So if fallout 1 took place 84 years after the bombs dropped thats 84 years * 356 days * 24 hours = 717696 hours since the end of the world. 7^6 = 117649 and 7^7 = 823543 so the radiation in Fallout 1 should be between 1/1,000,000 and 1/10,000,000 of what it was right after the war (though...