DOE OSTI2014
This test, documented as LA-43-CT-2, was performed to verify calculations which indicate that the smoothing layer employed for Ranchero Armatures is not required when the slapper point spacing is 18 mm (“On the efficacy of an acrylic layer in the Ranchero armature,” Bob Watt, published in “Ranchero Status Report” LA-14463). [Naming this test –CT-2 acknowledges the previous test performed during 1/11 as the initial test in the series, and we will refer to that test as LA-43-CT-1 in the future.] In addition, higher velocity is achieved when the volume occupied by the smoother is replaced by HE. Two framing cameras were used on the shot, and a 20 point PDV array was fielded to ascertain armature performance in specific conditions. The conclusions are that the armature is smooth enough, and the terminal velocity is increased from ~3.1 mm/μs to ~3.3 mm/μs. The armature tested had casting voids in the HE that were observed in pre-test inspections, and were expected to cause ruptures. (See Appendix 3 of the Ranchero Status Report.) Such “blowouts” were observed in all three locations identified in pre-shot inspection. In addition, ruptures occurred in locations having no pre-shot indication of a problem. These unpredicted blowouts have a difference in appearance from those typically seen. Further visual examination of the inspection radiographs do not reveal the cause, and that is a serious concern for future efforts with such castings. A path forward will include attempting to digitize the inspection x-rays for the charge tested, to see if the cause of the “new” ruptures can be found via computer enhancement. In addition, there are two additional armatures from the same casting lot, and these might also be tested to see if there is some problem with the HE or the armature material in this batch. For now, this plan is on hold, pending the outcome of tests and cost estimates related to using PBX-9501 in place of the PBXN-110. Casting issues would be eliminated in such configurations.