Alex Wellerstein: on the world’s nuclear weapon arsenal?

Nuclear weapons have unfortunately been brought to the fore once more with Russia's invasion of Ukraine despite most experts agreeing deployment is unlikely. No nation has detonated a nuclear weapon in conflict since 1945 and many of those weapons are getting pretty old. Alex Wellerstein is a nuclear weapons historian at the Stevens Institute of Technology. He talks to Jim about the state of nuclear weapons and how reliable they are.