Assessment of Containment Structures Against Missile Impact Threats

In order to ensure the highest safety requirements, nuclear power plant structures (the containment structures, the fuel storages and transportation systems) should be assessed against all possible internal and external impact threats. The internal impact threats include kinetic missiles generated by the failure of high pressure vessels and pipes, the failure of high speed rotating machineries and accidental drops. The external impact threats may come from airborne missiles, aircraft impact, explosion blast and fragments. The impact effects of these threats on concrete and steel structures in a nuclear power plant are discussed. Methods and procedures for the impact assessment of nuclear power plants are introduced. Recent studies on penetration and perforation mechanics as well as progresses on dynamic properties of concrete-like materials are presented to increase the understanding of the impact effects on concrete containment structures.

Electronic Structure of the Clusters Containing Oxygen in Ni

The electronic structure of the clusters containing oxygen, the stacking fault and the complex in the transition metal Ni are calculated by the multiple-scattering Xa method. Energy levels,density of states and transfer of charge are obtained. Based on the calculation and analysis,the influences of impurity oxygen and structure defect on the electronic structure of the clusters are discussed, and it is found that the local Ni-o cluster with the interstitial oxygen is a stable atomic configuration.

Research and development of airtight biosafety containment facility for stainless steel structures

Objective:Airtightness of containment structures of a high-level biosafety laboratory is a critical parameter for preventing leakage of harmful bioaerosols.The aim of this study is to investigate the sealing technology of stainless steel structural airtight biosafety containment facilities.Methods:An experimental study was conducted on a domestic high-level pathogenic microorganism model laboratory,considering the sealing process of the containment structure,including airtight doors,pass boxes,dunk tanks,through-wall pipeline sealing devices,and sealed floor drains.Results:The results indicate that the airtightness of the model laboratory containment structure meets the tightness requirements of a biosafety level-4(BSL-4)laboratory.They also indicate that the construction technology of stainless steel enclosure structures used by the laboratory and the tightness performance and installation process of the developed airtight protective equipment meet the technical requirements of a BSL-4 laboratory.Conclusions:This successful model laboratory indicates that China has the research and development capacity for stainless steel airtight containment structure manufacturing processes,airtight protective equipment,and technical capacity for independent construction of the highest-level pathogenic microorganism laboratories.

The Synthesis and Crystal Structure of the First Trinuclear Molybdenum Complex Containing PyS Ligands [Mo_3(CO)_6(μ-PyS)_2(μ_3-PyS)_2]

The deprotonated derivative pyridine-2-thiolato （PyS-） of pyridine-2-thione （PySH）is a potentially amibidentate or multi-functional donor which coordinates toward transitionmetals with either the exocyclic S or heterocyclic N atom or both atoms to form differentcoordination modes. We have recently reported the synthesis and crystal structure ofthe first dinuclear molybdenum complex with doubly-bridging PyS ligands [Mo2（CO）4（μ-PyS）2（PPh3）2]which was obtained from the reaction of [Mo（CO）3（CH3CN）3]

Ab initio studies on the electronic structure of the complexes containing Mo——S bond using relativistic effective core potentials

An ab initio calculation was performed on the electronic structures of MoS,MoS_4^(2-) and Mo_2S_2 using relativistic effective core potential(RECP)for molybdenum,and non-relativistic ECP for sulfur.We predicted that the equilibrium bond length and the dissociation energy of MoS in ground state are 3.89 a.u.and 4.67 eV,respectively,and that the bond is a triple-bond.The ground state of MoS_4^(2-) in Td symmetry is ~1A_1 and π-bonding dominates σ-donation in the molybdenum- sulfur interaction.The Mo_2S_2 is a model contracted from bi-nuclear sulfur-bridged clusters,and the bonding orbitals 1 b_(1u),1b_1g and 1b_2g make the dominant contribution to the stabilization of sulfur- bridged species.