Lab testing of method for clay isolation of spent reactor fuel in very deep boreholes

• In Sweden and Finland and some other countries, two basically different multibarrier concepts for disposal of spent reactor fuel (HLW) are the often cited KBS-3 methods and Very Deep Boreholes methods (VDH), on which the paper focuses. These concepts have engineered barriers in the form of clay-embedded canisters with spent reactor fuel.. The clay, placed around the canisters and between them, provides ductility and tightness for minimizing the risk of canister breakage, and for tightness. The large-diameter VDH holes have dense clay seals of smectite-rich material in combination with clay mud for stabilization of the rock. In this paper, clay mud of smectite-rich Danish Holmehus clay was investigated for evaluating the physical interaction with the dense clay blocks. The possibility of solving the problem of too quick hydration of the blocks, which can make the resistance to insertion of the units of dense clay and canisters (“supercontainers”) in the mud difficult, was investigated by using prewetted dense clay blocks prepared by a new method (“DW” technique). The laboratory experiments, which were made to simulate the installation of supercontainers in clay mud using model versions of them, have given promising results.

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Engineering and Technology  (hsv)

Civil Engineering  (hsv)

Geotechnical Engineering  (hsv)

Teknik och teknologier  (hsv)

Samhällsbyggnadsteknik  (hsv)

Geoteknik  (hsv)

Soil Mechanics  (ltu)

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