Operation Upshot–Knothole

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 Upshot-Knothole Grable shot. Grable was a 280mm Artillery Fired Atomic Projectile (AFAP) 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 AFAP shell was fired (GRABLE Shot), 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. One primary device (RACER) was tested in thermonuclear system mockup assemblies of TX-14, TX-16, and TX-17/TX-24, to examine and evaluate the behaviour of radiation cases and the compression of the secondary geometries by the primary's x-rays prior to full-scale testing during Castle. Following RACER's dodgy performance, the COBRA primary was used in the emergency capability ALARM CLOCK, JUGHEAD, RUNT I, RUNT II thermonuclear devices, as well as in the SHRIMP device. RACER IV (as redesigned and proof-tested in the Simon test) was employed as primary for the ZOMBIE, RAMROD and MORGENSTERN devices.

Navy scientist Pauline Silvia conducted experiments during the tests, and would later be profiled in the 2010 documentary Atomic Mom.

Nuclear tests Annie Planned yield for Annie was , actual yield based on radiochemical analysis was .

Nancy Planned yield for Nancy was , actual yield based on radiochemical analysis was .

Simon Planned yield for Simon was , actual yield based on radiochemical analysis was .

Harry Planned yield for Harry was , actual yield based on radiochemical analysis was .

Encore Planned yield for Encore was , actual yield based on radiochemical analysis was .

List of tests

+ United States' Upshot-Knothole series tests and detonations NameThe 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. Date time (UT) Local time zoneTo 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. Historical time zone data obtained from the IANA time zone database. LocationRough 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. Elevation + heightElevation 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. DeliveryAtmospheric, 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.PurposeInclude weapons development, weapon effects, safety test, transport safety test, war, science, joint verification and industrial/peaceful, which may be further broken down. DeviceDesignations 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. YieldEstimated energy yield in tons, kilotons, and megatons. A ton of TNT equivalent is defined as 4.184 gigajoules (1 gigacalorie). FalloutRadioactive 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 Notes Annie 13:20:00.3 PST (-8 hrs) NTS Area 3

+ tower,weapons development TX-5HE "XR-3" Type D pit

I-131 detected,

Investigated yield-vs-initiation time curve. Live news coverage. Desert Rock V. Two 2-story houses, 50 autos, bomb shelters in effects test. Nancy 13:10:00.0 PST (-8 hrs) NTS Area 4

+ tower,weapons development TX-14 "Nevada Zombie"

I-131 detected,

Component test of TX-14 containing minimal quantities of Li-6D. Desert Rock V. First proof-test of the RACER boosted primary with disappointing performance. Ruth 13:00:00.0 PST (-8 hrs) NTS Area 7

+ tower,weapons development MK-6 "Hydride I"

I-131 detected,

1st UCRL device, a uranium deuteride core, meant to explore deuterated polyethylene mixed with uranium as thermonuclear fuel, and if successful to lead also to a compact thermonuclear primary. Predicted yield was 1.5 to 3 kilotons, max. theoretical was 20 kt. Device fizzled - deuterium moderated (slowed-down) neutrons more than expected and quenched the reaction. Embarrassing for designers, as it left of tower still standing (see image of tower). Dixie 15:29:38.4 PST (-8 hrs) NTS Area 7

+ free air drop,weapons development MK-5D "DD-1"

I-131 detected,

TX-5D proof test, a boosting experiment using lithium deuteride in solid or crystalline form, investigating initiation via deuterium; a cheap method to initiate a chain reaction. Exploded ENE of intended zero point. Ray 12:44:59.8 PST (-8 hrs) NTS Area 4

+ tower,weapons development MK-6 "Hydride II"

I-131 detected,

2nd UCRL device, uranium deuteride meant to explore deuterated polyethylene mixed with uranium as thermonuclear fuel, and if successful to lead also to a compact thermonuclear primary; Used different mix from Ruth and it also fizzled. A 100-foot tower was apparently used to avoid embarrassment in case of fizzle. Badger 12:35:00.0 PST (-8 hrs) NTS Area 2

+ tower,weapons development TX-16 "Buzzard"

I-131 detected,

Component test of the TX-16 using a cryogenic mockup secondary and the TX-16 radiation case. Also tested RACER primary, which performed below expectations again. Desert Rock V. Simon 12:29:59.8 PST (-8 hrs) NTS Area 1

+ tower,weapons development TX-17/24 "Simultaneity"

I-131 detected,

Component test of TX-17/24 series using the RACER IV primary, a modified RACER core containing two additional kilograms of HEU in the original design tested in Nancy, a thermonuclear secondary mockup. Encore 15:29:55.4 PST (-8 hrs) NTS Area 5

+ free air drop,weapon effect MK-6D

I-131 detected,

"Effects" test. Dropped SSW of target. Desert Rock V, bad exposures for troops and bad downwinder fallout. Harry 12:04:59.5 PST (-8 hrs) NTS Area 3

+ tower,weapons development TX-13D "Hamlet"

I-131 detected,

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 15:30:00.3 PST (-8 hrs) Launch from NTS Areas 5, 11, Frenchman Flat: 5 , elv: ;Detonation over NTS + gun deployed,weapon effect W9 AFAP "Gun"

I-131 detected,

The 2nd of four gun-type device tests. Fired from the M65 Atomic Cannon "Atomic Annie" downrange. 280mm shell, . Detonation at SW of target. Desert Rock V. Major effects test. Climax 11:14:56.7 PST (-8 hrs) NTS Area 7

+ free air drop,weapons development MK-7, "Cobra", Type D pit

I-131 detected,

Proof test of a boosted MK-7 device, intended to be used as a primary in Castle. Initially it was intended only for the TX-15. After RACER's inconsistent behaviour it was opted for all "emergency capability" devices instead.. The bomb detonated NW of target. Composite implosion system in a Type D pit. Used Cyclotol 75/25 explosive mixture.

Gallery

References Notes

Citations

Bibliography

Chuck Hansen, Swords of Armageddon, Version 2 (Chukelea Publications, 1995–2007)

Operation Upshot–Knothole

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