A review panel is urging the US Nuclear Regulatory Commission to tighten its licensing procedures for radioactive materials. Last year, congressional investigators set up a bogus company and said they were able to obtain enough radioactive material for a small "dirty bomb." In response, the NRC's Independent External Review Panel is now urging the agency to visit an applicant's facilities before issuing a license and to conduct background checks. An NRC spokesman, Eliot Brenner, says the agency had already implemented both changes before the panel's report. Republican Senator Norm Coleman, who requested the investigation along with Democrat Carl Levin, says the government must be vigilant in regulating and tracking radioactive materials.