Original scope (2003): The Act provided for the gradual phase-out of nuclear energy for commercial electricity production. It prohibited the construction of new nuclear power plants and set a 40-year operational limit on existing plants (constructed between 1974 and 1985), scheduling their decommissioning over the 2015–2025 period. The progressive phase-out was to be accompanied by energy market restructuring measures, including reduction of energy consumption by the largest industrial consumers. The 2013 amendment postponed the phase-out and shutdown of the last nuclear reactor to 2025.
May 2025 amendment (Law of 17 May 2025, "loi Bihet"): Parliament voted by a large majority (102 for, 8 against, 31 abstentions) to abrogate the core articles of the 2003 Act, effectively reversing its original purpose. The Act's title was simultaneously amended to remove all reference to phase-out ("sortie progressive de" was deleted from the title). The 2025 law suppresses any reference to a closure deadline of 2025, removes the prohibition on constructing new nuclear installations, and opens the legal path to extending the operational life of existing reactors and planning new capacity, including small modular reactors (SMRs). The 2003 Act thus survives as a legal instrument under its original date but with a fundamentally different purpose, serving as the framework for Belgium's renewed nuclear energy policy.

