To develop South Korea’s own SFR nuclear fuel cladding tube that has excellent high temperature creep characteristics, candidate alloys for a new cladding material that has better performance than the conventional Gr.92 (9Cr–2W–Nb–V) steel were selected by conducting a high temperature tensile test and creep test for the candidate alloys fabricated by adequately combining precipitation and strengthening of alloy elements (C, Ta, Nb, V, N) with solid solution treatment and hardening of alloy elements (Cr, Mo, W, B). Among the candidate alloys, two types—FC92B and FC92N—that had excellent creep characteristics were used to fabricate the cladding tubes. In the results of the creep test, when a cladding tube was fabricated by using FC92N, which showed excellent creep performance in the air atmosphere, the creep performance declined. After the creep tests of FC92B and FC92N cladding tubes, this study examined the microstructures of specimens and analyzed the relationship between microstructure and creep rupture life. When the creep test was performed in the air and argon gas atmosphere, FC92N showed a larger increase in the thickness of an oxide layer than FC92B. It was determined that the FC92B alloy, in which 130 ppm of B was added, showed excellent creep performance in both the air and argon gas atmospheres because its oxidation resistance was relatively excellent compared to that of FC92N.

Graphic Abstract

中文翻译：

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FC92B和FC92N包壳管蠕变断裂特性：SFR燃料包壳管材料的候选合金

为了开发韩国自己的具有优异高温蠕变特性的 SFR 核燃料包壳管，选择了性能优于传统 Gr.92 (9Cr-2W-Nb-V) 钢的新型包壳材料的候选合金。将合金元素（C、Ta、Nb、V、N）的沉淀和强化与合金元素（Cr、Mo、W、B）的固溶处理和硬化充分结合制备的候选合金的高温拉伸试验和蠕变试验. 在候选合金中，两种具有优异蠕变特性的类型——FC92B 和 FC92N 用于制造包壳管。在蠕变试验的结果中，当使用在空气气氛中表现出优异蠕变性能的FC92N制造包壳管时，蠕变性能下降。在对 FC92B 和 FC92N 复合管进行蠕变试验后，本研究检查了试样的微观结构，并分析了微观结构与蠕变断裂寿命之间的关系。当在空气和氩气气氛中进行蠕变试验时，FC92N 显示出比 FC92B 更大的氧化层厚度增加。已确定添加 130 ppm B 的 FC92B 合金在空气和氩气气氛中均表现出优异的蠕变性能，因为与 FC92N 相比，其抗氧化性相对优异。与 FC92B 相比，FC92N 显示出更大的氧化层厚度增加。已确定添加 130 ppm B 的 FC92B 合金在空气和氩气气氛中均表现出优异的蠕变性能，因为与 FC92N 相比，其抗氧化性相对优异。与 FC92B 相比，FC92N 显示出更大的氧化层厚度增加。已确定添加 130 ppm B 的 FC92B 合金在空气和氩气气氛中均表现出优异的蠕变性能，因为与 FC92N 相比，其抗氧化性相对优异。

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