Operation Upshot–Knothole

Operation Upshot–Knothole
The Grable test, with the Atomic Annie artillery piece used to fire the warhead.
Information
Country	United States
Test site	NTS Areas 5, 11, Frenchman Flat; NTS, Areas 1-4, 6-10, Yucca Flat
Period	1953
Number of tests	11
Test type	free air drop, gun deployed, tower
Max. yield	61 kilotonnes of TNT (260 TJ)
Navigation
Previous test series	Operation Ivy
Next test series	Operation Castle

Operation Upshot–Knothole was a series of eleven nuclear test shots conducted in 1953 at the Nevada Test Site. It followed Operation Ivy and preceded Operation Castle.

Over 21,000 soldiers took part in the ground exercise Desert Rock V in conjunction with the Grable shot.^[1] Grable was a 280mm shell fired from the “Atomic Cannon” and was viewed by a number of high-ranking military officials.

The test series was notable as containing the first time an atomic artillery shell was fired (shot Grable), the first two shots (both fizzles) by University of California Radiation Laboratory—Livermore (now Lawrence Livermore National Laboratory), and for testing out some of the thermonuclear components that would be used for the massive thermonuclear series of Operation Castle.

United States' Upshot-Knothole series tests and detonations

Name [note 1]	Date time (UT)	Local time zone [note 2][2]	Location [note 3]	Elevation + height [note 4]	Delivery,[note 5] Purpose [note 6]	Device [note 7]	Yield [note 8]	Fallout [note 9]	References	Notes
Annie	17 March 1953 13:20:00.3	PST (-8 hrs)	NTS Area 3 37°02′52″N 116°01′19″W / 37.0477°N 116.022°W	1,230 m (4,040 ft) + 90 m (300 ft)	tower, weapons development	TX-5HE "XR-3" Type D pit	16 kt	I-131 venting detected, 2.4 MCi (89 PBq)	[3][4][5][6][7]	Investigated yield-vs-initiation time curve. Live news coverage. Desert Rock V. Two 2-story houses, 50 autos, bomb shelters in effects test.
Nancy	24 March 1953 13:10:00.0	PST (-8 hrs)	NTS Area 4 37°05′44″N 116°06′13″W / 37.0955°N 116.1037°W	1,230 m (4,040 ft) + 90 m (300 ft)	tower, weapons development	TX-15 "Nevada Zombie"	24 kt	I-131 venting detected, 3.6 MCi (130 PBq)	[3][4][5][6][7]	Proof test of TX-15. Desert Rock V. Tested RACER boosted primary.
Ruth	31 March 1953 13:00:00.0	PST (-8 hrs)	NTS Area 7 37°04′58″N 116°01′29″W / 37.0827°N 116.0248°W	1,270 m (4,170 ft) + 90 m (300 ft)	tower, weapons development	"Hydride 1"	200 t	I-131 venting detected, 28 kCi (1,000 TBq)	[3][4][6][7]	1st UCRL device, a uranium hydride core, meant to be a thermonuclear primary, predicted yield was 1.5 to 3 kilotons. Device fizzled - hydride to slow neutrons was too slow. Embarrassing for designers, as it left 200 feet (61 m) of tower still standing (see image of tower).
Dixie	6 April 1953 15:29:38.4	PST (-8 hrs)	NTS Area 7 37°05′05″N 116°01′08″W / 37.0847°N 116.0189°W	1,284 m (4,213 ft) + 1,830 m (6,000 ft)	free air drop, weapons development	Mk-5D "Deuterium"	11 kt	I-131 venting detected, 1.7 MCi (63 PBq)	[3][4][5][6][7]	TX-5D proof test, lithium hydride boost experiment. Exploded 600 ft (180 m) ENE of intended zero point.
Ray	11 April 1953 12:44:59.8	PST (-8 hrs)	NTS Area 4 37°05′56″N 116°05′36″W / 37.09889°N 116.09332°W	1,296 m (4,252 ft) + 30 m (98 ft)	tower, weapons development	"Hydride 2"	200 t	I-131 venting detected, 28 kCi (1,000 TBq)	[3][4][6][7]	2nd UCRL device, uranium deuteride; it also fizzled. Legend has it that 100 foot tower was used, to avoid embarrassment in case of fizzle.
Badger	18 April 1953 12:35:00.0	PST (-8 hrs)	NTS Area 2 37°08′18″N 116°07′07″W / 37.1383°N 116.1187°W	1,370 m (4,490 ft) + 90 m (300 ft)	tower, weapons development	TX-16 "Buzzard"	23 kt	I-131 venting detected, 3.6 MCi (130 PBq)	[3][4][5][6][7]	Test of the TX-16 cryogenic design. Also tested RACER primary. Desert Rock V.
Simon	25 April 1953 12:29:59.8	PST (-8 hrs)	NTS Area 1 37°03′11″N 116°06′13″W / 37.053°N 116.1036°W	1,294 m (4,245 ft) + 90 m (300 ft)	tower, weapons development	TX-17/24 "Simultaneity"	43 kt	I-131 venting detected, 6.3 MCi (230 PBq)	[3][4][5][6][7]	Tested TX-17/24 series, and the RACER primary.
Encore	8 May 1953 15:29:55.4	PST (-8 hrs)	NTS Area 5 36°48′00″N 115°55′44″W / 36.8°N 115.929°W	940 m (3,080 ft) + 740 m (2,430 ft)	free air drop, weapon effect	Mk-6D	27 kt	I-131 venting detected, 3.9 MCi (140 PBq)	[3][4][5][6][7]	"Effects" test. Dropped 950 ft (290 m) SSW of target. Desert Rock V, bad exposures for troops and bad downwinder fallout.
Harry	19 May 1953 12:04:59.5	PST (-8 hrs)	NTS Area 3 37°02′25″N 116°01′34″W / 37.0402°N 116.0261°W	1,224 m (4,016 ft) + 90 m (300 ft)	tower, weapons development	TX-13D "Hamlet"	32 kt	I-131 venting detected, 4.6 MCi (170 PBq)	[3][4][5][6][7]	New hollow core design, most efficient pure-plutonium device under 100 kt indicates very good compression. Major effects testing of a high elevation explosion. Heaviest downwind contamination measured.
Grable	25 May 1953 15:30:00.3	PST (-8 hrs)	Launch from NTS Areas 5, 11, Frenchman Flat: 5 36°42′15″N 115°58′26″W / 36.70428°N 115.97387°W, elv: 950 + 5 m (3,117 + 16 ft); Detonation over NTS 36°47′35″N 115°54′56″W / 36.793°N 115.9156°W	960 m (3,150 ft) + 160 m (520 ft)	gun deployed, weapon effect	W9 (nuclear warhead) AFAP "Gun"	15 kt	I-131 venting detected, 2.1 MCi (78 PBq)	[3][4][5][6][7]	The 2nd of four gun-type device tests. Fired from Annie M65 Atomic Cannon 11 km (6.8 mi) downrange. 280mm shell, 365 kg (805 lb). Detonation at 200 feet (61 m) SW of target. Desert Rock V. Major effects test.
Climax	4 June 1953 11:14:56.7	PST (-8 hrs)	NTS Area 7 37°05′15″N 116°01′09″W / 37.0875°N 116.0192°W	1,288 m (4,226 ft) + 410 m (1,350 ft)	free air drop, weapons development	Mk-7, "Cobra", Type D pit	61 kt	I-131 venting detected, 8.6 MCi (320 PBq)	[3][4][5][6][7]	Proof test of Mk-7 to be used as a primary in Castle, detonated 320 ft (98 m) NW of target. Composite implosion system in a Type D pit. Used Cyclotol 75/25 explosive mixture.

1. The US, France and Great Britain have code-named their test events, while the USSR and China did not, and therefore have only test numbers (with some exceptions – Soviet peaceful explosions were named). Word translations into English in parentheses unless the name is a proper noun. A dash followed by a number indicates a member of a salvo event. The US also sometimes named the individual explosions in such a salvo test, which results in "name1 – 1(with name2)". If test is canceled or aborted, then the row data like date and location discloses the intended plans, where known.
2. To convert the UT time into standard local, add the number of hours in parentheses to the UT time; for local daylight saving time, add one additional hour. If the result is earlier than 00:00, add 24 hours and subtract 1 from the day; if it is 24:00 or later, subtract 24 hours and add 1 to the day. All historical timezone data (excepting Johnston Atoll) are derived from here:
3. Rough place name and a latitude/longitude reference; for rocket-carried tests, the launch location is specified before the detonation location, if known. Some locations are extremely accurate; others (like airdrops and space blasts) may be quite inaccurate. "~" indicates a likely pro-forma rough location, shared with other tests in that same area.
4. Elevation is the ground level at the point directly below the explosion relative to sea level; height is the additional distance added or subtracted by tower, balloon, shaft, tunnel, air drop or other contrivance. For rocket bursts the ground level is "N/A". In some cases it is not clear if the height is absolute or relative to ground, for example, Plumbbob/John. No number or units indicates the value is unknown, while "0" means zero. Sorting on this column is by elevation and height added together.
5. Atmospheric, airdrop, balloon, gun, cruise missile, rocket, surface, tower, and barge are all disallowed by the Partial Nuclear Test Ban Treaty. Sealed shaft and tunnel are underground, and remained useful under the PTBT. Intentional cratering tests are borderline; they occurred under the treaty, were sometimes protested, and generally overlooked if the test was declared to be a peaceful use.
6. Include weapons development, weapon effects, safety test, transport safety test, war, science, joint verification and industrial/peaceful, which may be further broken down.
7. Designations for test items where known, "?" indicates some uncertainty about the preceding value, nicknames for particular devices in quotes. This category of information is often not officially disclosed.
8. Estimated energy yield in tons, kilotons, and megatons. A ton of TNT equivalent is defined as 4.184 gigajoules (1 gigacalorie).
9. Radioactive emission to the atmosphere aside from prompt neutrons, where known. The measured species is only iodine-131 if mentioned, otherwise it is all species. No entry means unknown, probably none if underground and "all" if not; otherwise notation for whether measured on the site only or off the site, where known, and the measured amount of radioactivity released.

References

1. Operation UPSHOT-KNOTHOLE Fact Sheet, Defense Threat Reduction Agency
2. "Timezone Historical Database". iana.com. Retrieved March 8, 2014.
3. Estimated exposures and thyroid doses received by the American people from Iodine-131 in fallout following Nevada atmospheric nuclear bomb tests, Chapter 2 (PDF), National Cancer Institute, 1997, retrieved 2014-01-05
4. Sublette, Carey, Nuclear Weapons Archive, retrieved 2014-01-06
5. Hansen, Chuck (1995), The Swords of Armageddon, Vol. 8, Sunnyvale, CA: Chukelea Publications, ISBN 978-0-9791915-1-0
6. United States Nuclear Tests: July 1945 through September 1992 (PDF) (DOE/NV-209 REV15), Las Vegas, NV: Department of Energy, Nevada Operations Office, 2000-12-01, retrieved 2013-12-18
7. Yang, Xiaoping; North, Robert; Romney, Carl (August 2000), CMR Nuclear Explosion Database (Revision 3), SMDC Monitoring Research

External links

• Operation Upshot-Knothole
• The short film Nuclear Test Film - Operation Upshot-Knothole (1953) is available for free download at the Internet Archive
• The short film Nuclear Test Film - Operation Upshot-Knothole, 5.2 (1953) is available for free download at the Internet Archive
• The short film The 280 mm Gun at the Nevada Proving Ground (1953) is available for free download at the Internet Archive
• Operation Upshot-Knothole - 1953
• Film about Upshot Knothole Tests