The New Nether Reactor Core!

It will be like a lava/nether conduit. The NRC can be crafted with a "Concentrated Heat Core" (more on that later) in the middle of the crafting grid, with 4 gold blocks in the top, bottom and sides, and 4 Ancient Debris at each corner. The NRC needs to be submerged in lava, or atleast be surrounded on every side and corner of it. Just like the Conduit, it needs to be surrounded by some specific blocks to strengthen it's power. The block that it will need is Copper. Since Copper is a pretty good heat conductor and it gives more use to the new ore. The NRC will create a 50x50 area where you are completely fireproof. Adding more Copper Blocks to it will make the lava clearer and will start to hurt nearby hostile mobs. A fully powered NRC will allow you to swim in lava, with the same speed as in water. The Concentrated Heat Core can be found inside a deep pit in the Soul Sand Valley, submerged in lava. It only has a 25% chance to generate inside the biome. The Pit is heavily guarded by Skeletons with armor, bows and Iron Swords. The idea is that the CHC sucked out almost all of the lava in the Soul Sand Valley, and it became so dense, that it sinked down to near bedrock. The textures for the CHC would be like an extremely bright yellow block with some bright orange sunspots pulsating. The Nether Reactor Core would have a similar texture to the OG thing, except for some colour changes.