[en] The ''Instituto de Asuntos Nucleares'' of Colombia is responsible for IAN-R1 reactor operation, a 20 Kw. nuclear power machine, which became critical the first time on January 20th, 1965. The introduction of nuclear energy in Colombia has allowed to carry out many peaceful applications, where the reactor has played a significant role in support of these programmes. At this time, the main activities are: Educational and training activities; nuclear research; neutron activation analysis; delayed neutron analysis and radioisotopes production for using in agriculture, industry, hydrology and engineering. A description is made of the reactor aspects that have contributed to scientific and technological improvements