What's a nether reactor?

It is NOT a portal. Using a pattern of gold and cobblestone blocks, the reactor builds a 17x17x17 nether cube in which you are trapped while the thing spews out all kinds of resources like ingots, beds, glow stones, and zombie pigmen. The cube then slightly deteriorates and the reaction is over. The core can be used as many times as desired.

It's a single-use Nether Portal replacement. It takes you into the Nether as a replacement for Portals in the pocket edition, but since it can't be used it's much more costly and risky.

The pattern only work in the pocket edition 4 blocks of gold some cobblestone and 1 nether reactor core if you click on it this will trap/teleport you in a builded cube If you don't follow the pattern it won't take you where you get trapped in