The Lady Godiva device was an unshielded, pulsed

nuclear reactor A nuclear reactor is a device used to initiate and control a fission nuclear chain reaction or nuclear fusion reactions. Nuclear reactors are used at nuclear power plants for electricity generation and in nuclear marine propulsion. Heat fr ...

originally situated at the

Los Alamos National Laboratory Los Alamos National Laboratory (often shortened as Los Alamos and LANL) is one of the sixteen research and development laboratories of the United States Department of Energy (DOE), located a short distance northwest of Santa Fe, New Mexico, ...

(LANL), near Santa Fe,

New Mexico ) , population_demonym = New Mexican ( es, Neomexicano, Neomejicano, Nuevo Mexicano) , seat = Santa Fe, New Mexico, Santa Fe , LargestCity = Albuquerque, New Mexico, Albuquerque , LargestMetro = Albuquerque metropolitan area, Tiguex , Offi ...

. It was one of a number of criticality devices within Technical Area 18 (TA-18). Specifically, it was used to produce bursts of

neutron The neutron is a subatomic particle, symbol or , which has a neutral (not positive or negative) charge, and a mass slightly greater than that of a proton. Protons and neutrons constitute the atomic nucleus, nuclei of atoms. Since protons and ...

s and

gamma ray A gamma ray, also known as gamma radiation (symbol γ or \gamma), is a penetrating form of electromagnetic radiation arising from the radioactive decay of atomic nuclei. It consists of the shortest wavelength electromagnetic waves, typically ...

s for irradiating test samples, and inspired development of Godiva-like reactors. The radiation source within the Godiva device was a

fissile In nuclear engineering, fissile material is material capable of sustaining a nuclear fission chain reaction. By definition, fissile material can sustain a chain reaction with neutrons of thermal energy. The predominant neutron energy may be t ...

metallic mass (usually highly enriched ²³⁵U), about in diameter. This was located at the top of a high metal tower. The burst of radiation was produced when a piston of fissile material was quickly inserted into and extracted from a cavity within the larger fissile mass. During the time these two masses were combined, they formed a

critical mass In nuclear engineering, a critical mass is the smallest amount of fissile material needed for a sustained nuclear chain reaction. The critical mass of a fissionable material depends upon its nuclear properties (specifically, its nuclear fi ...

and a

nuclear chain reaction In nuclear physics, a nuclear chain reaction occurs when one single nuclear reaction causes an average of one or more subsequent nuclear reactions, thus leading to the possibility of a self-propagating series of these reactions. The specific nu ...

was briefly sustained.Garcia page 1 Godiva's design was inspired by a self terminating property discovered when incorrectly experimenting with the Jemima device in 1952. Jemima operated by remotely lifting one stack of enriched uranium-235 disks up towards another, fixed, stack. On 18 April 1952, due to a miscalculation, Jemima was assembled with too many disks; this caused an excursion of 1.5 x 10¹⁶ fissions—an automatic

scram A scram or SCRAM is an emergency shutdown of a nuclear reactor effected by immediately terminating the fission reaction. It is also the name that is given to the manually operated kill switch that initiates the shutdown. In commercial reacto ...

—but no damage. On 3 February 1954 and 12 February 1957, accidental criticality excursions occurred causing damage to the device, but only insignificant exposures to personnel. This original Godiva device, known as ''Lady Godiva'', was irreparable after the second accident and was replaced by the ''Godiva II''.McLaughlin et al. pages 78, 80-83. "Jemima ... apparent self terminating property of this excursion stimulated study with Lady Godiva,46,47,48"

Godiva II

Godiva II was constructed inside a concrete building with walls and roof in a canyon a quarter-mile (400 m) away from the control room. In 1959, Los Alamos agreed to make Godiva II available to DOD contractors free of charge for 2 days each month, acknowledging its unique facility for radiation tests. Godiva's success in creating intense bursts spurred development of similar pulsed reactors, which also suffered accidental excursions, for example: 28 May 1965 at the

White Sands Missile Range White Sands Missile Range (WSMR) is a United States Army military testing area and firing range located in the US state of New Mexico. The range was originally established as the White Sands Proving Ground on 9July 1945. White Sands National P ...

(parts were thrown ); and 6 September 1968 at the

Aberdeen Proving Ground Aberdeen Proving Ground (APG) (sometimes erroneously called Aberdeen Proving ''Grounds'') is a U.S. Army facility located adjacent to Aberdeen, Harford County, Maryland, United States. More than 7,500 civilians and 5,000 military personnel work a ...

(middle melted, disks warped and bolts stretched). In December 2002, the U.S. Department of Energy announced it was to move its TA-18 testing equipment including the Godiva burst machine from the LANL to the Device Assembly Facility (DAF) at the

Nevada Test Site The Nevada National Security Site (N2S2 or NNSS), known as the Nevada Test Site (NTS) until 2010, is a United States Department of Energy (DOE) reservation located in southeastern Nye County, Nevada, about 65 miles (105 km) northwest of the ...

(NTS).U.S. Department of Energy page 1

Notes

Explanatory notes

Citations

General references

* * * id=UCRL-TR-214269 * * McLaughlin et al. ** LA-13638 covers United States, Russia, United Kingdom, and Japan, and is also availabl
here
an
at this page
which also tries to track down documents referenced in the report. * U.S. Department of Energy. * OSTI ID: 4268715

External links

* {{DEFAULTSORT:Godiva Device Nuclear reactors Nuclear research reactors Los Alamos National Laboratory Nevada Test Site Nuclear accidents and incidents in the United States