THE CENTRAL ELECTRICITY GENERATING BOARD FLASK TEST PROJECT

In 1981, the UK Central Electricity Generating Board set up a wide-ranging programme of theoretical and experimental work to develop a detailed understanding of the way in which Magnox flasks behave in severe transport accidents. Specific objectives of the project included an investigation into the validity of the use of scale models to represent full-size flask behaviour and the relevance of the IAEA regulatory tests in relation to real transport accidents. In all, over a hundred tests on flask components, model flasks and other test pieces were conducted, culuminating in the drop testing of a full-sized Magnox flask and a simulated rail crash test carried out in public in July 1984. The project was based on a steady progression from the study of fundamental principles to the execution of the train crash. Extensive use was made of experimental drop-test facilities and computer-aided analytical techniques, such as the finite element method. The project confirmed that, with some important exceptions, linear scalability can be applied with confidence to predict flask behaviour under impact loading. Where those exceptions were encountered, some guidance was obtained as to how it should be properly accounted for when interpreting scale model data. Good correlation was achieved between finite element analyses (carried out using DYNA-30 and ANSYS) and experimental results. The knowledge gained as a result of developing and running the finite element model proved to be invaluable in developing a high degree of understanding of flask impact behaviour. This knowledge ultimately allowed a series of very simple mathematical models to be developed and used as engineering tools in other studies.