Patent Number: 041982711
Section: summary

BACKGROUND OF THE INVENTION This invention relates to liquid metal cooled nuclear reactor constructions. In one well known example of liquid metal cooled nuclear reactor construction the reactor is submerged in a pool of coolant contained in a primary vessel. The primary vessel is housed in a concrete containment vault and is suspended from the roof of the vault. There is a leak jacket or catchpot surrounding the primary vessel for catching coolant in the event of leakage. The core is carried on a diagrid which depends from the roof of the vault by tie rods and the roof carries control rods which are vertically insertable in the core to control reactivity. In the event of displacement of the core relative to the control rods during operation of the reactor core the resultant change of reactivity could have serious consequences and it is an object of the present invention to provide a construction of liquid metal cooled nuclear reactor having means for limiting uncontrolled displacement of the core relative to the control rods. SUMMARY OF THE INVENTION According to the invention in a liquid metal cooled nuclear reactor construction wherein the reactor core is submerged in a pool of coolant in a primary vessel, the primary vessel being suspended from the roof structure of a containment vault and surrounded by a leak jacket, there being control rods supported from the roof structure and insertable in the core, the reactor core is supported from the wall of the base region of the primary vessel and there is secondary core support means, non-loaded during normal operation of the reactor said means being located in an interspace between the primary vessel and the leak jacket for limiting the extend of downward deflection of the base region of the primary vessel. Thus in the event of deflection of the wall of the primary vessel such as would allow downward displacement of the reactor core relative to the control rods, the leak jacket provides secondary support means for the core and limits its displacement.