FIXING STRUCTURE OF INTERNAL PUMP

PURPOSE:To provide a fixing structure of an internal pump which can prevent mutual interaction by preventing the relative displacement between a pump impellar and a diffuser, sufficiently maintain the pump function and on the other hand, has superior earthquake-resistance and large stiffness. CONSTITUTION:In the fixing structure of an internal pump 15 to the periphery of the lower end plate 1a of a reactor pressure vessel 1, a stub 28 is projected from the periphery of the lower end plate 1a of the reactor pressure vessel 1 and on this stub 28, a diffuser 31 constituting the pump part 18 of the internal pump 15 is placed. The axial length of the stub 28 are made nearly equal over the periphery of the stub.