Anomalous tungsten transport driven by ion temperature gradient turbulence

The present study reveals that the anomalous tungsten particle transport based on the nonlinear gyrokinetic simulations shares some similarities with that of the linear gyrokinetic study, meanwhile there exist some significant differences. In particular, nonlinear excitation of the linearly stable modes plays a non-negligible role in anomalous tungsten particle transport. The highlighted results are the downshift of the critical density gradient for zero tungsten particle transport and the mod- ification of the poloidal profile of the outward tungsten particle transport, which are both related to the small scale turbulent fluctuations. The former one is due to the outward particle convection produced by the linearly stable modes. The later one is brought by both the linearly stable modes and the large-scale eddies with finite ballooning angle, which flatten the poloidal profile of the particle diffusion and further shift the peak positions of the strongest outward particle transport to the high poloidal angle regions.

Mechanical and thermal characterization of tungsten particulate reinforced epoxy polymer composites

Polymer matrix composites find a wide range of industrial applications due to its unique properties like lightweight, improved strength and the properties could also be tailored to suit specific applications. In this present work, a new class of polymer matrix composites with epoxy resin as matrix and tungsten metal particles as fillers were developed. The influence of the addition of tungsten fillers on mechanical and thermal properties of the composites has been investigated. The composites are fabricated by hand lay-up method and the specimens containing tungsten particle content by 1%, 3%, 5%, 7% and 9% by weight were developed. The developed specimens were subjected to mechanical and thermal investigations. Mechanical behavior was analyzed by conducting a flexural test and hardness as per ASTM standards. Thermal behavior was analyzed by conducting Thermogravimetric analysis (TGA) and Differential Scanning Calorimetry (DSC) of the developed composites. The results show that the addition of 7 wt. % filler has a higher value of flexural strength and hardness. Further addition of particulate fillers deteriorates the flexural strength and hardness due to agglomeration of filler content in the epoxy. Analysis by TGA and DSC shows that the thermal stability of composites is improved by increasing the addition of tungsten content in the epox.

Applying Energy-Dispersive X-Ray Fluorescence Analysis to Detect Tungsten Inclusions in Nuclear Fuel Rod End Plug TIG Welds

This study proposes a new method of detecting tungsten inclusions in nuclear fuel rod upper-end plug welds using energy-dispersive X-ray fluorescence (EDXRF) analysis. The Monte Carlo simulation method was used to simulate the process of detecting tungsten inclusions in nuclear fuel rod upper-end plug welds by the EDXRF. The detectable tungsten particle diameters in the zirconium alloy at different depths in welds and the detection limits of the trace tungsten dispersed in welds were obtained. Then, we constructed an experimental device that uses a CdTe detector with an X-ray tube. The results showed that the relative standard deviation of the net count rate of tungsten K-series characteristic X-rays [W (Kα)] was 1.46%, and the optimum parameters are a tube voltage of 150 kV and current of 0.5 mA. These values were used to perform energy-dispersive X-ray fluorescence analysis. These results were compared to the X-ray radiographic results, which were broadly similar. Furthermore, the results of EDXRF analysis were more legible and reliable than those from X-ray radiographic inspections. This study demonstrates the feasibility of applying EDXRF analysis to detect tungsten inclusions.