This is a simple explosion. Only particle system and some lines of code. The ball has been scatter in several pieces and then instance all pieces to the initial particles.

A incandescence as been added through a ramp shader.

Inside of the particleCoudShader I put the Diffuse Coefficient to 0, and even with this option turned off, the render took me about 15min each frame with mental ray.

With the Diffuse Coefficient put to 1, translucence coeff to 0.15 and Surface shading shadow turned on the render took about 4h each frame, but the result can be very realistic, but is not a efficient way to do the render.