The MegaPorts initiative (to scan over 80% of containers bound to the USA) was launched in 2003 with the purpose to counter possible terrorist attacks to the USA. However, the measure potentially affects the competitiveness of the maritime industry. In fact, so far, the industry has expressed concerns on the expected increase in ports congestion –specially in their land side- and its effects on the supply chain as well as on the cost overruns from scanning all containers. This paper deals with the effects of installing scanning facilities in an already operating seaport terminal, and assesses what would be the optimum number and placement of the equipment, in terms of quality of the service provided. The assessment is conducted by means of a simulation model of the delivery and receipt process of the terminal using real data from a semi automated container terminal in Barcelona, Spain. Different scenarios with different configurations in terms of number and placement of the scanners are considered. The results show where the best scanner locations are and the amount necessary in terms of truck turnaround time in the terminal.