Sensors in Place to Detect Nuclear Threat
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. It has 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.
Ordinary Geiger counters, worn on belt clips and resembling pagers, have been in use by the U.S. Customs Service for years. The newer devices are called gamma ray and neutron flux detectors. Until now they were carried only by mobile Nuclear Emergency Search Teams (NEST) dispatched when extortionists claimed to have radioactive materials. Because terrorists would give no such warning, and because NEST scientists are unequipped for combat, the Delta Force has been assigned the mission of killing or disabling anyone with a suspected nuclear device and turning it over to the scientists to be disarmed.
The new radiation sensors are emplaced in layers around some fixed points and temporarily at designated "national security special events" such as last month's Olympic Games in Utah. Allied countries, including Saudi Arabia, have also rushed new detectors to their borders after American intelligence warnings. To address the technological limits of even the best current sensors, the Bush administration has ordered a crash program to build next generation devices at the three national nuclear laboratories.
These steps join several other signs, described in recent interviews with U.S. government policymakers, that the Bush administration's nuclear anxieties have intensified since American-backed forces routed Osama bin Laden's network and its Taliban backers in Afghanistan.
"Clearly . . . the sense of urgency has gone up," said a senior government policymaker on nuclear, biological and chemical terror. Another high-ranking official said, "the more you gather information, the more our concerns increased about al Qaeda's focus on weapons of mass destruction of all kinds."
In "tabletop exercises" conducted as high as Cabinet level, President Bush's national security team has highlighted difficult choices the chief executive would face if the new sensors pick up a radiation signature on a boat steaming up the Potomac River or a truck heading for the capital on I-95.
Participants in those exercises said the gaps in their knowledge are considerable. *******But the intelligence community, they said, believes that al Qaeda could already control a stolen Soviet-era tactical nuclear warhead or enough weapons-grade material to fashion a functioning, if less efficient, atomic bomb. Even before more recent discoveries, some analysts regarded that prospect as substantial. Some expressed that view when the intelligence community devoted a full-day retreat to the subject early last year in Chantilly, Va., according to someone with first-hand knowledge. A majority of those present assessed the likelihood as negligible, but none of the more than 50 participants ruled it out.
*****The consensus government view is now that al Qaeda probably has acquired the lower-level radionuclides strontium 90 and cesium 137, many thefts of which have been documented in recent years. These materials cannot produce a nuclear detonation, but they are radioactive contaminants. Conventional explosives could scatter them in what is known as a radiological dispersion device, colloquially called a "dirty bomb." The number of deaths that might result is hard to predict, but probably would be modest. One senior government specialist said "its impact as a weapon of psychological terror" would be far greater.
These heightened U.S. government fears explain Bush's activation, the first since the dawn of the nuclear age, of contingency plans to maintain a cadre of senior federal managers in underground bunkers away from Washington. The Washington Post described the features of the classified "Continuity of Operations Plan" on Friday.
Bush's emphasis on nuclear terrorism dates from a briefing in the Situation Room during the last week of October. According to knowledgeable sources, Director of Central Intelligence George J. Tenet walked the president through an accumulation of fresh evidence about al Qaeda's nuclear ambition. *****Described by one consumer of intelligence as "an incomplete mosaic" of fact, inference and potentially false leads, Tenet's briefing raised fears that "sent the president through the roof." With considerable emotion, two officials said, Bush ordered his national security team to give nuclear terrorism priority over every other threat to the United States.
*****Tenet told Bush that Pakistan's nuclear weapons program was more deeply compromised than either government has acknowledged publicly. Pakistan arrested two former nuclear scientists, Sultan Bashiruddin Mahmood and Abdul Majid, on Oct. 23, and interrogated them about contacts with bin Laden and his lieutenants. Pakistani officials maintain that the scientists did not pass important secrets to al Qaeda, but they have not disclosed that Mahmood failed multiple polygraph examinations about his activities.
Most disturbing to U.S. intelligence was another leak from Pakistan's program that has not been mentioned in public. According to American sources, *******a third Pakistani nuclear scientist attempted to negotiate the sale of an atomic weapon design to Libya. The Post was unable to learn which Pakistani blueprint was involved, whether the transaction was completed, or what became of the scientist after discovery. Pakistan's nuclear arsenal is believed to include bombs of relatively simple design, built around cores of highly enriched uranium, and more sophisticated weapons employing Chinese implosion technology to compress plutonium to a critical mass.
At the October briefing, Bush learned of a remark by a senior member of al Qaeda's operational command. The operative had been an accurate, though imprecise, harbinger of al Qaeda plans in the past. After U.S. bombing began in Afghanistan, an American official said, the same man was reliably reported to have said "there will be another attack and it's going to be much bigger" than the one that toppled the World Trade Center and destroyed a wing of the Pentagon on Sept. 11.
"What the hell did that mean?" the official said, recalling the stunned reaction of those briefed on the remark. Other reports reaching Washington described al Qaeda references to obtaining, or having obtained, special weapons. "The benign explanation is bucking up the troops" with false bravado, the official said, but the Bush administration took the report "extremely seriously."
Searches of al Qaeda sites in Afghanistan, undertaken since American-backed forces took control there, are not known to have turned up a significant cache of nuclear materials. The New York Times reported that U.S. personnel in Afghanistan sent three suspected samples to American labs for analysis, but found no significant radioactive source.
There is evidence that some of al Qaeda's nuclear efforts over the years met with swindles and false leads. In one case, officials said, the organization was taken in by scam artists selling "red mercury," a phony substance they described as a precursor, or ingredient, of weapons-grade materials.
If al Qaeda has a weapon or its components, U.S. officials said, its whereabouts would be the organization's most closely guarded secret. Addressing the failure of American searchers to find such materials in abandoned Afghan camps, one policymaker noted that "we haven't found most of the al Qaeda leadership either, and we know that exists."
***The likeliest source of nuclear materials, or of a warhead bought whole, is the vast complex of weapons labs and storage sites that began to crumble with the end of the Soviet Union in 1991. Russia has decommissioned some 10,000 tactical nuclear weapons since then, but it has been able to document only a fraction of the inventory.
The National Intelligence Council, an umbrella organization for the U.S. analytical community, reported to Congress last month that there are at least four occasions between 1992 and 1999 when "weapons-grade and weapons-usable nuclear materials have been stolen from some Russian institutes." Of those thefts, the report said "we assess that undetected smuggling has occurred, although we do not know the extent or magnitude."
Victor Yerastov, chief of nuclear accounting and control for Russia's ministry of atomic energy, has said that in 1998 a theft in Chelyabinsk Oblast made off with "quite sufficient material to produce an atomic bomb." An American official, commenting on that theft, said that "given the known and suspected capabilities of the Russian Mafia, it's perfectly plausible that al Qaeda would have access to such materials." The official added, "They could get it from anybody they could bribe."
Col. Gen. Igor Valynkin, chief of the Russian organization responsible for safeguarding nuclear weapons, said on Oct. 27 that any claim Russia has lost an intact warhead is "barking mad."
The U.S. government is not accepting that assurance at face value. "We don't know with any confidence what has gone missing, and neither do they," said one American official.
Thefts of less threatening nuclear byproducts, especially isotopes of strontium, cesium and partially enriched uranium, have been reported more frequently. In November 1995, Chechen rebels placed a functioning "dirty bomb" using dynamite and cesium 137 in Moscow's Izmailovo park. They did not detonate it. Al Qaeda is closely aligned with the Chechens.
There are limits, "governed by the laws of physics," as one official put it, to American technology for detecting these materials. In broad terms they have to do with sensing radioactivity at a distance and through shielding, and with the balance between false positives and false negatives. There are classified Energy Department documents that catalogue what one of them called "shortcomings in the ability of NEST equipment to locate the target materials which if known by adversaries could be used to defeat the search equipment and/or procedures." The Post has agreed to publish no further details.
A division of the Los Alamos National Laboratory, known as NIS-6, is leading efforts to build an improved generation of sensors. Some will use neutron generators to "interrogate" a suspected object, and others are planned for long-range detection of alpha particles.
A measure of the government's grave concern is the time devoted by top national security officials to developing options for a crisis involving nuclear terrorism. One hypothetical scenario, participants said, began with a sensor detecting what appeared to be the radiation signature of a nuclear weapon amid a large volume of traffic on a highway such as Interstate 95.
According to two participants, the group considered how the Energy Department's NEST teams, working with Delta Force, might find and take control of the weapon without giving a terrorist time to use it. Roadblocks and car-by-car searches, for example, would create chaos, require hours, and give ample warning to those hiding the device. But without roadblocks the searchers might fail to isolate the weapon within a radius defined by the limits of sensor technology. If commandos found the device, they could expect to encounter resistance. Would the president delegate to on-scene commanders a decision that might result in nuclear detonation? Which officials, meanwhile, should be evacuated? Would government inform the public of the threat, a step that would wreak panic without precedent in any country and complicate the job of finding the weapon?
"Evacuation is one of those issues you throw your hands up and say, 'It's too hard,' " said one participant in a tabletop exercise. "Nobody wants to make that decision, certainly not in advance."