France has upped the ante in the quest for fusion power by maintaining a plasma reaction for over 22 minutes – a new record. The milestone was reached on February 12 at the Commissariat à l'énergie atomique et aux énergies alternatives (CEA) WEST Tokamak reactor.
The walls get hot, you absorb the heat from the walls with a fluid. You use the fluid to heat water, you use the steam to drive a turbine, you use the turbine to turn a permanent magnet inside of a coil of wire. In addition, you can capture neutrons using a liquid metal (lithium) which heats the lithium, which heats the walls, which heats the water, which makes steam, which drives a turbine, which generates electricity.
If you poured water onto them they wouldn’t explode. 100 million degrees Celsius doesn’t mean much when the mass is so low compared to the mass of the water.