Dichlorodifluoromethane decomposition to CO2 with simultaneous halogen fixation by calcium oxide based materials

The decomposition of CCl2F2 to CO2 and accompanying halogen fixation by a CaO based material was studied. To improve the low reactivity of CaO, a consequence of its low surface acidity, transition metal oxides were added. Impregnation of metal acetylacetonate followed by removal of the ligand under vacuum was found to be an effective method. This method resulted in the formation of carbonaceous species and the reduction of metal oxide to metal, both of which were thought to initiate the decomposition reaction. The reactivity of these materials (MOx(a)/CaO-vac) was found to be in the following order: M = Ni > Cu > V = Fe > Mn > Co > Ca. In particular, nickel supported on CaO was most effective for the decomposition of CCl2F2. During the preparation, nickel oxide was reduced to the metal phase. CCl2F2 was decomposed to CO2 with a small amount of CO, and halogens were fixed as CaFCl, without significant deactivation at 723 K.     

Analysis of capacitance ratio of a rectangular X-cut length-extensional mode quartz crystal resonator by stresses

The electrical properties of an X-cut, length-extensional mode quartz crystal resonator of a cut angle theta around the X-axis were calculated by a variational method using stresses as trial functions. Analytical expressions of stresses were estimated by a linear regression on a cut angle best-fit to the results of finite-element method. The calculated dependence of the capacitance ratio on the cut angle was consistent with the measured results.     

Direct Observation of k∥ and k⊥ Stripe Excitations in La2?x Sr x CuO4

The superconducting transition temperature in the cuprate is pointed to be enhanced by the self-organized spin-charge separated stripes. The magnetic excitations are very different in k?? and k???stripes. Therefore if one detects the different excitations, it is a clear evidence of the stripe. Neutron scattering, however, always observes the mixed excitations. We first succeeded to detect the k???stripe excitations of the separated dispersion induced by the super-lattice structure of the stripe in distinction from the k???stripe excitations by two-magnon Raman scattering. The stripe structure is ubiquitous in the whole carrier density range at low temperatures.     

Widening of harvesting layer and area of P3HT/PCBM bulk-heterojunction photovoltaic cells

We have fabricated P3HT/PCBM based bulk-heterojunction photovoltaic cells with P3HT layer as the hole transport layer and PCBM layer as the electron transport layer between electrode and blended P3HT/PCBM layer in order to widen the photon harvesting layer. Current density has increased by about 1 mA/cm² by the insertion of P3HT layer and the resulting conversion efficiency has been improved by about 20%. We have also fabricated a centimeter-scale active area with an efficiency of ∼1%.     

Status of ceramic breeder pebble bed thermo-mechanics R&D and impact on breeder material mechanical strength

Among the international fusion solid breeder blanket community, there exists steady progress on the experimental, phenomenological, and numerical characterizations of the pebble bed effective thermo physical and mechanical properties, and of thermomechanic state of the bed under prototypical operating conditions. This paper summarizes recent achievements in pebble bed thermomechanics that were carried out by members of the IEA Fusion Nuclear Technology Subtask I Solid Breeding Blanket. A major goal is on developing predictive capability while identifying a pre-conditioned equilibrium stress state that would warrant pebble bed integrity during operations. The paper reviews and synthesizes existing computational modeling approaches for pebble bed thermomechanics prediction, and differentiating points of convergence/divergence among existing approaches. The progress toward modeling benchmark is also discussed. These advancements have led to a framework to help navigate future research.     

Development of the Water Cooled Ceramic Breeder Test Blanket Module in Japan

The development of a Water Cooled Ceramic Breeder (WCCB) Test Blanket Module (TBM) is being performed as one of the most important steps toward DEMO blanket in Japan. For the TBM testing and evaluation toward DEMO blanket, the module fabrication technology development by a candidate structural material, reduced activation martensitic/ferritic steel, F82H, is one of the most critical items from the viewpoint of realization of TBM testing in ITER. In Japan, fabrication of a real scale first wall, side walls, a breeder pebble bed box and assembling of the first wall and side walls have succeeded. Recently, the real scale partial mockup of the back wall was fabricated. The fabrication procedure of the back wall, whose thickness is up to 90 mm, was confirmed toward the fabrication of the real scale back wall by F82H. Important key technologies are almost clarified for the fabrication of the real scale TBM module mockup. From the view point of testing and evaluation, development of the technology of the blanket tritium recovery, development of advanced breeder and multiplier pebbles and the development of the blanket neutronics measurement technology are also performed. Also, tritium production and recovery test using D-T neutron in the Fusion Neutronics Source (FNS) facility has been started as the verification test of tritium production performance. This paper overviews the recent achievements of the development of the WCCB TBM in Japan.     

A calculation methodology proposed for liquid droplet impingement erosion

Bent pipe wall thinning has been often found at the elbow of the drain line and the high-pressure secondary feed-water bent pipe in nuclear reactors. Liquid droplet impingement (LDI) erosion could be regarded as one of the major causes and is a significant issue of the thermal hydraulics and structural integrity in aging and life extension for nuclear power plant safety. In this paper a computational methodology is established for simulation of LDI erosion using computational fluid dynamics (CFD) simulation and theoretical calculation. Two-phase flow numerical simulations are conducted for standard elbow geometry, typically with the pipe diameter of 170 mm. This computational fluid model is built up by incompressible Reynolds Averaged Navier–Stoke equations using standard k–? turbulence model and the SIMPLE algorithm, and the numerical droplet model adopts the Lagrangian approach. The turbulence damping in vapor–droplets flow is theoretically analyzed by a damping function on the energy spectrum basis of single phase flow. Locally, a droplet impact angle function is employed to determine the overall erosion rate. Finally, the overall and local investigations are combined to purpose a general methodology of LDI erosion prediction procedure, which has been complemented into CFD code. Based on our more physical computational results, comparison with an available accident data was made to prove that our methodology could be an appropriate way to simulate and predict the bent pipe wall thinning phenomena.     

Analysis of Cs-adsorption behavior using a column filled with microcapsule beads of potassium copper hexacyanoferrate

Ash-washing technology is a crucially important technology for removing radioactive Cs from contaminated ash. For that technology, Cs⁺ removal from the ash-washing solution by the adsorbent is necessary. This study was conducted to establish rapid preparation of appropriate adsorption columns for Cs⁺ uptake. A one-site model was not used for analysis because the model cannot accommodate sites with different adsorption speed. Results demonstrated that the adsorption behavior of the column filled with the granules of potassium copper hexacyanoferrate was well reproduced by a two-site adsorption model with parameters chosen through analysis of batch adsorption test results.