Development of the Nano-mineral Phases at the Steel-Bentonite Interface in Time of the Evolution of Geological Repository for Radioactive Waste

摘要

Today, the optimal prototypes for geological storage (GS) facilities (GS) that are planned to be located in crystalline rocks of Chernobyl Exclusion Zone or adjacent regions of Ukraine are geological repositories (GR) of high-level waste (HLW) and spent nuclear fuel (SNF) that are situated in Precambrian crystalline rocks (granites) of Sweden and Finland [34]. The GR safety concept is based on the usage of multiple barriers in the disposal systems that perform protective functions over different time periods. Standard design of the storage facilities foresees the following barriers: matrix with HLW, metal canister for the matrix, clay buffer between the canister and the containing rock, and filler for main tunnels and other underground workings (the backfill) - engineered barrier system (EBS) - including the host rock in contact with or near the EBS and the environment as a whole that separates EBS from the geosphere and biosphere. The canisters relate to the most important elements of EBS, which are usually made of iron alloys (carbon steel, cast iron, stainless steel, etc.) [37]. A main function of the clay buffer is to isolate the waste container from the environment due to its high ability to retain radionuclides in the engineered barrier system (EBS) and to prevent entry of groundwaters [9].