Microstructures and mechanical properties of GH4169 alloy cylinder and its weld joints in a supercritical water reactor are studied after operating 2000 h. The results show that the GH4169 alloy cylinder exhibits good corrosion resistance under conditions of high temperature, high pressure, and sucrose mixed solution; the thickness loss rate of the cylinder is 0.005-0.255 μm/h; the corrosion products primarily consist of oxides and phosphates. However, the welded joints connecting the cylinder and other components represent a vulnerable point that significantly impacts the remaining lifespan of the reactor. The calculated crack propagation rate of the GH4169 alloy cylinder is 5.25 μm/h, indicating that it would only take 762 h for the crack to penetrate through the wall of the connector. Additionally, severe fracture occurs (the circumferential length of the crack is approximately 1/4 of the circumference) at the weld joint between cylinder and stainless-steel, resulting from the synergistic effects of galvanic corrosion, crevice corrosion, and concentrated stress. Despite these challenges, the strength loss of the cylinder is relatively small, which means that the cylinder maintains satisfactory mechanical properties.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |