%IBr The USAEC, Division of Space Nuclear Systems, has initiated v7ork on an advanced heat source convertor design, designated as the Multi-Hundred Watt (MHW) program. The following paragraphs describe Mound Laboratory's efforts, in developing and testing areas, in support of the MHW program. The MHW heat source consists of 24 (100-watt thermal) spherical modules, arranged in a 4 x 6 element cylindrical matrix. The fuel which comprises these modules is encapsulated in a 0.020-in. thick post

more »

... ct containment sphere which is encased in a 0.5-in. thick wound graphite impact energy absorber. The four-sphere tiers are then inserted in graphite reentry aids, and the entire assembly is welded in an outer container as shown in Figure 1. / Two fuel candidates were considered: 1) plutonia-molybdenum cermet (PMC) and 2) pure plutonium oxide (PPO). PMC fuel sphere *Mound Laboratory is operated