[2B05-08] Design and technology options

11:30 AM - 11:45 AM JST(2:30 AM - 2:45 AM UTC)

[2B08] A Study on Manufacturing and Assembly Technology Options for PEM Method in Geological Disposal(3) Fundamental Study on Selecting Filter Material for the Advanced PEM

*HIROHITO KIKUCHI¹, Daisuke Hayashi¹, Tomoo Fujita¹, Kenji Ishii² (1. RWMC, 2. KAJIMA)

Keywords:

High-level radioactive waste,Geological disposal,Advanced PEM,Perforated steel handling shell for PEM,Filter layer

In the improved PEM for geological disposal released in January 2025, a filter layer in a perforated structure (11% porosity) is expected to promote uniform groundwater infiltration and suppress buffer extrusion. As a basic study for filter selection, local loading strength tests were conducted on three basalt cloths, and the one with the highest rupture strength was selected. In infiltration tests with one to three layers of the selected cloth, bentonite extrusion through fiber gaps was observed with a single layer, but no rupture occurred even under swelling pressures up to 2,500 kPa. After 86 days, water content and dry density distributions were nearly uniform. These results suggest that two or more layers can suppress extrusion without rupture.