Quarter century of innovation at RSRL Harwell’s active handling facility
May 31, 2012
After more than 25 years Harwell’s active handling facility has completed its final project. Opened in 1985, the facility was a centre of excellence; its most notable expertise lay in the field of research into reprocessing, particularly the treatment and immobilisation of radioactive wastes, and in the study of simulated reactor accidents. Now, with the last can of radium contaminated waste dispatched to the solid waste store, the facility is prepared for a period of long-term care and maintenance, prior to final decommissioning and removal.
History
Built in the 1980s as the remote handling wing to Harwell’s radiochemistry laboratories (Building 220), the active handling facility (Building 220.29) used the concept of remotely removable stainless steel containment boxes, inside concrete shielded enclosures.
Design
The facility was designed to be flexible, enabling it to adapt to the changing demands. It offered the higher degree of containment demanded by emerging reactor fuel designs, and was equipped with the very latest technology, including sophisticated master slave manipulators.
Cell line
The cell line contains five cells and one larger decommissioning cell. The cells consist of high-integrity stainless steel containment boxes within heavily shielded enclosures with walls 1.4m thick. Shielding windows are made of lead glass, 105cms thick.
Each cell has a removable containment box so that as one experiment ended, the box could be remotely moved, emptied and the waste transferred, without the need for operator
intervention.
Waste transfer area
At the rear of the cell line is the transfer area, where service ports gave access to the boxes. Gamma gates, which interconnect with flasks, were designed to give shielding during waste transfer operations. Six storage holes were used for short-term waste storage purposes. Activity levels of the ingoing and outgoing boxes were monitored from a materials control area.
Decommissioning cell
The decommissioning cell was designed to avoid the need for operators to enter the cell to carry out decontamination and servicing processes.
Applications
The flexibility of the facility enabled it to provide, over the years, a wide range of services.
These included: the dissolution of thermal and fast reactor fuels; the investigation of simulated accident conditions; the development of new immobilisation methods for waste disposal; research into reactor fuels, isotope production and source recovery; and the development of remote handling support for the design and operation of plant and equipment.
Key projects latterly included the refurbishment of neutron starter sources for reactors and the manufacture of sealed neutron and high energy gamma sources for a variety of customers.
The final project involved the treatment of Radium contaminated materials where the candidate wastes were opened, repackaged, immobilised in either grout or polymer resin and then finally packaged in welded containers, for consignment to Harwell’s solid waste store. The innovative process for immobilising the radium contaminated waste was developed and implemented entirely by the staff of B220.29. On 30 March 2012 the last can of radium contaminated waste was dispatched from the B220.29 facility.
The final phase
The decommissioning of cells began in 1996 with Cell 5 and the receipt and disposal of neutron sources ceased in 2002.
Since then the cells have been sequentially cleared, culminating in the Post Operational Clean Out (POCO) of the active handling facility which is now underway, in preparation for the whole radiochemical laboratory to be prepared for a period of care and maintenance. In the longer term, the area will be fully decommissioned, the building demolished and the land restored for future use.
For the active handling wing, a unique facility implementing cutting edge concepts to the highest of safety standards, it will be the end of a productive era.
Picture: B220.29 Operations, 1986
For more information please contact Angela Vincent, RSRL Communications Manager
