Firstly, you will need to have a good sized area to work at, and second you will need a total of 3 diamonds, 36 gold ingots, 6 iron ingots, and 14 cobblestone.
In the center of the area, you will need to place 4 gold blocks on the corners of a 3x3 area in the center of your workspace like so:

Next, fill the spaces in between the gold blocks with cobblestone like so:

On the top of the 4 gold blocks, place 4 more cobblestone:

To make the nether reactor core you will need 3 diamonds, and 6 iron:

Place your nether reactor core in the center:

Place 1 cobblestone on the top of the nether reactor core:

On the 4 sides of that, you will need to place 4 more cobblestone so it looks like a +:

Once that is done, you now have your nether reactor. To activate it, simply click on it.
When the nether reactor is activated it will spawn pigmen, and a few items such as mellons, glowstone, and other items for a short amount of time. The casing of the reactor is made of obsidian, and it is recommended you build only 1 per world.
Unfortunately, I can not post a picture to show what it looks like seeing as how I am short on materials. Missing a little gold, I have more than enough diamonds.
Anyway, I am sure someone from here can post a picture showing the nether reactor when activated. But that's the lesson for today, hope you guys enjoy the update. Good luck with your adventures!
The aftermath:
This picture was taken from over 20 blocks away:

This picture was taken less than 10 blocks away:

Please note, this was only after using 1 nether reactor. This is not something you want to do close to home.









