Patent ID: 7158605
Filing Date: 2007-01-02
Classification: G21C,Y02E

Abstract:
1. A head assembly for a reactor pressure vessel, comprising: a reactor pressure vessel closure head; a seismic support platform spaced from the closure head; an array of control rod drive mechanisms, each control rod drive mechanism including an electro-magnetic coil stack assembly and having a lower end supported by the reactor pressure vessel and an upper end extending through the seismic support platform; a lower shroud surrounding the electro-magnetic coil stack assemblies and having an upper end spaced from the seismic support platform in air flow communication with the atmosphere around the control rod drive mechanisms; a plurality of internal ducts disposed between control rod drive mechanisms within the array of control rod drive mechanisms, each duct having a lower end extending below the electro-magnetic coil stack assemblies and in air flow communication with the lower shroud and each duct having an upper end extending above the seismic support platform; an upper plenum disposed above the seismic support platform having inlet air openings in air flow communication with the upper ends of the internal ducts; a missile shield assembly disposed within the upper plenum, the missile shield having a plate superposed over and spaced from the inlet air openings of the upper plenum in air flow communication with the upper ends of the internal ducts; a plurality of fan assemblies disposed on the upper plenum in air flow communication with the upper plenum; and lift legs connected with the reactor pressure vessel closure head and supporting the seismic support platform, the upper plenum and the missile shield assembly for removal of the head assembly as an integral assembly.