Modular reactor head area assembly

A modular reactor head area assembly is provided to facilitate maintenance of a control rod driving device placed inside a reactor head area assembly by removing a part of the reactor head area assembly through a relatively simple disassembling process. A modular reactor head area assembly includes a top module(100) and a bottom module(200). The top module is an assembly of components placed at a top side of an earthquake-proof support for a control rod driving device. The bottom module is an assembly of components placed at a bottom side of the earthquake-proof support for the control rod driving device. The top and bottom modules are separated from each other to perform maintenance of the control rod driving device. The top module includes a top shroud shell(110) and a top baffle. The top shroud shell is formed in a shape of top and bottom opened cylinder. The top baffle is supported and fixed inside the top shroud shell and forms an air channel to cool the control rod driving device.