Simulating in optimized massive explosion without crashing the game?

I want to make an ability that makes a giant explosion that spans across like 300 blocks. Using the explosion prodecure block however crashes at around 150 explosion power which is not sufficient. For example, the draconic evolution reactor explosion minus all the cool effects. Here's a video of that, Draconic Evolution - Draconic Reactor Meltdown (youtube.com)