Abstract: At least one injector condenser (20) is used to supply secondary feedwater to the steam generator (1) during a phase in the course of which the temperature and the pressure of the coolant of the reactor coolant system (2) of the nuclear reactor are varied between hot shutdown conditions of the nuclear reactor and conditions making it possible to bring into service the residual heat cooling system (RRA). The injector condenser (20) is fed with steam withdrawn from an upper part of the steam generator (1), at a first inlet, and with feedwater from a storage tank (10), at a second inlet. High-temperature pressurized feedwater is supplied to the steam generator (1) by means of one injector condenser (20) outlet. The steam generator (1) is fed without using an additional pump for withdrawing feedwater from the storage tank (10) and for injecting feedwater into the secondary part (3) of the steam generator (1).

Abstract: At least one injector condenser (20) is used to supply secondary feedwater to the steam generator (1) during a phase in the course of which the temperature and the pressure of the coolant of the reactor coolant system (2) of the nuclear reactor are varied between hot shutdown conditions of the nuclear reactor and conditions making it possible to bring into service the residual heat cooling system (RRA). The injector condenser (20) is fed with steam withdrawn from an upper part of the steam generator (1), at a first inlet, and with feedwater from a storage tank (10), at a second inlet. High-temperature pressurized feedwater is supplied to the steam generator (1) by means of one injector condenser (20) outlet. The steam generator (1) is fed without using an additional pump for withdrawing feedwater from the storage tank (10) and for injecting feedwater into the secondary part (3) of the steam generator (1).

Abstract: The device for providing an emergency electrical supply comprises a fuel cell (2) supplied with hydrogen and with air or even with pure oxygen from special compressed air and hydrogen systems of the nuclear power station or from special oxygen systems. It may also be produced in the form of a hybrid system comprising the fuel cell (2) and a supercapacitor plant placed in parallel or in series with respect to the fuel cell and via a suitable interface (chopper, for example). The fuel cell may be a cell of the PEMFC type. The fuel cell may in particular provide the electrical supply to the motor of a pump for injecting water into the seals of a primary pump of a pressurized-water nuclear reactor. It may also be used for the purpose of supplying certain monitoring and control systems of the nuclear power station should the normal supply to these systems be lost. The power of the systems according to the invention may reach 500 kVA.

Abstract: The method consists in removing the cooling fluid of the primary circuit, and, as a function of the cooling fluid concentration, in passing either all of the cooling fluid into at least one electrodialysis module, or only a part of the cooling fluid into the electrodialysis modules and the other part towards at least one reverse osmosis apparatus, in adding to the cooling fluid, when it leaves the primary circuit, an additive to promote dissociation of the boric acid, and in then returning the cooling fluid into the primary circuit.

Abstract: Device for condensing steam under pressure consisting of a unit incorporating a storage vessel (6) containing cooling water, a distribution and heat exchange unit (15) fixed inside the storage vessel (6) and a water supply (30,31) for replacing the water in a storage tank (6) which is vaporized by contact with the tubes (24) of the distribution and heat exchange unit (15). A stack (7) is connected to the upper part of the storage vessel (6) and a tranquilizer grid is arranged in the storage vessel, above the heat exchange unit (15). The circulation of the fluid which is constituted of a two-phase mixture of water and steam is thus activated, while avoiding drawing out a significant quantity of water with the steam.

Abstract: Intrinsically safe emergency cooling device for a pressurized-water nuclear reactor, comprising an auxiliary circuit which feeds the steam generator and in which is arranged a condenser (10) receiving the steam from the generator and condensing it. The condensate is returned to the steam generator by means of gravity. The device also incorporates a passive adjustment means comprising an adjustable valve (21), a cylinder (23), the chamber of which communicates with the steam pipe (7) and contains a piston (33), and a coupling means (32) between the piston (33) and the shut-off element (30) of the valve (21). The feed rate of the steam generator and the cooling power of the condenser (10) can be regulated in this way.

Abstract: Modular ultrafiltration device for the cooling liquid of a nuclear reactor, comprising a radiation absorbing containment (1), an ultrafilter (15) arranged in the containment (1), a heat exchanger (32) placed in the containment (1), and connection pieces intended for the various parts of the ultrafilter (15) and heat exchanger (32) and passing through the wall of the containment (1) in a leak-proof manner. A heat-insulating material (41) fills the inner volume of the containment (1). The modular device can easily be connected to an auxiliary circuit of the nuclear reactor. The ultrafiltration wall can be replaced without any difficulty.

Abstract: Device for the ultrafiltration of a pressurized high-temperature liquid, having, inside a pressure resistant casing (1), a second casing (11) to which are fastened tube plates (15,16) carrying tubes (14) forming an ultrafiltration wall, and a first set of partitions inside the second casing (11) for channelling the flow of the filtrate. A second set of partitions (27) arranged in the casing (11) above the upper tube plate (16) and partitions placed in the casing (1) underneath the lower tube plate (15) make it possible to channel the fluid to be purified and the concentrate. The part of the filter which incorporates the tubes (14) can easily be removed. The fluid circulates at a constant rate in all parts of the filter.

Abstract: Ultrafiltration circuit for the primary cooling fluid of a pressurized-water nuclear reactor, comprising a first loop (27) taken off from the discharge branch (10) of the volumetric and chemical monitoring circuit (8) and a second loop (28) taken off from the charge branch (11) of the circuit (8). Each of the loops (27, 28) incorporates an ultrafilter (30, 50). The concentrate from the ultrafilter (30) located on the first loop (27) is cooled, depressurized and conveyed into the chemical monitoring circuit (8) via a pipe (38) downstream of the main cooling and depressurizing device (12, 13) of the circuit (8). The concentrate from the ultrafilter (50) of the loop (28) is conveyed into the chemical monitoring circuit (98) via a pipe (58) upstream of the device (12, 13).

Abstract: Process and apparatus for ultrafiltration of the cooling water of a pressurized water nuclear reactor, during operation of the reactor. A fraction of the flow of pressurized water is withdrawn continuously in at least one cold branch (8) of the primary circuit (2). This withdrawn water is circulated, while it is still at the temperature and pressure of the primary circuit (2), in contact with the entry face of an ultrafiltration wall (40). The filtrate is withdrawn at a pressure which is less than 15 bars lower than the primary water pressure. The concentrate is kept in circulation with the entry face of the wall (40). The wall (40) can consist of an assembly of tubes maintained between two tube plates. The invention applies to pressurized water nuclear reactors whatever the number of primary circuit loops.

Abstract: The concentration of an acid in a weakly ionized aqueous solution, more particularly the concentration of boric acid in solution in demineralized water from the primary circuit of a pressurized water nuclear reactor, is modified by effecting simultaneously the dissociation of the acid and the electrodialysis of the solution using at least one electrodialysis membrane comprising a polymer support such as PTFE or FEP and having aminated groups introduced for example according to a process comprising a step of grafting.