If the cooling systems on 1/3 of the world's nuclear power plants ever fail it won't matter where you live.
Not quite! Most of the nuclear power plants are in the Northern Hemisphere. Global wind and ocean currents are roughly divided along the equator. What is released in the Northern Hemisphere, will for the most part remain there in perpetuity.
That's one reason that those who want to avoid a potential northern nuclear apocalypse, are considering the Southern Hemisphere as an optimal location for survival.
I know people who are relocating to Australia, and Africa. They consider the USA to be a lost cause, destroyed by socialism, integration, and political correctness. They like Trump, yet they don't believe he will have enough time, even if he serves 8 whole years, to correct the mess, that the leftist lunatics, have made of this country.