NUCLEAR NINJAS

By DOUGLAS WALLER/WASHINGTON

IT MIGHT BE HARD TO PICTURE AT THIS juncture in American history, but there are times, even now, when working for the government can be exciting. Consider a secret Department of Energy training exercise--code name: Mirage Gold--that was staged in New Orleans in October 1994. Hundreds of normally lab-bound nuclear scientists fanned out through the French Quarter carrying briefcases with hidden radiation detectors, while rental vans packed with high-tech electronics roamed the streets and planes fitted with spy cameras swooped overhead. After three days, they found what they were hunting for: a simulated nuclear weapon hidden on a nearby naval base.

There is more to these games than merely giving government employees the chance to play James Bond. The point is to test the preparedness of a secretive task force organized to combat the possibility--eventuality, some would say--of nuclear terrorism in the U.S. Welcome to Fail Safe, the post-cold war edition.

Until now, and hopefully for a long time to come, the spectacle of the U.S. government being blackmailed by nuclear terrorists has been the province of books, movies (including a forthcoming John Travolta film) and a recent series of scary, attention-getting commercials by attention-needing presidential candidate Richard Lugar. Of course, the appeal of nuclear weapons to terrorists is obvious: if destabilizing society or drawing attention to one's cause is the goal, a mushroom cloud outranks truck bombs and sarin attacks.

The danger is real. Making a nuclear weapon is a complex business, but in essence all anyone would need to lay waste to a medium-size city like New Orleans are two things. The first is an understanding of the technology involved, the easy availability of which has been demonstrated by innumerable high school science whiz kids. The second component is actual fissionable material--55 lbs. of enriched uranium, say, which would be enough to turn the heart of New Orleans into radioactive dust. With the increasing use of nuclear technology around the world and the destabilization of Russia, the once stringent global controls on uranium and plutonium are increasingly being subverted. U.S. intelligence officials admit that a terrorist would have no more difficulty slipping a nuclear device into the U.S. than a drug trafficker has bringing in bulk loads of cocaine.

This, however, is a good-news story--in the sense that the public is largely unaware of the lengths to which the U.S. government has already gone to combat the potential of nuclear terror. The cia and fbi work at stopping threats before they happen, while the Energy Department focuses on responding to actual emergencies. Though the department has had its funding cut more than 9% over the past four years, it has almost doubled its budget for responding to nuclear emergencies, now at $70 million annually. The core of the effort is the Nuclear Emergency Search Team--NEST. These are the people America will call on if and when someone claims to have hidden an atom bomb in the Mall of America.

NEST was formed in 1975 after an extortionist threatened to blow up Boston with a nuclear device unless he was paid $200,000. Since then, NEST has evaluated 110 threats, and mobilized itself to deal with about 30 of them; like the Boston incident, all have been hoaxes. Yet NEST is more than a high-tech SWAT team. At the remote Pajarito site in the Los Alamos Nuclear Weapons Laboratory complex in New Mexico, 17 scientists are using technology found on the shelves of Radio Shack and the type of nuclear fuel sold on the black market to construct homemade bombs. To dismantle a makeshift device, scientists first must know the various ways in which it might be constructed; so far, the team has assembled more than a dozen.

Over the past few months, TIME has been permitted to take an inside look at the operations of nest, which employs more than 1,000 men and women. Many are scientists who helped build America's nuclear arsenal. Others are volunteers from Energy Department offices around the country. All must be ready to spring into action at a moment's notice.

The first line of defense is made up of people like Lewis Newby, a former Navy pilot who heads a team of NEST scientists at Sandia National Laboratory in Albuquerque, New Mexico. Newby travels everywhere with a cellular phone and call-out roster for other team members; at home, a special beeper sits on his nightstand. When a nuclear threat is received, Newby and his colleagues must assess it. At Lawrence Livermore National Laboratory near San Francisco, nest has a computer filled with thousands of pages of everything publicly written about making a nuclear weapon: newspaper clips, magazine articles, reports in scientific journals, even passages from spy novels. The computer can quickly run a cross-check to see if the extortionist knows what he is talking about or has merely lifted his blackmail note from a Tom Clancy book.

Assuming the threat sounds genuine, the team's first crucial task is to locate the bomb, which is presumably hidden. After flying in from around the country on military transport, NEST searchers divide the threatened city--the cia and fbi assume terrorists will target an urban area in order to incur maximum casualties--into search grids. Energy Department aircraft, specially fitted with photographic equipment, are sent aloft to take shots of the city for detailed maps that can be used if intelligence sources narrow the search to a particular area or type of structure. Helicopters equipped with radiation detectors can sweep over the city as well, but a nuclear weapon gives off little telltale radiation and is nearly impossible to find from above a dense, urban area.

Most of the search must be conducted on the ground. Minivans are rented at the local airport, the backseats removed and replaced with electronic detectors that can sniff the neutrons and gamma radiation a nuclear device might emit. The vans, however, are only good for use in large open areas like parking lots and highways. To search narrow streets and buildings, as many as 100 two-person teams, dressed as inconspicuously as possible, are sent on foot patrols. One team member carries a special radiation detector designed to be hidden in briefcases, student backpacks, laptop computer bags--even beer coolers, in the case of a threat to vaporize the Super Bowl.

One of the searchers, "Becky" (she asked that her real name not be used), described how she made her rounds on a recent training exercise in a large city. A 31-year-old Energy Department employee who began training as a nest searcher seven years ago, Becky and 10 colleagues were assigned to hunt for a simulated nuclear device in a hotel with 32 floors and 2,052 rooms.

Walking down the corridors, Becky and her male partner looked like the typical tourist couple on vacation, dressed in Bermuda shorts and T shirts, cameras slung over their necks. But hidden in Becky's suitcase was a sophisticated sodium iodide crystal detector to sniff minute amounts of gamma radiation from as far away as another room.

Halfway down a corridor, Becky suddenly heard "the voice," an irritating robotic message transmitted from the suitcase to a wireless, button-sized beige receiver in her ear. "Gamma alarm four," the voice droned. That was a strong radiation signal. She glanced left at the room number on the next door and subtracted three from it. The detector's microcomputer takes several seconds to analyze the radiation and calculate its strength, so the room three doors behind her must have been the one actually giving off gamma rays.

Becky and her partner never turned around or slowed their pace, lest they attract attention from other guests. At the end of the corridor, they looked back nonchalantly, then ducked into the stairwell. Becky pulled out a small radio from her purse. "We have a hit," she whispered, and relayed the room number. The searchers had found the simulated nuclear device, which had been emitting a harmless amount of radiation, in less than two hours.

As if the searching weren't nerve-racking enough, operating the detectors requires great skill because the instruments, sensitive enough to home in on a bomb, can be confused by the soup of a metropolis' naturally occurring radiation. Freshly paved roads, yellow rest-room tiles, the Vermont granite used in some of Washington's federal buildings, a patient walking out of a hospital after radiation therapy, even a bunch of bananas can set off the detectors. Finding a nuclear bomb in a city, according to a searcher, "is like looking for a needle in a haystack of needles."

Though NEST has yet to find a nuclear device, the team has unearthed conventional bombs. The only case involving nuclear material involved an employee at a Wilmington, North Carolina, nuclear fuel plant who stole a small amount of low-grade uranium and threatened to disperse it. The fbi quickly recovered the uranium, and NEST didn't have to be summoned.

In case a real nuclear device ever is found, NEST's diagnostic and assessment teams have all kinds of equipment, such as portable X-ray machines, with which to peek under the bomb's wrapping. An instrument that looks like a Dustbuster is swept over the outside of the bomb to vacuum up any faint but telling fumes it might emit.

The disabling team has a number of ways to cripple a bomb. Working with Army demolition experts, they might decide to place their own bombs around the device and blow it up in such a way that the terrorist bomb's conventional explosives wouldn't set off its nuclear component (nuclear weapons always have both a conventional and a nuclear element). nest also has a 30-mm cannon designed to blast a terrorist bomb into harmless pieces. Another option is to pour liquid nitrogen over the device to freeze its electronics.

If the bomb is a radiological dispersion device (that is, a conventional bomb larded with deadly radioactive shrapnel that will be scattered across a wide area) a special NEST team can quickly erect a nylon tent 35 ft. high and 50 ft. in diameter. Thirty thousand cubic feet of thick foam is then pumped into this "containment cone." When the terrorist's explosive is detonated, the tent is shredded, but the foam theoretically traps the radiological debris.

In various game-playing scenarios, NEST has imagined itself presenting the President of the U.S. with the worst choices of his life, choices he may have only minutes to make. In one apparently plausible scenario, there is a 10% chance that if nest tries to defuse a bomb it will accidentally detonate with its full 10-kiloton yield, killing 100,000 Americans. But there's another choice: the bomb could be blown up in such a way that it would produce only a 1-kiloton yield, which would vaporize a mere 10,000 citizens. It will be cold comfort for survivors to know that the government has a special emergency room for just this eventuality at the Methodist Medical Center in Oak Ridge, Tennessee. Called the Radiation Emergency Assistance Center (REAC), it is the only E.R. in the country dedicated solely to treating nuclear-radiation patients.

Currently NEST doesn't operate overseas, where much of the nuclear danger lies. Russia and the other states with nuclear weapons still guard their atom bomb secrets closely. But scientists at the U.S. nuclear-weapons labs maintain back-channel contacts with their counterparts from the other nuclear countries, and Washington has begun selling Moscow special equipment for recovering and handling stolen weapons.

Some nuclear scientists like John Nuckolls, associate director at the DOE's Livermore lab, believe that America's nuclear preparedness team will eventually have to join others overseas in an international nest force. "The destruction of any city in the world by nuclear terrorists would threaten all cities and nations," he insists. If so, we are all potential hostages. And the men and women of NEST may be the only ones who can come to the rescue.