Dounreay’s cementation plant went back to work this year, following an extensive remediation programme.
The plant receives highly radioactive raffinate (a liquid by-product of fuel reprocessing), and conditions it chemically, before immobilising it in drums of cement, making it passively safe for long-term storage. The whole procedure is carried out remotely inside heavily shielded cells.
The plant had been shut down in September 2005 following a spillage of raffinate and cement powder in the cell. There was no release of radioactive material to the environment.
During the clean up, workers were hampered by the high levels of radioactivity, and the need to work in extremely confined areas wearing bulky air-fed suits. Because the activity was so high, man entry to the cell was severely restricted and workers used remotely operated tools wherever possible.
However, once the contaminated equipment and the cement residues inside the cell had been removed, and the cell washed down with water, the activity level dropped considerably.
During the plant’s shut-down, the workforce took the opportunity to install upgraded systems and equipment in the plant.
The facility restarted cementation process operations in April, and since then over 200 drums have been produced.