The Latin American countries' interest in nuclear power development contrasts with dwindling support for the alternative to hydrocarbons as fuel, especially after the Fukushima nuclear disaster in Japan.
Argentina has a nuclear program going back to the 1950s and Brazil first initiated nuclear fission development in the 1930s. Both pursued covert nuclear weapons program under their respective military regimes but, even as they put those programs on hold, both maintained and enhanced their nuclear power generation capacity.
Despite the latest pronouncements, Brazil is on track to build its first nuclear-powered submarine with French help and Argentina is actively following similar aims to integrate its military and nuclear programs.
The two countries in a joint declaration confirmed a strategic alliance and pledged to campaign for a South Atlantic zone of peace free of nuclear weapons.
Neither country has a known enemy country but Argentina has ratcheted up its rivalry with Britain over its claim of sovereignty over the Falkland Islands, the British overseas territory Argentina's former military dictatorship tried to seize in a 1982 invasion.
The attempt failed with a formal Argentine surrender and deaths of more than 1,000 military personnel and civilians from both sides but didn't extinguish Buenos Aires' championing of Argentine sovereignty over the Falklands.
The joint declaration signaled the two countries' preparations for a more vigorous pursuit of nuclear power, in which Brazil would help Argentina with its more advanced expertise and technologies. Brazil has set development of nuclear fuel reprocessing as one of its high-earning business objectives.
Argentina has plans to build two more nuclear reactors, with Canadian help, in addition to two in operation.
Argentine Defense Minister Arturo Puricelli and Brazilian counterpart Celso Amorim met in Buenos Aires to follow up on a recent summit in Brasilia between Presidents Cristina Fernandez de Kirchner and Dilma Rousseff.
The joint declaration outlined a mechanism for closer political dialogue on defense cooperation and joint production.
Both sides want to go into joint production of military vehicles and transport planes, advancing Brazil's experience in both fields.
However, the ministers also outlined plans to hold combined military exercises to which they would invite neighboring Latin American countries.
Climate change in the Antarctic has heightened Latin American concerns that the region will likely attract more countries interested in exploring and exploiting the thawing ocean's natural resources. Chile has begun reinforcing security measures in its southern territories.