Inconel 600 및 690의 원자로 냉각재에 의한 부식에 관한 연구

Abstract

Radioactive Corrosion Products formed by corrosion in the primary coolant system of domestic pressurized water reactors occupy more than 70 percents of radiation exposure to plant maintenance personnel and draw much attention to the study on this field in order to reduce radiation exposure by the radioactive corrosion product. As nuclear species contributing to exposure among materials existing into radioactive corrosion product are it is necessary to estimate comparatively exactly the relative production amount of these nuclear species accumulated according to the operation of nuclear power plants. Because coolant contact area of Steam Generator tube in primary coolant system occupies about 75 percents, it is judged that the amount of radioactive Corrosion Products formed by the corrosion of Steam Generator Tube(S/G tube) is also considerably much. Therefore, it is judged that corrosion experiments are performed according to pH on more severe water quality and chemical treatment condition than those of actual PWR plants, and dose on plant maintenance personnel is predicted by evaluating corrosion velocity as well as corrosion trend based on experimental result. For this, in this paper, an experiment on uniform corrosion with the object of estimating the generation quantity of into Inconel 600 and 690 material which are used of S/G tube was carried out. For this, twelve test sections were made of Inconel 600 and 690, and corrosion experiments were performed for 20 days according to pH on more severe water quality and chemical treatment condition than those of actual PWR plants, also Glow Discharge Spectrometer was used to analyze experimental result quantitatively. According to quantitative analysis result, Inconel 600 corrodes more than Inconel 690 does on the condition of pH 7 and pH 9, but on the other hand it is evaluated that Inconel 690 corrodes more than Inconel 600 does at pH 4. It is judged that this trend is because the effect of transient state was reflected excessively. Therefore, it is judged that by performing corrosion experiment during a long period to evaluate result comparatively exactly the effect of transient state must be minimized.