The thruster has a cryptic description about how it's dangerous if you run out of power. I tried forcing that on a world and well... Nothing happened.
Is this a feature that's gonna be available in the future? Or is it just not working for me?

If it is gonna be in the future I expect a huge explosion, it would look amazing.

The benefit of the Promethium Thruster is extra speed and better fuel efficiency. The balance is meant to be "next level" for Vanilla Factorio, so it doesn't make you go Warp 9. I've had ships up to 600km/s without thruster stacking.

If the thruster loses power, the containment field that contains the Promethium radiation fails. Then the surrounding entities take about 1-2 damage per second. Again, "next level" difficulty". If the thruster does get destroyed, yes there is an explosion that does additional explosion damage to surrounding entities. It's not a huge nuclear explosion, but it hurts if you have the whole back of your ship lined with exploding thrusters.

I may put in a difficulty setting to dial this up in future releases.

Hm. Well then it didn't do anything on my save. What radiation method does it use? Cause I have that mod that removes spoilage and it might spawn an item that uses that spoiling radiactivity system. If that is the case I'd need to have it's ID so I can make it an exception for that mod and let it explode and deal radiation damage.

That's what's breaking it. Radiation uses the spoil mechanic to control timing and damage. The thruster should still explode when health reaches zero.

I know... So I am once again asking, what id do the items that are used to trigger the explosion and the radiation have? If they use the unstable isotope and one of the basic ores I have already made them spoilable but I haven't yet tested if those are the ones

name = "hidden-radiation-source",

Thank you