Since 2000, the Bandung TRIGA 2000 reactor, formerly named the Bandung TRIGA Mark II reactor, was upgraded from 1 MW (th) to 2 MW (th). The main purpose of the upgrade was to increase the radioisotope production capabilities to support the Serpong Siwabessy Multipurpose Reactor, as well as to increase the safety features of the Bandung TRIGA reactor. The upgrade project began in 1994 with the establishment of an upgrade team that successfully released a Bid Invitation Specification (BIS) document in 1995. The actual upgrade started in April 1996. Originally, the upgrade was expected to be completed in one year; however, the upgrade was not completed until 2000. During the upgrade, the following systems were subject to either change, refurbish, addition or modification: reactor core configuration (from annular to hexagonal), number of control rods (from 4 to 5), chimney and emergency core cooling system (ECCS), graphite reflector, cooling system (primary and secondary, including: new heat exchanger and cooling tower), emergency ventilation system. Although the reactor tank was not part of the upgrade project at first, it was decided to replace the old tank after an inspection of the tank. The paper also describes some experiences and lessons learned during the removal of the old tank, installation of the new tank, disassembly and reassembly of the core structure, thermal-and thermalizing column and others.