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

Runqiu Gu,Guangxi Wang,Jianfeng Cheng,Wanchang Lai,Thomas Walther

doi:10.1155/2021/9999042

Abstract

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.

Highlights

Most nuclear fuel rods contain an upper-end plug, a cladding tube, fuel pellets, and a lower-end plug [1, 2]
Detecting tungsten inclusions in nuclear fuel rod upper-end plug welds is an indispensable and vital step in the manufacturing process of nuclear fuel assemblies. is step is critical to ensure the safe operation of nuclear reactors
E main disadvantages of current methods are destructiveness, complicated procedures, lack of real-time data, and the limited size and content of detectable inclusions. is paper uses Monte Carlo software to simulate the energy-dispersive X-ray fluorescence (EDXRF) analysis of tungsten inclusions in nuclear fuel rods. e results show that the EDXRF analysis method is superior to the X-ray radiography method, as it can detect welds at the depth range of 0 to 0.4 mm

Summary

Introduction

Most nuclear fuel rods contain an upper-end plug, a cladding tube, fuel pellets, and a lower-end plug [1, 2]. Tungsten inert gas welding (TIG) produces relatively strong and higher quality welds, so it is widely used to weld precision instruments in the atomic energy and aviation industries [6,7,8,9]. If they are not inspected during welding, these welds can contain many types of defects. There were obvious characteristic X-ray peaks of tungsten element in the X-ray energy spectrum of fuel rod No 7, where the peaks of W (Kα1), W (Kα2), W (Kβ1), and W (Kβ2) are visible. There were obvious characteristic X-ray peaks of tungsten element in the X-ray energy spectrum of fuel rod No 7, where the peaks of W (Kα1), W (Kα2), W (Kβ1), and W (Kβ2) are visible. e results demonstrated that there were tungsten inclusions in that rod

Methods

Results

Conclusion