The world’s 440 nuclear power plants are on track to deal with the millennium computer bug, the International Atomic Energy Agency said yesterday. The agency’s reviews of plants uncovered some “vulnerabilities” in data and monitoring systems, but the IAEA claims there are no problems related to safe operation of the plants. Meanwhile, the Norwegian environmental group Bellona yesterday warned of possible dangers because Russia’s Northern Fleet, which has a number of nuclear weapons, lacks money to cope with the Y2K problem.