Nuclear Materials

After a year's delay, the Energy Department said it will conduct two underground explosions this year using nuclear materials at the federal test site in Nevada. The tests have prompted protests from anti-nuclear-proliferation groups. Energy Department scientists took pains to emphasize that each of the tests--one in June and a second in the fall--will involve chemical, not nuclear, explosions.

WASHINGTON - Iran has increased its stockpile of 20% enriched uranium by nearly a third since May, United Nations investigators reported Thursday, indicating that Tehran is pushing ahead with nuclear development despite tightening U.S. and European sanctions and the threat of an Israeli military strike. The International Atomic Energy Agency, the U.N.'s nuclear watchdog agency, also reported that Iran has doubled the number of centrifuges, which are used to enrich uranium, in an underground bunker near the holy city of Qom that experts say has been built to withstand an attack.

The United States signed an agreement to pay for radioactivity detectors at Rotterdam, Europe's largest seaport, in an effort to block the smuggling of nuclear material. U.S. Energy Secretary Spencer Abraham said the $3-million system will scan some of the 6 million containers passing through Rotterdam each year and will "improve our mutual efforts to prevent the illicit traffic of nuclear materials." The project is the latest in a series of U.S.

The hard-to-predict and often-threatening plans of North Korea shadowed President Obama's nuclear security summit as soon as he arrived in Seoul, injecting a Cold War note to a meeting designed to deal with newer threats of terrorism and the spread of nuclear materials. The opening hours of the trip reprised similar journeys by his last two predecessors, reflecting the Korean peninsula's status as one of the last vestiges of what used to be a worldwide divide. Like Presidents George W. Bush and Bill Clinton, Obama traveled to the demilitarized zone that separates north and south, donning binoculars at a forward outpost only yards form the armistice line.

Russian police have arrested seven people accused of trying to sell more than two pounds of highly enriched weapons-grade uranium, Russian television said. The men, arrested in the town of Balashikha just east of Moscow, were trying to sell a capsule containing uranium-235 for $30,000, NTV television said. The suspects were charged with illegal handling of nuclear materials, it said.

U.S. Energy Secretary Bill Richardson praised the "courage" of Russian authorities on Sunday after visiting a once-top-secret submarine base at the close of a tour aimed at making nuclear supplies more secure. Richardson was taken across a foggy bay to view rows of aging, nuclear-powered submarines due to be dismantled in the port of Petropavlovsk-Kamchatsky on the remote Kamchatka peninsula in Russia's far east.

Alarmed by growing hints of Al Qaeda's progress toward obtaining a nuclear or radiological weapon, the Bush administration has deployed hundreds of sophisticated sensors since November to U.S. borders, overseas facilities and choke points around Washington. Officials have placed the Delta Force, the nation's elite commando unit, on a new standby alert to seize control of nuclear materials that the sensors may detect.

Warning that "shadowy figures may someday have their finger on a nuclear button," Sen. John F. Kerry outlined a plan Tuesday that he said would make America safer by reducing terrorists' access to the components of nuclear weapons. The Massachusetts senator said the Bush administration has dragged its feet in protecting the nation from the threat of nuclear terrorism by withholding resources from existing programs designed to secure nuclear materials in the former Soviet Union.

The Energy Department will examine moving plutonium and highly enriched uranium out of California's Lawrence Livermore National Laboratory to help improve security against a terrorist attack, Secretary Spencer Abraham said Friday. The announcement probably will set off a high-stakes political battle over the future of Livermore, one of the nation's two nuclear weapons design labs and a cornerstone of the Bay Area's technology sector.

Pressure is mounting for high-level resignations in Germany in the wake of a report that last summer's spectacular arrest of three men smuggling weapons-grade plutonium out of Russia was a setup.

— A 50,000-acre wildfire raging through tinder-dry ponderosa forest sent up towering plumes of smoke, rained down ash and forced the mandatory evacuation Monday of Los Alamos, home to the nation's premier nuclear weapons research lab. The Las Conchas fire started Sunday in parched, windy conditions in the Jemez Mountains, 12 miles west of Los Alamos. By early Monday, it had destroyed 30 structures south and west of town and forced the closure of the Los Alamos National Laboratory, where scientists developed the first atomic bomb during World War II. The blaze stirred memories of a devastating fire in May 2000 that destroyed hundreds of homes and buildings.

A physicist and his wife who once worked at the Los Alamos National Laboratory in New Mexico were arrested Friday on charges of attempting to sell "restricted data" to an undercover FBI agent posing as a top Venezuelan official trying to build an atomic bomb. Pedro Leonardo Mascheroni, 75, a nationalized U.S. citizen from Argentina, and his wife, Marjorie Roxby Mascheroni, 67, appeared in federal court in Albuquerque on charges of trying "to injure the United States" by passing along classified nuclear weapons material in return for millions of dollars.

In what could be a stunning breakthrough in the years-long diplomatic deadlock over Iran's nuclear program, Tehran has agreed to send the bulk of its nuclear material to Turkey as part of an exchange meant to ease international concerns about the Islamic Republic's aims and provide fuel for an ailing medical reactor, the spokesman for Iran's foreign ministry told state television Monday morning. Iranian foreign ministry spokesman Ramin Mehmanparast told state television that a letter describing the deal would be sent to the Vienna-based International Atomic Energy Agency within a week.

The leaders of more than 40 nations agreed Tuesday to a voluntary but far-reaching program to prevent thousands of tons of weapons-grade nuclear materials from falling into the hands of terrorists. World leaders, called to Washington by President Obama to take action on one of his signature issues, also agreed to step up the sharing of nuclear information and help develop common standards and procedures for the security of fissile materials. Obama said the agreement recognized a "cruel irony of history": After surviving a Cold War arms race and the threat of nuclear war, the world now must confront the even larger danger of nuclear terrorism.

Deft diplomacy and regional security woes are driving Tehran and Washington toward a deal on Iran's nuclear program, experts say, illustrated by movement Wednesday in talks to transfer most of the Islamic Republic's fissile material abroad to be processed for medical uses. For three decades, Iran and the U.S. have been locked in a frustrating diplomatic flirtation. When one felt strong enough to offer a deal, the other felt too weak to accept. This time may ultimately prove to be no different.

The head of the world's atomic energy watchdog said Iran and world powers have until Friday to approve a proposed deal to transfer most of Iran's nuclear material abroad to be reformatted for medical purposes. International Atomic Energy Agency chief Mohamed ElBaradei disclosed no details about the draft deal, hammered out over 2 1/2 days of talks between Iranian, American, French and Russian diplomats in Vienna. But he said that it reflected a "balanced approach" that would help Iran fuel a medical research reactor for diagnosing and treating cancer while building confidence to resolve long-standing suspicions about the nature of Tehran's nuclear ambitions.

In a move that stunned but delighted its critics, Rockwell International announced plans Friday to close its nuclear "hot lab" at the Santa Susana field laboratory west of Chatsworth, which had become a lightning rod for protests by neighborhood and anti-nuclear activists.

Blinding yellow smoke swallowed part of the Los Alamos National Laboratory on Thursday afternoon as a fierce brush fire burned several hundred yards from Technical Area 55, the bland name for America's most heavily guarded--and arguably most dangerous--warehouse. "There it is," Bill Richardson, the secretary of Energy, said with audible relief when the acrid smoke finally cleared.

Iran has significantly boosted its supply and output of reactor-grade nuclear material, according to a quarterly report issued Friday by the United Nations' arms control division. Meanwhile, in Syria, international inspectors reported finding unexplained particles of modified uranium at a lab in Damascus, far from an alleged nuclear site.

U.S. Defense Secretary Robert M. Gates promised today to hold North Korea accountable for selling or transferring nuclear material outside its borders, providing the first clear expression of the Obama administration's thinking on a vexing foreign policy challenge. A succession of U.S. presidents have tried to persuade the reclusive government to give up its nuclear arms, and Gates made it clear that President Obama was open to using diplomacy to end the threat.