Ukrainian President Volodymyr Zelensky appealed to world leaders to keep his country’s fight against Russia’s invasion a top priority in his address to the UN General Assembly on Wednesday. He raised to spectre of a global nuclear disaster at the start of his speech, saying Russia was planning attacks on Ukrainian nuclear power plants in order to further hobble the country’s energy supply. “Any missile or drone strike, any critical incident in the energy system, could lead to a nuclear disaster,” Zelensky said. “A day like that must never come. Moscow needs to understand this, and this depends…