3710 Reactor Pressure Vessel

Components of RPV

• Reactor Vessel

• Reactor Core

• Fuel Assemblies

• Control Rods

• Core support

• Inlet and outlet nozzles

• Internals

Reactor Vessel

• Steel pressure vessel that houses the reactor core and coolant

Reactor Core

• Contains the nuclear fuel assemblies where fission occurs and heat is generated

Fuel Assemblies

Hold the nuclear fuel rods containing uranium fuel.

Control Rods

• Absorb neutrons to regulate reactor power

• Can shutdown chain reaction

Reactor Vessel head

• Top closure that seals with penetrations for control rods

Primary flow paths of coolant through RPV

• Enters RPV through cold leg inlet nozzles

• Coolant goes between the reactor vessel wall and the core barrel

• Flows upward through the core to remove heat from fission

• Exits through the hot leg to the steam generators

Secondary flow paths through RPV

• Portion of coolant goes through upper internals around fuel assemblies and rods

• maintains circulation and cools internals

Upper internals

• Support and restrain core and fuel assemblies

• Guide rods into fuel assemblies

• direct coolant

Lower Internals

• Distribute coolant upward through core

• support for core barrel, fuel

Upper RPV Head enetrations

• Allow rod to enter vessel and positions them

• Thimbles help guide

Lower RPV Head Penetrations

• Access to neutron flux detectors, and other instrumentation that monitor conditions

Reactor coolant pump plywheel

• Stores rotational energy

• Allows the pump to slow even after a loss of power

• Maintains circulation during coatsdown

• Ratchet prevents reverse circulation