Monte Carlo studies in accelerator-driven systems for transmutation of high-level nuclear waste (Conference Paper)

13th International Conference on Emerging Nuclear Energy Systems 2007, ICENES 2007 -- 3 June 2007 through 8 June 2007 -- Istanbul -- 85239A spallation neutron source was modeled using a high energy proton accelerator. The aim is to maximize the minor actinides and fission products transmutation rates, which is created from the operation of nuclear power reactors for the production of electricity. The transmutation system is composed of a natural lead target, beam window, subcritical core, reflector, and structural material. The neutrons are produced by the spallation reaction of protons from a high intensity linear accelerator in the spallation target, and the fission reaction in the core. It is used a hexagonal lattice for the waste and fuel assemblies. The system is driven by a 1 GeV, 10 mA proton beam incident on a natural lead cylindrical target. The protons were uniformly distributed across the beam. The core is a cylindrical assembly. The main vessel is surrounded by a reflector made of graphite. The axes of the proton beam and the target are concentric with the main vessel axis. The structural walls and the beam window are made of the same material, stainless steel, HT9. We investigated the following neutronics parameters: spallation neutron and proton yields, spatial and energy distribution of the spallation neutrons, and protons, heat deposition, and the production rates of hydrogen and helium, transmutation rate of minor actinides and fission products. In the calculations, the Monte Carlo code MCNPX, which is a combination of LAHET and MCNP, was used. To transport a wide variety of particles, The Los Alamos High Energy Transport Code (LAHET) was used

[1,3-Bis(2-ethoxyphenyl)imidazolidin-2-ylidene]bromo(cycloocta-1,5-diene) rhodium(I)

The title complex, [RhBr(C8H12)(C19H 22N2O2)], has a distorted square-planar geometry. There are two molecules, A and B, in the asymmetric unit. The Rh-C bond distance between the N-heterocyclic ligand and the metal atom is 2.039 (2) Å in molecule A and 2.042 (2) Å in molecule B. The angle between the carbene heterocycle and the coordination plane is 87.56 (12)° in molecule A and 87.03 (11)° in molecule B. It is shown that the average Rh-C(COD) (COD is cyclooctadiene) distance is linearly dependent on the Rh-C(imidazolidine) distance in this type of compound. This can be ascribed to the steric hindrance produced by the packing. The crystal structure contains intramolecular C-H?O and intermolecular C-H?Br interactions. © 2005 International Union of Crystallography