A nuclear plant, comprising:
- a nuclear reactor;
- a containment structure having one or more inner surfaces at least partially defining a containment environment in which the nuclear reactor is located;
- a passive containment cooling system, including
- a coolant reservoir configured to hold a coolant fluid,
- a coolant channel coupled to the containment structure such that the coolant channel extends vertically from a coolant channel inlet at a bottom of the coolant channel to a coolant channel outlet at a top of the coolant channel,
- a coolant supply conduit extending downwards from an inlet of the coolant supply conduit that is open to a lower region of the coolant reservoir, an outlet of the coolant supply conduit is coupled to the coolant channel inlet, such that the coolant supply conduit is configured to direct a flow of the coolant fluid downwards out of the lower region of the coolant reservoir and into the bottom of the coolant channel via the coolant channel inlet according to gravity, such that the coolant fluid rises through the coolant channel from the bottom of the coolant channel to the top of the coolant channel according to a change in buoyancy of the coolant fluid based on the coolant fluid absorbing heat rejected from the nuclear reactor in the containment environment via at least the containment structure, and
- a coolant return conduit having an inlet coupled to the coolant channel outlet at the top of the coolant channel, the coolant return conduit extending upwards from the inlet of the coolant return conduit to an outlet of the coolant return conduit that is open to an upper region of the coolant reservoir that is above the lower region of the coolant reservoir, such that the coolant return conduit is configured to direct a flow of the coolant fluid to rise out of the top of the coolant channel via the coolant channel outlet and into the upper region of the coolant reservoir according to increased buoyancy of the coolant fluid at the top of the coolant channel over buoyancy of the coolant fluid at the bottom of the coolant channel;
- and
- a first check valve assembly at a first vertical depth below a top surface of the coolant fluid in the coolant reservoir, the first check valve assembly in fluid communication with the coolant reservoir through the coolant channel and in fluid communication with the containment environment, wherein
- the first check valve assembly includes one or more check valves coupled between a first check valve assembly inlet and a first check valve assembly outlet, the first check valve assembly inlet being open to the containment environment, the first check valve assembly outlet being in fluid communication with the coolant reservoir through the coolant channel,
- the one or more check valves are configured to open in response to a pressure at an inlet of the one or more check valves being equal to or greater than a first threshold magnitude, the first threshold magnitude at least partially corresponding to a hydrostatic pressure of the coolant fluid at the first check valve assembly outlet at the first vertical depth, and
- the first check valve assembly is configured to selectively enable one-way flow of a containment fluid, from the containment environment via the first check valve assembly inlet to the coolant reservoir through the coolant channel via the first check valve assembly outlet and the coolant channel, based on the one or more check valves opening in response to a pressure of the containment environment at the first check valve assembly inlet at the first vertical depth being equal to or greater than the first threshold magnitude.