Effect of Waste Slurry Composition on the Radiolytic Stability of Polyethylene for Isolation of Waste From Water Treatment After the Fukushima Daiichi NPS Accident

The gamma radiolysis of simulated waste environments has been investigated to represent the environment of waste containers used following the removal of radionuclides from contaminated water released following the incident at the Fukushima Daiichi Nuclear Power Station in 2011. The effect of the solid flocculants on the yield of oxidative species formed during radiolysis was investigated to determine the potential for polymer degradation induced by oxidative radicals. Changes to the properties of polyethylene induced by gamma radiolysis in the presence of the different waste types have also been investigated. The aqueous environment was shown to alter the hydrogen peroxide yields, in all cases G(H₂O₂) was reduced relative to the irradiation of pure water. Bulk polyethylene degradation was investigated by gel fraction measurement, the aqueous environment was found to have little effect due to the low rate of diffusion of water into the polymer.