Man where did you study physics, water has a heat capacity of 4.2 joules per gram per degree C, a 200W kettle can boil 1L of water (from 30C-100C) in about 20mins
1Wh = 3600J
... assuming
zero heat transfer into the surrounding air. Which, in case you missed it, is not how reality tends to work. So ... maybe you should have paid more attention during physics class? Also:
boiling is not equal to water temperature being 100°C.
Boiling means
rapid phase change (above the general evaporation of water into ambient air, which is also temperature dependent but happens even at freezing temperatures). Bringing water up to ~100°C is not sufficient to boil it - you need significant excess energy to tip it over the phase change threshold. As temperatures rise, water evaporation would increase, which would slow temperature rise as said evaporation dissipates heat into ambient air - and evaporation also drives convection, causing airflow around the water and container, further increasing thermal transfer. And, of course, as thermal deltas increase, water-air thermal transfer would also increase. The hotter the water got, the more of its heat would be transferred into the air, and the more energy you would need to put into the system to heat it up further. Would this reach equilibrium for a 200W heat source before boiling? That depends on the container, ambient air temperatures, and a bunch of other variables. In a sufficiently sealed container it would
eventually boil with a 200W heat source, sure, but it would take
ages unless it was covered in thick insulation.
Yup, and the heat dissipation at the radiator is more efficient the higher temp difference between ambient/coolant, that's why 120mm AIO can even cool 300W GPU but the coolant will reach higher temp at equilibrium.
Which in turn points back to the problem (if it really is a problem) with these chips: high thermal resistance and a resulting low ability to get said heat into the cooling system while keeping the chip at low temperatures (unlike GPUs, with their low thermal density and direct die cooling).
That being said, with coolant temp at above 60C, lots of things can go wrong.
That's true - both plastics and pumps can fail at those temperatures. But again, for that you need efficient thermal transfer
from the heat source - excactly what these CPUs lack. The exact reason why the CPU reaches 95°C is that it
isn't transferring its thermal energy efficiently into the cooling loop - so water temperatures will be quite low.
I have doubts you could make it explode even without fans on the radiator to aid in the cooling because the CPU is designed to throttle anyway plus it also will shut off if a certain temp is exceeded. There damn near no way you could make AIO explode with pretty much any CPU w/o it being deliberate user error. You could have a leak, but that is a different can of worms.
Water does like to evaporate even at freezing temperatures, but AFAIK that requires it to actually be in contact with air (i.e. it doesn't spontaneously transition into gas if in a closed, air-free container). Beyond that, 95°C is below 100°C, and thus
can't boil water, and according to
this, propylene glycol additives
increase the boiling point of coolants. So no, there would under no circumstances be any explosions or pressure-related leaks.