Nuclear Science and Engineering / Volume 33 / Number 1 / July 1968 / Pages 51-55
Technical Paper / dx.doi.org/10.13182/NSE68-A20917
Central reactivity contributions of gram-sized samples of 244Cm, 239Pu, and 235U have been obtained in a fast critical assembly of bare 239Pu in a spherical geometry. Resulting values are: 244Cm = (1276 ± 5%) cents/g at.; 239Pu = (1393 ± 3%) cents/g at.; 235U = (701 ± 2%) cents/g at. From these data, the critical mass of a bare sphere of 244Cm is estimated to be (27.7 ± 2.5) kg at a density of 13.5 g/cm3.