A TGA study on the chlorination reaction kinetics of Zircaloy-4 cladding hulls

作者：Jeon Min Ku^*; Choi Yong Taek; Kang Kweon Ho; Park Eun Il

来源：Journal of Nuclear Materials, 2015, 459: 175-182.

DOI：10.1016/j.jnucmat.2015.01.034

The chlorination reaction kinetics of Zircaloy-4 cladding hulls were investigated using a home-made thermogravimetric analysis for a hull chlorination (TGA-HC) system. The reproducibility of the TGA-HC system was verified by repeated measurements at an identical condition, which showed only 6.6% of maximum difference. The effect of total flow rate (Q) was investigated for Q of 120 and 240 mL/min, and it was revealed that the reaction rate is not influenced in this condition. Using the Sharp Hancock plot, the volumetric contraction model was identified as the most suitable model for the Zircaloy-4 chlorination reaction. The influence of chlorine partial pressure was studied at 9.21, 16.9, and 23.4 kPa of Cl-2 partial pressure conditions, and it was identified that the reaction rate is proportional to the chlorine partial pressure on the order of (0.669). The effect of reaction temperature was investigated for 300-450 degrees C, and it was revealed that the chlorination reaction exhibits an activation energy of 26.2 kJ/mol. Using the experimental and fitting results, the reaction rate equation for the Zircaloy-4 chlorination reaction was achieved, but the equation was valid only until the conversion fraction (alpha) reaches up to (0.60). When alpha is higher than 0.60, the volumetric contraction model was not applicable. A second-order reaction rate equation was suggested for the 0.6 < alpha region, although it needs further investigation.

• 出版日期2015-4