Two important high hazard risk reduction milestones have been achieved in the clean up of the historic pile fuel storage pond facility at Sellafield.
16 fuel skips have been retrieved from the pond, while six of the facilities’ twelve decanning bays have now been desludged.
Constructed between 1948 and 1952, the pond and adjoining decanning building provided the storage and cooling facility for irradiated fuel and isotopes from the two windscale reactors.
Work has been ongoing to retrieve the corroded and wind-blown material, known as ‘sludge’, which has accumulated in the pond since it was commissioned.
To date, the team have exported 16 skips via the new skip wash and tipper machines, which were installed as part of the sludge retrievals project.
The skips were then wrapped in purpose built PVC bags prior to being sent to the waste monitoring and compaction facility for size reduction and disposal.
The additional room on the pond floor will now enable further desludging and clean up operations to continue.
In achieving the second milestone, the team has desludged six of the facilities’ twelve decanning bays. The sludge has been moved from the bays into the main pond area using water jet lances and underwater impellors, prior to onward treatment.
Project manager Tony Calvin said: “The pond needs to remain at a fairly constant level and as we were introducing water into the pond to clean the bays, we had to constantly monitor and manage water levels and pump out excess water out as necessary.”
“Long periods of rain before Christmas meant that additional water could not be introduced into the pond so we experienced some delays, then we had a real hard freeze which meant that the instrumentation and the pond froze. In addition, when the winds reach a certain speed, cranes can’t be operated. All of these factors added to the complexity of the project.”
One of the next key milestones for the project is due later in the year when the team will transfer the sludge from the pond into the in-pond corral before it is removed from the facility and sent for treatment in the local sludge treatment plant. From there the material will be sent to the sludge packaging plant (currently under construction) where it will be stored prior to long term disposal.
Head of programme delivery Dave Polkey said: “We are desludging one of the highest hazard facilities at Sellafield. This is a significant achievement for the team working on the project and is a step forward in achieving our decommissioning goals.”