Abstract: Provided is a modular reactor head area assembly. The modular reactor head area assembly is installed on a reactor head, and includes: a seismic support structure that performs functions of lifting, moving and reinstallation of the reactor head and control rod driving apparatuses, cooling of the control rod driving apparatuses, shielding of missile parts, and supporting with respect to a seismic load, and disperses a load applied to the control rod driving apparatuses; an upper module that is an assembly of components located at an upper portion of the seismic support structure for the control rod driving apparatuses; and a lower module that is an assembly of components located at a lower portion of the seismic support structure for the control rod driving apparatuses. The upper module and the lower module are 252 detachably coupled to each other so that maintenance of the control rod driving apparatus can be performed easily.

Abstract: Provided is a modular reactor head area assembly. The modular reactor head area assembly is installed on a reactor head, and includes: a seismic support structure that performs functions of lifting, moving and reinstallation of the reactor head and control rod driving apparatuses, cooling of the control rod driving apparatuses, shielding of missile parts, and supporting with respect to a seismic load, and disperses a load applied to the control rod driving apparatuses; an upper module that is an assembly of components located at an upper portion of the seismic support structure for the control rod driving apparatuses; and a lower module that is an assembly of components located at a lower portion of the seismic support structure for the control rod driving apparatuses. The upper module and the lower module are 252 detachably coupled to each other so that maintenance of the control rod driving apparatus can be performed easily.

Abstract: The invention provides: (1) a modified hydrogenase obtained by removing electron-transfer sites from a hydrogenase constituted of: active subunits including active sites having a hydrogen oxidization-reduction activity; and electron-transfer subunits having the electron-transfer sites through which electrons are transferred between the active sites and the outside of the hydrogenase; (2) a modified hydrogenase obtained from a hydrogenase, wherein when the hydrogenase is isolated from bacteria that produces the hydrogenase, a process for exposing the hydrogenase to an oxygen atmosphere is executed; (3) an enzymatic electrode made of at least one of the foregoing modified hydrogenases; and (4) a hydrogenase modification method including: a step of isolating from hydrogenase-producing bacteria; and a step of removing the electron-transfer sites of the electron-transfer subunits from the hydrogenase by exposing the hydrogenase to an oxygen atmosphere.