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China's Nuclear Tests: Dates, Yields, Types, Methods, and Comments

# TEST AND DATE	YIELD	TYPE	METHOD	COMMENTS
(#45) 29 July 1996	1-5 kT	Underground	--	China's 45th and most recent test
(#44) 8 June 1996	20-80 kT	Underground	--	Reported detonation of two warheads
(#43) 17 August 1995	60-80 kT	Underground	--	Prompted the Japanese Diet (legislativebody) to pass a resolution protesting China's testing; later that month, Japan froze government grants for the remainder of 1995
(#42) 15 May 1995	95 kT	Underground	--	Prompted Japan to suspend the grant portion of its foreign aid program to China
(#41) 7 October 1994	40-50 kT	Underground	--	--
(#40) 10 June1994	40-50 kT	Underground	--	--
(#39) 5 October 1993	40-80 kT	Underground	--	--
(#38) 25 September 1992	1-20 kT (About 8 kT)	Underground	--	--
(#37) 21 May 1992	660 kT-1 MT (650 kT)	Underground	--	China's largest underground test
(#36) 16 August 1990	50-200 kT (189 kT)	Underground	--	--
(#35) 26 May 1990	15-65 kT (11.5 kT)	Underground	--	--
(#34) 29 September 1988	1-20 kT (2.5 kT)	Underground	--	Reported to be a 1-5 kT enhanced radiation weapon ("neutron bomb") test
(#33) 5 June 1987	Unknown yield (250 kT)	Underground	--	--
(#32) 19 December 1984	5-50 kT (1.3 kT)	Underground	--	--
(#31) 3 October 1984	15-70 kT (9.1 kT)	Underground	--	--
(#30) 6 October 1983	20-100 kT (14.9 kT)	Underground	--	--
(#29) 4 May 1983	Unknown yield (About 1 kT)	Underground	--	--
(#28) 5 October 1982	3-15 kT	Underground	--	--
(#27) 16 October 1980	200 kT-1 MT	Atmospheric	--	The last atmospheric nuclear explosion by China or any country
(#26) 13 September 1979	Unknown yield	Underground	--	--
(#25) 14 December 1978	Below 20 kT	Atmospheric	--	Fission
(#24) 14 October 1978	Below 20 kT (3.4 kT)	Underground	Shaft method	China's first shaft explosion
(#23)15 March 1978	6-20 kT	Atmospheric	--	Fission
(#22) 17 September 1977	Below 20 kT	Atmospheric	--	Fission
(#21) 17 November 1976	About 4 MT	Atmospheric	Air (H-6 bomber)	Thermonuclear; Largest Chinese test
(#20) 17 October 1976	10-20 kT (2.6 kT)	Underground	--	Fission
(#19) 26 September 1976	200 kT	Atmospheric	--	Fission; Partial failure of fusion; "special weapon"
(#18) 23 January 1976	Below 20 kT	Atmospheric	--	Fission
(#17) 27 October 1975	Below 10 kT (2.5 kT)	Underground	--	Fission
(#16) 17 June 1974	200 kT-1 MT	Atmospheric	--	Thermonuclear
(#15) 27 June 1973	2-3 MT	Atmospheric	Air (H-6 bomber)	Thermonuclear
(#14) 18 March 1972	100-200 kT	Atmospheric	Air (H-6 bomber)	Possibly trigger device, containing Pu, for thermonuclear warhead
(#13) 7 January 1972	8-20 kT	Atmospheric	Air (Q-5 bomber)	Fission; Possibly containing Pu
(#12) 18 November 1971	15-20 kT	Atmospheric	Ground (tower-mounted)	Fission; Possibly containing Pu
(#11) 14 October 1970	3-3.4 MT	Atmospheric	Air (H-6 bomber)	Thermonuclear
(#10) 29 September 1969	About 3 MT	Atmospheric	Air (H-6 bomber)	Thermonuclear
(#9) 23 September 1969	20-25 kT (19.2 kT)	Underground	Tunnel method	Fission ; China's first underground test
(#8) 27 December 1968	3 MT	Atmospheric	Air (H-6 bomber)	Thermonuclear device; China's first test using plutonium (U235, with some Pu)
(#7) 24 December 1967	15-25 kT	Atmospheric	Air (H-6 bomber)	Fission (U235, U238, and Li-6)
(#6) 17 June 1967	3-3.3 MT	Atmospheric	Air (H-6 bomber)	China's first full-yield multi-stage thermonuclear test (U235)
(#5) 28 December 1966	122 kT/300-500 kT	Atmospheric	Ground (tower-mounted)	Boosted fission (U235); Test used to confirm the design principles of a two-stage device
(#4) 27 October 1966	12-30 kT	Atmospheric	DF-2 (CSS-1) MRBM	Fission (U235)
(#3) 9 May 1966	200-300 kT/	Atmospheric	Air (H-6 bomber)	Boosted fission (U235); China's first test of a boosted fission device (using Lithium-6)
(#2) 14 May 1965	20-40 kT	Atmospheric	Air (H-6 bomber)	Fission (U235); China's first air-drop explosion by aircraft
(#1) 16 October 1964	20-22 kT	Atmospheric	Ground (tower-mounted)	Fission (U235); China's first nuclear explosion, named "Device 596," representing the year and month in which the Soviets refused to provide China with a prototype device (June 1959)

"...The Teller-Ulam concept was later rediscovered by the other four nuclear weapon states, all of which have tested and deployed these weapons. No other nation is known to have deployed these designs, although the undeclared nuclear powers of Israel and India almost certainly have done development work on them.

Three stage designs have been tested and deployed to produce very high yield weapons. The first three stage U.S. test, and probably the first three stage weapon test ever, was the Bassoon device detonated in the Redwing Zuni test (27 May 1956 GMT, Bikini Atoll, 3.5 Mt). The largest nuclear explosion ever set off (50 Mt) was the Tsar Bomba (King of Bombs), a Soviet three stage fission-fusion-fission design. It was exploded on 30 October 1961 over Novaya Zemlya at an altitude of 4000 m.

By jacketing the third stage with non-fissionable material, three stage devices can produce high yield clean weapons. Both Zuni and Tsar Bomba were in fact very clean devices - Zuni was 85% fusion and Tsar Bomba was 97% fusion. Both designs permitted replacing the lead or tungsten third stage jacket with U-238 however. A version of Bassoon called Bassoon Prime was tested in the dirty Tewa test mentioned above. A dirty device derived from the Bassoon was weaponized to create the highest yield weapon the U.S. ever fielded, the 25 megaton Mk-41. The Tsar Bomba design was for a fission-fusion-fission bomb with a staggering yield of at least 100 megatons!

A possible variation on the staged radiation implosion design is one in which a second fission stage is imploded instead of a thermonuclear one. This was actually the initial concept developed by Stanislaw Ulam before he realized its possible application to thermnuclear weapons. The advantage of this approach is that radiation implosion speeds are hundreds of times higher, and maximum densities tens of times greater, than those achievable through high explosives. This allows achieving higher yields than is practical with high explosive driven fission weapons, and the use of lower grades of fissile material. If some fusion fuel is included in this second fission stage to boost yield, a sort of hybrid two-stage boosted weapon design results that blurs the distinction between two-stage fission and classic Teller-Ulam thermonuclear weapons. The TX-15 "Zombie" developed by the U.S. was originally planned to be a two stage pure fission device, but later evolved into this sort of hybrid boosted system. The Zombie was tested in the Castle Nectar shot (13 May 1954 GMT; Bikini Atoll; 1.69 Mt), and was fielded as the Mk-15..."