Among other ventures, this concern has led to a rather bizarre, and highly expensive, preoccupation with port security, driven by the assumptions, apparently, 1) that after manufacturing their device at great expense and effort overseas, an atomic terrorist or desperately diabolical rogue state would supply a return address and then entrust his or her precious product to the tender mercies of the commercial delivery system, and 2) that analyst Randall Larsen is incorrect to conclude that “anyone smart enough to obtain a nuclear device will be smart enough to put half an inch of lead around it.” As a result, a great deal of money has been hurled in that direction to inspect and to install radiation detectors, generating 500 false alarms daily at the Los Angeles/Long Beach port alone, triggered by such substances as kitty litter and bananas.

This is from John Mueller, Atomic Obsession: Nuclear Alarmism from Hiroshima to Al-Qaeda, Oxford University Press, 2010.