Abstract: Power generating plant which comprises a heat source, at least one main steam turbine and at least one main boiler heated by heat from the heat source and providing the steam to drive the turbine, comprises additionally at least one further steam turbine, smaller than the main turbine, and at least one further boiler, of lower capacity than the main boiler, and heated from the same heat source and providing steam for the further turbine.Particularly advantageous in nuclear power stations, where the heat source is a nuclear reactor, the invention enables peak loads, above the normal continuous rating of the main generators driven by the main turbines, to be met by the further turbine(s) and one or more further generators driven thereby. This enables the main turbines to be freed from the thermal stresses of rapid load changes, which stresses are more easily accommodated by the smaller and thus more tolerant further turbine(s).

Abstract: In a nuclear-reactor power-generating installation having a main and an auxiliary steam-generating boiler, both arranged to receive heat from the reactor core (for example by circulation of reactor coolant gas), and having a turbogenerator which includes a multistage steam turbine through whose stages the steam from the main boiler passes in sequence, there being a steam reheater unit connected between two of the stages to provide reheating of the steam from the main boiler, the invention provides that the auxiliary boiler is connected to supply to the reheater unit steam which reheats the said steam from the main boiler.

Abstract: In a water-cooled pressure-tube reactor in which each fuel-containing pressure tube is included in one of two main coolant circuits each of which comprises a bottom header supplying coolant water to the pressure-tube lower ends, a steam drum to which the pressure-tube upper ends are connected, main circulator means pumping water from the steam drum to the bottom header, further pump means pumping an auxiliary coolant water flow from the steam drum of each coolant circuit directly into the pressure tubes of that circuit in the form of spray cooling in such pressure tubes, with the bottom headers of the two circuits interconnected and main feedwater pumps supplying make-up water to the steam drums to replace generated steam, the invention provides, between the main feedwater pumps and the steam drums, water inlet valves which are controlled by pressure in the coolant circuits and are arranged to close in response to a fall in such pressure, and also provides further connections arranged to supply feedwater dire

Abstract: In a nuclear reactor installation comprising a fluid-cooled nuclear heat source within a primary pressure vessel, this latter and also auxiliary facilities including new and spent fuel stores are enveloped together within an outer envelope which is designed to afford protection from external missiles; but within this envelope the auxiliary facilities are isolated from the primary pressure vessel by pressure tight structure which, with the major part of the outer envelope, constitutes secondary containment means of the installation.

Abstract: A protective arrangement for a cooling system of the kind in which a fluid, which may be in the form of a liquid, gas, vapor or a two-phase fluid, is arranged to be circulated around the system under pressure, said protective arrangement comprising means for injecting into the system fluid under pressure for maintaining a flow in the normal direction through a region of the system, or for preventing cessation or reversal of flow through said region, for a period following a reduction in the pressure of the normal circulating fluid feeding said region, which may be due for example to a breach in a part of the system upstream from said region.

Abstract: A gas-cooled nuclear reactor has a main circulatory system for the gaseous coolant incorporating one or more main energy converting units, such as gas turbines, and an auxiliary circulatory system for the gaseous coolant incorporating at least one steam generating boiler arranged to be heated by the coolant after its passage through the reactor core to provide steam for driving an auxiliary steam turbine, such an arrangement providing a simplified start-up procedure also providing emergency duties associated with long term heat removal on reactor shut down.