By Steve Kingstone BBC Sao Paulo correspondent

Brazil wants to restrict access to its Resende plant

The Brazilian government says it is ready to enrich uranium at its Resende nuclear plant.

For Brazil to go ahead, the International Atomic Energy Agency must be able to tell the world that its facilities are legitimate.

It must verify that nuclear fuel is being used for energy and not weapons.

At issue during this visit is how much ongoing access the agency will need to give Brazil that green light.

No favouritism

The government has refused to show all of its centrifuge technology responsible for enrichment.

It says its hardware is more advanced than that of other countries and it must be protected from industrial espionage.

As the inspectors were touring the plant on Tuesday, an IAEA spokeswoman in Vienna was making it clear that they would not need total access to the facility.

But she said there were strict visual criteria to be sure that no nuclear material could be diverted.

The agency knows it cannot be seen to give Brazil preferential treatment at a time when it is taking a tough line with Iran on exactly the same issue.