Air-cooled heat exchanger and system and method of using the same to remove waste thermal energy from radioactive materials

A system for removing thermal energy generated by radioactive materials comprising:

• an air-cooled shell-and-tube heat exchanger comprising a shell and plurality of heat exchange tubes arranged in a substantially vertical orientation within the shell, the plurality of heat exchange tubes comprising interior cavities that collectively form a tube-side fluid path, the shell forming a shell-side fluid path that extends from an air inlet of the shell to an air outlet of the shell, the first air inlet located at a lower elevation than the air outlet and the plurality of heat exchange tubes located within the shell-side fluid path;
• the shell comprising a second air inlet located at an elevation between the first air inlet and the air outlet;
• a heat rejection closed-loop fluid circuit comprising the tube-side fluid path of the air-cooled heat exchanger, a coolant fluid flowing through the heat rejection closed-loop fluid circuit, the heat rejection closed-loop fluid circuit thermally coupled to the radioactive materials so that thermal energy generated by the radioactive materials is transferred to the coolant fluid;
• and
• the air-cooled shell-and-tube heat exchanger transferring thermal energy from the coolant fluid flowing through the tube-side fluid path to air flowing through the shell-side fluid path;
• wherein the shell-side fluid path comprises a first venturi located at an elevation between the second air inlet and the air outlet, the first venturi created by fins of the plurality of heat exchange tubes;
• wherein the shell-side fluid path comprises a second venturi located at an elevation between the first air inlet and the second air inlet, the second venturi created by fins of the plurality of heat exchange tubes;
• wherein the fins are discontinuous in structure such that the plurality of heat exchange tubes between the first venturi and second venturi at the second air inlet do not have fins.