Method and means for abruptly terminating the flow of fluid in closed fluid circulating systems of nuclear reactor plants or the like

摘要

A nuclear steam supply system wherein each of a plurality of centrifugal pumps begins to operate with full cavitation in response to an abrupt drop of system pressure in the event of leakage. This is achieved by influencing the net positive suction head of each pump over the entire range of fluid flow and/or by influencing the net positive suction head upstream of the pumps. The first mode of causing the pumps to operate with full cavitation includes an appropriate selection of the inlet angle and/or inlet diameter of pump impeller, or the provision of suitably curved guide vanes in the pumps. The second mode includes interrupting the admission of undercooled fluid into the system upstream of the pumps.