This reduces the amount of heavy water required for operations compared to CANDU, still using natural uranium as fuel.
A contract was signed in 1972 with Ansaldo to build a 40 MWe prototype at the Latina station.
Construction faced numerous delays and the site was still not complete in 1987 when nuclear development in Italy ended.
Construction was allowed to continue, as opposed to canceling ongoing contracts, and the plant was completed in 1988.
CIRENE was ultimately the only one these that progressed to the prototype phase; after the Chernobyl accident a 1987 referendum ended the development of nuclear power in Italy and since then all existing reactors have been shut down.