Atucha I is one of two operational nuclear power plants of Argentina.
The plant is a Pressurised Heavy Water Reactor (PHWR). It employs a mixture of natural uranium and enriched uranium (0.85% of 235U), with heavy water for refrigeration and moderation. It has a thermal power of 1,179 MWth, and generates 357 MWe of electricity, which is delivered at 220 kilovolts to the Argentine Interconnection System, supplying about 2.5% of the total electricity production (2005).
Atucha II is a projected nuclear power plant in Argentina, located in Lima, Buenos Aires, on a site next to Atucha I. Its construction started in 1980, but it has never been finished (it is around 80% completed). Like Atucha I, it is a Pressurised Heavy Water Reactor (PHWR), but was planned to have a much higher power (thermal power approx. 2,000 MW, electrical 750 MW). At the time when it was started, it had the largest reactor pressure vessel of any nuclear power plant worldwide. The total cost is now estimated at US$3.8 billion, or about $5500/kWe, considerably higher than the worldwide mean of about $1500/kWe.
Partly as a response to the energy shortage caused by natural gas crisis of 2004, the issue of Atucha II was taken up by the Argentine government. In 2005 President Néstor Kirchner signed a decree to reactivate the construction and pledged to finish it by 2009. New technicians were hired and a budget of about $120 million was requested for 2006. Eduardo Messi, president of Nucleoeléctrica Argentina S.A. (the firm in charge of the plant), told reporters that 93% of the components were either in storage or already installed.
On 23 August 2006 the government announced the re-activation of the national nuclear programme, and updated its promise to finish Atucha II by 2010, devoting a total of 1,850 million pesos ($596/€466 million). The plant is now slated to generate about 750 MW (5% of Argentina's total energy production).