Comparative field experiment on gas permeability of cover sheets for temporary storage sites of decontamination waste

Abstract

We have developed gas-permeable/waterproof sheet (GPWS), comprising a micro-porous sheet which is waterproof and have gas permeability, coated with nonwovens to protect and reinforce it, and carried out many experiments in both laboratories and fields. GPWS has been applied as cover sheet for temporary storage sites of decontamination waste due to the Fukushima nuclear accident. On the other hand, geomembrane which is waterproof but gas-impermeable has also employed as cover sheet of the decontamination waste in conjunction with gas-vent pipes. In this study, temperature and oxygen-concentration of the decontaminated wastes, over which GPWS and geomembrane were installed respectively, were experimentally measured in real temporary storage site to compare the influence of weather condition. As the results, it was demonstrated that GPWS can achieve sufficient performances as the cover sheet in that both temperature and oxygen-concentration, closely relating with the consistency of gas permeability in the cover system, was less influenced by weather condition.