During the process of moving a consignment of three empty High Level Waste flasks from the Barrow docks spur line onto the main railway line (heading for Sellafield), one of the three flasks derailed and a second flask partially derailed. Drawn by two Direst Rail Services locomotives (DRS – a wholly-owned subsidiary of the Nuclear Decommissioning Authority), the transport is said to have been travelling at approximately 5 mph when the derailment occurred on the main line causing a partial blockage of the line and forcing the cancellation of some main line services for several days.
The third transport flask had remained upright and, following the rectification of the partially derailed flask, the two flasks were returned to the Ramsden Dock nuclear shipping terminal for inspection. Righting the fully derailed flask took a further 4 days because of what was described by Network Rail as a process that was ‘extremely challenging due to the location and the ground conditions in the area’. An investigation has been launched and whilst the exact cause of the derailment has not yet been established, it is understood that some repairs to the main railway line are necessary. Once repairs are completed, the three flasks will be taken to Sellafield.
The empty HLW flasks (type TN28 VT weighing 100 tonnes each) had earlier arrived at the Ramsden Dock nuclear shipping terminal from Japan on board the ship Pacific Grebe – one of three Pacific Nuclear Transport Ltd (PNTL) vessels. At Sellafield, the flasks will subsequently be loaded with further canisters of HLW – each flask holding 28 canisters of vitirified (glassified) HLW – before returning to Japan as required under the ‘returns clause’ of the contracts signed up to by overseas customers whose spent nuclear fuel has been reprocessed at Sellafield. As Sellafield’s largest overseas reprocessing customer, Japan is scheduled to take back almost 900 canisters of vitrified waste in 35 flasks up to year 2017. To date, 132 canisters have so far been returned to Japan in three separate shipments.
Despite the claim by International Nuclear Services (INS) who oversee such shipments that ‘our heritage in transporting specialist nuclear materials is unique; our nuclear safety and security records are world class’, the programme of returning HLW to Japan has been jinxed by a number of events. When the first shipment of one flask (January 2010) arrived in Japan, the HLW canisters within the transport flask failed to tally with the official paperwork – a number of them being ‘out of position’ within the holding channels of the transport flask. As a result, a scheduled HLW return to Holland had to be postponed whilst an investigation was carried out. When the second shipment, made in July 2011 and consisting of 76 canisters in 3 flasks, arrived in Japan, radioactive contamination above Japanese acceptance limits was found on some canisters – with one found to be contaminated at almost 50 times the acceptance limit. And now the derailment of the empty HLW flasks at Barrow, following the return of the Pacific Grebe from its third shipment to Japan in January this year has further blotted the INS copy book.
A fourth and fifth HLW return shipment to Japan are scheduled from Sellafield in the first Quarter of 2014 and for mid-2015 respectively.