World Corrupts when there's a electricity shutdown (Seed reset to 0)

When you're playing in a world and the computer shutsdown by a electricity shutdown, minecraft detects the world as a creative world, and with seed 0.
If you're playing survival and this happens to you, when you re-enter the world and try to do an achievement, you won't get it. And if you try to generate new terrain, the world doesn't generate the terrain with the seed that you used before that happened.

How to reproduce:
1) Create a survival world.
2) Generate some terrain.
3) Cut off the power.
4) When you start again your computer, go to your worlds and see the world where you was, that world gets corrupted.