Pressurized water reactor with upper vessel section providing both pressure and flow control

摘要

A pressurized water reactor (PWR) includes a vertical cylindrical pressure vessel having a lower portion containing a nuclear reactor core and a vessel head defining an integral pressurizer. A reactor coolant pump (RCP) mounted on the vessel head includes an impeller inside the pressure vessel, a pump motor outside the pressure vessel, and a vertical drive shaft connecting the motor and impeller. The drive shaft does not pass through the integral pressurizer. The drive shaft passes through a vessel penetration of the pressure vessel that is at least large enough for the impeller to pass through.

主权项

1. A pressurized water reactor (PWR) comprising:
a cylindrical pressure vessel with its cylinder axis oriented vertically; a nuclear reactor core disposed in the cylindrical pressure vessel; a separator plate disposed in the cylindrical pressure vessel that separates the pressure vessel to define an integral pressurizer containing a pressurizer volume disposed above the separator plate and a reactor vessel portion defining a reactor volume disposed below the separator plate and containing the nuclear reactor core, wherein the separator plate restricts but does not completely cut off fluid communication between the pressurizer volume and the reactor volume; a hollow cylindrical central riser disposed concentrically with and inside the cylindrical pressure vessel in the reactor volume wherein a downcomer annulus is defined between the hollow cylindrical central riser and the cylindrical pressure vessel; a reactor coolant pump including an impeller disposed inside the pressure vessel in the reactor volume, a pump motor disposed outside of the pressure vessel, and a drive shaft operatively connecting the pump motor with the impeller, wherein the impeller, pump motor, and drive shaft are secured together as a unitary pump assembly; a pump diffuser containing the impeller; an annular support plate disposed below the separator plate and having a central opening coinciding with the hollow cylindrical central riser, the pump diffuser mounted on the annular support plate and not secured with the unitary pump assembly, the annular support plate defining a pressure divider separating suction and discharge sides of the pump diffuser; wherein the drive shaft passes through an opening in the pressure vessel that is at least large enough to pass the impeller; and wherein the impeller of the reactor coolant pump is configured to impel coolant water downward into the downcomer annulus.