Brazil says it is negotiating with UN nuclear inspectors to try to break a deadlock over inspections of a uranium enrichment facility.
Campos says Brazil has nothing to hide
Science and Technology Minister Eduardo Campos told the BBC that Brazil was "hiding absolutely nothing" and that its nuclear programme was peaceful.
But he added that his government needed to protect commercially-sensitive data.
In recent months Brazil has barred UN experts from looking at sections of the Resende facility near Rio de Janeiro.
Mr Campos said protective covers placed on centrifuges there were designed to ensure commercial protection of technology developed by Brazilian scientists at a cost of $1bn.
The Resende plant - which is under construction - will produce only low-grade uranium for nuclear plants, not weapons-grade material, the minister insisted.
He said his government was negotiating with the UN's International Atomic Energy Agency (IAEA) to try to find a mutually-acceptable way of inspecting the facility.
"Brazil is submitting itself to all inspections," Mr Campos told the BBC.
The IAEA told BBC News Online it was not prepared to comment on the issue.
Foes and friends
Brazil has the world's sixth largest uranium reserves and has had the capacity to enrich uranium since 1980.
Last October it announced that it would start producing industrially-enriched uranium in 2004 to feed its two
nuclear power plants.
The IAEA has been involved in efforts to investigate uranium-enrichment facilities in North Korea and Iran.
The Washington Post, in its Sunday edition, says US nuclear experts are urging Washington to insist on inspections in Brazil as well.
"If we don't want these kinds of facilities in Iran or North Korea, we shouldn't want them in Brazil," the paper quoted former US nuclear negotiator James Goodby as saying.
"You have to apply the same rules to adversaries as you do to friends."
The plant in Resende is legal under international treaties - but it remains subject to UN inspections aimed at making sure it is not used for producing weapons-grade material.