What type of reactor operates with a water coolant at approximately 150 atmospheres?

The pressurized water reactor (PWR) is designed to operate with water as its coolant at high pressure, typically around 150 atmospheres. This high pressure prevents the water from boiling, allowing it to transfer heat efficiently from the reactor core to a secondary system, where steam is generated to drive turbines for electricity production. The PWR uses this configuration to maintain a stable reactor environment and effectively manage the heat produced during fission.

In contrast, other reactor types operate under different principles. The boiling water reactor, for instance, allows water to boil in the reactor core, generating steam directly within the system, which is not suitable for operating at such high pressures. Gas-cooled reactors utilize gas rather than liquid coolant, and breeder reactors focus on creating more fissile material than they consume, often using liquid metals as coolant. Therefore, the characteristics and operating principles of the PWR make it the type of reactor that specifically uses water coolant at approximately 150 atmospheres.