RADWASTE MANAGEMENT | BITUMEN PYROHYDROLYSIS *TC = Transport Container Max. dimensions (LxWxH) 15,000 x 3,500 x 2,500 Py Steam supply
Master-Slave- Manipulator
Pyrogas
Double lid-lock for TC*
Double lid lock for drums
Monorail Monorail
3x basket Pusher
Puller
Double lid lock for TC*
Entry
Flange roller conveyor Flange roller conveyor
Above, figure 1: Illustration of an Industrial scale facility
Waste drums after sorting
V laboratory-scale facility processing up to 20 kg of bitumen. A second step will establish a demonstrator unit able to treat a 200-litre drum in order to gain full understanding of the pyrohydrolysis process involved in the treatment of a bitumen matrix. In its final stage, the demonstrator unit should prove the process using real radioactive bituminized waste. It is assessed that the Technical Readiness Level (TRL)
based on US DoD and EC assessment system was TRL3 prior to the start of the R&D programme. When the lab- scale development is successfully completed the TRL will increased to TRL5 and after completion of the full demonstrator work TRL7 should be achieved. In 2020 NUKEM Technologies launched its R&D project,
starting with the design and procurement of the lab-scale furnace able to process 30-litre drums containing simulated bituminized waste. At the beginning of 2021 the furnace was delivered to DBI Virtuhcon and successfully installed and commissioned. Parallel to the works on the lab-scale facility, drain tests using a 400 ml canister filled with pure bitumen were executed, in order to investigate the behaviour of bitumen
and to simulate the necessary pre-treatment step for the proposed co-incineration process. These results will serve to benchmark the pyrohydrolysis approach. For the drain test the canisters were punched around the
circumference and up to the height of the bitumen filling before the canisters were slowly heated up at a rate of 10°K/min to temperatures between 100°C and 180°C. After successful installation and commissioning of the lab-scale furnace, first tests were performed using pure bitumen in 30-litre stainless steel drums containing between 10 and 20 kg. The value of 20 kg was chosen because the remaining volume will be used in the next step for the addition of salt, ion exchange resins or metal, simulating radioactive waste embedded into the bitumen matrix.
In a first phase of the lab-scale furnace test programme,
‘approach-tests’ were executed to determine the best temperature profile and to gather data on the behaviour of the bitumen in larger volumes. Although the bitumen was mainly decomposed during the pyrohydrolysis process, at the bottom and on the surfaces of the 30-litre drum some powdery residue nevertheless remained after the
Above, figure 2: Filled Canister, draining the bitumen and showing the residue after the draining process 38 | August 2022 |
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FEED BOX
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FURNACE
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