High pressure hose pumps used at nuclear sludge re-processing plant
One of the UK’s largest private nuclear service providers, RWE NUKEM Ltd have an eight year contract to maintain and decommission one of UKAEA’s radioactive reactors in Winfrith, Dorset. A key part of this is a treatment plant, designed to process legacy intermediate level radioactive waste (ILW) ion exchange resin sludge, by cement encapsulation, uses Watson-Marlow Bredel’s peristaltic high pressure hose pumps.
The old nuclear reactors, last used in the mid 1950’s, were set for clean up when the government earmarked the spot to be returned to a greenfield site. UKAEA turned to one of the experts in the industry, RWE NUKEM Ltd to carry out this task.
The radioactive sludge, which needs to be stored for 50 - 60 years of its half-life, needs to be kept in manner that allows for safe packing and transportation to secure location. This process required RWE NUKEM Ltd to build a specialist plant on the Winfrith site to perform packing of the sludge. By mixing the sludge with cement and packing in drums, it can be physically encapsulated. This involves retrieving homogenised sludge from existing tanks, pumping sludge through a cross flow filter system to dewater it, and then discharging batches of conditioned sludge to the drums. The heart of the bottling process is dependent on peristaltic pumps from the Watson-Marlow Bredel SPX range, including two SPX 65 models and another two SPX 80 models.
These were sourced and installed by Poole Process Limited, who analysed the sites requirements and designed a pumping system to fulfil the bottling processes needs.
Richard Chacksfield, Project Engineer from RWE NUKEM Ltd comments: “Using a pump that could be mounted on the outside of the tanks containing radioactive sludges, meant that having a high suction lift was an important criteria for the pump. Using submersible pumps in this environment was not an option, equipment reliability can be compromised and maintenance can become problematic. “
The damper vessels on the suction and discharge were specially designed for the bottling plant’s flow pulsation by Watson-Marlow Bredel and manufactured by Poole Process Equipment. The SPX65 and 80 pumps are also able to act as accurate metering pumps, which is important for controlling volumes of the sludge. The fact that they can cope with solids laden and erosive process streams made the SPX ideal for the harsh nuclear environment.
“After having looked at various alternative products in the market place, Watson-Marlow Bredel’s SPX range came out head and shoulders above the rest. In addition to meeting all the requirements, they were also relatively compact. Furthermore, the use of a peristaltic hose with a machined internal bore will ensure that metering accuracy and suction lift is maintained throughout the pump life.”
Apart from providing the performance, ease of maintenance and compact construction, the SPX range from Watson-Marlow Bredel has direct-coupled design that allows the drives to be removed and replaced without having to dismantle the pumphead. Pumps are available in a variety of sizes from 25mm to 100mm.
