Final answer:
The principal controlling components of the pressurization system in a pressurized water reactor are the condenser, steam generator, and reactor, while the containment structure is not a principal controlling component.
Step-by-step explanation:
In a pressurized water reactor, the principal controlling components of the pressurization system are the condenser, steam generator, and reactor. The condenser and steam generator are responsible for converting the heat produced by the fission reaction in the reactor into steam for generating electrical energy. The reactor itself is designed to control the fission process and adjust the neutron flux using control rods. These components work together to maintain the desired pressure and criticality in the reactor.
However, the containment structure is not a principal controlling component of the pressurization system. Its main function is to house the radioactive water in the reactor and prevent it from mixing with the nonradioactive water in the condenser and steam generator. While an important safety feature, the containment structure does not directly control the pressurization process.