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 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.^: 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.^: 200 RACER IV (as redesigned and proof-tested in the Simon test) was employed as primary for the ZOMBIE,^: 200 RAMROD and MORGENSTERN^: 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).

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).

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).

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).

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).

List of tests

Gallery

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/