Tiger Trap

by David Wise

  To emphasize that China had the neutron bomb, the New China News Agency put out a dispatch that same day headlined, "China Masters Neutron Bomb Technology." The story said Beijing had begun work on the bomb in the 1970s. "China has already mastered the neutron bomb design technology," the story declared.

  The Cox Report asserted that in 1996 the intelligence community learned that China "had successfully stolen" more secret information about the neutron bomb from a US weapons lab. It offered no further details about the second alleged theft or whether the source of the leak had been uncovered by the FBI. But there was a TOP SECRET investigation, apparently code-named SILENT CHORUS, of the second reported theft.

  One published account, cited by the Congressional Research Service, quoted unnamed American officials who speculated that China may have sought more US information about the neutron bomb because the Chinese test in 1988 was not successful.

  In January 1999 the classified version of the Cox Report circulated among White House and government officials, and the Clinton administration knew it would have to react when the report became public. In February, George Tenet, then the director of the CIA, appointed Robert D. Walpole, a senior agency manager and former State Department official, to head an interagency task force to conduct a damage assessment on Chinese acquisition of US nuclear weapons secrets.

  Despite the uproar over the Cox Report, in the end the damage assessment agreed with a number of the report's central conclusions:

  China obtained by espionage classified US nuclear weapons information that probably accelerated its program to develop future nuclear weapons....

  China also obtained information on a variety of US weapon design concepts and weaponization features, including those of the neutron bomb.

  Like the Cox Report, the damage assessment—or at least the version made public—never mentioned by name the case it was referring to, the case that had begun two decades earlier, code-named TIGER TRAP.

  Chapter 8

  THE WALK-IN

  EARLY IN 1995, an event took place that jolted American intelligence agencies and touched off years of controversy inside their closed and secret world.

  A middle-aged Chinese man appeared at a CIA station in Southeast Asia with a large cache of documents. Among them was a blockbuster, a Chinese government memo, classified SECRET, that described, in chilling and specific detail, the miniaturized W-88 thermonuclear warhead that sits atop the ballistic missiles on US Trident submarines. The W-88 is the crown jewel, the most advanced weapon in the nation's arsenal.

  The man who brought the documents was a classic walk-in, the designation in the intelligence business for someone who shows up and volunteers information. In this case, the walk-in presented a document that displayed the classified measurements of America's most secret nuclear weapon. He might just as well have walked in with a bomb in a suitcase.

  The walk-in, whose identity has never been revealed by US intelligence, was cautious. He did not, in his initial contact, bring the documents. But he told the CIA he had what he described as a duffle bag full of Chinese classified secrets that he wanted to sell. The next time he came, he brought the papers with him. He said he had gotten them out of China by shipping them to himself abroad—by DHL.

  The walk-in then told the CIA officers who questioned him at length a story so bizarre that it just might have been true. He said he worked in China's nuclear weapons program and had access to a library storage facility that housed sensitive classified information. The library was in a government institute.

  He said he entered the storage area at night, rifled the files, collected the documents, and put them in the duffle bag. But the next problem was how to get the duffle bag out of the building and past security. He hit on an unusual solution. He threw the duffle bag out of a second-story window.

  But the duffle bag broke, and papers scattered all over the ground. The man lost his nerve and, fearful of being caught, hid in the storage area and waited for a chance to get away undetected. At one point he heard footsteps approaching, but he was not seen and eventually the footsteps went away.

  Relieved, he lit a cigarette. Bad move. Someone came into the room and saw the smoke rising. He was caught. He explained coolly that he had been working late, fallen asleep in the library, and decided to have a smoke. But he was leaving now.

  As the walk-in related the story, he then ran downstairs, out of the facility, and found the papers that had scattered when the duffle bag broke. He scrambled and recovered them, stuffing them all back into the bag.

  His story might have been dismissed as improbable but for the fact that one of the documents in his possession accurately described the measurements of the W-88. The stark fact, which could not be ignored, was that China had somehow acquired highly secret data about America's most sophisticated nuclear warhead.

  The documents were flown to CIA headquarters in Langley, Virginia, where teams of translators began poring over the trove. There were so many documents to translate that the CIA had to hire contractors to supplement its own staff.

  The effort went on for years. As the documents were translated, the work began of sifting through and analyzing the mass of data.

  Initially, the CIA did not share its hoard of documents with the FBI and other US intelligence agencies, under the rationale that the agency first needed to translate and study the material. Not until several months later, in the fall of 1995, was the Department of Energy given the W-88 document, and an interagency group, including the FBI, DOE, and scientists from the national weapons labs, was brought in to assess the documents.

  The CIA, it appeared at first glance, had struck gold. Intelligence operators always hope to keep a walk-in as an "agent in place," so that he or she can continue to supply information. A spy who becomes a defector and loses access to more secrets is much less valuable.

  Under the CIA's rules, a prospect cannot be recruited as a full-fledged agent until vetted. The CIA station that proposes the recruitment must also receive provisional operational authority from Langley headquarters. Traces were run on the walk-in, and it was determined that he had no previous contact with the CIA and no known connection to the MSS or the MID, the Chinese military intelligence arm of the People's Liberation Army.

  CIA headquarters officials then gave provisional operational approval to enroll the walk-in and keep him on the job as an agency asset. With provisional status, he was one step away from being recruited.

  The walk-in was closely questioned on how he had obtained the documents. He claimed that he had access to the library containing the documents because he worked in the Chinese nuclear weapons program, and he stuck to his story about collecting the information in a duffle bag and throwing it out the window. He also said that his official status allowed him to travel. Although he wanted money in return for the documents, at the same time he alleged that his motive was ideological.

  Not only did the walk-in provide the key document with astonishing and highly classified details about the W-88, he also turned over data describing five other thermonuclear warheads designed for ballistic missiles in the US arsenal.

  The five other warheads were the W-78, for the Minuteman III intercontinental ballistic missile (ICBM); the W-76, like the W-88 designed for a submarine-launched ballistic missile (SLBM) on the Trident sub; the W-87, designed for the Peacekeeper (MX) ICBM; the W-62, for the Minuteman III ICBM; and the W-56, for the Minuteman II ICBM. The first two and the W-88 were designed at Los Alamos National Laboratory in New Mexico; the others were created at the Lawrence Livermore National Laboratory. All were deployed.

  In the walk-in's documents the warheads were shown on a matrix, or grid. The warheads were listed down the left side and the headings across the top described the yield, size, and weight of each warhead, along with a drawing of the outer dimensions. The data, the scientists determined, was accurate.

  The CIA's analysts concentrated on the W-88 document. The information about the outside dimensions of t
he other warheads was generally available from public sources. But in the case of the W-88, the walk-in's document gave precise measurements of the components inside the warhead, information that was secret and highly classified.

  Thermonuclear weapons consist of two parts, the core, or "the pit," known as the primary, a fission bomb containing either plutonium-239 or highly enriched uranium. The bomb, the size of a grapefruit, is triggered by conventional explosives, creating an implosion and a chain reaction. That in turn triggers the secondary, the much more powerful thermonuclear, or fusion, bomb. It is called a fusion bomb, or H-bomb, because during detonation, the thermonuclear fuel lithium deuteride is compressed and two isotopes of hydrogen, deuterium and tritium, fuse to rival the energy of the sun.

  Alarmingly, the Chinese secret document, which bore a 1988 date, gave the exact diameter of the W-88's primary, 115mm, or about four and a half inches. Even more significantly, the document disclosed that the W-88's primary was "two-point aspherical"—a highly sensitive and, it was thought, carefully guarded US secret—which meant that it was shaped more like a football or a pear than a grapefruit, with implosion points at each end. Instead of packing a series of explosives all around a perfectly round primary, the explosives could be set off at only two points. And Beijing knew it.

  It got worse. The Chinese document accurately gave the radius of the round secondary as 172mm, or just under 7 inches, and it disclosed that, unlike other nukes, the primary of the W-88 was at the tapered tip of the warhead, forward of the secondary, another secret that was supposed to be closely held.

  Finally, the document accurately reported the overall length of the warhead as 1522mm, or 5 feet. There were other documents in the walk-in's cache, hundreds that dealt with other foreign missile and defense systems, including those of Russia and France. But it was the W-88 that was, from the outset, the focus of the CIA's interest.

  The W-88 warhead is the payload of the Trident II (D5) sub-based missile carried by the Ohio-class submarines, which are usually called Trident subs, after the name of the missiles they carry. Each Trident sub is armed with twenty-four missiles. The nuclear warheads are multiple independently targetable reentry vehicles (MIRVs), which means that several W-88s are released by the missile as individual targets come within range.

  The importance of the W-88 is that it is small. Miniaturized nuclear bombs, unlike the huge early versions, fit into warheads that can be launched from a single missile at multiple targets. The United States was able to produce small hydrogen bombs by the late 1950s and early 1960s. US intelligence concluded that China did not test its first miniature nuclear warhead, similar to the W-88, until September 1992.

  The precise number of warheads carried by each MIRVed Trident missile is secret, but is thought to be four. As many as eight, perhaps even ten, reentry vehicles, each with a W-88 warhead, could fit atop the Trident II missile, which has a range of forty-six hundred miles.

  The current Trident II missiles cost $30.9 million each, are forty-four feet long, and weigh 130,000 pounds. The missile is launched underwater by gas that expands in the launch tube; when it is far enough away from the sub, the first stage ignites, an "aerospike" telescopes out to reduce drag, and the boost stage starts. In two minutes, the third-stage motor ignites, and the missile travels at the speed of twenty thousand feet per second toward its targets.

  There was a fundamental reason that the W-88 document produced by the walk-in caused so much consternation inside the US intelligence community. The United States relies on a triad of nuclear weapons to deter an attack: land-based ICBMs, Air Force bombers, and nuclear-armed submarines. In the Strangelovian world of nuclear deterrence theory and mutual assured destruction (MAD), land-based missiles might be destroyed in an enemy first strike, bombers can be shot down, but submarines are relatively invulnerable. The Navy boasts that the Trident subs give the United States "its most survivable and enduring nuclear strike capability." And now the Trident's payload, the W-88, had been compromised.

  The Trident subs, known as "boomers," are huge—560-feet-long nuclear-powered ships that can travel at speeds up to twenty-five miles an hour underwater. With their crews of 155, the subs can spend two and a half months at sea. Of the eighteen Ohio-class subs, fourteen carry the Trident II missiles and W-88 warheads. Each sub has twenty-four missiles, and each W-88 has an estimated yield of 475 kilotons.

  Writing in an official Navy publication, retired captain Edward L. Beach, a highly decorated World War II sub veteran and author of the best-selling 1955 novel Run Silent, Run Deep, described the enormous power of the Trident subs. "A single broadside from such a submarine—all 24 missiles fired at the same time—can destroy any nation on the face of the earth. No nation—and this includes our own—could even hope to function, or even continue to exist, in the face of such a salvo."

  To the intelligence agencies and the US military, China's acquisition of the design details of the W-88 meant that there had been a horrendous leak somewhere along the line. But how, when, and where was unknown. The walk-in was seen as the key; perhaps he could unravel the mystery and help the counterintelligence operators trace the leak back to its source.

  But a problem soon developed. Before the walk-in could move from provisional status to that of a recruited agent, he had to be polygraphed. The CIA sets great store by the polygraph, even though the results of lie detector tests are notoriously inaccurate. Aldrich Ames, the CIA traitor who revealed agency secrets to Moscow and caused the death of ten agents—Russians working for the CIA—passed a polygraph test after consulting the KGB for advice. He was told to get a good night's sleep, come in rested and refreshed, be relaxed, calm, and cooperative, and try to establish a rapport with the examiner. It worked.

  When the walk-in was "fluttered"—given a polygraph test—the CIA concluded he was lying. "When asked, 'Are you being run by another intelligence service?' his answer went off the charts," said one CIA officer. "Eventually the guy was practically admitting it."

  The CIA decided, from the lie detector test and interrogations, that the walk-in was "a dangle," a dispatched agent under the control of Chinese intelligence. In the summer of 1996, despite the astonishing accuracy of the W-88 document, the CIA circulated an internal memo to its officers warning that some of the Chinese material was disinformation provided by a source being run by Beijing. The walk-in was not recruited.

  Aside from the walk-in's failure to pass the lie detector test, the CIA concluded he was a plant because some of the documents contained information that appeared to be wrong. "At first," the CIA officer said, "he [the walk-in] said he stole the stuff, then the agency discovered there was bogus stuff mixed in, so that meant he was given material by Chinese intelligence."

  There were additional reasons to be skeptical, another intelligence official asserted. "He wanted to give us more information inside China, during Chinese New Year, when nobody was on the streets. That sounded like a setup for the arrest of a [CIA] officer trying to clear a drop inside China. We didn't like the way this whole thing looked."

  The FBI, however, did not agree with the CIA's analysis. "There was a woman at CIA who always says no to a source," one FBI agent said. "She's notorious for saying no. She must have a big 'No' stamp. She pulled out her stamp and used it on the walk-in documents. She is the one who said it's a provocation, the walk-in was sent."

  The bureau gave the walk-in a separate polygraph, and the FBI's China specialists decided he was exactly who he said he was. By 1999, if not earlier, the walk-in had left China and settled in California. Later, he moved to another state, where the FBI was able to locate and interview him.

  To question the walk-in, the FBI sent Special Agent Doug Gregory, whom the bureau considered its most skilled interviewer, and Dave Lambert, an FBI counterintelligence agent who had worked on the Aldrich Ames and Robert Hanssen spy cases. They came away convinced that both the walk-in and his material were legitimate.

  The FBI, thus reassured, continued to dea
l with the walk-in. The split between the two agencies, historic rivals in the intelligence world, caused a major row. To this day, both sides have stuck to their positions.

  The CIA, despite its disavowal of the walk-in, was able to validate the 1988 date of the W-88 document. Whether or not the walk-in was a directed agent, his information on the W-88 was accurate.

  Although the walk-in's document made it clear that China had somehow learned the measurements of the W-88, the Chinese would need more to replicate and support the miniaturized warhead. According to one intelligence official, "If the Chinese have the W-88, the next thing they would be looking for are the computer programs to maintain these systems. There is a high possibility of failure unless you understand these weapons. They would need computer codes that simulate what would happen to the warhead with age. It has to be constantly tested over time with computer simulations. To certify that the weapons actually work."

  Was China in fact able to use the data its spies acquired to build a miniaturized warhead and replicate the W-88? That was one of the key questions that the CIA faced. "The agency wrestled with this in its classified damage assessment," an intelligence official said. "An earlier 1997 study by CIA only agreed that whatever they got saved them time, maybe two to fifteen years, and saved them resources.

  "Chinese underground testing hit a peak in 1994-95 of a device somewhat similar to the W-88. You can't really tell, but you can bracket the yield, an analyst can put multiple sources together, and with the yield from seismographic information they can guess what was tested. Also you pick up a lot of SIGINT [signals intelligence]. They're chattering when a test takes place."