Full Title: President Putin says five men killed in huge explosion in northern Russia that caused sudden radiation spike died trying to create a weapon that ‘has no equal in the world’ Russian President Vladimir Putin has told widows of the five scientists who died in a nuclear explosion earlier this year that their husbands were working on 'the most advanced and unmatched technical' weaponry. Putin's comments came during a ceremony of state decorations at the Kremlin today where he awarded the deceased employees of Russia's state nuclear company with the Order of Courage, posthumously.