Godiva device
{{Short description|Pulsed nuclear reactor radiation source}}
{{Use dmy dates|date=March 2024}}
Image:Godiva-before-scrammed.jpg
The Lady Godiva device was an unshielded pulsed nuclear reactor originally situated at the Los Alamos National Laboratory (LANL), near Santa Fe, New Mexico. It was one of a number of criticality devices within Technical Area 18 (TA-18). Specifically, it was used to produce bursts of neutrons and gamma rays for irradiating test samples, and inspired development of Godiva-like reactors.{{efn|according to the physicist Otto Frisch, "We were building an unusual assembly, with no reflecting material around it; just the reacting compound of uranium-235 ... For obvious reasons we called it the Lady Godiva assembly." {{harv|Frisch|1980|p=161}}}}
The radiation source within the Godiva device was a fissile metallic mass (usually highly enriched 235U),McLaughlin et al. page 109, "93%" about {{convert|11.8|in|cm}} in diameter. This was located at the top of a {{convert|6.5|ft|m|0|adj=on}} 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 and a nuclear chain reaction was briefly sustained.Garcia page 1
Godiva's design was inspired by a self terminating property{{Elucidate|date=January 2017}} 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—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
File:Godiva critical mass assembly machine.jpg
Godiva II was constructed inside a concrete building with {{convert|20|in|cm|adj=mid|-thick}} walls and {{convert|8|in|cm|adj=mid|-thick}} roof in a canyon a quarter-mile (400 m) away from the control room.Engelke pages 3-4{{Cite journal|last1=Wimett|first1=T. F.|last2=White|first2=R. H.|last3=Stratton|first3=W. R.|last4=Wood|first4=D. P.|date=1 December 1960|title=Godiva II—An Unmoderated Pulse-Irradiation Reactor|journal=Nuclear Science and Engineering|volume=8|issue=6|pages=691–708|doi=10.13182/NSE60-2|bibcode=1960NSE.....8..691W |issn=0029-5639}}
In 1959, Los Alamos agreed to make Godiva II available to DOD contractors free of charge for two days each month, acknowledging its unique facility for radiation tests.Zipprich, L.J.
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 (parts were thrown {{convert|15|ft}});McLaughlin et al. page 86, "Unreflected uranium–molybdenum metal fast burst reactor" and 6 September 1968 at the Aberdeen Proving Ground (middle melted, disks warped and bolts stretched).Kazi et al., "center third of the safety block was melted"
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 (NTS).U.S. Department of Energy page 1
See also
Notes
= Explanatory notes =
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= Citations =
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General references
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- {{cite web| url=http://www.fas.org/sgp/othergov/doe/lanl/lib-www/la-pubs/00316018.pdf| title=LA-2569 Neutron tissue dose rate survey for the Godiva II critical assembly| date=May 1961| author=Engelke, Morris J.| author2=Bemis, Edwin A. Jr.| author3=Sayeg, J. A.| publisher=Los Alamos Scientific Laboratory| access-date=28 February 2008}}
- {{cite book |last=Frisch |first=Otto Robert |title=What Little I Remember |year=1980 |publisher=Cambridge University Press |isbn=978-0-52-128010-5 |url=https://books.google.com/books?id=WNXQ0EXYyIMC&q=%22lady+godiva%22 }}
- {{cite web| url=http://www.llnl.gov/tid/lof/documents/pdf/323286.pdf| title=Test Plan for Godiva Move from LANL TA-18 to NTS DAF| date=8 August 2005| author=Garcia, Manual| publisher=Lawrence Livermore National Laboratory| access-date=28 February 2008}}{{Dead link|date=November 2023 |bot=InternetArchiveBot |fix-attempted=yes }} id=UCRL-TR-214269
- {{cite conference| url=http://www.at.gnucash.org/mirrors/www.csirc.net/2004.03.26/10_Library/00_Reports/13638/ref_059.pdf| title=Preoperational Test Experience with the Army Pulse Radiation Facility Reactor| book-title=Proc. of the National Topical Meeting on Fast Burst Reactors| last=Kazi| first=A.H.| author2=Dubyoski, H.G.| author3=Dickinson, R.W| publisher=United States Atomic Energy Commission| location=Albuquerque, NM| pages=353–371| year=1969| access-date=28 February 2008}}{{Dead link|date=December 2019 |bot=InternetArchiveBot |fix-attempted=yes }}
- McLaughlin et al. {{cite web |url=http://www.csirc.net/docs/reports/la-13638.pdf |title=A Review of Criticality Accidents / 2000 Revision / LA-13638 |date=May 2000 |publisher=Los Alamos National Laboratory |access-date=28 February 2008 |url-status=usurped |archive-url=https://web.archive.org/web/20090320023235/http://www.csirc.net/docs/reports/la-13638.pdf |archive-date=20 March 2009 }}
- LA-13638 covers United States, Russia, United Kingdom, and Japan, and is also available [http://www.orau.org/ptp/Library/accidents/la-13638.pdf here] and {{usurped|1=[https://web.archive.org/web/20080609054436/http://www.csirc.net/library/la_13638.shtml at this page]}}, which also tries to track down documents referenced in the report.
- U.S. Department of Energy. {{cite web| url=http://www.nv.doe.gov/library/factsheets/DOENV_1063.pdf| title=Criticality Experiments Facility| date=15 June 2005| publisher=National Nuclear Security Administration Nevada Site Office| access-date=28 February 2008| archive-url=https://web.archive.org/web/20060923055159/http://www.nv.doe.gov/library/factsheets/DOENV_1063.pdf| archive-date=23 September 2006| url-status=dead}}
- {{cite journal| title=Radiation effects testing at the Los Alamos Godiva II A facility| author=Zipprich, L.J.| date=1 April 1959| osti=4268715| doi=10.2172/4268715| url=https://digital.library.unt.edu/ark:/67531/metadc1022827/| hdl=2027/umn.31951d03527625h| hdl-access=free}} OSTI ID: 4268715
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External links
{{commons category|Godiva nuclear reactors}}
- {{cite conference|url=http://www.csirc.net/docs/reports/ref_052.pdf |title=Applications of Godiva II Neutron Pulses |author=Wimett, T. F. |author2=Orndoff, J. D. |book-title=Proc. UN Intern. Conf. Peaceful Uses At. Energy, 2nd |volume=10 |publisher=United Nations, Geneva |location=Geneva |pages=449–460 |year=1958 |access-date=29 February 2008 |url-status=usurped |archive-url=https://web.archive.org/web/20090107112557/http://www.csirc.net/docs/reports/ref_052.pdf |archive-date=7 January 2009 }}
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Category:Nuclear research reactors
Category:Los Alamos National Laboratory
Category:Nuclear accidents and incidents in the United States