The nuclear power industry wants the government to require companies to design new nuclear reactors that would better withstand large fires and explosions, such as those that could be caused by a terrorist attack using hijacked aircraft. "If you need to change the design to accommodate greater security, particularly for large fires and explosions, you want to do that up front in the design process, not after you build the plant" as the government requires, said Scott Peterson, a spokesman for the Nuclear Energy Institute. The industry's position, set out in a December 8 letter, runs counter to the government's. More than a month ago, the Nuclear Regulatory Commission decided to keep the current design rules - now more than a decade old - for new plants and make those facilities fulfill security requirements later. At question is the Design Basis Threat, or DBT, the largely secret requirements for threats for which nuclear plant operators must be prepared. A hijacked airliner is not on that list of threats, Peterson said, because defending against that kind of attack requires assistance from other government agencies and the military.