Experts at the International Atomic Energy Agency (IAEA) have been unable to determine what caused a fire at the Zaporizhzhya nuclear power plant in the southern Ukrainian city of Enerhodar. The fire broke out in the cooling system of the plant on Sunday, with Russia and Ukraine blaming each other for the incident. The head of the IAEA, Rafael Grossi, said experts accessed the cooling tower area on Monday. They had assessed that it was unlikely that the primary source of the fire began at the base of the cooling tower, he said. “During the team’s visit to the cooling tower, it determined that …