An insurmountable amount of nearly 600C steam comes out from refinery when destroyed

Same here it occur when output pipe broke then all excess coolant will be trapped. dupe still continue to operate even output pipe is broken causing hot coolant to built up.

Changed Status to Known Issue

Changed Redmine to https://redmine.klei.com/issues/4413

That's a whole heck of a lot of steam. Katsunari is correct, but even the "minimal" amount of 400kg of coolant would be too much! Thanks for reporting this.