[2B01-04] Geological disposal

10:15 AM - 10:30 AM JST(1:15 AM - 1:30 AM UTC)

[2B04] Overview of a full-scale construction experiment on hydraulic plugs for sedimentary rock at the Horonobe URL(4) Consideration of the tunnel backfill by shot-clay method using Horonobe mudstone

*Shun Kimura¹, Hirokazu Ohno¹, Keisuke Yagi², Sachie Iso² (1. JAEA, 2. TAISEI)

Keywords:

Geological disposal,Tunnel backfill,Bentonite,Shot-clay method,Horonobe Underground Research Laboratory

During the closure phase of a repository for geological disposal, tunnel backfill and hydraulic plug installation are considered to reduce the migration of radionuclides through the tunnel and its excavation damaged zone.At the Horonobe Underground Research Laboratory, an in-situ experiment is ongoing at 350m Niche No. 6 to verify and demonstrate a series of design and construction technologies from backfilling to plug installation. For this experiment, the specification of the backfill material, consisting of a mixture of bentonite and crushed Horonobe mudstone, has been designed.This report presents the investigation results on the material properties for the shot-clay method and the outcomes of the demonstration tests at ground facilities performed prior to the in-situ experiment.