If yeu look at the actual information on stuff like 3 mile island and chernobyl though, these 'accidents' weren't really all that accidental, and took alot of effort to force them to occur, and/or were using very old crappy designs.
The current models are designed in such a way that it's not physically possible for them to "melt down"; the only real risk is honestly someone getting ahold of used control rods, which's more a terrorist situation than anything else, and wouldn't be dangerous in a large scale, due to the nature of that material.
Nuclear reactors are currently some of the cleanest, and safest of methods of creating electricity at the moment.
Religion, however, has actually killed more people in total, and tends to account for full blown active attempts to cause a genocide. Technology may provide tools to do so, but if we just had rocks and the name of god, that's all we'd need to try to do it anyway. The tools just make it easier is all.
As for Noz, keep in mind that a singularity with the power to sustain itself does not mean it's powerful enough to actually 'do' anything of value.
The definition of a black hole is just one at which the density is higher than a specific value relative to its' volume.
I'll just steal a quote from wikipedia because they say it fairly clearly:
The Schwarzschild radius (sometimes historically referred to as the gravitational radius) is a characteristic radius associated with every quantity of mass. It is the radius of a sphere in space, that if containing a correspondingly sufficient amount of mass (and therefore, reaches a certain density), the force of gravity from the contained mass would be so great that no known force or degeneracy pressure could stop the mass from continuing to collapse in volume into a point of infinite density: a gravitational singularity (colloquially referred to as a black hole).
The Schwarzschild radius of an object is proportional to the mass. Accordingly, the Sun has a Schwarzschild radius of approximately 3 km,[3] while the Earth's is only about 9 mm, the size of a peanut.
Meaning that if yeu had something as massive as the entirety of the entire planet earth... compressed small enough to be considered a black hole... it would have a radius of 9 mm.
Even *IF* they somehow managed to make a sustained black hole, it wouldn't have enough mass to actually draw in anything more than a few nanometers away, and that additional mass wouldn't increase its' gravitational force enough to pull in anything farther away than it already had.
In short, yes, they could make a black hole, it's highly unlikely, but they could. If they did, it wouldn't really matter though because it wouldn't be the 'infinite gravitational anomaly' we've come to associate the term with... it just literally wouldn't have enough mass to even move an atom via gravity alone, in comparison to the neccesary amount required to overpower the gravity of the rest of the earth.
Seriously, let's take a baseball for an example. Are yeu worried about a baseball's gravity being strong enough to move even a pebble from the ground next to it? No, because the friction is way stronger than the gravity output of the baseball. If yeu make the baseball smaller, but leave the mass the same, it still has the same identical force of gravity... the only difference being that *IF* something happens to touch it, it'll stick. Considering how ridiculously tiny the event horizon of a sub-atomic sized black hole would be... (smaller than the radius of an atom...), it would be pretty difficult to even have anything actually fall within that radius in the first place, and even if something did, it wouldn't increase the mass enough to increase the event horizon far enough for it to pick up anything else.
So anyways, if they made a black hole, it wouldn't suck the entire planet into it by any stretch of the imagination; best it would do is maybe manage to suck in a few dozen atoms, and then it wouldn't have the strength to move anything else, and would just sit there. Maybe the rare neutrino would bump into it and over millions of years it would grow large enough to have a miniscule effect on its' surroundings. The sun would burn out long before it ever had the time to grow to any size of worry.
In short, I'd be more concerned about the sun dying in a few billion years, because even if a black hole is made from the LHC, it'll take longer than that to even be noticeable.
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