Let's say we have a stellerator outputting a steady 200 GW of electrical power.

[cheater]

Let's say we have a stellerator outputting a steady 200 GW of electrical power. If someone dropped a conventional bomb / explosive / shell on it that was just enough to breach plasma containment, how much energy would be released, and what would the aftermath of this be? Assume a worst case scenario. Additionally, will any dangerous chemicals be released into the atmosphere?

I'm trying to compare this to a similar scenario in a typical nuclear power plant. My guess is that the plasma will quickly dissipate and there will be no large radius of destruction beyond what a conventional bomb could do, and that no radiation or dangerous chemicals will be released - but I have no idea how to even approach this sort of question.

PS I hope it's OK that I didn't put this in the renewable energy sub-forum, somehow I feel that wouldn't have been the best place for that sort of question.

[tom66]

Well, stellarators/tokamaks are "barely" stable with the building intact!!  And 200GW implies a seriously massive reactor building.

So assume the stellerator collapses from 200 GW to zero within five seconds then the energy released would be about 500 GJ, assuming a linear decrease in output power.   That is roughly 100 tonnes of TNT or about 20x less than the explosion in Beirut in Aug 2020.

I suspect you would need a lot more explosive power to break containment in the first place. 

A bigger risk might be the leakage of all the heavy water, which is toxic to most lifeforms in high enough doses, not sure if studies have been done on long term contamination of environments with that.