Numerical analysis of the activity of irradiated alloy-N in an FHR

• Published in: Nuclear science and techniques 2016-04, Vol.27 (2), p.149-154, Article 44
• Main Authors: Peng, Chao, Zhu, Xing-Wang, Zhang, Guo-Qing, He, Zhao-Zhong, Chen, Kun
• Format: Article
• Language: English
• Subjects: Energy; Hadrons; Heavy Ions; Nuclear Energy; Nuclear Physics; 反应堆容器; 反应堆退役; 数值分析; 结构材料; 腐蚀作用; 辐射源项; 辐射防护; 辐照
• ISSN: 1001-8042; 2210-3147
• DOI: 10.1007/s41365-016-0044-3

The fluoride salt-cooled high-temperature reactor（FHR） uses molten FLi Be salt as the coolant, which introduces a corrosive effect on the alloy-N structure material. Fission neutrons activate the corroded alloy-N,along with alloy-N structures inside the reactor vessel. The activation products of the alloy-N have a big impact on radiation protection during operation, maintenance, and decommissioning of the reactor. We have constructed a SCALE 6.1 model for the core of a typical 10 MW th FHR and analyzed the activity of each constituent of the irradiated alloy-N. The results show that the activity is predominantly due to short-lived~（28） Al,~（60m） Co,~（56） Mn,~（51）Ti, and ~（52） V, as well as long-lived ~（60） Co,~（51）Cr,~（55）Fe,~（59）Fe, and ~（54） Mn.Furthermore, because of their relatively long half-life and high-energy c-rays emissions,~（60） Co and ~（54）Mn are the major contributors to the radiation source terms introduced by alloy-N activation. The yield of ~（60）Co and ~（54）Mn per unit mass of alloy-N under the current core design is 5.58＊10~5 and 1.55 ＊ 10~3 Bq MWd~（-1）g~（-1）, respectively.The results of this paper, combined with future corrosion studies, may provide a basis for evaluating long-term radiation source terms of the primary loop salt and components.