WASHINGTON — Early on Nov. 8, 2007, armed men penetrated a 10,000-volt security fence, disabled intrusion detectors and scaled a ladder into the emergency control center of the Pelindaba nuclear facility, the repository of highly enriched uranium removed from the six bombs of South Africa's defunct nuclear arsenal.
The gang, which shot and wounded a security officer during the 45 minutes they spent inside the center, left empty-handed. Its members have never been captured or identified, however, and their ability to penetrate what was supposedly one of South Africa's most heavily guarded installations highlights what experts warn is growing danger that terrorists or criminals will obtain small amounts of highly enriched uranium and build a crude nuclear weapon.
Securing the world's stocks of highly enriched uranium, also known as HEU, and weapons-grade plutonium is the goal of a two-day nuclear summit involving leaders from 46 countries that begins Monday in Washington. President Barack Obama hopes that the attendees will acknowledge the threat and will begin a concerted effort to "lock down" all HEU and plutonium stocks vulnerable to theft within four years.
"Our biggest concerns right now are actually the issues of nuclear terrorism and nuclear proliferation: more countries obtaining nuclear weapons; those weapons being less controllable, less secure; nuclear materials floating around the globe," Obama said in Prague on Thursday after signing the new nuclear arms reduction treaty with Russia.
The summit — the largest gathering of international leaders in the U.S. in more than 60 years — is the next step in Obama's plan to rid the world eventually of nuclear weapons. In addition to the treaty with Russia, Obama this week announced a new U.S. nuclear strategy that embraced further cuts in the U.S. arsenal, ruled out the development of new warheads and excluded most of the world's countries from U.S. nuclear attack.
Whether the summit will accomplish its goal, however, is unclear.
On Friday, Iran, which denies U.S. charges that it's seeking to build a nuclear weapon, unveiled a new device that it claimed would accelerate the uranium enrichment program that it has pursued in defiance of U.N. demands that it be suspended.
Israeli Prime Minister Benjamin Netanyahu withdrew from the summit after allegedly learning that Turkey and Egypt planned to call on Israel to give up its nuclear arsenal.
Meanwhile, more counties are planning to build nuclear power plants; smuggling networks such as the one led by Pakistan's A.Q. Khan have flourished, and terrorists are thought to be ready to use any nuclear bomb-making materials they might lay their hands on.
"Terrorist groups such as al Qaida are clearly interested in obtaining and using nuclear technology," said a U.S. counter-terrorism official, who requested anonymity because he wasn't authorized to speak publicly. "At this point, they don't appear to have made much progress, but we continue to review every bit of information that comes in."
No new agreements are expected at next week's summit, though the U.S. and Russia will sign a long-delayed agreement under which each side will dispose of 34 tons of weapons-grade plutonium left over from the Cold War, U.S. officials said.
Instead, the administration hopes to win the commitment of the leaders attending to take their own steps to strengthen the security of HEU and plutonium stocks, most of which is fuel for research or medical isotope reactors.
For instance, the U.S. is expected to push the leaders to ratify an amended U.N. convention that requires nations to protect nuclear materials on their territories. Currently, it only mandates protecting materials that are being shipped across borders.
"Everybody would benefit from strong national and international actions," said Gary Samore, the White House nonproliferation expert who's overseen the summit preparations. "This is an area where we do believe there is an ability to build broad consensus."
An estimated 500 tons of HEU and plutonium are in civilian and military custody worldwide. Most is in the U.S. and Russia, but there are considerable amounts in nations with serious security concerns, such as Pakistan.
To date, U.S. programs aimed at reducing the danger posed by non-secure warheads or HEU and plutonium stocks have focused primarily on the former Soviet Union, where most of the 18 cases acknowledged by the International Atomic Energy Agency involving the theft or loss of bomb-grade materials have occurred.
The administration is seeking a 67 percent increase in funds to accelerate a U.S. program that helps other countries reduce their HEU stocks either by shipping it to the U.S., converting reactors to low-enriched uranium fuel or improving security. This week, Chile announced that it would send its HEU to the U.S.
Many countries, however, don't see the threat of nuclear terrorism with the same urgency as the U.S., experts say. Those countries think their stocks of weapons-grade materials are secure and that even if terrorists were to get their hands on HEU or plutonium, they'd be unable to build even a crude nuclear device. Many experts disagree.
If they did, many countries think such a bomb would "go off in Manhattan or Washington, and so it's a U.S. problem, not theirs," explained Matthew Bunn of Harvard University's Project on Managing the Atom.
Many countries, Bunn said, also are reluctant to acknowledge how much HEU or plutonium they possess or are unwilling to give up their stocks. Moreover, they think the U.S. and Russia haven't done enough to eliminate their own massive stocks of bomb-level materials.
Edwin Lyman of the Union of Concerned Scientists, an arms control organization, noted that the U.S. has remained silent as France, Britain, Russia and Japan have increased their stockpiles of weapons-quality plutonium by reprocessing spent fuel from commercial power reactors.
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