Nuclear reactor provided with a raised heat exchanger

A nuclear reactor, comprising:

• a reactor vessel that houses a hot collector at least partially above a core and a cold collector surrounding the hot collector, the cold collector being separated from the hot collector by a separation structure and configured to circulate a primary fluid for cooling the core;
• and
• at least one heat exchanger secured to the reactor vessel and including:
• a bottom configured to receive the primary fluid coming from the hot collector;
• and
• an external shell positioned at least partially within the cold collector and defining a circumferential outlet window, the circumferential outlet window defining a singular opening through the external shell positioned at an intermediate position of a tube bundle of the at least one heat exchanger;
• wherein the heat exchanger houses internally a circulation pump which, when operating, pumps the primary fluid in the cold collector at a level higher than the level of the primary fluid in the hot collector;
• and the circumferential outlet window of the heat exchanger is positioned proximate to a free surface of the primary fluid in the cold collector higher than the level of the primary fluid in the hot collector;
• and
• an interspace between the reactor vessel and a safety vessel;
• wherein the circumferential outlet window comprises an upper edge and a lower edge of the singular opening such that if a level of the free surface of the primary fluid in the cold collector is lowered when at least some of the primary fluid of the reactor vessel leaks into and at least partially fills the interspace, the lower edge of the outlet window remains below the free surface of the primary fluid in the cold collector.