The Two Koreas_ A Contemporary History - Don Oberdorfer [153]
When they were actually walking through this facility, Blix and his team had two surprises: first, that the six-story-high building, the length of two football fields, was even more imposing than they had expected from the CIA briefings; and second, that the building was only about 80 percent complete, and the equipment inside only about 40 percent ready for full-scale production. An IAEA official described the works inside the giant building as "extremely primitive" and far from ready to produce the quantities of plutonium needed for a stockpile of atomic weapons. This conclusion contradicted worst-case U.S. assessments, such as that by CIA director Robert Gates on March 27 that "we believe Pyongyang is close, perhaps very close, to having a nuclear weapon capability."
North Korea had reported to the IAEA in its initial declaration that in 1990 it had already produced about 90 grams of plutonium, roughly three ounces, on an experimental basis in the "radiochemical lab." In a third surprise, the seemingly obliging North Koreans shocked Blix by proudly presenting him with a vial of the plutonium in powdered form, which is deadly when inhaled. (Back in Vienna, the IAEA team underwent immediate medical exams that confirmed that they had not been contaminated.) This small amount was far short of the 8 to 16 pounds needed to produce a weapon. Nevertheless, if plutonium had been manufactured at all, it would be difficult to ascertain scientifically how much had been produced, raising the possibility that North Korea had squirreled some away.
While very small quantities of plutonium could be separated using test methods in a laboratory, IAEA officials found it illogical that North Korea would have erected a huge and expensive facility without first building a pilot plant to test its procedures. North Korea denied that such a pilot plant existed, but doubts persisted.
In late May, after Blix and his team returned to Vienna, the agency sent its first set of regular inspectors to Yongbyon. "The first inspection was just to get the picture," said 0111 Heinonen, a sandyhaired IAEA veteran who eventually became chief inspector of the North Korean program. "The second inspection [in July] saw something that didn't fit the picture, the first signals that something was wrong." More discrepancies appeared beginning with the third inspection, which took place in September.
North Korea had reported that it had separated the three ounces of plutonium in an experimental procedure in 1990, when a small number of faulty fuel rods had been taken from its 5-megawatt indigenous reactor. To confirm what had been done, IAEA inspectors swabbed the inside of the steel tanks used to process the plutonium. The inspectors assumed that the North Koreans had previously scrubbed down the equipment, but the IAEA teams employed gamma ray detectors and other gear capable of finding minute particles clinging to grooved surfaces. The IAEA also convinced the North Koreans to cut into a waste storage pipe to obtain some of the highly radioactive waste that is a by-product of the plutonium production process.
Tests on some of this material were run at the IAEA's laboratory near its headquarters in Vienna. Far more sophisticated tests were conducted for the IAEA in supporting laboratories run out of the U.S. Air Force Technology Applications Center at Patrick Air Force Base, Florida. Much of the work of this laboratory, which had pioneered the analysis of Soviet nuclear tests, had been secret during the cold war.
Precise measurements of the rates of decay of the constituent elements of the plutonium samples indicated that three different episodes of plutonium separation could have taken