Secretary of State Cyrus Vance was apparently unable today to persuade Brazil to abandon plans to acquire a nuclear reprocessing plant.

The issue was discussed in Vance's meeting today with President Ernesto Geisel and Foreign Minister Antonio Azeredo da Silveira. State Department spokesman with Vance had no progess to report but they noted that the United States had not been "looking for any tangible results."

Vance's one-day visit here is the first under the terms of a 1976 agreement creating a "special" bilateral relationship between the two countries. The accord specially called for semi-annual consultations at the foreign minister's level.

The special relationship has come under strain because of the Carter administration's drive to deter Brazil from going ahead with plans to buy nuclear reprocessing technology from West Germany. Reprocessing creates plutonium that can be employed in nuclear weapons and it has become a major target in the Carter administration's campaign against proliferation of nuclear weapons.

Washington has maintained that adequate safeguards do not exist to deal with the reprocessing technology and has asked Brazil to put off acquiring that part of its $10-billion nuclear power purchase agreement with West Germany.

Brazil has insisted that its safeguards are sufficient and has accused the United States of "big brotherism" and a desire to keep nucler secrets to itself. A March visit by Deputy Secretary of State Warren Christopher was cut short when he pressed Washington's concerns. He left town to a chorus of indignant editorials and commentary from across Brazil's political spectrum.

Commenting yesterday on the possibility of negotiations on the issue during the Vance visit, the Brazilian presidential spokesman, Luis Felipe Lampreia, said, "If negotiate means to back down, the Brazilian government has nothing to negotiate.

Judging by U.S. comments and the expressions of American officials following today's meeting, there was no change from that position. State Department spokesman John Trattner said there were "no further developments I can enumerate."

Local observers regarded as significant the absence from the talks of Paulo Noguiera Batista, Brazil's nuclear power chief. Trattner characterized the discussion as "frank, businesslike and friendly."

Vance and his party had hoped to convince Brazil that there was a growing danger of a nuclear race with Argentina, where the secretary visited yesterday.

Argentina, long Latin American's nuclear leader with the area's only working reactor has the capacity to build a reprocessing plant, according to U.S. officials, and is well on its way to developing its own plutonium supply. In talks yesterday with Vance, the Argentines indicated they would suspend those efforts if Brazil agreed to defer reprocessing.

Argentina has a traditional, and occasionally bitter rivalry with Brazil. Many Argentine officials firmly believe that their large northern neighbor intends to build a bomb, despite Brazilian denials.

U.S. energy specialists, including chief nuclear negotiator Garard Smith continued, to no apparent avail, to try to convince Brazil that current reprocessing technology should be developed within 10 years.

Brazil, with few energy resources, spends a large portion of its national budget on oil imports. It believes the West German deal for eight reactors and the capacity to reprocess nuclear fuel - eliminating the need to import - will give it the energy self-sufficiency it eagerly seeks.

Despite the lack of progress, U.S. officials seem determined as ever Trattener noted that the Vance was in part a preparation for President Carter's trip here early next year.Presumably, the issue will be brought to the table again then.

Although disagreements continue, both countries appear more businesslike than in the past and almost routine in their discussions on the two issues that find them farthest apart - the nuclear problem and human rights. Vance and his party, including Assistant Secretary of State for Human Rights patricia Derian, reitherated concern for human rights asan integral part of U.S. policy.

Of particular concern to the Americans are the status of a reported 300 political prisoners held by the Brazilian military government, and recently renewed allegations of prisoner torture.

In duscussions today, Brazil, although remaining "frank and friendly," repeated its belief that human rights are a strictly internal matter and not a subject for diplomatic talks.

Vance and his party leave early Wednesday for an afternoon stop in Caracas, where talks with Venezuelan President Carlos Andres Perez are expected to center on next month's meeting of the Organization of Petroleum Exporting Countries which will be discussing possible increases in the price of oil.

Vance plans to return to Washington Wednesday evening.