Design and approval testing of the Transhield-20 Type B ISO container

The Transhield-20 Type-B(U)F ISO container is designed to carry up to 35 x 200-litre drums of contact-handleable ILW. Its maximum permitted fissile content is 3 kg in 25 drums. It comprises an ∼ 5.5mx1.9m diameter stainless steel inner containment vessel which is surrounded with resin bonded cork for insulation and protection. It carries up to five carousels each containing between five and seven 200-1 drums depending upon the fissile content. A full scale prototype Transhield-20 container was subjected successfully to two series of impact tests in 1995 and 1996 under drop conditions that were either equal to, or in excess of, the IAEA ST-1 (1996) regulations. Calculations were performed to assess the thermal performance of the package in a damaged state. After 30 minutes exposure to an 800 deg. C environment, the temperature in the area of the seals did not rise above 94 deg. C, well below the maximum permitted seal operating temperature of 120 deg. C. The packaging is expected to gain its certificate of approval by 1998. (author)