Nuclear power is a highly efficient clean energy. With the widely applying of nuclear energy, nuclear waste disposal is increasingly paid attention. Bentonite is selected as the buffer material of high-level radioactive waste repository which is because that it has a very low water conductivity, great capability of thermal insulation, excellent expansion and good adsorption properties of radionuclides. While bentonite as a buffer material needs to be compacted and remodeling. Its special properties are not fully applicable to existing norms bentonite laboratory tests. In this paper, bentonite, the buffer material for nuclear waste disposal, is studied by axial compression tests. According to associated test codes and references, specimen preparation method is designed, and the related strength of buffer material specimens in laboratory experiments analyzed.
Disposal of highly radioactive nuclear waste is to divide high-level radioactive waste from the human living environment. In order to prevent the migration of radioactive substances to the biosphere, a lot of methods was raised to solve the problem, including "deep geological disposal", "glacier disposal", "space disposal", "molten rock disposal" and so on. After years of research around the world and practice, now it is acceptable that the most feasible solution is deep geological disposal of nuclear waste.
According to the method of deep geological disposal of nuclear waste, a metal can will be built in the underground repository with 500–1000 m deep, and the buffer and backfill material will be filled between the metal cans and rock mass to assure the safe disposal of high level radioactive nuclear waste and a permanent and isolated environment from human survival. Solidified nuclear waste, the waste canister, buffer and backfill materials, repository and rock together constitute a "multiple barrier system". Buffer and backfill material is filled between the waste cans and the rock mass. Nearly three decades' research shows that bentonite containing montmorillonite is ideal buffer material because of low permeability, high absorption, good thermal conductivity, excellent expansion performance and suitable mechanical properties.