if fallouts bombs were as strong as the real thing, there would be very little life in the wasteland, if any. radiation at lethal levels would be everywhere and radiation doesnt just clean itself up.
Actually it does clean up by itself. Basic physics radio active material something called half life, most of radioactive material created by nuclear weapons has very short half life so short term radioactivity drops fast, to about 1/2000th in about 24 hours in case of air blast. Long term fallout is another thing... whole different ball game.
Type of bomb and type of blast are determining factors in fallout.
A very short primer on nuclear weapons and warfare:
There are two basic types of nuclear weapons technical sense fission and fusion devices. Fission bomb creates energy with fission of heavy material like plutonium or uranium, it's dirty and leaves long time radioactive material around. Fusion device always have fission bomb as primary stage as it's energy output is needed to create conditions needed for fusion of light material like hydrogen. Most of isotopes that form in fusion are short term radioactive material so fusion bomb is relatively clean when it's yield is considered. Most of
Then there is combinations of those two principles, witch make up most of nuclear armament of all but new nuclear armed countries. First most of fission devices are in reality boosted fission devices that have small amount of fusion material in those to increase neutron count and boost yield a lot. Then most most of fusion devices are so called three stage weapons or Fission-Fusion-Fission bombs. F-F-F use fission primary stage to create conditions needed for fusion, then fusion to create roughly under 50% of energy and natural uranium tamper as outer shell, natural uranium doesn't fission in normal circumstances but fast neutrons created by fusion makes that possible and last fission stage makes up usually over 50% of yield. F-F-F bomb is dirty. Then there is two other types of nuclear weapons neutron bomb and "salted" bomb. Neutron bomb is basically tamperless fusionbomb that doesn't stay in one piece as long as it would take create big blast but to create lot of initial radiation, those were dubbed capitalist bombs in 80's as they kill people and troops but do less physical damage. Salted bombs are F-F-F bombs that contain selected materials that create suitable resultant materials to create as much as possible fallout, gold could when added to nuclear weapon would make radiation more severe for few days longer... cobalt could make radiation far worse for far longer periods. Salted bombs were designed to make more fallout.
Nuclear deterrence in essence worked on so called MAD principle, that comes from mutually assured destruction. During cold war strategic planners of both west and soviets had little obsession known as overkill, they made their plans little bit on side of screwing up is normal or something. Most of nuclear targets were overkilled by launching at least couple nukes on almost all targets, all sorts of mishaps can happen in launching an intercontinental ballistic missile: Doors of launch silos might have malfunctions, in US plans that took out almost 10% of US ICBM's. Then in flight inertial guidance of missile could fail. Engine of missile could fail. Or finally near target another own nuke to nearby or same target could destroy that nuke, fratricide effect. Another thing that might worth considering is that practically no nuke had be targeted in civilian targets like cities, there is plenty of military targets in most of big cities. In New York Soviets identified dozen military targets: ports, air ports and railway stations and highways feeding those. Those all would be used in case of war by military logistics to move war material and troops to front lines. New York would have been wiped out in case nuclear war dozen or two dozen times just as collateral damage.
On even more basic kind there are two kinds of nuclear weapons: tactical and strategic. Strategic nukes are big and used against strategic targets. Tactical nukes are used against tactical targets like batalions in front lines, tactical nukes are normally far smaller than bombs used on Japan at end WWII. Those were about 12 (Hiroshima) and 20kt (Nagasaki) in yield. Typical tactical nuke is from 0.1kt to 1kt, biggest of tactical nukes are usually up to 10kt. Modern strategic nukes are from 100 to 750kt in yield. In 50's and 60's bigger bombs were made and tested, those become obsolete as missile accuracy has evolved.
Type of blast used would depend on type of target. There are basically five kinds of nuclear explosions: high altitude burst, air burst, partial ground burst, ground burst and subterranean burst. All of those have their own tactical application. Air bursts would be used against area targets like normal military bases, troop concentrations, logistical targets and cities in case of counter strike. Hard targets like leadership bunkers and nuclear missile bases would require ground blasts to destroy, those create always far worse radiological threat than air bursts as. Partial ground burst is something that would happen due to accidents, mostly weapon system failures, fire ball created by bomb would touch ground. High altitude bursts would be used against strategic communication, electronic sensor systems and electric networks, to destroy those or to disable those via electro magnetic pulse.
Back to fallout issues....
There is basically two radiological threats created by use of nuclear weapon. Initial radiation, it's very deadly but doesn't last for long. Basically staying in basemant for few hours or days, if you aren't in killed in blast, would make the difference in this case. Long term radiation is another matter, there weren't good modeling on how long term fallout would effect on life. Just more or less hypotetical studies, where scale of events could be anything from minor to apocalypse. Current knowledge over lethal doses of radiation is more or less spotty, as far as it has been proven some people die from certain radiation doses, others don't. That has gone that way in Hiroshima, Nagasaki and in Chernobyl. Most people would die from exposure, but there are some guys that were in reactor building in Chernobyl and are still very much alive. Reality is that we know that much that we don't really reliably know.
» Wed Aug 26, 2009 8:56 am 
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