COMPUTATIONAL MODELLING TO PREDICT WASTE PACAKGE PERFORMANCE UNDER FIRE ACCIDENT CONDITIONS

In the UK, NDA is developing a design safety report for the Standard Waste Transport Container (SWTC) for the transport of intermediate level waste. The approach for confirming the protection afforded to the contents (waste packages) is nested modelling: a model of the SWTC is used to predict the internal temperatures during a fire. These temperatures are then applied to a separate model of the external surface of waste packages to predict possible releases. The thermal test, for demonstrating ability to withstand accident conditions in transport, specifies an external temperature of 800o C for 30 minutes. Heat transfer considerations mean that the contents of the SWTC will experience temperatures which are much lower than 800o C, but over a longer period than 30 minutes. The main focus for demonstrating safety are first to ensure that the lid / body gap opening remains small, second that the local temperatures are within the design limits of the seal and third that the internal pressure can be contained throughout the fire conditions. The safety of the SWTC against all these loadings is discussed in this paper.