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Operation Nougat
September 1961 to June 30, 1962
Nevada Test Site

In its closing days, the Eisenhower administration initiated negotitations on a nuclear test ban with the Soviet Union (this intention was announced by Eisenhower on 22 August 1958). As an important confidence building measure, Eisenhower also announced a one-year voluntary moratorium on nuclear testing (if the Soviets made a reciprocal commitment) would go into effect on 31 October 1958. This ban was later extended to 13 months (31 December 1959), but on 29 December 1959 the U.S. announced an end to the voluntary moratorium although it also promised not the renew testing without advance public notice. This decision not the extend the formal moratorium commitment may have been due to the status of the negotiations, which were faring very poorly. On 3 January 1960, Khrushchev pledged that the Soviet Union would not conduct nuclear testing unless the Western nations resumed it. The US, the UK and France made no move to resume testing, and so the matter rested for nearly three years.

On 31 August 1961, Khrushchev announced that the Soviet Union was abruptly abandoning the prevailing de facto nuclear testing moratorium, which they (and the United States) had observed for 34 months. The next day, on 1 September 1961, the Soviet Union began an atmospheric test series of unprecedented magnitude with a 16 Kt atmospheric nuclear shot. Two weeks later, the U.S. responded by initiating Operation Nougat.

This series was conducted at the Nevada Test Site, which permitted rapid initiation of tests, but restricted them to low yields (and mostly underground test shots) due to fallout concerns. Although this was still the "era of atmospheric testing", Nougat was actually the first underground test series. Higher yield atmospheric tests followed seven months later with Operation Dominic in the Pacific.

The assignment of tests to individual "operations" between this time and the end of atmospheric testing is confused and complicated by several overlapping operations - Nougat, Dominic (or Dominic I), Sunbeam (or Dominic II), Fishbowl, Storax, and Roller Coaster. The available documentation on these operations is somewhat unclear unclear or confusing, and it may be that in some cases a shot may be officially included in more than one operation. Definitely and unambiguously assigning shots to operations for this period is thus hard or impossible. Some disagreement about which shots should be properly included with a particular operation may occur. According to this account Operation Nougat included a total of 44 shots, exceeding the previous record holder, Operation Hardtack II, with 37 tests.

Nougat generally resembles Hardtack II in the nature of testing that was conducted. Low yield tactical devices were extensively tested. Thermonuclear primaries and radiation imploson mockups were tested. Much attention was paid to simultaneously achieving desired performance and one-point safety in "sealed pit" fission devices, some designs requiring numerous shots.

Since all the tests were fired underground, and only a few of them produced true blast craters (i.e. not subsidence craters caused by blast cavity collapse), there are few pictures available of these tests.

The one test for which any relevant images are available is much publicized Gnome shot.

Time:12:10 10 December 1961 (GMT)
Location:Carlsbad, NM
Test Height and Type:Shaft Shot, -1184 ft
Yield:3.1 kt

This Plowshare shot, conducted by Lawrence Radiation Laboratory (later Lawrence Livermore), was fired in an underground salt dome formation. A permanent stable cavity 170 ft. in diameter, and 80 ft. high, was formed. This one of the very few nuclear test cavities (perhaps the only one) to avoid collapse. Some radiation accidentally released as a result of pot shot drilling, and detected off-site.
Gnome cavity
Gnome cavity (547x412, 67K)

Gnome diagram
Gnome diagram (879x960, 69K)

Operation Nougat Summary

Legend:WD=Weapons Development, WE=Weapons Effects, ST=Safety Test, TN= Thermonuclear, LASL=Los Alamos Scientific Laboratory, LRL=Lawrence Radiation Laboratory (later Lawrence Livermore), DOD=Department of Defense, PS=Plowshare, sim.=similar, proto.=prototype, Zipper=neutron initiator,
Test NameTime and Date (GMT)LocationTest TypeHeight (Ft)Yield (Kt)SponsorPurposeComments
Antler17:00.00.12 15-Sep-61NTS, Area 12eTunnel-1,3182.6LRLWDPossible W-45 test, yield slightly higher than expected
Shrew19:45.00.12 16-Sep-61NTS, Area 3acShaft-3220.017LASLWDPossible XW-54 test, performed as expected
Boomer22:00 1-Oct-61NTS, Area 3aaShaft-330<0.1LASLWDPossible XW-54 test, performed as expected
Chena18:00.00.12 10-Oct-61NTS, Area 12bTunnel-838<20LRLWDArrow device, possible W-44 proto., sim. to D-I Swordfish, yield much lower than pred.
Mink18:00.00.13 29-Oct-61NTS, Area 3aeShaft-630<20LASLWDSim. to HT-II Quay, HT-I Linden, fizzle
Fisher23:04.59.63 3-Dec-61NTS, Area 3ahShaft-119113.4LASLWDRepeat of Mink, possible XW-50 primary test, yield below pred. due to Zipper failure
Gnome19:00.00.00 10-Dec-61Carlsbad, NMShaft-11843.1LRLPSPlowshare shot, fired in salt dome, cavity formed was 170 ft. in diameter, and 80 ft. high, some radiation accidentally released and detected off-site
Mad18:00.00.16 13-Dec-61NTS, Area 9aShaft-5940.5LASLWDSim. to Hoosic and Stillwater, yield below pred., attempt to standardize low yield energy source for future experiments
Ringtail16:35.00.13 17-Dec-61NTS, Area 3akShaft-1,192<20LRLWDPossible XW-54 test, sim. to Shrew and Boomer, purpose to optimize small light system for high yield tactical weapon
Feather16:30.00.13 22-Dec-61NTS, Area 12bTunnel-8120.15LRLWD"...results quite striking."
Stoat16:30.00.14 9-Jan-62NTS, Area 3apShaft-9925.1LASLWDPerformed as expected, 1st in series to develop new multi-point detonation system, sim. to Agouti, Armadillo, Ermine, Chinchilla I/II
Agouti18:00.00.13 18-Jan-62NTS, Area 3aoShaft-8566.4LASLWDDevelop test for new 10 inch implosion system, sim. Stoat
Dormouse18:00.00.13 30-Jan-62NTS, Area 3aqShaft-1191<20LASLWDConfiguration optimization test, sim. to Mink, Fisher, Raccoon, Dormouse Prime, Packrat
Stillwater18:00.00.16 8-Feb-62NTS, Area 9cShaft-5953.07LRLWDSimilar to Mad and Hoosic
Armadillo16:30.00.13 9-Feb-62NTS, Area 3arShaft-7867.1LASLWDDevelop test for new 10 inch implosion system, sim. Stoat
Hardhat18:00.10.16 15-Feb-62NTS, Area 15aShaft-9435.7DODWETest of underground structure hardening
Chinchilla I16:30.00.13 19-Feb-62NTS, Area 3agShaft-4921.9LASLWDTest of new 10" implosion system, performed as expected, showed device not 1-point safe
Codsaw17:50.00.16 19-Feb-62NTS, Area 9gShaft-696<20LRLWDPossible W-45 test, sim. to Hoosic, Hudson, Arikaree
Cimarron18:00.00.16 23-Feb-62NTS, Area 9hShaft-100011.9LRLWDConfirmed advanced warhead design, device performed better than expected
Platypus16:30.00.13 24-Feb-62NTS, Area 3adShaft-190<20LASLWDSim. to Shrew, Boomer, Ringtail
Pampas19:10.00.09 1-Mar-62NTS, Area 3alShaft-11919.5LASL/UKWDFirst joint Us-UK test at NTS
Danny Boy18:15.00.12 5-Mar-62NTS, Area 18Subsurface-1100.43DOD/LRLWETest of atomic demolition munition (ADM) cratering effects in basalt, crater 265' by 84', design yield 470 tons
Ermine16:30.00.13 6-Mar-62NTS, Area 3abShaft-240<20LASLSTTest of new 10" implosion system, 1-point safety test
Brazos18:00.00.21 8-Mar-62NTS, Area 9bShaft-8418.4LRLWDSuccessful system proof test, possible XW-55 primary test, developmental test of advanced implosion system, design yield 5-10 Kt
Hognose16:30.00.13 15-Mar-62NTS, Area 3aiShaft-784<20LASLWDSim. to Ht-II Mercury and Oberon
Hoosic18:00.00.16 28-Mar-62NTS, Area 9jShaft-6143.4LRLWDTest to determine minimum boosted yield for device previously tested in Mad and Stillwater, possible XW-45 test, pred. yield 2-3.5 Kt, sim. to Hudson and Arikaree
Chinchilla II18:00.00.13 31-Mar-62"NTS, Area 3as"Shaft-448<20LASLWDRetest of Chinchilla I which was not 1-point safe, sim. to Stoat
Dormouse Prime18:00.00.13 5-Apr-62NTS, Area 3azShaft-85610.6LASLWDYield verification test, design yield 10.5 Kt, boron lined shot hole, sim. to Dormouse, Mink, Fisher, Raccoon, Packrat, HT-I Linden, HT-II Quay
Passaic18:00.00.16 6-Apr-62NTS, Area 9iShaft-766<20LRLWDVerification test
Hudson18:00.00.16 12-Apr-62NTS, Area 9hShaft-495<20LRLWDSim. to Arikaree, Hoosic, Codsaw; possible W-45 test
Platte18:00.00.13 14-Apr-62NTS, Area 12kTunnel-6281.85LRLWDYield reproducibility test, failed, retested in Des Moines
Dead18:40.00.16 21-Apr-62NTS, Area 9kShaft-634<20LRLWD
Black18:00.00.16 27-Apr-62NTS, Area 9pShaft-714<20LRLWDXW-55 primary in TN mockup
Paca19:33.00.0 7-May-62NTS, Area 3axShaft-848<20LASLWDTest of "100 lb/100 Kt" class device
Arikaree15:00 10-May-62NTSShaft-549<20LRLWDSim. to Hudson, Hoosic, Codsaw; possible W-45 test
Aardvark19:00.00.10 12-May-62NTS, Area 3Shaft-142440LASLWDTest of improved TX-33Y2 AFAP
Eel15:00.00.16 19-May-62NTS, Area 9mShaft-7144.9LRLWDSuccessful
White15:00.00.15 25-May-62NTS, Area 9bShaft-635<20LRLWDProbable XW-58 primary test, sim. to Sacramento
Racoon17:00.00.14 1-Jun-62NTS, Area 3aShaft-539<20LASLWDSuccessful, sim. to Dormouse, Dormouse Prime, Mink, Fisher, Packrat, HT-I Linden, HT-II Quay
Packrat17:00.00.12 6-Jun-62NTS, Area 3awShaft-860<20LASLWDSuccessful (see above for similarities), investigated internal initiator to improve safety, increase yield, reduce weight 10 lb.
Des Moines21:00.00.12 13-Jun-62NTS, Area 12jTunnel-6602.9LRLWDSim. to Platte
Daman I17:00.00.13 21-Jun-62NTS, Area 3beShaft-854<20LASLWDSuccessful
Haymaker18:00.00.12 27-Jun-62NTS, Area 3ausShaft-134067LASLWDPossible Mocassin device (tested in Project 58 #2, HT-II Hidalgo)
Marshmallow17:00 28-Jun-62NTS, Area 16aTunnel-1050<20DOD/LRLWESimulated high altitude effects shot in low pressure chamber, successful, x-ray effects of re-entry vehicles investigated
Sacramento21:30.00.16 30-Jun-62NTS, Area 9vShaft-500<20LRLWDSim. to White device, probable XW-58 test

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