China’s Nuclear Update – 1999

China continues to modernize its nuclear weapons, which could pose an increasing threat to the United States and its regional allies. In recent years, China defied international opinion to continue nuclear testing until the final negotiation of the Comprehensive Test Ban Treaty. China’s objective was to perfect smaller and lighter nuclear warheads.

While the nuclear threat from China is limited, it is growing. Robert Walpole, the CIA’s National Intelligence Officer for Strategic and Nuclear Programs, said in September 1998 that China’s “modernization efforts will likely increase the number of Chinese warheads aimed at the United States.” According to a recent Pentagon report, a sleeker, more powerful Chinese nuclear arsenal would have two aims. First, it would enhance deterrence of major strategic rivals, such as the United States or a resurgent Russia; second, it would improve China’s “status as an international power.” In addition to these aims, an improved arsenal would give China the ability to defeat American-supplied theater missile defenses, which might come to include Taiwan.

Historical development

China’s nuclear weapons program officially began in 1955, when China and the Soviet Union began a series of nuclear cooperation agreements. The Soviet Union rapidly built up China’s nuclear infrastructure until relations cooled in 1960. China tested an A-bomb in 1964 and three years later tested its first thermonuclear weapon. Since then, China has produced an arsenal estimated at around 400 warheads, of which about 250 are on land-based ballistic missiles, bombers, and submarine-launched ballistic missiles, and some 150 are tactical nuclear weapons. Estimates of the numbers of specific missiles deployed vary widely. (For further information on the historical development of China’s nuclear forces, see “China’s Nuclear Ambition Grows,” Risk Report, vol. 1, no. 9, November 1995.)

China is now modernizing its nuclear forces by developing lighter warheads for the longer-range, more accurate missiles it is building. Currently, China is not believed to be producing fissile material, but it has a stockpile sufficient to increase or improve its weapon inventory significantly. It is estimated that China has up to 4 tons of plutonium and 23 tons of high-enriched uranium, enough material for more than 2000 nuclear weapons. While the Chinese rely on a far smaller number of warheads than that to achieve deterrence, the existence of this stockpile facilitates Chinese modernization efforts and keeps strategic options open for the future.

China’s modernization efforts

Until the Comprehensive Test Ban Treaty (CTBT) was opened for signature in September 1996, the Chinese braved international condemnation to continue to test nuclear weapons. China conducted about two tests per year until July 1996, after which China declared a self-imposed moratorium. In September 1996, China signed the CTBT but it has yet to ratify it.

Chinese Nuclear Tests After 1990

Date of Test Estimated Yield
May 21, 1992660 kT – 1 MT
September 25, 19921-20 kT
October 5, 199340-80 kT
June 10, 199410-100 kT
October 7, 199440-150 kT
May 15, 199540-150 kT
August 17, 199520-80 kT
June 8, 199620-80 kT
July 29, 19961-5 kT

China detonated its largest nuclear device at its Lop Nur test site on May 21, 1992. The device was widely reported by the media to have a one megaton yield, but one respected group of analysts put the yield at closer to 660 kilotons, roughly 50 times the power of the bomb dropped on Hiroshima. This large underground test greatly exceeded the 150 kiloton limit agreed to by the United States and the Soviet Union in 1976. The device was reportedly a warhead for one of China’s new intercontinental ballistic missiles, either the DF-31 or DF-41.

The purpose of China’s last sequence of tests was modernization. China wanted to develop smaller, more potent warheads before it could no longer conduct underground tests under the CTBT. With smaller warheads, China would be able to increase the range of its ballistic missiles by reducing their payload. In addition, China appears to be interested in deploying multiple reentry vehicles (MRVs) or multiple independently-targeted re-entry vehicles (MIRVs) on ballistic missiles. In order to do so, China must develop warheads small enough to be grouped on the top of a single rocket.

In addition to pursuing its own development program, China has sought nuclear weapon technology abroad, by means licit and illicit. The recent report of a select committee of the U.S. House of Representatives, chaired by Representative Christopher Cox, indicates that China stole secret nuclear weapon design information from the Los Alamos National Laboratory in the mid-1980s. The design was for the W-88 nuclear warhead, which tops the US Trident II submarinelaunched ballistic missile. The information is said to have included general, but secret information about the warhead’s weight, size, explosive power, and internal configuration. Although China has not developed a weapons system using the W-88 information, US analysts believe it tested a warhead with similar characteristics in the mid-1990s. The stolen information could reduce the research and design time necessary to develop a small, mobile and MIRVed nuclear missile.