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Before and after shipment: interim storage
facilities
The radioactivity of the short-lived fission products, and thus the
heat produced, decreases naturally very rapidly in the first few years
and continues to reduce significantly in the first decades after the
production of the glass.
At both ends of the transportation chain, an interim storage facility
is needed for the cooling of the canisters. The French and Japanese
interim storage facilities are based on the same concept.
- In France, at La Hague, the canisters of vitrified residues produced
by the two vitrification facilities (R7 and T7) are temporarily kept
in a buffer storage for initial cooling before return transportation
to the customer's countries. The buffer storage of each facility includes
400 storage channels, each containing 9 canisters. Transfer of the
canisters from the vitrification unit to the storage channels, as
well as from the storage channels to the transportation casks, is
performed by a remotely controlled, shielded transfer machine, thus
ensuring a permanent and complete containment of the canisters.
- In Japan, the long-term programme for research, development and
utilisation of nuclear energy requires an interim surface storage
of vitrified HLW for further cooling over three to five decades before
final disposal. Consequently, a waste management facility has been
built at Rokkasho-Mura for the accommodation and storage of all the
canisters of HLW returning from overseas (France and United Kingdom).
The initial capacity of the interim storage facility will be 1,440
canisters with further extensions added as needed.
The canisters are being placed in 160 storage channels, each accommodating
9 canisters in a thimble tube to ensure containment. Cooling is performed
by air flow along the tubes. The impact of this installation on the
environment is well below the authorised limits.
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