Herman Nackaerts of the International Atomic Energy Agency speaks to reporters at the airport in Vienna, Austria, on Sunday, Feb. 19, 2012, as he prepares to depart for Tehran for a nuclear-inspection visit. (AP Photo/AP Television News)
Herman Nackaerts, a deputy director general of the International Atomic Energy Agency, is interviewed upon his arrival from Iran at Schwechat Airport in Vienna, Austria, on Wednesday, Feb. 1, 2012. (AP Photo/Ronald Zak)
** FILE ** International Atomic Energy Agency experts Jozef Misak (third from right) and Charles Casto (second from right) walk past an emergency air-cooled power generator as they inspect the Ohi nuclear power plant in Ohi, Fukui prefecture, Japan, on Thursday, Jan. 26, 2012. (AP Photo/Shizuo Kambayashi, File)
Herman Nackaerts, the deputy director general of the International Atomic Energy Agency in charge of the Iran file, prepares to depart for Iran from the Vienna, Austria, airport on Saturday, Jan. 28, 2012. (AP Photo/Ronald Zak)
** FILE ** Glyn Davies, U.S. ambassador to the International Atomic Energy Agency, was named on Wednesday, Oct. 19, 2011, as the new U.S. envoy on North Korea. (AP Photo/Ronald Zak, File)
U.S. Energy Secretary Steven Chu speaks at the general conference of the International Atomic Energy Agency in Vienna, Austria, on Monday, Sept. 19, 2011. (AP Photo/Ronald Zak)
Yukiya Amano, director general of the International Atomic Energy Agency, speaks during a news conference after the first meeting of the IAEA's board of governors in Vienna, Austria, on Monday, Sept. 12, 2011. (AP Photo/Ronald Zak)
The International Atomic Energy Agency's board of governors meets at the International Center in Vienna, Austria, on Monday, Sept. 12, 2011. (AP Photo/Ronald Zak)
International Atomic Energy Agency Director General Yukiya Amano inspects the crippled Fukushima Dai-Ichi nuclear-power plant in northeastern Japan earlier this week. Mr. Amano, on a weeklong trip to Japan, said that the nation's tsunami-damaged nuclear plant is steadily making progress to recover from the March disaster triggered by an earthquake. (Associated Press)
Yukiya Amano, director general of the International Atomic Energy Agency, speaks during a news conference at an IAEA meeting in Vienna, Austria, on Monday, April 4, 2011. (AP Photo/Ronald Zak)
International Atomic Energy Agency chief Yukiya Amano, center, speaks to journalists upon his arrival at Narita International Airport in Narita, near Tokyo Friday, March 18, 2011. (AP Photo/Keisuke Kimura)
The Japanese national flag flies outside of the United Nations building that hosts the International Atomic Energy Agency, IAEA, office, in Vienna, Austria, Tuesday, March 15, 2011. (AP Photo/Ronald Zak)
Director General of the International Atomic Energy Agency, IAEA, Yukiya Amano from Japan speaks to the media about the nuclear emergency triggered by the devastating earthquake and tsunami in Japan before his takeoff to Japan at Vienna's Schwechat airport, Austria, on Thursday, March 17, 2011. (AP Photo/Ronald Zak)
Former Director General of the International Atomic Energy Agency and Nobel Peace Prize winner Mohammed ElBaradei arrives at Cairo's airport. He tells reporters "the regime has not been listening." (Associated Press)
** FILE ** Head of Iran's Atomic Energy Organization, Ali Akbar Salehi, delivers a speech at the International Atomic Energy Agency, IAEA, in Vienna, Austria, in this file photo dated Monday, Sept. 20, 2010. (AP Photo/Ronald Zak, file)
Yukiya Amano of Japan, director general of the International Atomic Energy Agency, addresses the general conference of the IAEA at the International Center in Vienna, Austria, on Monday, Sept. 20, 2010. (AP Photo/Ronald Zak)
Glyn Davies, U.S. ambassador to the International Atomic Energy Agency, waits for the start of the IAEA's board of governors meeting at the International Center in Vienna, Austria, on Wednesday, Sept. 15, 2010. (AP Photo/Ronald Zak)
Iran's Ambassador to the International Atomic Energy Agency, Ali Asghar Soltanieh, ckecks his papers prior to the start of the IAEA's board of governors meeting at the International Center, in Vienna, Austria, on Monday, Sept. 13, 2010. (AP Photo/Ronald Zak)
** FILE ** In this Aug. 21, 2007, file picture, Deputy Director General of the International Atomic Energy Agency (IAEA) Olli Heinonen, listens to a question during a joint press conference with a top Iranian nuclear negotiator, Javad Vaeedi, unseen, after their talks in Tehran, Iran. The International Atomic Energy Agency says senior nuclear inspector Olli Heinonen will be leaving his post at the end of August. (AP Photo/Vahid Salemi,File)