(Oops! Posted this in the wrong forum... :-[ )
While I am not sure of the exact mega-tonnage with which an Atmospheric Processor detonates, it is easier to be certain of the damage caused by different classes of nukes over at NUKEMAP (http://nuclearsecrecy.com/nukemap/). As Private Hudson would say, "Check it out!"
(https://www.avpgalaxy.net/forum/proxy.php?request=http%3A%2F%2Fthenostromofilesblog.files.wordpress.com%2F2017%2F04%2Ffor-avp-post-2017-04-28.png&hash=23149cdae8f869a1564a0c387a57aa7300aecf00)
Oddly enough a number of people used Nukemap to illustrate just how dumb it was for Hadley to survive largely intact for Aliens Colonial Marines after a 40 megaton explosion. ;D
Yeah what was the excuse on that again? the explosion went up instead of outward or something. :P
Well, then. Maybe I didn't post the wrong forum after all. ;D
Considering this thing was made for space travel, traveling through the atmosphere without being aerodynamic at all, while being massive, I can see alot of it surviving and being a reasonable thing to happen, that and remodeling WY forces would have made after coming back to LV-426.
It wasn't just dropped from orbit.
No, but something like it, something massive that is not aerodynamic, has to still survive the stresses of travel both in space and out of it. The stress the engines would cause traveling through space and int atmosphere would be horrific as well.
maybe the explosion was more like a nutron bomb and Cameron just used thermonuclear because it was a cold war buzz word and audiences for the most part didnt know what a nutron bomb was
Neutron bombs don't mushroom cloud