“
Because of the extreme heat fission generates, the reactor core must be kept cool at all costs. This is particularly important with an RBMK, which operates at an, “astonishingly high temperature,” relative to other reactor types, of 500°C with hotspots of up to 700°C, according to British nuclear expert Dr. Eric Voice. A typical PWR has an operating temperature of about 275°C. A few different kinds of coolant are used in different reactors, from gas to air to liquid metal to salt, but Chernobyl’s uses the same as most other reactors: light water, meaning it is just regular water. The plant was originally going to be fitted with gas-cooled reactors, but this was eventually changed because of a shortage of the necessary equipment.75 Water is pumped into the bottom of the reactor at high pressure (1000psi, or 65 atmospheres), where it boils and passes up, out of the reactor and through a condensator that separates steam from water. All remaining water is pushed through another pump and fed back into the reactor. The steam, meanwhile, enters a steam turbine, which turns and generates electricity. Each RBMK reactor produces 5,800 tons of steam per hour.76 Having passed through this turbogenerator, the steam is condensed back into water and fed back to the pumps, where it begins its cycle again.
”
”
Andrew Leatherbarrow (Chernobyl 01:23:40: The Incredible True Story of the World's Worst Nuclear Disaster)