Analysis for the Selection of Experimental Configurations for Heterogeneity and Be Multi-Layered Experiments of U.S.DOE/JAERI Collaborative Program on Blanket Neutronics

Phase IIC of the experimental program is to begin in fall of 1988. An extensive pre-analysis has been carried out to select the experimental configurations. The investigations were confined to looking at the effect of (i) multi-layer arrangement of Be multiplier, (ii) the presence of contiguous layers of structure and coolant, (iii) the introduction of protective graphite armor in front of the first wall, on tritium production rate (TPR) in a Li₂O assembly. The basic materials and geometrical structure of the assembly, are derived from that of the Phase IIA. The structure is simulated by stainless steel (SS) and the coolant is either polyethylene (PE) or water. Generally, the heterogeneities strongly distort the local T₆ and T₇ distributions; their effect on global TPR is less marked. One of the two selected configurations has Be, in edge-on layered arrangement with Li₂O, as multiplier. In the second configuration, three coolant channels (SS+PE) will be incorporated to simulate structural heterogeneity.