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

A tube-and-shell air-cooled heat exchanger apparatus comprising:

• a shell having a shell cavity, a primary air inlet at a first elevation, a secondary air inlet at a second elevation, and an air outlet at a third elevation, wherein the second elevation is greater than the first elevation and the third elevation is greater than the second elevation, each of the primary air inlet, the secondary air inlet, and the air outlet collectively forming an airflow passageway through the shell defining a shell-side fluid path;
• and
• a plurality of heat exchange tubes that collectively form a tube bundle having a substantially vertical longitudinal axis, the tube bundle located within the shell cavity, a tube-side fluid path collectively comprised of interior cavities of the plurality of heat exchange tubes;
• the tube bundle comprising a first finned tube section, a second finned tube section, and a non-finned tube section interspersed between and adjacent to the first and second finned tube sections, the first finned tube section, second finned tube section, and non-finned tube section arranged in axial alignment along the longitudinal axis, the secondary air inlet transversely aligned with the non-finned tube section;
• wherein air flows into the shell cavity through the primary and secondary air inlets and exits the shell cavity through the air outlet;
• wherein the first and second finned tube sections each comprise a plurality of heat transfer fins which are vertically elongated in an axial direction along lengths of each tube.

A tube-and-shell air-cooled heat exchanger apparatus comprising:

• a shell having a shell cavity, a primary air inlet at a first elevation, a secondary air inlet at a second elevation, and an air outlet at a third elevation, wherein the second elevation is greater than the first elevation and the third elevation is greater than the second elevation, each of the primary air inlet, the secondary air inlet, and the air outlet collectively forming an airflow passageway through the shell defining a shell-side fluid path;
• and
• a top tube sheet and a bottom tube sheet;
• a plurality of heat exchange tubes extending between the top and bottom tube sheets that collectively form a tube bundle having a substantially vertical longitudinal axis, the tube bundle located within the shell cavity, a tube-side fluid path collectively comprised of interior cavities of the plurality of heat exchange tubes;
• a shroud forming a shroud cavity, the shell located within the shroud cavity, the shroud cavity defining an annular shroud outlet plenum circumferentially surrounding a top portion of the shell above the top tube sheet and extending vertically and horizontally over a top of the shell;
• wherein the air outlet from the shell is located within the shroud outlet plenum such that air discharged by air outlet flows into the shroud outlet plenum over a top of the shell.