Abstract: A reactor pressure vessel with an upper support plate, in which an equalization opening is provided as a bypass is described. A process for temperature equalization between an upper dome chamber above a support plate and a lower chamber below it is described. It is proposed that the cross section of the equalization opening be variable as a function of the temperature, so that the flow of medium between the upper dome chamber and the lower chamber is varied as a function of the temperature.

Abstract: A reactor pressure vessel with an upper support plate, in which an equalization opening is provided as a bypass is described. A process for temperature equalization between an upper dome chamber above a support plate and a lower chamber below it is described. It is proposed that the cross section of the equalization opening be variable as a function of the temperature, so that the flow of medium between the upper dome chamber and the lower chamber is varied as a function of the temperature.

Abstract: A method for safeguarding discharge of residual heat from a nuclear power station reactor upon a lowered filling level in a primary circuit of a reactor cooling system, includes initially shutting down the reactor and running through an initial cooling and pressure reduction phase in the primary circuit. Then an aftercooling system is cut in for taking over heat discharge from the primary circuit, when heat discharge is no longer guaranteed by a steam generator plant. Then complete pressure relief and a lowering of the filling level in the cooling system to a mid-loop level of a main coolant conduit take place. A coolant reservoir is present for a required refilling of the primary circuit and aftercooling system.

Abstract: In the event of an incident in a pressurized water reactor with a safety feed and borating system, it is necessary that sufficient primary cooling water be available in the reactor cooling system or be resupplied, and it must also be possible to render the reactor subcritical with added boron and to maintain it in that state. The invention is a safety feed and borating system for a pressurized water reactor with series-connected safety feed and additional borating pumps. The additional borating pump is connected downstream of the safety feed pump and it has a parallel-connected bypass line with a check valve. Both pumps have a common minimum quantity line with different and reversible throttle restrictions. Thus the feed level and throughput of the entire system can be adapted optimally to existing demands. It is no longer necessary to provide a separate high-pressure borating system.

Abstract: A containment spray system for a light-water reactor includes a water trough being disposed in a safety tank. An immersion pump disposed in the vicinity of the bottom of the water trough, a spray branch and an outlet-side spray nozzle array, are connected to the water trough for injecting water into the containment in finely dispersed form in the event of an operational incident.

Abstract: A nuclear reactor, in particular a pressurized water reactor, has a containment, a containment shell surrounding the containment and a concrete construction of a reactor building surrounding the containment shell. A heat dissipation system for the nuclear reactor includes a sump volume disposed in a lower region of the containment shell for receiving coolant. A sump cooler is disposed inside the sump volume, has cooling tubes with a primary side and a secondary side and has feed and return lines. The primary side of the cooling tubes is covered at least when the sump volume is largely filled with coolant. An intermediate cooler has a tertiary side and is connected through the feed and return lines of the sump cooler to the secondary side of the cooling tubes. A heat sink is disposed outside the reactor building and is connected to the intermediate cooler on the tertiary side.