Disclosed is a removable cooling module (1), for use in a reactor (20) for carrying out an exothermic reaction, comprising a coolant feed tube (2); a distribution chamber (4); a plurality of circulation tubes (5); and a collection chamber (6); said coolant feed tube (2) having at its first end an inlet (3), for charging the coolant module (1) with coolant, and communicating with said distribution chamber (4) at its second end; each of said circulation tubes (5) communicating with the distribution chamber (4) through a first end and communicating with said collection chamber (6) through a second end; the collection chamber (6) having an outlet for discharging coolant. The modular nature of the invention facilitates removal of individual cooling module (1) from a reactor shell (21).