N.B. Alexander, L.C. Brown, G.E. Besenbruch
General Atomics, P.O. Box 85608, San Diego, California 92186-5608, USA
Neil.Alexander
gat.com
Lloyd.Browngat.com
Gottfried.Besenbruchgat.com
Fueling of IFE power plants requires not only the production and assembly of the target components, but filling the target capsules with DT and layering the DT into a highly uniform layer onto the inner wall of the capsules. Approximately 500,000 targets per day will need to be layered with DT. The use of a cryogenic fluidized bed is proposed as a technique for achieving target layering at this high rate. Bed fluidization is a volume scaleable technique. Capsule movement and tumbling in the agitated bed averages out thermal fluctuations on the surface of the capsule. In a time averaged sense, the bed provides the capsules with the highly uniform surface temperature required to produce a highly uniform DT layer in the beta-layering process. Microwaves or IR can also be injected into the fluidized bed to augment the beta-decay heat naturally generated in the DT. This speeds up layering and reduces the size of the required bed. The bed agitation also serves to provide time average uniformity of the heating provided by these augmenting heat sources. This reduces the need to inject the IR or microwaves in a uniform manner. Initial calculations of bed parameters will be presented. Concepts for integrating the bed into the target production and injection assembly line will also be presented.
Initial experiments on layering in fluidized beds were conducted. Surrogates for DT fuel were utilized. Surrogates were chosen to be solid at room temperature and sublime with modest vapor pressures at temperatures below 100°C. This allowed a quick proof of principle demonstration of fluidized bed layering with simple equipment. It also allowed the use of room temperature characterization equipment on the final product. An IR lamp provided a source of volumetric heat generation into the surrogate material so that they could undergo a pseudo beta-layering process. Capsules were levitated in nitrogen gas. Layers were successfully formed in batches of capsules using both oxalic acid and neopentyl alcohol as surrogates. The equipment and results will be described.
