Lee Byeonggwan, Choi Jung-Hoon, Lee Ki Rak, Kang Hyun Woo, Eom Hyeon Jin, Shin Kyuchul, Park Hwan-Seo
Korea Atomic Energy Research Institute, 111 Daedeok-daero 989, Yuseong-gu, Daejeon, 34057, Republic of Korea.
Department of Hydrogen & Renewable Energy, Kyungpook National University, 80 Daehak-ro, Buk-gu, Daegu, 41566, Republic of Korea.
Heliyon. 2023 Jul 17;9(7):e18406. doi: 10.1016/j.heliyon.2023.e18406. eCollection 2023 Jul.
When disposing of spent fuel, nuclides such as Cs-137 and Sr-90, which generate short-term decay heat, must be removed from the spent nuclear fuel for efficient storage facility utilization. The Korea Atomic Energy Research Institute (KAERI) has been developing a nuclide management process that can enhance disposal efficiency by sorting and collecting primary nuclides and a technology for separating Sr nuclides from the spent nuclear fuels using precipitation and distillation. In this study, we prepared Sr ceramic waste form, SrTiO, using the solid-state reaction method to immobilize the Sr nuclides, and its physicochemical properties were evaluated. Moreover, the radiological and thermal characteristics of the Sr waste form were evaluated by estimating the composition of Sr nuclides considering the spent nuclear fuel history such as burn-up and cooling period. The waste form was found to be stable with good mechanical strength and leaching properties in addition to a low coefficient of thermal expansion, which would be advantageous for intermediate storage. Based on the experimental and radiological results, the centerline temperature of the waste form caused by Sr-90 nuclide was estimated using the steady-state conduction equation. The centerline temperature increased with increasing diameter of the waste form. When generating the SrTiO waste form using the Sr nuclide recovered after a cooling period of 10 years, the centerline temperature was estimated to exceed the melting point of SrTiO at a diameter of 0.275 m, under all burn-up conditions. These results provide fundamental data for the management and intermediate storage of Sr waste.
在处理乏燃料时，必须从乏核燃料中去除诸如Cs - 137和Sr - 90等会产生短期衰变热的核素，以便高效利用储存设施。韩国原子能研究所（KAERI）一直在开发一种核素管理工艺，该工艺可通过对主要核素进行分类和收集来提高处置效率，同时还在开发一种利用沉淀和蒸馏从乏核燃料中分离Sr核素的技术。在本研究中，我们采用固态反应法制备了用于固定Sr核素的Sr陶瓷固化体SrTiO，并对其物理化学性质进行了评估。此外，通过考虑乏核燃料的燃耗和冷却期等历史情况来估算Sr核素的组成，从而评估了Sr固化体的放射性和热特性。结果发现，该固化体具有稳定性，除了热膨胀系数低外，还具有良好的机械强度和浸出性能，这对于中间储存是有利的。基于实验和放射性结果，使用稳态传导方程估算了由Sr - 90核素引起的固化体中心线温度。中心线温度随固化体直径的增加而升高。当使用冷却10年后回收的Sr核素生成SrTiO固化体时，在所有燃耗条件下，估计直径为0.275 m时中心线温度将超过SrTiO的熔点。这些结果为Sr废物的管理和中间储存提供了基础数据。
