Abstract
KAERI is conducting research on spent cladding hulls and additive metals to generate a solidification host matrix for the noble metal fission product waste in anode sludge from the electro-refining process to minimize the volume of waste that needs to be disposed of. In this study, alloy compositions Zr-17Cr, Zr-22Cr, and Zr-27Cr were prepared with or without eight noble metals representing fuel waste using induction melting. The microstructures of the resulting alloys were characterized and electrochemical corrosion tests were conducted to evaluate their corrosion characteristics. All the compositions had better corrosion characteristics than other Zr-based alloys that were evaluated for comparison. Analysis of the leach solution after the corrosion test of the Zr-22Cr-8NM specimen indicated that the noble metals were not leached during corrosion under 500 mV imposed voltage, which simulates a highly oxidizing disposal environment. The results of this study confirm that Zr-Cr based compositions will likely serve as chemically stable waste forms.
KAERI에서는 파이로프로세싱에서 발생하는 금속폐기물의 부피 및 무게 감량을 위해 고방사성 장반감기 핵종을 포함하는 anode sludge내 NM의 고화매질로써 폐피복관과 첨가금속을 재활용하는 연구를 진행하고 있다. 본 연구에서는 Cr 함량을 조절한 Zr-17Cr-8NM, Zr-22Cr-8NM, Zr-27Cr-8NM 합금을 유도용융을 통해 제조하였고, 전기화학적 부식시험을 실시하여 부식특성을 평가하였다. 모든 조성에서 기존 연구 중인 Zr계 합금고화체 조성보다 우수한 부식특성을 나타냈다. 또한 Zr-22Cr-8NM 시편의 부식시험 후 침출용액 조성 분석 결과, 500 mV 전압 조건 이하에서는 NM 침출이 없었고 이를 통해 우수한 화학적 안정성을 갖는 합금고화체 조성을 확보하였다.
