MEB decontamination trials

Multi element bottles decontamination trials save on costs and valuable disposal space.

As part of Sellafield Ltd’s drive to continually minimise waste generation and volumes requiring long term disposal, a trialling project to treat Multi Element Bottles (MEBs) through a decontamination process, rather than consigning the material directly as Low Level Waste (LLW), is underway.

MEBs are used to store Light Water Reactor spent fuel assemblies in Thorp storage ponds. Each weighing over two tonnes, a number of these currently held in the ponds are suitable for export as LLW, however some are categorised as Intermediate Level Waste (ILW).

The most recent project has seen ten MEBs dispatched to Studsvik, Lillyhall for treatment having undergone decontamination by teams at Sellafield. Two of these were categorised as ILW which meant that they required additional decontamination to reclassify them as LLW. At Studsvik the MEBs will be size reduced, and eventually sent to Studsvik’s facility in Sweden for smelting – which reduces the volume and weight of the waste.

The by-product of the smelting is a series of metal ingots which can be released as conventional scrap metal. Although some secondary waste will arise in the form of ‘slag’ which will require disposal at the Low Level Waste Repository (LLWR), this is still significantly less than had the MEBs been disposed of in their entirety. In total, the treatment of the 10 MEBs in this way will result in the avoidance of five ISO freights requiring disposal at the repository.

Ian MacKay, MEB acceleration manager said: “The success of this project is down to the collaborative working of the teams involved –from Thorp, the consignments team and the waste operating unit.

“MEB removal from the ponds is a key strategic enabler in making space within the storage pond – necessary for continued long term storage of spent fuel for UK customers. In addition, the fact that we have successfully decontaminated two ILW MEBs down to LLW has resulted in significant cost savings in on site storage costs – in the region of £400,000. Delivery of this project demonstrates our drive towards efficiency as a business.”

Simon Rowe, head of Manufacturing Metals recycling and ILW added: “At the heart of this project is the implementation of the waste management hierarchy which is about reducing the volumes of waste that are directly disposed of, beginning with the avoidance of waste at source. Treating MEBs in this way reduces the volumes of material requiring disposal at the LLWR, which is better for the environment.”

Going forward Sellafield Ltd plans to work in partnership with the LLWR and Studsvik to decontaminate and treat a further 100 MEBs.