As the 76th anniversaries of the U.S. atomic bombings of Hiroshima and Nagasaki approach, survivors of the catastrophe are pinning their hopes on Japan joining a U.N. treaty prohibiting nuclear weapons that took effect in January, seeing it as a key step in realizing their dream of a nuclear-free world.

But some experts say the goal is unrealistic for Japan as nuclear threats continue to grow in the region while an existing nonproliferation treaty is not working properly amid growing tensions between the United States and fellow nuclear superpowers Russia and China.

Terumi Tanaka, 87, a co-chairperson of the Japan Confederation of A- and H-Bomb Sufferers Organizations (Nihon Hidankyo), insists that Japan, the only country to have experienced nuclear attacks, should approve the treaty signed by 86 countries, criticizing the government for making "a foolish choice" not to join it.