The Canadian Certified Reference Materials Project (CCRMP) agreed in 1984 to prepare a uranium reference material, RGU-I, on behalf of the International Atomic Energy Agency, IAEA. The work was accepted by the Canada Centre of Mineral and Energy Technology as Cost Recovery Job No. 025202. RGU-1 was the first to be prepared by dilution with silica sand of CCRMP Uranium ore BL-5. The certification of BL-5 is described in by Faye, Bowmen and Sutarno [3]. 

RGU-I was prepared in two batches because of equipment limitations. For one batch, 245.8 kg of silica were blended with 1.395 kg of BL-5 for 8 h in a 570-L blender. The other batch consisted of 253.8 kg of silica and 1.440 kg BL-5 and was treated similarly. These batches were divided approximately in half and each portion of one batch was blended with a portion of the other batch for 3 h, thereby giving two new batches. This procedure was repeated twice more to ensure that the two batches obtained at the end were homogeneous.  RGU-1 was bottled in 500-g lots in plastic bottles supplied by IAEA.

TABLE 1. CERTIFIED VALUES FOR MASSIC ACTIVITIES 
(based on dry mass)