Nuclear Tests

On May 28, 1998 Pakistan announced that it had successfully conducted five nuclear tests. The Pakistani Atomic Energy Commission reported that the five nuclear tests conducted on May 28 generated a seismic signal of 5.0 on the Richter scale, with a total yield of up to 40 KT (equivalent TNT). Dr. A.Q. Khan claimed that one device was a boosted fission device and that the other four were sub-kiloton nuclear devices.

On May 30, 1998 Pakistan tested one more nuclear warhead with a reported yield of 12 kilotons. The tests were conducted at Balochistan, bringing the total number of claimed tests to six. It has also been claimed by Pakistani sources that at least one additional device, initially planned for detonation on 30 May 1998, remained emplaced underground ready for detonation.

Pakistani claims concerning the number and yields of their underground tests cannot be independently confirmed by seismic means, and several sources, such as the Southern Arizona Seismic Observatory have reported lower yields than those claimed by Pakistan. Indian sources have also suggested that as few as two weapons were actually detonated, each with yields considerably lower than claimed by Pakistan. However, seismic data showed at least two and possibly a third, much smaller, test in the initial round of tests at the Ras Koh range. The single test on 30 May provided a clear seismic signal.

DEVICE	DATE	YIELD [announced]	YIELD [estimated]
[boosted device?]	28 May 1998	25-36 kiloton	total 9-12 kiloton
Fission device	28 May 1998	12 kiloton
Low-yield device	28 May 1998	sub-kiloton	--
Low-yield device	28 May 1998	sub-kiloton	--
Low-yield device	28 May 1998	sub-kiloton	--
Fission device	30 May 1998	12 kiloton	4-6 kiloton
Fission device	not detonated	12 kiloton	--
This table lists the nuclear tests that Pakistan claims to have carried out in May 1998 as well as the announced yields. Other sources have reported lower yields than those claimed by Pakistan. The Southern Arizona Seismic Observatory reports that the total seismic yield for the May 28th tests was 9-12 kilotons and that the yield for the May 30th tests was 4-6 kilotons.

According to a preliminary analysis conducted at Los Alamos National Laboratory, material released into the atmosphere during an underground nuclear test by Pakistan in May 1998 contained low levels of weapons-grade plutonium. The significance of the Los Alamos finding was that Pakistan had either imported or produced plutonium undetected by the US intelligence community. But Lawrence Livermore National Laboratory and other agencies later contested the accuracy of this finding.