The Department of Homeland Security office responsible for protecting the nation from nuclear and radiological terrorism is largely scrapping plans for new high-tech detectors for screening vehicles and cargo, saying they cost too much and do not work as effectively as security officials once maintained. As reported first by The Washington Post, in a to the chairman of the Senate Homeland Security and Governmental Affairs Committee, the acting chief of the Domestic Nuclear Detection Office said officials will possibly use the machines only for secondary screening, at no more than about a third of the cost originally planned. The development virtually ensures the collapse of one of the most prominent national security initiatives in the previous Presidential administration, which aggressively touted the machines as a high-tech front-line defense against the importation of nuclear materials.