Potential Effects of Gamma Irradiation on the Chemistry and Alkalinity of Brine in High-Level Nuclear Waste Repositories in Rock Salt

Radiolysis of Salts and Long-Term Storage Issues for Both Pure and Impure PuO{sub 2} Materials in Plutonium Storage Containers

“…Generally, the MIS data at LANL on spherical equivalent mean particle-size analysis (insoluble particles) and mean spherical equivalent by volume, for oxide from Hanford and RFETS materials calcined at 950°C also support these findings (Mason et al 1999). But, for smaller-sized particle, the chlorine gas is evolved more readily (Panno and Soo 1984).…”

“…The formation of chloride ion in salts is often accompanied by an increase in molecular hydrogen concentration because the Clø ions act as scavengers for the hydroxyl radicals (as shown in reactions 26Ð29 on p. 26 and water (Panno and Soo 1984). This would reduce the yield of chloride concentration over time (Lewis and Warren 1989).…”

“…Moreover, the detection of chlorine and HCl would be extremely difficult because these gases are extremely aggressive. To detect these gases, even at relatively high concentrations, an optimization of experimental setup and analytical methods will be required (Compton et al 1972, Didyk et al 1971, Jenks and Bopp 1977, Levy 1983, Palut et al 1993, Panno and Soo 1984. The permeability, the porosity, the diffusivity, and the mechanism of transport will determine the gas transport in the material.…”

“…When alkali halides, such as NaCl, are irradiated at temperatures in which F centers are known to be mobile enough to form colloids (i.e., ≥50¡C in NaCl), then the growth of colloids could be significant (Levy 1991, Lidiard 1998, Panno and Soo 1984. Once the nucleation takes place, a colloid becomes an effective sink for mobile F centers.…”

“…This condition makes detecting HCl in field tests impossible. Panno and Soo (1984) suggested that, depending on the irradiation conditions, the pH of the brine solutions that results from the presence of water around irradiated rock salts changes (i.e., the higher the temperature of the salt during irradiation, the higher the pH of the resulting brine). The high alkalinity of the solutions made from irradiated salts was explained to be caused by NaOH formation.…”