There was a recent report that Japan has finally agreed to give up its nuclear weapon grade stockpile of plutonium:
Japan possesses 331 kilograms of mostly weapons-grade plutonium offered by the US during the Cold War era for research purposes. The highly-concentrated plutonium can produce 40 to 50 nuclear weapons.
The US has repeatedly asked Japan to return the plutonium for the sake of nuclear security. Tokyo rejected initially, citing that the nuclear stock is needed for fast reactor research, but it finally gave in to the demands of its ally in January, according to the Kyodo News Agency.
At the Nuclear Security Summit in the Netherlands, Abe and US President Barack Obama said Monday that Japan would turn over the nuclear stockpile to the US to be downgraded and disposed of, which will “help prevent unauthorized actors, criminals, or terrorists from acquiring such materials,” Reuters reported. The plutonium would be prepared for “final disposition.”
However, what triggered concerns is not just the plutonium originally from the US. Japan also possesses more than 1.2 tons of highly enriched uranium and 44 tons of low-quality plutonium from reprocessing spent nuclear fuel, far exceeding its need for nuclear energy.
I had always been lead to believe that Japan had renounced nuclear weapons in Article 9, which forbids war. The worry is always expressed that the danger is that the terrorists will somehow get hold of these materials, and cause the world irreparable harm. However, the facts are that the vast majority of the nuclear destruction has been done by governments or the corporations to their own people: Three Mile Island, Chernobyl, Mayak.