The diagram above shows the plan view of the overpacking cell.
FLOW OF DAMAGED PACKAGE
- The facility consists of 4 cells, which are the crane to conveyor belt interchange, working cell, buffer storage and empty package storage.
- The empty package storage cell will store empty packages. This includes 3m3 boxes, overpacking boxes and drums (2.02m by 2.02m by 1.525m and 2.02m diameter by 1.525m).
- The empty package storage cell will be accessible to human personnel, as it is shielded and non radioactive.
- The airlock doors will shield radiation from the hot cell to the empty package storage cell.
- Empty packages will be transferred to the conveyor belt between the airlock doors via a forklift.
- Damaged package will be transferred to the overpacking cell via transfer tunnel. A lifting crane lift damaged packages into the empty overpacking packages.
- The packages are then transferred to the working cell where grouts will be poured into. The lid is then being bolted and sealed.
- Another crane (GREEN) will be used to transfer overpacked packages in buffer storage for 24 hours. This is to allow the grout to cure.
- The overpacked package will then be transferred back to the vault.
COMMENTS
- Personnel access is allowed in the empty package storage facility. Hence transferring empty packages on to the conveyor belt can be performed without remotely.
- Direct viewing is made possible in every lifting phase and every processes.
- Yellow crane requires both twist lock and ‘grabber’ feature, while green crane only requires ‘T-lock’ feature.
- Inspection of overpacked packages will be performed remotely in the buffer-storage cell. This is to act as a quality control, before sent to the vault.
- A total of 4 crane liftings is to be performed and 1 fork lifting.
The diagram above illustrates an improved version of the previous layout.
COMMENTS
- The flow of damaged packages is the same as the previous layout.
- Instead of inspecting packages in the buffer storage, it was thought that inspecting overpacked packages in a different cell would allow inspection work to be carried out easier.
- The partition walls (in front of the facility) between both rail tracks will be removed to allow access for packages on and off the transfer tunnel. This however causes maintenance of the transfer tunnel to be carried out by sealing one of the transfer tunnel sections remotely.
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Upgraded Version
FLOW ON DAMAGED PACKAGES
- An empty package storage cell will store 3m3 boxes and drums as well as overpacking packages.
- The Empty Package Storage Cell will be accessible to human personnel. Shielding will be provided by airlocks.
- These empty packages will be sent to the Working Area by a conveyor belt.
- Damaged packages will be transferred from the transfer tunnel into empty packages in the Working Area, via lifting crane.
- The crane will possess twist locks and grabber features.
- Grout will then be filled in overpacking packages in the Working Area. The packages are then sealed and the lid will be bolted.
- The package is then transferred to a buffer storage cell for 24 hours. This is to allow curing of the grout.
- The overpacked packages will then be sent to the Working Area again for inspection purposes. This is to ensure the quality of the packages.
- After inspection, it is then transferred back to the vault via transfer tunnel.
COMMENTS
- The layout above has the advantage of optimising the space available.
- Direct viewing is possible in every cell as well as being able to send in personnel to work.
- This layout only requires one conveyor belt and one lifting crane, hence it is thought to be the cheaper design.
- The layout however has the disadvantage of not being able to overpack packages and inspect overpacked packages at the same time. Hence, congestion is likely to happen, unless the probability of overpacking packages can be justified.
- If further expansion or upgrades are required, the personnel access space can be converted into working areas. It would also be more sensible to have an additional Working Area.