Hazard reduction at Sellafield has taken a major step forward today with the successful transfer of 14,800 litres of historic radioactive liquid waste from a fifty year old nuclear waste storage silo for safe treatment.
Facility Manager Byron Smith explained: “This facility represents one of the most significant decommissioning challenges we are faced with at Sellafield. Completion of this liquor transfer from the Magnox Swarf Storage Silo is an important step towards emptying the silos, processing the waste and decommissioning a legacy plant.”
“The original Magnox Swarf Storage Silo was constructed in the 1960s with three further extensions built in the 1970s and 1980s. Intermediate Level Waste mainly comprising Magnox fuel cladding was stored under water in the twenty two individual compartments within the facility.
“We have already retrieved 586te of solid waste cladding from the silos in the 1990s and now we have successfully demonstrated that we can empty the liquid effluent from the facility. This has been the culmination of 5 years planning and testing by the project team.”
The process known as Liquor Activity Reduction (LAR) removes active silo liquor from the Magnox Swarf Storage Silo and transfers it to the Site Ion eXchange Effluent Plant (SIXEP) where the active effluent is treated.
This first production transfer marks the start of a scheduled programme of LAR movements to SIXEP designed to reduce the activity of silo liquor by about 90% over the next 3 or 4 years. Following this, the solid waste inventory will be removed from the facility, processed and encapsulated for safe long term storage.
After each transfer, the silos will be topped up with clean water before the operation is repeated on a weekly cycle. This will gradually reduce the silo liquor activity through dilution, significantly reducing the overall environmental risk from the facility and radiation dose to the plant workers.
Hugh Bourque, Head of Programme Delivery said: “The significance of this achievement cannot be underestimated. This is a high hazard project with which we have had to work very closely with the regulators in order to prove that we have the capability to safely commence the process.
“The active liquor has had to be pumped from the compartments and transferred across the Sellafield site in a high level shielded pipebridge. The liquor is then treated in our SIXEP facility which filters contaminated water using a special sand called clinoptilolite to remove radioactivity from the effluent. The SIXEP process captures more than 99% of the main radioactive feed in a solid form and discharges cleaned water to the sea.
“The LAR programme is an excellent example of flexible permissioning which has been developed with our regulators to accelerate risk reduction through an expedited licensing process. This has meant that the period between handover of information and regulatory permission was reduced to 3 weeks as opposed to the standard 18 weeks.”
Decommissioning Director Russ Mellor said: ”It is hard for those not involved with the project to appreciate what a milestone this is in terms of decommissioning and cleaning up the Sellafield Site. This project is not only one of our key priorities, but that of the regulators and also for the Nuclear Decommissioning Authority (NDA) who have provided the funding for this job.
“This is exactly why Nuclear Management Partners (NMP) was brought in by the NDA. We are a consortium of the world’s leading nuclear industry experts and have brought this expertise to this project and safely demonstrated how we can clean up the high hazard projects at Sellafield.”