Japan will contribute an additional $22.5 million in aid to an international project aimed at ensuring the safety of the Chernobyl nuclear power plant in Ukraine, government sources said Friday.

The aid will be pledged at a meeting of senior officials from the Group of Seven major economies and Ukraine scheduled for May in Berlin, the sources said. The G7 comprises Britain, Canada, France, Germany, Italy, Japan and the United States.

The goal of the Berlin meeting, which will be jointly chaired by Germany and Ukraine, is to raise funds for the second — and final — phase of a $700 million project launched three years ago to reduce the risks still posed by the Chernobyl plant.