Argentina’s 692-MW Atucha 2 nuclear reactor achieved criticality in early June, marking a major milestone for the country’s third reactor, development of which began nearly four decades ago.

A pressurized heavy water reactor (PHWR), Atucha 2 is now expected to ramp up production in stages, reaching full power within two or three months. The reactor is expected to replace some of the oil that Argentina exports but also combusts for power generation.

The South American country now produces about 4.7% of its power from two existing nuclear reactors—the 335-MW Atucha 1 plant 100 km northwest of capital Buenos Aires and the 600-MW Embalse plant in Cordoba. About 50% of the total comes from natural gas, 25% from hydro, 15% from oil, and only about 2% from coal. Following commercial operation of Atucha 2 later this year, the country’s nuclear capacity will jump 74%.

Argentina’s government approved Atucha 2, which was based on the Siemens PHWR design for the 1974-commissioned Atucha 1 unit, in 1979. Construction began in 1981, but work was suspended for lack of funds in 1994 when the project was about 80% complete.

Nucleoeléctrica Argentina was set up in 1995 to take over the country’s nuclear power plants and resume construction of Atucha 2. However, no progress was made until 2006, when the government announced a $3.5 billion plan to support the country’s nuclear plants and build new ones. It required the completion of Atucha 2 (Figure 3) and the extension of the operating lifetimes of Atucha 1 and the 1983-commissioned Embalse plant. The life of the Embalse CANDU-6 reactor will be extended by 25 years under a contract signed in August 2011. That project is expected to last five years and cost about $1.37 billion.

3. Setting up for nuclear. This image shows workers loading fuel assemblies at the Atucha 2 nuclear reactor in Argentina in December 2012. The reactor achieved criticality on June 3. Courtesy: Nucleoeléctrica Argentina

The government’s 2006 plan also called for the construction of a 27-MWe prototype of the CAREM reactor, a modular simplified pressurized water reactor with integral steam generators. First concrete for the CAREM reactor was poured this February. If successful, the research reactor could spawn larger versions (100 MW or 200 MW) for construction in Argentina’s Formosa province by 2021.

Sonal Patel, associate editor (@POWERmagazine, @sonalcpatel)