@oralloy,
I'm not sure Hiroshima is that widely read. According to Goodreads, it was rated by 60,000 users, which is not bad (decent readership, actually).
But compared to other perennial high school books, it is not widely read: Moby Dick, 478,000; To Kill a Mockingbird, 4 million; Frankenstein, 1 million; The Scarlet Letter, 704,000.
If I may, I would like to recommend
Swan Song by Robert McCammon. It is about a group of survivors struggling to live in the aftermath of a nuclear war between the US and the Soviet Union. It is often compared to
The Stand by Stephen King, another book about the end of the world.