Regional Basic Professional Training Course in Korea

Regional Basic Professional Training Course (BPTC) on Nuclear Safety
repository. They may be co‐located, or alternatively, the encapsulation facility may be
situated next to an interim storage for HLW.
In the encapsulation facility, HLW bundles are inserted into prefabricated waste canisters.
The lid or lids of the canister are then closed and after inspection, the waste canister is
transferred to the repository. An example of an encapsulation facility design is given in
Figure. 20.1. The encapsulation process occurs in air atmosphere. Uncovered HLW
bundles are handled in a hot‐cell chamber; the fuel bundles are enclosed elsewhere, either
inside a transport container or a waste canister. All handling operations are done with
remote control techniques, thus the occupational radiation doses can be kept at a very low
level.
The encapsulation process involves no great radiological risks. Risk potential is low
because no high pressure or temperature is needed in the process. Fires and explosions
can be reliably prevented by means of the design of facilities and selection of materials.
Particulate radioactive material will spread inside the hot‐cell but their releases outside
the facility can be prevented by using under pressure in the hot‐cell and by filtering its
exhaust air. Consequently, very stringent radiation safety requirements can be set for the
encapsulation facility.
An example of a final repository to be constructed in crystalline bedrock is given in Fig.
20.2. It is an idealistic picture, because the geological structure of the host formation will
determine the layout of the repository. In this scheme, waste canisters are emplaced into
deposition holes, one canister in each hole. The spaces in deposition holes are backfilled
with bentonite. The transfer and emplacement operations must be done very carefully in
order not to cause damage to the canister, which is an important barrier with respect to
long‐term safety.
Because the fuel bundles are enclosed into hermetic canisters, no releases of radioactive
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