Obtaining optimum exposure conditions for digital X-ray radiography of fresh nuclear fuel rods

X-ray radiography is widely used as a non-destructive method for defect detection and quality checks of nuclear fuel rod’s components in the fabrication process. In this paper, an approach based on Monte Carlo method is proposed to obtain optimum filter and exposure parameters such tube voltage, current and exposure for digital radiography of a nuclear fuel rod including UO2 pellets with a maximum diameter of 11.9 mm. Monte Carlo N-Particle (MCNP) code was implemented to model an digital X-ray radiography system composed of an industrial X-ray machine and a computed radiography phosphor imaging plate. Three main image quality parameters of contrast, resolution and signal to noise ratio (SNR) were evaluated in various exposure conditions. The results show that using a Cu intermediate filter with a thickness of 0.5 mm and a tube voltage in the range of 400–500kV with a minimum exposure of 20 mA min, can provide the highest quality for imaging the mentioned fuel rod. Moreover, the highest quality can be also achieved for tube voltages in the range of 500–600kV in condition that a minimum exposure of 40 mA min is provided. In addition to obtaining optimum conditions, the mentioned method can propose best exposure conditions proportional to the limitation of laboratory apparatuses. As a case study, the obtained results from simulation were implemented for the existence apparatuses in our laboratory and then an experimental work was carried out. The laboratory apparatuses included an X-ray machine with a peak voltage of 300 kV and a standard phosphor imaging plate. In the obtained experimental image, the details and components of the fuel rods including pellets, springs, Zircaloy clad and also the gap between the pellets were clearly observed. The proposed method can easily be implemented for all types of nuclear fuels with various dimensions and material types.

Jaar van publicatie:2019

Trefwoorden:A1 Journal article

Toegankelijkheid:Closed