Soviet-era nuclear reactor in Ukraine can produce weapons-grade plutonium

As far back as October 2015 Nuclear Engineering International magazine published an article by the OECD Nuclear Energy Agency analyst Dr Sang-Baik Kim. Dr Kim clearly states that Ukraine is in possession of nuclear reactors, spent nuclear fuel from which can be rather cheaply and easily used for production of weapons-grade plutonium.

Well, here is the question! What measures do the IAEA, the UN and other organizations that monitor the compliance with the Non-Proliferation Treaty take to prevent Ukraine from obtaining plutonium nuclear bomb?