The company is working with specialist radiation sub-contractor Nuvia to recover the remains of historic discharges from the site.
Its return to the seabed marks the third consecutive year of full-scale offshore clean-up and the fourth involving remotely-operated equipment on the seabed.
The 1500-tonne barge LM Constructor is now deployed off the site, providing a recovery platform for an underwater ROV and a team working around the clock for the rest of the summer.
The ROV is fitted with systems capable of detecting and recovering particles, similar in size to a grain of sand, in an area of seabed equivalent to 600 Olypmic swimming pools.
Almost 2000 particles have been recovered from the seabed to date. Of these, 395 were “significant” in terms of their potential health effects.
DSRL senior project manager Bill Thomson said this year’s work aims to:
complete coverage of the 60-hectare plume where “significant” particles are concentrated
repeat the most affected areas to recover more particles and understand better how the higher-activity particles have moved in the sediment
gain more information about the spatial extent of the plume and drop-off rates at depth and distance.