The Two Koreas_ A Contemporary History - Don Oberdorfer [142]
n the early 1990s, North Korea's program to develop nuclear weapons concentrated the minds of many of the world's political and military leaders and held their attention to an unprecedented degree. This frightening development was a potential threat not only to South Korea, the American troops on guard there, and the immediate Asian neighborhood; it was a threat as well to international stability and world order. A North Korean bomb could touch off a dangerous nuclear arms competition involving South Korea, Japan, and perhaps other industrialized nations and spread nuclear weapons materials to pariah nations in the Middle East through North Korean sales. More than that, an atomic weapon in the hands of an isolated and unpredictable regime with a record of terrorism would be a nightmare. It was, as South Korea's presidential national security adviser, Kim Chong Whi, told me while he was in office, not an issue of normal politics but "a question of civilization."
The more the outside world feared it, the more its nuclear program was a valuable asset to North Korea, which had few other resources of external worth after the decline of its alliances with the Soviet Union and China. There is no evidence that Pyongyang saw the nuclear program as a bargaining chip at its inception, but the record is clear that by the 1990s it had learned the program's value in relations with the world outside.
North Korea's nuclear debut, in the eyes of outsiders, dated back to April 1982, when an American surveillance satellite whirring unseen in the skies photographed what appeared to be a nuclear reactor vessel under construction in the bend of a river at Yongbyon, sixty miles north of the capital. When the photographs were examined in Washington a few days later, they drew the intense interest of American intelligence analysts, who marked the spot for special attention. In March 1984, as construction proceeded, a satellite pass showed the outline of a cylindrical nuclear smokestack rising from the site. Another set of photographs taken in June 1984 clearly showed the reactor, its cooling tower, and some limited power lines and electrical grid connections for local transmission of the energy to be produced.
Intelligence experts in Washington concluded from the photographs that the reactor utilized two minerals found in abundance in North Korea: natural uranium, to create an atomic reaction, and graphite, to moderate and control it. The layout was startlingly similar to old-model French and British reactors of the late 1950s, built to produce material for atomic weapons.
Taken alone, the North Korean reactor, while highly suspicious, was not conclusive evidence of a weapons program because it could also be the initial element of a civil nuclear power program. However, suspicions were heightened in March 1986, when satellite photographs of the Yongbyon area detected cylindrical craters in the sand of the nearby river bank. Analysts believed they were the residue of experimental high-explosive detonations in a certain pattern familiar to nuclear weapons experts: the precisely simultaneous explosions that are basic to implosion, one of the standard means of detonating an atomic bomb. After this discovery, restudy of earlier photographs produced evidence of similar craters in the same area since 1983.
With a reactor set to burn uranium and the technique of finely honed explosions appearing to be under development, the principal missing element in a serious atomic weapons program was a reprocessing plant. Using a complex chemical process, such a plant can separate plutonium, the raw material for a nuclear weapon, from other by-products of spent uranium fuel. Starting in March 1986, satellite photographs detected the outlines of a huge oblong building, nearly the length of two football fields, under construction at Yongbyon. In February 1987 the U.S. cameras looked down into the unroofed plant to see a long series of thick-walled cells in the typical configuration for separation of plutonium. A short time later, when the plant was roofed,