A unique method produces perfectly ordered packed beds of spheres that are dropped randomly into rigid rectangular columns. This method is applicable to loading fuel elements for many types of reactors. Experiments were conducted with 0.125-, 0.250-, and 0.500-in. (0.318-, 0.635-, and 1.270-cm)-diam stainless-steel, bronze, and aluminum balls in 1.8- to 7.6-in. (4.5- to 19.3-cm)-wide square Lucite columns. Quantitatively reproducible ordered beds were obtained consistently. Irregular spheres as well as mixtures of two sizes of balls with diametral differences as great as 5% in 10 to 50% mixtures could be packed in an ordered fashion. The bed can be fluidized and subsequently re-settled into an ordered array again. These ordered beds were found to possess great structural flexibility because they move in spring-like fashion. This flexibility permits the fuel elements to compensate for thermal and hydraulic fluctuations and for radiation-induced fuel swelling.