| 摘要 |
PURPOSE:To compact the heat exchanger and obtain the intermediate heat exchanger, excellent in the reliability of structure, by a method wherein a material, having a thermal expansion coefficient larger than the same of the material of heat transfer tube, is employed for the material of a lower cylinder of the intermediate heat exchanger for a nuclear reactor. CONSTITUTION:The intermediate heat exchanger 33 consists of a hollow tubular upper cylinder 38 and a lower cylinder 39, hung vertically from a roof slub 2. An upper tube plate 41 is provided at the connecting section between the upper cylinder 38 and the lower cylinder 39, while a lower tube plate 42 is provided horizontally at the lower end of the lower cylinder 39. 39Cr series ferrite steel or the like, excellent in high-temperature strength and having comparatively small thermal expansion coefficient, is employed for the materials of the upper tube plate 41, the lower tube plate 42 and the heat transfer tube 43 while stainless steel, excellent in high-temperature strength and having comparatively larger thermal expansion coefficient, is employed for the material of one part of the lower cylinder 39 and both of them are connected through a different material coupling 23. According to this constitution, a tension load, applied on the heat transfer tube 43, effects in a direction of mitigating the load when the temperature of the tube 43 is increased suddenly and the tube 43 expands further in the case of hot-shock accident and whereby Euler buckle of the heat transfer tube 43, which is caused in case the tube 43 and the lower cylinder 39 are made of the same material, may be avoided.
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