Explainer: How close is Iran to producing a nuclear bomb?

With the killing of a top nuclear scientist in Iran, efforts to revive a 2015 nuclear deal between Tehran and world powers have hit a roadblock. So how close is Iran to producing a nuclear bomb? Subscribe: http://smarturl.it/reuterssubscribe Reuters brings you the latest business, finance and breaking news video from around the globe. Our reputation for accuracy and impartiality is unparalleled. Get the latest news on: http://reuters.com/ Follow Reuters on Facebook:   / reuters   Follow Reuters on Twitter:   / reuters   Follow Reuters on Instagram: https://www.instagram.com/reuters/?hl=en