1. To use nuclear weapons, as by the military, often considered a last resort. I'm worried about the repercussions if our military officials decide to go nuclear.
2. In the US Senate, to pursue a course of action allowing the majority party to end filibustering with a simple majority, rather than the usually required supermajority of 60%. Senators could, however, go nuclear and approve this nomination.
3. To behave wildly. You only turn 21 once, so I plan to go nuclear at my birthday party this weekend!
4. To aggressively express one's anger. When mom finds out you dented her brand-new car, she's going to go nuclear!
5. To take drastic action. Whoa, calling the CEO about this issue is definitely going nuclear—let's see what we can do on our own first.
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.
go nuclearmainly BRITISH, INFORMAL
If someone goes nuclear, they get extremely angry and start shouting or behaving violently. The row during which he went nuclear and resigned from his post was much reported in the press. Compare with go ballistic.
Collins COBUILD Idioms Dictionary, 3rd ed. © HarperCollins Publishers 2012