Construction of a new waste plant at Sellafield has taken a major step forward by completing assembly of the first Buffer Storage Vessel (BSV) for the Sellafield Sludge Packing Plant 1 (SPP1) project.
The vessel is the largest stainless steel fabrication assembled on the site since the 1980s. It is the first of three vessels which will hydraulically receive legacy sludge from the First Generation Magnox Storage Pond (FGMSP).
The FGMSP is one of the priority decommissioning projects at Sellafield. It was originally built to store, cool and prepare Magnox fuel for reprocessing. The legacy sludge has to be retrieved from the pond floor to allow the pond to be emptied of nuclear fuel and the facility decommissioned.
The enormous vessel is 33 metres long, 7 metres high and 3 metres wide, is made of 25 millimetre thick stainless steel and weighs 240 tonnes. The welding of the tank involved over 1600 metres of weld run, which all had to be radiographed to ensure that the vessel will have the required integrity and this was achieved with less than 1% defects.
Karl Mason, project manager said: “We are committed to accelerating decommissioning at Sellafield as part of our commitment to reduce high hazards.
“Assembly and welding of the first tank sections was a major challenge which took 16 weeks to complete. We applied the learning from this through the fabrication process and we managed to reduce the timescale to two weeks for the final sections.
“Our contractors Doosan Babcock and Balfour Beatty delivered a quality product on schedule, which gives us good confidence that we can complete the remaining two vessels to meet the overall project requirements.”
The SPP1 will be ready to retrieve sludge during 2014/15 and the export of fuel and skips is scheduled to begin the following year.