The experimental program considered plutonium nitrate solution in an annular cylinder. The outer and inner diameters of the annular cylinder were 50 cm and 20 cm. This 50/20 annular cylinder was reflected by water on the side and at the bottom. The central volume contained either water or air. A plutonium concentration range of 23.95 to 62.1 g/l was examined. The plutonium contained 9.95% 240Pu.
The experiments are selected from 730 critical experiments performed in the Valduc critical facility between 1963 and 1976.
They were subcritical approaches extrapolated to critical. The multiplication factor reached was very close to 1.000 (within 0.1%). Evaluated here are 12 experiments with air in the central region and 5 with water. All 17 are acceptable benchmark experiments.
The experimental program
a is described in the basic report (Reference 1) written by the experimentalists and in a new report (Reference 3) written in the framework of this evaluation. This report gathers additional data found in archives. Similar experiments performed in the Valduc facility with 50/30 and 50/20 annular cylinders (with diameters 50, 30, and 20 cm) and different 240Pu contents are presented in PU-SOL-THERM-028, 029, 030, 031, and 022.
a A selection of 30 experiments from the total 730 experiments were also described and presented at ICNC’99. Among this set, two of them (Exp. 698 and 712) are also described in the present evaluation.
All programs are briefly presented in a special volume of Nuclear Science and Engineering (Reference 5) and in the catalogue and history of criticality experiments performed in Saclay and Valduc (Reference 6), where an exhaustive set of references and photographs found in archives are provided, but not published in the experimental reports.
(2)Retired from IRSN