RD&D-Programme 2004 - SKB

10.3 Deposition technology
By “deposition technology” is meant the equipment and machines required for reception,
handling, transport and deposition of canisters and buffer in the deep repository.
10.3.1 Requirements and premises
Operation of the deep repository may have only a limited impact on the safety performance of
the rock and the other barriers. Equipment and procedures for handling and deposition of spent
nuclear fuel must be designed so that radiation doses to personnel are limited. The equipment
and procedures must also be designed so that the consequences of mishaps and abnormal
incidents are mitigated. It must be possible to carry out deposition in parallel with rock investigations,
construction and operation.
10.3.2 Handling and deposition
Conclusions in RD&D 2001 and its review
In RD&D 2001, SKB concluded that:
• A full-scale prototype of a deposition machine has been manufactured to permit testing and
demonstration of the technology for deposition of canisters and buffer in the deep repository.
• The peripheral functions that will be required for transporting transport casks from the
encapsulation plant down to repository level and transferring the canister from the transport
cask to the deposition machine’s radiation shielding tube have so far only been superficially
studied.
In its review of RD&D 2001, SKI considers that if SKB encounters problems in connection with
a separate deposition of bentonite and canister, they should prepare to develop a technique and
technology for simultaneous deposition.
Newfound knowledge since RD&D 2001
The execution of the installations in the Prototype Repository required the development of
full-scale equipment for handling and deposition of buffer and canister. This has entailed studies
of different tools for handling of blocks and rings of compacted bentonite. Altogether, more than
130 buffer units have been handled without mishap in the experiments conducted at the Äspö
HRL. This experience will be very useful in the continued work of developing the equipment
for the buffer units that will be used in the future deep repository.
Similarly, the deposition of the seven canisters in the Prototype Repository and the Canister
Retrieval Test at the Äspö HRL have yielded valuable experience for the choice of the final
design of a deposition machine.
Moreover, development of deposition technology and machines for the KBS-3 variant with
horizontal deposition is also under way, see section 10.7.
Programme
The design of the deposition machine determines the dimensions of the deposition tunnels. It
is therefore important to be able to limit the size of the machine while meeting the stringent
requirements made with regard to radiation protection, reliability and a low risk of mishaps in
conjunction with the handling of canisters with spent nuclear fuel. The equipment for handling
and emplacement of the buffer units will not determine the layout of the deposition tunnels, but
it is important to design the equipment for safe and rational handling. The continued programme
will be carried out partially in cooperation with Posiva, since they intend to handle similar
canisters and buffer units.
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