Integrated head assembly of reactor pressure vessel, integrated head assembly unit of reactor vessel, and method of cooling control rod drive mechanism in integrated head assembly unit

摘要

An integrated head assembly (14) for a nuclear reactor pressure vessel (10) includes a closure head (20) with CRDM assemblies (22) extending upwardly from the head. A CRDM seismic support (24) disposed above the closure head (20) provides lateral support for the CRDM assemblies (22). The seismic support (24) also has air flow holes (60,62) which communicate with the interior of a shroud (32) enclosing the CRDMs (22) and extending upwardly from the closure head (20) to the seismic support (24). The shroud (32) has an air port (96) in direct air flow communication with the surrounding atmosphere, so that the closure head (20), shroud (32) and seismic support (24) define an air flow passageway directly communicating with the surrounding atmosphere via the air port and without the extensive ductwork and, therefore, with substantially less pressure drop, thus requiring substantially less power. IMAGE