A Question for people prepping ‘END OF TIMES’ type catastrophe.

I fully support people being prepared for events that could ‘disrupt’ civilizations day to day, (i.e. earthquake, whatever) and having a few weeks of food and water on hand.

That said, I wonder if the idea of preparing to the extent of having seeds for planting/harvesting, years of stored food, etc planning to basically 'come out of hiding' after things settle down, (i.e. most people are dead) is really something that will protect ‘civilians’ in the case of a worldwide disaster, (Elenin, Nibru, super volcano, solar flare etc, etc)?

This is a serious question, not a trolling or bashing post, I am honestly curious.

Let’s say ‘something’ causes massive damage in the world that wipes out massive numbers of people, renders technology basically unusable and totally pushes us back to survivalist mode. Ok now some people who have prepared for such an event and survived the initial apocalypse might think they have a fighting chance right?

But what keeps pushing itself into my head is the situation with Fukushima. One plant has some trouble and the effects are massive and likely will be felt for many years to come. And this was with a mostly operational Japan and world 'trying' to prevent a full disaster.

Back to our catastrophe; what would happen when every single nuclear reactor on the planet all basically go through an uncontrolled meltdown, followed likely by explosions at roughly the same time? The atmosphere is going to become so irradiated as well as soil and most importantly water, both above and below ground for at a minimum of decades. Even the most remote parts of the world will feel the effects of this nuclear winter.

I would then think, really the only people who have a chance of surviving are going to be the ones living fairly deep underground in protected and sealed self sustaining habitats with the ability to hydroponically grow foods, recycle water, etc for a minimum of decades.

Now maybe that’s why all the bunkers? But really this question is for those who have/are prepping and are just an average Joe (or Jane), have you accounted for this nuclear winter factor?