September 7, 1999
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The Breakthrough: China Takes Giant Nuclear Step
China finally succeeded in exploding a miniaturized bomb on Sept. 25, 1992, American officials revealed. It took intelligence analysts more than two years to fully understand what China had accomplished, its feat becoming clear only after a Chinese nuclear expert who had been recruited to spy for the United States delivered an intriguing report to his American handlers.
The spy said China's September test blast, which had been initially viewed by American analysts as routine, was anything but. The bomb detonated that day was miniaturized with a core, the spy said, in the distinctive shape of an ovoid, indicating China had begun to master the art of making modern warheads.
In the mid-1990's, the task of tracking the technical ins and outs of other nations' nuclear programs fell to the national weapons labs. Among the sleuths was Dr. Robert M. Henson, an experienced weapons designer at Los Alamos who had been analyzing intelligence on foreign programs since 1988.
In January 1995, Dr. Henson said in an interview, he began looking more closely at how China had solved the miniaturization puzzle. For help he turned to Lawrence A. Booth, a friend who specialized in Russian analyses.
"We kept looking into it for two weeks," Dr. Henson recalled. "Then, we decided to do something."
They drew up their analysis and eventually took it to Mr. Trulock, who the previous year had become director of intelligence at the Energy Department, which oversees Los Alamos. Mr. Trulock, who has a bachelor's degree in political science and no formal technical training, said he wanted to bring in other nuclear experts, particularly ones who had long experience in developing the miniaturized nuclear triggers for H-bombs. John L. Richter of Los Alamos, a scientist who filled that void, joined the team.
The group looked more closely at a clue provided by the Chinese spy, who described the size of the bomb's atomic core with an analogy to a common household object, officials said in a new disclosure. Working from that, the scientists calculated a more precise size and Dr. Henson and Dr. Richter went through the American stockpile of nuclear arms, looking up measurements to see if any matched.
The atomic trigger of the W-88, they discovered, was close enough in size to raise suspicions.
The Energy Department held meetings in which the Los Alamos team was joined by analysts from the C.I.A. and the Defense Intelligence Agency. Federal officials now say the intelligence agencies were skeptical, reasoning that too much was being made of a foreigner's rough analogy. But the Energy Department and the Los Alamos team felt the evidence was provocative.
The breakthrough came in 1995, as has been previously disclosed, when a Chinese Government official sent a package of secret Chinese documents to American officials.
Mr. Trulock said the most revealing document, dated 1988, laid out China's nuclear modernization plans for Beijing's First Ministry of Machine Building, which, among other things, made missiles and nose cones. It not only described China's plans but compared them to the nuclear arms of the American arsenal.
Relatively crude hand drawings sketched out the nose cones enveloping the W-88, the W-87, the W-78, the W-76, the W-62 and the W-56 -- warheads of the Trident, MX and Minuteman missiles -- and also gave their overall weights and dimensions.
In itself, these were not damning. Though still officially classified secret in some cases, such information by then was widely available in many unclassified American papers and articles.
But the Chinese document, some 20 pages in translation, went on to give sensitive data about the W-88, Federal officials revealed. It accurately described the shape of the atomic trigger as not spherical and said it was situated in the nose cone's narrow forward end -- an arrangement used in some but not all American warheads. And it correctly described the hydrogen fuel, or secondary, as having a spherical shape.
More unsettling to the team, it described the width of the casing that surrounds the atomic trigger to within a millimeter, or four-hundredths of an inch. "That's pretty damn accurate," Mr. Trulock recalled.
A senior Federal official agreed. "That opened eyes," he said. "It seemed to confirm earlier assessments that had seemed insubstantial."
Mr. Trulock said his team later found that the Chinese document gave a similarly exact measure for the width of the W-88's secondary, or hydrogen stage. "Primaries are the long pole in the tent," he said, referring to the importance of the atomic trigger. "But that measurement was as good as the one for the primary."
The C.I.A. eventually concluded that the agent who sent the documents was acting under the instruction of Chinese intelligence. No one has ever come up with a persuasive explanation of why China sent the documents to American spies.
From 1992 to 1996, American officials revealed, China used its new atomic match to ignite a variety of hydrogen bombs, including one similar in some respects to the W-88. After this series of blasts shook the ground at the Lop Nur test site, China signed the Comprehensive Test Ban Treaty, signaling an end to its nuclear experimentation.
The Investigation: Federal Sleuths Hunt for a Spy
The Energy Department opened an investigation into the possible theft of W-88 secrets on Sept. 28, 1995, and over the next three years, Federal officials quietly tried to find out whether there was a Chinese spy in their midst.
If espionage occurred, Mr. Trulock and his team reasoned, it must have happened between 1984, when the warhead entered engineering development, and 1988, the date of the Chinese document.
Energy Department officials focused on Los Alamos, which had designed the bomb. They looked particularly closely at anyone who had traveled to China in those years or met visiting Chinese scientists.
Mr. Vrooman, then head of counterintelligence at Los Alamos and later a vocal critic of the inquiry, said investigators scrutinized only those people whose trips to China were paid for by the Energy Department.
Left unexamined, he said, were at least 15 additional people whose trips were paid for by the Chinese, the C.I.A., the Air Force or privately. These travelers tended to be top weapons designers and high officials -- the people who knew the most American arms secrets and had the most intimate contact with Chinese peers, Mr. Vrooman said.
In May 1996, the Energy Department turned over a list of a dozen suspects to the Federal Bureau of Investigation, which began a criminal case that eventually narrowed to Dr. Lee, an American scientist of Taiwanese birth working at Los Alamos.
Dr. Lee and his wife, Sylvia, had traveled to China in 1986 and 1988. Mrs. Lee was a secretary at Los Alamos who often met visiting Chinese delegations. And Dr. Lee, though a mechanical engineer by training and never a weapons designer, was familiar with the W-88 and many other nuclear arms and secrets (including the atomic trigger advance) because of his work on secret computer codes.
The F.B.I. believed it had enough evidence to seek a secret wiretap on Dr. Lee's phone calls, citing 20 reasons he was a prime suspect. But the Justice Department found the evidence unpersuasive and refused to seek a court order for the eavesdropping, a routine step in most spy cases.
Mr. Vrooman has charged that the inquiry was marred by a racist bias to target Chinese-Americans, an assertion Federal officials have vehemently denied. But the Republican chairman and the ranking Democrat of the Senate Governmental Affairs Committee, which investigated the spy case and heard testimony from Mr. Vrooman, concluded that Federal investigators had focused prematurely on Dr. Lee.
After the spy case became in public, Bill Richardson, the Secretary of Energy, recommended that Mr. Vrooman be disciplined for letting Dr. Lee have continuing access to secrets even after doubts about him had been raised.
Dr. Lee, fired this year from Los Alamos for security violations, including failing to report foreign contacts, has been charged with no crime and has denied any spying. After his ouster, investigators found that he had loaded many secret files onto an unsecured computer, raising the risk that they could have fallen into the wrong hands.
The inquiry most likely would not have come into public view had it not been for a series of unrelated disclosures about China.
In April 1998, The Times reported that two United States aerospace companies were under criminal investigation for providing rocket data to Chinese scientists.
A furor erupted in Congress. The House created a select committee, led by Mr. Cox, who had recently vied unsuccessfully for the House speakership, to look into whether the Administration's increasingly open policies on satellite exports had compromised national security.
There was no hint the committee would end up studying nuclear bombs.
Composed of five Republicans and four Democrats, the committee did not learn of the suspected Chinese nuclear espionage until October 1998, just a few months before its mandate expired. On Nov. 12 and Dec. 16 it held secret hearings in which Mr. Trulock was called as the star witness.
In January, after three months of investigation, the committee completed a secret manuscript. In May, after a long argument with the White House over what could be made public, it released an 872-page report. The chapter on atomic espionage, just 37 pages, garnered most of the headlines.
In fiery prose accompanied by vivid color pictures and charts, the committee charged that Chinese spies had carried off vital secrets about seven of America's most advanced arms.
The People's Republic of China, it alleged, "has stolen classified information on all of the United States' most advanced thermonuclear warheads," leaping from the clumsy designs of the 1950's to those that are far more modern and deadly.
The main evidence cited was the Chinese document obtained by the C.I.A. in 1995 and an inquiry in the 1980's into spying at the Livermore lab that concluded China had most likely obtained design secrets of the neutron bomb. The unclassified version of the committee's report gave no details of the 1995 document's secret details about the W-88.
The report was signed by the committee's four Democrats. But immediately after its release, Representative John M. Spratt Jr. of South Carolina, one of the Democrats, criticized it as rushed, superficial and exaggerated. The witnesses heard by the committee, he added, "did not have the technical background to fully assess the nature or value of the information lost."
The Debate: Analysts Sift for the Truth
Since then, Mr. Spratt's critique has been echoed and amplified by a range of top scientists and bomb designers who say Beijing could have miniaturized its warheads on its own without spying.
Richard L. Garwin, a physicist who has long advised Washington on nuclear arms, recently on a bipartisan team led by former Defense Secretary Donald H. Rumsfeld, said, "there is no reason to believe that China could not have built perfectly adequate warheads" for a range of modern missiles "from nuclear technology that it developed itself."
China, several officials said, simply went down the same path as other nuclear powers, helped along by the general knowledge of what the United States had achieved: proof that hydrogen bombs can be made very small but nonetheless very powerful.
"Every state has come to it," said one Federal official, referring to breakthroughs in atomic triggers by the Soviet Union, Britain and France. "Now they've got it too."
Mr. Hawkins, the head of international security studies at Los Alamos, which is clearly on the defensive because of the spy scandal, said the basic physics of bombs and missiles push weapons designers in roughly the same direction. To obtain the best performance, he said, engineers are invariably led toward narrow nose cones about 16 degrees wide -- if cut from a pie, a very modest slice.
"Once you realize that," Mr. Hawkins said, "it drives every nation down similar paths. Eventually, all weapons systems will look alike. It has to do more with physics than espionage."
That view is not universally accepted.
Dr. Henson, the analyst who first sounded the alarm at Los Alamos, said there was nothing in the design of missile nose cones that propelled a scientist to shape the core of an atomic trigger into an oval.
Do scientific and technical analyses automatically "draw you to a watermelon?" he asked, alluding to the shape of the top-secret design.
"That's not true."
"It's beyond a shadow of a doubt," Dr. Henson added. "Major espionage took place."
American intelligence agencies are less categorical. Analysts have concluded that espionage played a role in Beijing's advance, but cannot identify a hard link comparable to the Soviet Union's theft in the 1940's of the American design for the first atom bomb.
"Everybody has come to the same conclusion," said a top Administration official who has closely scrutinized the secret data. "We don't have a smoking gun."
A Federal intelligence study done last year, which the Cox committee drew on, said American secrets lost between 1984 and 1988 let the Chinese "accelerate their nuclear weapons program well beyond indigenous capabilities," a view that echoed the original Los Alamos finding.
A damage assessment by the American intelligence community, made public in April, said a mix of espionage, openly available data and scientific acumen had greatly lengthened Chinese strides. Stolen secrets, it said, "could help" Beijing develop a mobile missile and "probably accelerated its program to develop future nuclear weapons."
In June, the President's Foreign Intelligence Advisory Board, which did its own investigation, said both Congressional and Administration leaders had engaged in "simplification and hyperbole" in the spy case. Neither dramatic damage assessments nor categorical reassurances, it said, were wholly substantiated.
And Mr. Hawkins, the Los Alamos official, said the specific secrets known to have been seized by the Chinese, principally those detailed in the 1995 document, would have been little help to a bomb maker, and far from Mr. Trulock's road map.
As for an H-bomb's innards, what designers call the physics package, Mr. Hawkins said the documents "describe nothing significant."
Mr. Cox insisted that highly classified intelligence data available to his committee showed a more persuasive case than has emerged publicly. "There are more interpolating facts" that closely tie lost W-88 secrets to Beijing's advance, he said.
But a Federal official cited intelligence data about China's atomic trigger showing it to be anything but an exact copy.
"It turns out the W-88's is slightly smaller," said the official, who believes Beijing may have made the advance on its own.
It remains unresolved how China got the W-88 secrets in the first place, but a consensus is emerging that the search for the leak narrowed too quickly to Los Alamos.
Studies by the Senate as well as the President's foreign intelligence board this year raised serious questions about whether the F.B.I. and Energy Department had too quickly focused on the weapons lab. No evidence has pinpointed it as the leak's source.
Mr. Vrooman, the head of counterintelligence at the laboratory from 1987 until 1998, noted that one secret document describing the design of the W-88 warhead went to 548 mailing addresses throughout the Government and military. Some Administration experts believe the data described by the Chinese in the 1995 document came from engineering plans or from secret manuals on military bases.
"That kind of information was widely available," said Dr. Drell of Stanford, who served on the President's advisory board investigation. "The manuals that went out had pictures and numbers. If a submarine came in, and there was a problem, they had to know what they were dealing with."
However Beijing made its miniaturization advance -- on its own, by theft or a combination of the two -- it is apparently proud enough to boast about it publicly, at least among its friends in the mountains of New Mexico. Dr. Henson said a Chinese arms scientist, Sun Cheng Wei, bragged of the breakthrough at Los Alamos a few years ago, telling an open seminar that China had forged significantly ahead in nuclear arms.
"What he said," recalled Dr. Henson, who attended the talk, "was that for a long time they were dealing only with round designs, and then only watermelons."
Copyright 1999 The New York Times Company