Review of BNFL’s Operational Experience of Wet Type Flasks

BNFL International Transport’s operational experience includes shipping 6000te of spent fuel from Japan to Sellafield, through its dedicated terminal at Barrow, and to Cogema La Hague. This fuel was shipped under the PNTL (Pacific Nuclear Transport Ltd) banner for which BNFL is responsible. PNTL owned and operated a fleet of 5 ships for Japanese business and a fleet of 80 wet and 58 dry flasks, for the transport of Light Water Reactor (LWR) spent fuel, from both Pressurised Water Reactors (PWR) and Boiling Water Reactors (BWR). “Wet” or “dry” flask is the common terminology used to distinguish between spent fuel flasks transporting fuel where the fuel is immersed in water, or spent fuel flasks that have been drained of water and dried. Also from European customers 1500te (total weight) of spent fuel has been shipped to Sellafield under the auspices of NTL (Nuclear Transport Ltd), and latterly BNFL itself. Early oxide shipments from mainland Europe utilised rail and commercial ferry, whilst latterly a dedicated BNFL ship, the European Shearwater, has transported the flasks from Dunkirk (through a dedicated BNFL Terminal run by BNFL Sa), to Barrow. For transports of spent fuel to Sellafield, predominantly wet NTL / Excellox type flasks were utilised (apart from the NTL9, a TN type dry flask, which was used to transport fuel from Switzerland). For transports to La Hague, predominately dry TN type flasks were used, apart from some transports utilising the NTL11 flasks. (A wet Excellox type flask) Another main difference in the transports was the use of Multi–Element Bottles (MEB’s) for fuels transported to Sellafield, and open frames, used for transports to La Hague. The reason for this being the different pond storage philosophy adopted by BNFL and Cogema In the UK the flasks were received at THORP receipt and storage facility (fig 1), a purpose built facility for receipt of wet flasks.