A U.S. study says that in a nuclear detonation people in large cities would be better off sheltering in place rather than trying to evacuate immediately.

Researchers at Stanford University say that unless a lengthy warning period is provided, clogged exit roads would pose more significant risks by exposing evacuees to radiation than if people were to remain in place at the center of large buildings or in basements, a release from the Society for Risk Analysis says.

The Stanford research uses sophisticated mathematical models to investigate the impact of various response strategies.

"The logistical challenge of an evacuation appears to be beyond current response capabilities," study author Lawrence M. Wein of Stanford said.

The Stanford researchers cite previous studies saying first responders are unlikely to be able to establish evacuation stations until 12-48 hours after an attack, no significant federal response would be likely for 24 hours, and a full federal response is not likely to be achieved for 72 hours.

"Unlike a bioterror or chemical attack, it may not be possible for the government to provide timely advice to the populace after such an event," the study said.

The research was published in the journal Risk Analysis.

earlier related report
Iran says vetting UN nuclear inspectors is its right
Tehran (AFP) Sept 7, 2010 - Iran said on Tuesday that it was within its rights to vet UN inspectors who monitor its nuclear facilities after the UN watchdog said its work was being hampered by the barring of some of its staff.

"We have this right ... to change the inspectors as per their record," foreign ministry spokesman Ramin Mehmanparast told reporters.

"We insist that the IAEA (International Atomic Energy Agency) accomplish its legal activities regarding member states by disregarding political pressure."

The UN atomic watchdog, in a new restricted report released on Monday, said Iran was complicating a long-running investigation into its controversial nuclear drive by vetoing the nomination of some inspectors.

Earlier this year, Iran banned two IAEA inspectors from entering the country, accusing them of filing a "false report."

Speaking to the ISNA news agency late on Monday, atomic chief Ali Akbar Salehi said Iran had barred the two inspectors because they had filed reports that "were contrary to reality."

He charged that the IAEA itself had privately acknowledged there was some legitimacy to Iran's complaint but had refused to admit it publicly.

"It is our right to choose inspectors as it is the right of all members of the IAEA," ISNA quoted Salehi as saying.

Salehi said that even the IAEA was of the "opinion that the two inspectors gave reports contrary to reality but it does not want to admit it."

He stressed that Iran had accepted both replacement inspectors that the IAEA had nominated.

In its report, the IAEA said "repeated objection by Iran to the designation of inspectors with experience in Iran's nuclear fuel cycle and facilities hampers the inspection process."

It "detracts from the agency's capability to implement effective and efficient safeguards in Iran," the UN watchdog said.

The vetoing of certain inspectors "makes our work more difficult" because new inspectors need time to gain knowledge and experience of Iran's nuclear programme, said a senior diplomat familiar with the IAEA's Iran investigation.

"But it also adds to pressure on the inspectors. Some may feel unsure, they may fear being kicked out of the country" if the Iranians do not agree with their findings, the diplomat said.

IAEA inspectors routinely monitor the nuclear installations of member states, including Iran's uranium enrichment facility in the central city of Natanz.

Salehi said that inspection of Iran's heavy water plant in the central city of Arak was "not within the bilateral agreement between Iran and the IAEA."

"If the IAEA convinces us... that they must inspect Iran's heavy water installation and the heavy water produced there, I, in the quickest time, will allow inspectors to come," he said.

Iran had allowed IAEA inspectors to inspect the facility in August 2009.

World powers fear that Iran could configure the Arak plant in a way to help make an atom bomb, but Tehran says the reactor is planned to make isotopes only for agricultural and health purposes.

Heavy water reactors do not need enriched uranium fuel to function.

The foreign ministry spokesman said Iran was still waiting for a response from the major powers to its call for talks on the supply of fuel for a Tehran medical research reactor based on a deal brokered by Brazil and Turkey on May 17 but cold-shouldered by the United States.

Mehmanparast said Iran was waiting for the so-called Vienna group made up of France, Russia, the United States and the IAEA to "declare its readiness to talk based on the framework of the Tehran Declaration."

Under the May plan, Iran would have shipped 1,200 kilogrammes (2,640 pounds) of its stocks of low-enriched uranium (LEU) to Turkey, in return for the subsequent supply by Russia and France of fuel for the Tehran reactor.

The plan was a development of proposals first put forward by the UN watchdog in October last year but Washington said it failed to take account of the additional stocks of LEU that Iran had produced in the intervening period, and successfully pushed for a fourth set of UN sanctions.

On August 2, Foreign Minister Manouchehr Mottaki said Iran had received some "positive" signals from the Vienna group about fresh negotiations on a fuel swap deal.

Western governments are concerned Iran could covertly enrich its LEU stocks to the far higher level required for a nuclear weapon, an ambition it strongly denies.