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2026 Annual Conference
May 31–June 3, 2026
Denver, CO|Sheraton Denver
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Latest News
Bechtel-led SIMCO awarded three-year WIPP contract extension
The Department of Energy has issued a three-year contract extension to Salado Isolation Mining Contractors (SIMCO), a single-purpose entity comprising Bechtel National and Los Alamos Technical Associates as a teaming contractor, for the continued management and operations of the Waste Isolation Pilot Plant, the DOE’s geologic repository for defense-generated transuranic waste in southeastern New Mexico.
David Maxwell Barton
Nuclear Science and Engineering | Volume 33 | Number 1 | July 1968 | Pages 51-55
Technical Paper | doi.org/10.13182/NSE68-A20917
Articles are hosted by Taylor and Francis Online.
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.
