well, the idea wasn't bad, it only had severe technical issues
I think that radiation is, by itself, a very bad idea already.
This is not DF, turning a 2 and a half kilometer area into nuclear-powered Mordor is not acceptable.
Nuclear weapons do not leave behind radiation in the man-killing doses that people expect them to. Hiroshima is entirely livable today, in terms of radiation; it's only marginally above background in a few areas, and that only to the point where you don't want to eat something you find on the ground there. Plus, the W54 was a ten-ton-yield pony nuke and didn't particularly spread a whole hell of a lot. The system was worth exploring; propellant and small-scale rocketry just didn't exist to the necessary degree to be effective.
(The Chornobyl installation--not the area cordoned off around it, most of that's cordoned off to err on the side of caution, but the inside of the installation itself--has a higher radcount today than Hiroshima did a year after it was hit by a bomb. Radiation sucks if you're there while it's emitting--not a huge deal afterwards. Leaks of radiated coolant water, etc. from a fission reactor are far more dangerous than the leftovers from a nuclear bomb. Even less so today. Thermonuclear fusion weapons are astonishingly clean.)
Isn't Chornobyl more recent than the Hiroshima bombing, though?
Yes, but that's not particularly relevant to the comparison, especially given that most fissionable elements have half-lives that are geometric on scales well beyond human historical timeframes. Nuclear bombs do one thing: release a shit-ton of energy. That energy doesn't stick around and wait for decades--it
goes really fast and really far away and that's essentially the end of it.
Somebody who managed to be blast-shielded, but not rad-shielded, at Ground Zero of a nuclear explosion would be cooked by the radiation. A couple days later, he'd need treatment for moderate radiation poisoning. A week later, he's going to have a marginally increased rate of some types of cancer if he sticks around for a prolonged period of time.
Calling BS.
1) The claim that "OMG, UR IN THE BLAST RADIUS" has always been false. If one would take a Davy, with its max strength warhead, and set it for minimum distance, the crew would get a lethal dose. Of course, why the bloody hell would one do such a thing? Discounting some CMOA worthy final stand. Hypothetically, could one pull the pin on a garden variety fragmentation grenade and cook it off enough so it'd blow a foot away from your face? Sure. Same principle here.
You could easily avoid the 5,000 or so rems it would take to instantly kill someone if you used it properly but even 25 - 50 rems could ruin your life with endless medical complications.
Factually effing inaccurate. Nuclear workers can be exposed to up to fifty rems per year. The only major physiological result of a fifty rem dose
all at once is a temporarily depressed white blood cell count. You don't hit LD 50/30 for radiation until between 3 and 4 Sv (300-400 rem). "Yeah you're fucked" starts between 6 and 9 Sv, depending on body size, condition, and speed of exposure.
Time for some back-of-the-envelope calculations: setting aside all blast effects, a kiloton nuclear (non-neutron bomb; those are a whole different story) explosion delivers about 8,000 rems to people at 500 meters (8,000 rems being the magic "fried" number, thereabouts). A ten-kiloton detonation won't increase linearly, it's somewhat less--call it 80,000 rems. The effective dosage attenuates by a factor of 0.1 per 500 meters of air. If you're two klicks away, we're talking about 80 rem--less if you can find some kind of cover. You will not feel good, but you won't be rocking the bone marrow transplants.
Nothing particularly crazy about this method of delivery - the only problem was a lack of completely safe delivery system - the projectile was too heavy thanks to the warhead, there wasn't enough room for enough propellant to take it that far. As Strife mentioned, though, it wasn't a weapon for regular use - it was a weapon for frying entire tank battalions in case the Soviets tried to roll into Europe. It was a "we're fucked" button.
As for Chornobyl, the accident is fairly complex. They were testing the external power loss safety features of the reactor. They were trying to see if the steam emission from the reactor could power the coolant pumps of the reactor in the time it took for the diesel backup generators for the reactor to run up to full power. They tried shutting off the steam to the turbines suddenly in the test, and the water flow slowed enough that steam voids occurred in the coolant flow. That made the reactor run hotter (emitting more energy), which created more steam voids, and so on. The reactor counteracted this by inserting control rods part of the way into the core, but user error resulted in a full scram of the reactor and the coolant rods were inserted all of the way. The control rods were badly designed, and their structure
increased the output of the lower half of the core. The fuel rods shattered, locking the control rods, and the whole thing went "pop".
It should be noted that in modern (see: not AAA-Plus Best Soviet Special) reactors, this quite literally cannot physically happen. The worst result from a modern reactor failure is close to Three Mile Island: a few fish might glow as it does a release of radiated water, but it won't--it physically
can't--go boom.