Experimental Confirmation of CH Mandrel Removal from Be Shells

Cook, B ; Letts, S ; Buckley, S

Lawrence Livermore National Laboratory

关键词: Removal;    37 Inorganic, Organic, Physical And Analytical Chemistry;    36 Materials Science;    42 Engineering;    Gas Flow;   

DOI  :  10.2172/15014316
RP-ID  :  UCRL-TR-204747
RP-ID  :  W-7405-ENG-48
RP-ID  :  15014316

美国|英语

来源: UNT Digital Library

【 摘 要 】

Sputtered Be shells are made by sputter deposition of Be, with a radially graded Cu dopant as necessary, onto plastic mandrels supplied by General Atomics. Although the plastic mandrel may not be a design issue, it is a fielding issue because at cryo temperatures the plastic shrinks more than the Be and delaminates. We described in previous memos a proposed method for thermally removing the plastic by burning it in air at elevated temperature. A key aspect to this process is getting air in and out of the shell through the small diameter hole that must be laser drilled in the capsule wall to serve as a fill hole for the fuel. Because the hole is quite small, gas flow through the orifice must be forced, and an external pressure variation was suggested to do this. Further calculations showed that since the volume of the capsule is quite small and the amount of plastic in the shell by comparison is large, the ''pumping'' of air in and out of the shell must occur at least once per minute in order to supply enough O{sub 2} to completely burn the plastic to CO{sub 2} and H{sub 2}O in a reasonable time. Such an apparatus has been now built and this memo details both its construction and operation, as well as provides the first evidence of plastic mandrel removal from Be shells.