[1C08-12] Radionuclide migration assessment

3:45 PM - 4:00 PM JST(6:45 AM - 7:00 AM UTC)

[1C12] Evaluation of Water Infiltration Considering Impermeable Sheets and Other Barriers in Trench Disposal Facilities for Research Facility Waste

*Hikari Kitatani¹, Hisakazu Nakata¹, Kenji Ozone¹, Toshikatsu Sugaya¹, Daichi Abe¹ (1. JAEA)

Keywords:

Radioactive wastes from research,industrial and medecal facilities,Impermeable layer,Trench disposal facility

In trench disposal facilities for research facility waste, rainwater infiltration through the waste layer causes radioactive material migration into the environment. We evaluated water infiltration into the waste layer using the one-dimensional flow analysis HELP (Hydrologic Evaluation of Landfill Performance) code for an engineered barrier system comprising an impermeable sheet, a drainage layer, and a clay layer above the waste layer, alongside double impermeable sheets below it. A parametric study varied the impermeable sheet's subgrade contact conditions and defect count, and the drainage and clay layers' permeabilities. Results showed that an intact impermeable sheet significantly reduces water infiltration regardless of the clay layer's permeability. Conversely, for a degraded sheet, the clay layer's permeability becomes the primary factor governing the water infiltration rate.