A liquid metal cooled nuclear reactor steam generating system without an intermediate sodium system comprising:
- (a) a reactor vessel containing a reactor core, and associated neutron shields as well as liquid metal coolant, an inert gas blanket with said reactor vessel being placed within a safety jacket;
- (b) at least one heat exchanger located externally of said reactor vessel in order to effect heat exchange between said liquid metal and liquid water thus turned to steam;
- (c) piping means for establishing a two-way communication between said reactor vessel and said heat exchanger or heat exchangers;
- (d) a main storage tank connected to said reactor vessel for receiving said liquid metal and said inert gas;
- (e) said main storage tank being provided with a system of pipes consisting of at least:
- (i) one first overflow pipe to connect the top portion of the reactor vessel and the bottom of said storage tank,
- (ii) a second pressure-equalizing pipe having a diameter large enough to take care of sudden pressure differences to connect the top portion of the reactor vessel and the top portion of the main storage tank, said pipes being fitted with valves so as to ensure that under steady state operating conditions, said main storage tank communicates with said reactor vessel through said first and second pipes;
- (iii) a third pipe for filling said main storage tank with liquid metal, said third pipe connecting an external source with said main storage tank;
- (iv) a fourth pipe for connection with inert gas storage means of tank and said main storage tank;
- (v) a fifth pipe to connect between the interior of said storage tank and the reactor vessel, said fifth pipe being fitted with means for circulating and purifying the liquid metal;
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- (f) a containment structure constituted by controlled-atmosphere compartments which contain said reactor, heat exchanger and main storage tank to provide radiation protection for operating personnel and provide protection against impacts of external origin;
- (g) said heat exchanger comprising an outer shell for the circulation of said liquid metal, said shell being provided with a safety jacket and a discharge pipe to connect with the interior of said main shell through a bursting disc which opens abruptly in the event of abnormal overpressure within said shell, said discharge pipe arranged as to have its opening at the top portion of said main storage tank, and wherein the means for establishing a communication in the heat exchanger-reactor vessel direction are fitted with a valve which is closed in the event of an abnormal pressure drop within said shell as a result of the abrupt opening of said bursting disc.