O72- > SO42- > CO32-. Similarly, the nature of the cation also affects the d ecomposition.