Basic Research Needs for Advanced Nuclear Systems. Report of the Basic Energy Sciences Workshop on Basic Research Needs for Advanced Nuclear Energy Systems, July 31-August 3, 2006

Abstract

The cover depicts two cesium ions (orange) bound inside a molecule that belongs to the calixarene-crown ethers family. These calixarenes are capable of selectively separating more than 99.9975% of the cesium ions from million-fold-higher concentrations of other ions. By studying how such molecules function as extractants, scientists have developed a process * employing a derivative of the cover molecule that is the basis of the Salt Waste Processing Facility being built at the Savannah River Site to remove trace amounts of cesium and other radionuclides from waste left over from reprocessing spent fuel.The graphic is based on an experimentally determined structure † and shows nitrogen atoms in blue, oxygen atoms in red, and carbon ions in gray. The hydrogen atoms bound to each carbon are not shown.

Strong correlations in actinide redox reactions

“…However, incorporating the physics of strong electronic correlations among the 5f electrons presents a greater challenge as these are known to be poorly captured by DFT. 6 In this paper we take a hybrid approach to solving these problems by using DFT to construct a generalized Anderson impurity model of the frontier orbitals. [7][8][9][10][11][12] Exact diagonalization of the Anderson impurity model corrects the free energy obtained from DFT alone, yielding improved predictions for redox free energies.…”