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Palanquin: D + 7-Day Evaluation

CowsActivity LevelsDataPhotographsBlast EffectsPlowshare ProjectPalanquin EventRadioactive CloudsWhetstone OperationIodineGraphsDose RatesContainmentVentingMilk

REPORT

1965 Apr 26

1997 Nov 04

NV0075532

UCRL-ID-129631

Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)

2019 Aug 20

2026 Aug 21

Results of a visual inspection, several calculations, and very preliminary radiochemical analyses allow a preliminary evaluation of the Palanquin experiment. The conclusions are that the Palanquin explosive probably performed within the expected yield range, that peak pressures and motion of the ground were very much as expected so that no crater should have been formed and that a "plug" of material was ejected around the emplacement hole causing a breach in the cavity and consequently a sudden drop in cavity pressure. This stemming breach created a high-velocity jet of hot gases and rocks which led to an "erosional" crater similar to that produced by gas or steam-well "blowouts." Essentially all of the radioactivities were still in gaseous form and moved out with the initial jet. Most radioactivities condensed in fragments of vesicular glass varying from a millimeter up to several tens of centimeters in size. Only about one percent, on the average, passed beyond a range of five miles, although some radionuclides, of a volatile nature, were much more abundant at longer ranges. Because of extensive experimental measurements and meteorological conditions, ideal for making technical measurements, debris distribution data is being obtained in unprecedented detail. This information is of fundamental importance in assessment of future excavation experiments even though no direct scaling is possible because of the unusual method of release.