The utility model relates to a field is equipped to the nuclear power, and an owner on conventional island of 1000MW level nuclear power station booster pump that feeds water specifically says so. Including the pump body, set up left pump cover and right pump cover at the horizontal both ends of the pump body respectively, left side pump cover and right pump cover have radial open dysmorphism respectively and lead to the water structure, and the suction chamber of semi -spiral shape is constituteed respectively to left pump cover and right pump cover with the pump body. Through the suction chamber that sets up semi -spiral shape, the effectual net positive suction head who has reduced main feedwater booster pump, the dysmorphism leads to the water structure and has the flow of fluid of messenger direction switching -over effect, and the fluid kinetic energy loss is less, has consequently had stability. Through setting up left pump cover and right pump cover, can open left pump cover orright pump cover under the prerequisite of not dismantling water supply pipe and drainage pipe, the interior other part of the easy access impeller or the pump body.