41.   The country has been devastated by a sort of nuclear accident.

42.   The hard drives were used to store nuclear weapons data needed by the Nuclear Emergency Search Team, which responds to nuclear accidents and nuclear-related threats.

43.   The hard drives were used to store weapons data needed by an emergency team that responds to nuclear accidents and nuclear-related threats.

44.   The Nuclear Control Institute, an antiproliferation group based in Washington, argues that a plutonium core makes a nuclear accident slightly more likely.

45.   The odds are slim, but one nuclear accident or terror bombing could have devastating consequences.

46.   The nuclear accident, the worst in American history, released what the plant owner characterized as a small amount of radioactivity into the atmosphere.

47.   The mystery ended abruptly Thursday, when the fuel-reprocessing plant suffered the worst nuclear accident in Japanese history.

48.   The plant never opened because of public fears of a nuclear accident.

49.   The two computer hard drives contained data used to respond to nuclear accidents or terrorist attacks.

50.   The Ukraine is also sending officials to the meeting to press for help in cleaning up the Chernobyl nuclear accident site.