在模擬小型模組化沸水式反應器水環境敏化處理304L與XM-19不銹鋼的應力腐蝕龜裂之研究

Stress Corrosion Cracking of Sensitized 304L and XM-19 Stainless Steels in a Simulated Small Modular Boiling Water Reactor Water Environment

全球主要大型先進反應器在材料選擇與製造技術上並未出現顯著變革，因此當代輕水反應器與先進輕水反應器使用的材料，同樣具備應用於小型模組化反應器的潛力。304L不銹鋼具優異的抗IGSCC能力，是沸水式反應器常用材料；XM-19則為近代核電廠採用的新型不銹鋼。然而，焊接導致的敏化現象會影響其SCC行為。本研究探討固溶與敏化處理後的304L與XM-19在模擬小型模組化沸水式反應器環境中的SCC抗性，進行慢應變速率拉伸測試，並分析斷裂表面與氧化膜。結果顯示敏化304L之SCC敏感性增加且延展性降低；XM-19即使敏化後仍具較佳抗性。

Significant advancements in reactor designs have not led to notable changes in material selection or fabrication methods. The materials utilized in modern light-water reactors continue to be appropriate for small modular reactors. Type 304L stainless steel exhibits significant resistance to intergranular stress corrosion cracking and is commonly utilized in boiling water reactors, whereas XM-19 is employed in more recent facilities. Welding-induced sensitization may reduce resistance to stress corrosion cracking (SCC). This research investigates the stress corrosion cracking behavior of solution-annealed and sensitized 304L and XM-19 stainless steels in a simulated small modular boiling water reactor environment, employing slow strain rate testing along with fracture surface and oxide film analysis. Sensitized 304L exhibits increased susceptibility to stress corrosion cracking and diminished ductility, while XM-19 demonstrates enhanced resistance.