Following the shelling of the Russian-controlled nuclear power plant in Ukraine, the International Atomic Energy Agency (IAEA) has rung the alarm, warning of a possible nuclear catastrophe.Meanwhile, Iran has announced it is enriching uranium at its Fordow nuclear facility at 60 percent.Is there any sign Iran is trying to build a nuclear weapon?With the global nuclear arsenal nearing 13,000 weapons, mostly in the hands of the United States and Russia, it seems an increasing number of countries are trying to expand their nuclear capabilities.Should the non-proliferation treaty signed in 1968 be revised?Rafael Grossi, IAEA chief, talks to Al Jazeera.Subscribe to our channel http://bit.ly/AJSubscribeFollow us on Twitter https://twitter.com/AJEnglishFind us on Facebook https://www.facebook.com/aljazeeraCheck our website: http://www.aljazeera.com/Check out our Instagram page: https://www.instagram.com/aljazeeraenglish/@AljazeeraEnglish#Aljazeeraenglish#News