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.
| Operation Upshot–Knothole | |
|---|---|
 Upshot-Knothole Grable, 15 kilotons. | |
| Information | |
| Country | United States |
| Test site |
|
| Period | 1953 |
| Number of tests | 11 |
| Test type | free air drop, gun deployed, tower |
| Max. yield | 61 kilotonnes of TNT (260 TJ) |
| Test series chronology | |
Over 21,000 soldiers took part in the ground exercise Desert Rock V in conjunction with the Grable shot.[1] 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.[2]: 192 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.[2]: 200 RACER IV (as redesigned and proof-tested in the Simon test) was employed as primary for the ZOMBIE,[2]: 200 RAMROD and MORGENSTERN[2]: 318 devices.
Nuclear tests
Annie
Planned yield for Annie was 15 kilotonnes of TNT (63 TJ), actual yield based on radiochemical analysis was 16.2 kilotonnes of TNT (68 TJ).[3]
Nancy
Planned yield for Nancy was 40 kilotonnes of TNT (170 TJ), actual yield based on radiochemical analysis was 24.5 kilotonnes of TNT (103 TJ).[4]
Simon
Planned yield for Simon was 33 kilotonnes of TNT (140 TJ), actual yield based on radiochemical analysis was 43.4 kilotonnes of TNT (182 TJ).[5]
Harry
Planned yield for Harry was 37 kilotonnes of TNT (150 TJ), actual yield based on radiochemical analysis was 27 kilotonnes of TNT (110 TJ).[6]
Encore
Planned yield for Encore was 31 kilotonnes of TNT (130 TJ), actual yield based on radiochemical analysis was 26 kilotonnes of TNT (110 TJ).[7]
List of tests
| Name[note 1] | Date time (UT) | Local time zone[note 2][8] | 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 | March 17, 1953 13:20:00.3 | PST (-8 hrs) | NTS Area 3 | 1,230 m (4,040 ft) + 90 m (300 ft) | tower, weapons development | TX-5HE "XR-3" Type D pit | 16 kt | I-131 detected, 2.4 MCi (89 PBq) | [9][10][11][12][13] | Investigated yield-vs-initiation time curve. Live news coverage. Desert Rock V. Two 2-story houses, 50 autos, bomb shelters in effects test. |
| Nancy | March 24, 1953 13:10:00.0 | PST (-8 hrs) | NTS Area 4 | 1,230 m (4,040 ft) + 90 m (300 ft) | tower, weapons development | TX-14 "Nevada Zombie" | 24 kt | I-131 detected, 3.6 MCi (130 PBq) | [9][10][11][12][13] | Component test of TX-14[2]: 193, 195 containing minimal quantities of Li-6D.[2]: 170 Desert Rock V. First proof-test of the RACER boosted primary with disappointing performance.[Note 1] |
| Ruth | March 31, 1953 13:00:00.0 | PST (-8 hrs) | NTS Area 7 | 1,270 m (4,170 ft) + 90 m (300 ft) | tower, weapons development | MK-6[14]: 198 "Hydride I" | 200 t | I-131 detected, 28 kCi (1,000 TBq) | [9][10][12][13] | 1st UCRL device, a uranium deuteride core,[2]: 202 meant to explore deuterated polyethylene mixed with uranium as thermonuclear fuel,[15]: chap.15 [2]: 203 and if successful to lead also to a compact thermonuclear primary.[2]: 149 Predicted yield was 1.5 to 3 kilotons, max. theoretical was 20 kt.[14]: 96 Device fizzled - deuterium moderated (slowed-down) neutrons more than expected and quenched the reaction. Embarrassing for designers, as it left 200 ft (61 m) of tower still standing (see image of tower). |
| Dixie | April 6, 1953 15:29:38.4 | PST (-8 hrs) | NTS Area 7 | 1,284 m (4,213 ft) + 1,830 m (6,000 ft) | free air drop, weapons development | MK-5D "DD-1"[2]: 194 | 11 kt | I-131 detected, 1.7 MCi (63 PBq) | [9][10][11][12][13] | 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.[2]: 185 Exploded 600 ft (180 m) ENE of intended zero point. |
| Ray | April 11, 1953 12:44:59.8 | PST (-8 hrs) | NTS Area 4 | 1,296 m (4,252 ft) + 30 m (98 ft) | tower, weapons development | MK-6[14]: 198 "Hydride II" | 220 t[16]: 101 | I-131 detected, 28 kCi (1,000 TBq) | [9][10][12][13] | 2nd UCRL device, uranium deuteride[2]: 202 meant to explore deuterated polyethylene mixed with uranium as thermonuclear fuel,[15]: chap.15 [2]: 203 and if successful to lead also to a compact thermonuclear primary;[2]: 149 Used different mix from Ruth[2]: 202 and it also fizzled. A 100-foot tower was apparently used to avoid embarrassment in case of fizzle. |
| Badger | April 18, 1953 12:35:00.0 | PST (-8 hrs) | NTS Area 2 | 1,370 m (4,490 ft) + 90 m (300 ft) | tower, weapons development | TX-16 "Buzzard" | 23 kt | I-131 detected, 3.6 MCi (130 PBq) | [9][10][11][12][13] | 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 | April 25, 1953 12:29:59.8 | PST (-8 hrs) | NTS Area 1 | 1,294 m (4,245 ft) + 90 m (300 ft) | tower, weapons development | TX-17/24 "Simultaneity" | 43 kt | I-131 detected, 6.3 MCi (230 PBq) | [9][10][11][12][13] | 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.[10] |
| Encore | May 8, 1953 15:29:55.4 | PST (-8 hrs) | NTS Area 5 | 940 m (3,080 ft) + 740 m (2,430 ft) | free air drop, weapon effect | MK-6D | 27 kt | I-131 detected, 3.9 MCi (140 PBq) | [9][10][11][12][13] | "Effects" test. Dropped 950 ft (290 m) SSW of target. Desert Rock V, bad exposures for troops and bad downwinder fallout. |
| Harry | May 19, 1953 12:04:59.5 | PST (-8 hrs) | NTS Area 3 | 1,224 m (4,016 ft) + 90 m (300 ft) | tower, weapons development | TX-13D "Hamlet" | 32 kt | I-131 detected, 4.6 MCi (170 PBq) | [9][10][11][12][13] | 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 | May 25, 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); | 960 m (3,150 ft) + 160 m (520 ft) | gun deployed, weapon effect | W9 AFAP "Gun" | 15 kt | I-131 detected, 2.1 MCi (78 PBq) | [9][10][11][12][13] | The 2nd of four gun-type device tests. Fired from the M65 Atomic Cannon "Atomic Annie" 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 | June 4, 1953 11:14:56.7 | PST (-8 hrs) | NTS Area 7 | 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 detected, 8.6 MCi (320 PBq) | [9][10][11][12][13] | 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[2]: 195 . After RACER's inconsistent behaviour it was opted for all "emergency capability" devices instead.[2]: 197 . The bomb detonated 320 ft (98 m) NW of target. Composite implosion system in a Type D pit. Used Cyclotol 75/25 explosive mixture. |
Gallery
Full uncut detonation of Upshot-Knothole Grable, launched out of the Atomic Annie device on 5/25/1953. The footage at normal speed is about 2+1⁄2 minutes.
Close-up slow motion shot of Grable fire-ball, mach-stem and surface effects,
Upshot-Knothole Encore, 27-kilotons.
Upshot-Knothole Ruth, 0.2-kilotons.
Upshot-Knothole Ruth, Note close proximity to highway in foreground as to the scale of detonation.
The mangled tower for the Ruth test. The explosion failed to level the testing tower, only somewhat damaging it.
References
- Notes
- Citations
- Bibliography
External links
- Operation Upshot-Knothole
- The short film Nuclear Test Film - Operation Upshot-Knothole (1953) is available for free viewing and download at the Internet Archive.
- The short film Nuclear Test Film - Operation Upshot-Knothole, 5.2 (1953) is available for free viewing and download at the Internet Archive.
- The short film The 280 mm Gun at the Nevada Proving Ground (1953) is available for free viewing and download at the Internet Archive.
- Operation Upshot-Knothole - 1953
- Film about Upshot Knothole Tests Archived May 19, 2011, at the Wayback Machine
- Rice, James. Downwind of the Atomic State: Atmospheric Testing and the Rise of the Risk Society. (New York University Press, 2023): https://nyupress.org/9781479815340/downwind-of-the-atomic-state/