A nuclear-powered marine vessel is propelled by a pressurized water reactor (PWR) using enriched uranium-235 fuel. During steady cruising, the reactor maintains a constant thermal output, but during high-speed tactical maneuvers, the steam turbines demand a rapid increase in thermal power.
Explain:
- how the fission of uranium-235 is sustained as a continuous chain reaction to provide a constant source of power.
- how the physical movement of control rods is used to safely regulate the reactor's thermal output to match changes in operational demand, describing the process at the microscopic level.