IMPACT2010 (IMPACT) and Structures under Soft Impact (SUSI): IMPACT and SUSI joint report

An impact test apparatus has been built in autumn 2004 to test especially soft missile impacts against reinforced concrete walls. The apparatus has been designed to be suitable also for investigating fuel spreading, e.g. measuring droplet size and velocity. At the beginning of the project, one of the main purposes was to measure the force time function during the impact. It was enabled by a thick force plate with force transducers installed in front of the supporting frame. The main aim of the project is to produce data for verifying and developing numerical models and methods. This work has been carried out within the SUSI project. The spread of liquid fuel as a result of an aircraft crash may cause a sudden fire with hazardous effects on the safety of the NPP. The spread phenomena have been studied at VTT in the IMPACT tests both experimentally and numerically. The goals of the study were to increase a general understanding of the liquid dispersion phenomena under impact conditions, to measure some of the input parameters needed for numerical simulations, and to take in use and to validate simulation methods for the determination of fuel spread and fires. The Fire Dynamics Simulator (FDS) program was used to estimate the fraction of the aircraft fuel that accumulates into pools burning on the ground and to examine the heat exposures resulting from a 10 ton kerosene release.