Fig. 1. Corrosion of zirconium and Zircaloys in pressurized water and steam(pre-transiton regime) 23

Fig. 2. Phase diagram of the zirconium-oxygen system19)(이미지참조) 25

Fig. 3. Schematic diagram of oxude film of the Zircaloy-2 and the processduring oxidation20)(이미지참조) 26

Fig. 4. Schematic corrosion behavior of the Zircaloy-4 in the temperature rangeof 260 to 400'C23)(이미지참조) 29

Fig. 6. X-ray diffaction pattern to the specimen 56

Fig. 7. Stresses at the surface of a stress body ; o3=O and measured stress is(이미지참조) 57

Fig. 8. Vector diagram of plane spacing for a tensile stress(이미지참조) 59

Fig. 9. Maufacturing process of Zr-Nb-Sn alloys to study of alloying element effect on corrosion 44

Fig. 10. Manufacturing process of Zr-Nb-Sn alloys to study of stress effect on corrosion 45

Fig. 11. Schematic darwing of static autocave 50

Fig. 12. Optical Microstructures of Zr-Nb-Sn Alloys with variation of Nb and Sn contents (F. A.: 470'C) 62

Fig. 13. Optical Microsturctures of Zr-Nb-Sn Alloys wit vaaton of Nb and Sn contents (F. A.: 510'C) 63

Fig. 14. Micro-hardness of Zr-Nb-Sn alloys with variaton of Nb and Sncontents (F.A: 470'C) 66

Fig. 15. Micro-hardness of Zr-Nb-Sn alloys with variaton of Nb and Sncontents (F.A: 510'C) 67

Fig. 16. TEM images of Zr- Nb-Sn alloys with variation of Nb and Sn contents (F.A.: 510'C) 69

Fig. 17. TEM micrgraphs and EDS spectrum of precipitate in Zr-Nb-Sn alloys (a) Zr-0.2Nb-0.4Sn, (b) Zr-0.2Nb-1.2Sn 70

Fig. 18. TEM micrgraphs and EDS spectrum of precipitate in Zr-Nb-Sn alloys (a) Zr-0.4Nb-0.4Sn, (b) Zr-0.4Nb-1.2Sn 71

Fig. 19. TEM micrgraphs and EDS spectrum of precipitate in Zr-Nb-Sn alloys (a) Zr-1.0Nb-0.4Sn, (b) Zr-1.0Nb-1.2Sn 72

Fig. 20. TEM micrgraphs and EDS spectrum of precipitate in Zr-Nb-Sn alloys (a) Zr-1.5Nb-0.4Sn, (b) Zr-1.5Nb-1.2Sn 73

Fig. 21. Corrosion behavior of Zr-0.2Nb-xSn alloys under various conditions (x=0.2~1.2) F.A 470'C (a) 360'C water, (b) 360'C 70 pprn LiOH and (c) two conditions 76

Fig. 22. Corrosion behavior of Zr-0.4Nb-xSn alloys under various conditions (x=0.2~1.2) F.A 470'C (a) 360'C water, (b) 360'C 70 pprn LiOH and (c) two conditions 77

Fig. 23. Corrosion behavior of Zr-1.0Nb-xSn alloys under various conditions (x=0.2~1.2) F.A 470'C (a) 360'C water, (b) 360'C 70 pprn LiOH and (c) two conditions 78

Fig. 24. Corrosion behavior of Zr-1.5Nb-xSn alloys under various conditions (x=0.2~1.2) F.A 470'C (a) 360'C water, (b) 360'C 70 pprn LiOH and (c) two conditions 79

Fig. 25. Corrosion behavior of Zr-0.2Nb-xSn alloys under various conditions (x=0.2~1.2) F.A 510'C (a) 360'C water, (b) 360'C 70 pprn LiOH and (c) two conditions 84

Fig. 26. Corrosion behavior of Zr-0.4Nb-xSn alloys under various conditions (x=0.2~1.2) F.A 510'C (a) 360'C water, (b) 360'C 70 pprn LiOH and (c) two conditions 85

Fig. 27. Corrosion behavior of Zr-1.0Nb-xSn alloys under various conditions (x=0.2~1.2) F.A 510'C (a) 360'C water, (b) 360'C 70 pprn LiOH and (c) two conditions 86

Fig. 28. Corrosion behavior of Zr-1.5Nb-xSn alloys under various conditions (x=0.2~1.2) F.A 510'C (a) 360'C water, (b) 360'C 70 pprn LiOH and (c) two conditions 87

Fig. 29. Tetragonal phase volume fraction of Zr-Nb-Sn alloys corroded at water condition. (a) Oxide surface, (b) Mid-range and (c) Oxide/Metal interface 89

Fig. 30. Tetragonal phase volume fraction of Zr-Nb-Sn alloys corroded at 70ppm LiOH condition. (a) Oxide surface, (b) Mid-rage and (c) Oxide/Metal interface 90

Fig. 31. Optical microstructure of Zr-(0.4, 1.5)Nb-(0.4, 0.8)Sn alloys with the various temperature (F.A.; 580 or 680'C) 95

Fig. 32. Micro-hardness of Zr-Nb-Sn alloys with the final annealing temperature (F.A: 580'C, 680'C); (a) Zr-0.4Nb-xSn, (b) Zr-1.5Nb-xSn (x=0.4, 0.8) 96

Fig. 33. TEM images of Zr(0.4, 1.5)Nb-(0.4, 0.8)Sn alloys with the various temperature (F.A; 580 or 680'C) 98

Fig. 34. TEM micrographs and EDS spectrums of precipitate in Zr-0.4Nb-0.4Sn alloys at various temperature; (a) F.A. 580'C, (b) F.A. 680'C 99

Fig. 35. TEM micrographs and EDS spectrums of precipitate in Zr-0.4Nb-1.2Sn alloys at various temperature; (a) F.A. 580'C, (b) F.A. 680'C 100

Fig. 36. TEM micrographs and EDS spectrums of precipitate in Zr-0.4Nb-1.2Sn alloys at various temperature; F.A. 580'C: (a) β-enriched, (b) Zr2Fe-type ppt, F.A. 680'C: (c) β-Zr 101

Fig. 37. TEM micrographs and EDS spectrums of precipitate in Zr-1.5Nb-1.2Sn alloys at various temperature; F.A. 580'C: (a) Zr2Fe-type ppt (b)β-enriched, F.A. 680'C: (c) β-Zr 102

Fig. 38. Corrosion behaviors of Zr-0.4Nb-(0.4, 0.8)Sn alloys in 360'C water (F.A.; 580 or 680'C); (a) Zr-0.4Nb-0.4Sn, (b) Zr-0.4Nb-0.8Sn 104

Fig. 39. Corrosion behaviors of Zr-0.4Nb-(0.4, 0.8)Sn alloys in 360'C 70ppm LiOH (F.A.; 580 or 680'C); (a) Zr-0.4Nb-0.4Sn, (b) Zr-0.4Nb-0.8Sn 105

Fig. 40. Corrosion behaviors of Zr-0.4Nb-(0.4, 0.8)Sn alloys in 360'C water (F.A.; 580 or 680'C); (a) Zr-0.4Nb-0.4Sn, (b) Zr-0.4Nb-0.8Sn 106

Fig. 41. Corrosion behaviors of Zr-1.5Nb-(0.4, 0.8)Sn alloys in 360'C 70ppm LiOH (F.A.; 580 or 680'C); (a) Zr-0.4Nb-0.4Sn, (b) Zr-0.4Nb-0.8Sn 107

Fig. 42. Tetragonal phase volume fraction of Zr-0.4Nb-0.4Sn alloys corroded at water condition; (a), (d): Oxide surface, (b), (e): Middle and.... 109

Fig. 43. Tetragonal phase volume fraction of Zr-1.5Nb-0.4Sn alloys corroded at water condition; (a), (d): Oxide surface, (b), (e): Middle and.... 110

Fig. 44. Internal stresses at oxide in the Zr-0.4Nb-0.4Sn alloys; (a) 580'C: -802.5Mpa, (b) 680'C: -766Mpa 111

Fig. 45. Optical micrstructure of Zr-(0.4, 1.5)Nb-(0.4, 0.8)Sn alloys with the various texture 115

Fig. 46. (0002) pole figures with rolling method in Zr-0.4-(0.4, 0.8)Sn alloys; (a) Zr-0.4Nb-0.4Sn; Low texture, (b) Zr-0.4Nb-0.8Sn; Low texture, (c).... 116

Fig. 47. (0002) pole figures with rolling method in Zr-4.5-(0.4, 0.8)Sn alloys; (a) Zr-0.4Nb-0.4Sn; Low texture, (b) Zr-1.5Nb-0.8Sn; Low texture, (c).... 117

Fig. 48. Micro-hardness of Zr-Nb-Sn alloys with the textrue (Low texture, High texture); (a) Zr-0.4Nb-xSn, (b) Zr-1.5Nb-xSn (x=0.4, 0.8) 119

Fig. 49. Corrosion behaviors of Zr-0.4Nb-(0.4, 0.8)Sn aloys in 360.C water; (a) Zr-0.4Nb-OASn, (b) Zr-0.4-0.8Sn 122

Fig. 50. Corrosion behaviors of Zr-0.4Nb-(0.4, 0.8)Sn alloys in 360'C 70ppm LiOH; (a) Zr-0.4Nb-0.4Sn, (b) Zr-0.4Nb-0.8Sn 123

Fig. 51. Corrosion behaviors of Zr-1.5Nb-(A, 0.8)Sn alloys in 360'C water; (a) Zr-1.5Nb-0.4Sn, (b) Zr-1.5N-0.8Sn 124

Fig. 52. Corrosion behaviors of Zr-1.5N-(0.4, 0.8)Sn alloys in 360'C 70ppm LiOH; (a) Zr-1.5N-0.4Nb, (b) Zr-1.5Nb-0.8Sn 125

Fig. 53. Tetragona phase volume fraction of Zr-0.4Nb-0.4Sn alloys coroded at water condtion; (a), (d): Oxide surace, (b), (e): Mid-range and (c), (f)........ 127

Fig. 54. Tetragona phase volume fraction of Zr-1.5Nb-0.4Sn alloys coroded at water condtion; (a), (d): Oxide surace, (b), (e): Mid-range and (c), (f)........ 128

Fig. 55. Internal stresses at oxde in the Zr-1.5Nb-0.4Sn alloys; (a) Low Texture: -87.5Mpa, (b) Hgh Textue: -85.5Mpa 129

Fig. 56. Internal stesses at inta oxde in te Zr-l.5N-O.4Sn aloys; (a) Low Textre: -77.2Mpa, (b) Hgh Textue: -800.5Mpa 130

Fig. 57. Optica mcrostrcture of Zr-0.4Nb-(0.4, 0.8)Sn aoys with the hyddng or non-hyddng(Low Texture, 580'C) 134

Fig. 58. Optica mcrstrctue of Zr-0.4Nb-(0.4, 0.8)Sn alloys with the hyddng or non-hyddng(Hgh Textue, 580'C) 135

Fig. 59. Optica mcrstrcue of Zr-1.5Nb-(0.4, 0.8)Sn alloys with the hyddng or non-hydcng(Low Texture, 580°C) 136

Fig. 60. Optica mcrstrcture of Zr-1.5Nb-(0.4, 0.8)Sn alloys with the hyddng or non-hydcng(Hgh Textue, 580'C) 137

Fig. 61. Micro-hadess of Zr-0.4Nb-(0.4, 0.8)Sn alloys with the low textue and 580'C 139

Fig. 62. Micro-hadess of Zr-0.4Nb-(0.4, 0.8)Sn alloys with the high textue and 580'C 140

Fig. 63. Micro-hadness of Zr-1.5Nb-(0.4, 0.8)Sn alloys with the low textue and 580°C 141

Fig. 64. Micro-hadness of Zr-1.5Nb-(0.4, 0.8)Sn aoys with te hgh textue and 580°C 142

Fig. 65. Corrosion behaviors of Zr-0.4Nb-(0.4, 0.8)Sn alloys in 360'C water (Hydriding; None or 400ppm, 580°C, Low Texture); (a) Zr-0.4Nb-0.4Sn (b) Zr-0.4Nb-0.8Sn 144

Fig. 66. Corrosion behaviors of Zr-0.4Nb-(0.4, 0.8)Sn alloys in 360'C water (Hydriding; None or 400ppm, 580°C, Low Texture); (a) Zr-0.4Nb-0.4Sn (b) Zr-0.4Nb-0.8Sn 145

Fig. 67. Corrosion behaviors of Zr-1.5Nb-(0.4, 0.8)Sn alloys in 360'C water (Hydriding; None or 400ppm, 580°C, Low Texture); (a) Zr-1.5Nb-0.4Sn (b) Zr-1.5Nb-0.8Sn 146

Fig. 68. Corrosion behaviors of Zr-1.5Nb-(0.4, 0.8)Sn alloys in 360'C water (Hydriding; None or 400ppm, 580°C, Low Texture); (a) Zr-1.5Nb-0.4Sn (b) Zr-1.5Nb-0.8Sn 147

Fig. 69. Corrosion behaviors of Zr-0.4Nb-(0.4, 0.8)Sn alloys in 360'C 70ppm LiOH (Hydriding; None or 400ppm, 580'C, Low Texture); (a) Zr-0.4Nb-0.4Sn, (b) Zr-0.4Nb-0.8Sn 148

Fig. 70. Corrosion behaviors of Zr-0.4Nb-(0.4, 0.8)Sn alloys in 360'C 70ppm LiOH (Hydriding; None or 400ppm, 580'C, Low Texture); (a) Zr-0.4Nb-0.4Sn, (b) Zr-0.4Nb-0.8Sn 149

Fig. 71. Corrosion behaviors of Zr-0.4Nb-(0.4, 0.8)Sn alloys in 360'C 70ppm LiOH (Hydriding; None or 400ppm, 580'C, Low Texture); (a) Zr-1.5Nb-0.4Sn, (b) Zr-1.5Nb-0.8Sn 150

Fig. 72. Corrosion behaviors of Zr-0.4Nb-(0.4, 0.8)Sn alloys in 360'C 70ppm LiOH (Hydriding; None or 400ppm, 580'C, Low Texture); (a) Zr-1.5Nb-0.4Sn, (b) Zr-1.5Nb-0.8Sn 151

Fig. 73. Tetragonal phase volume fraction of Zr-0.4Nb-0.4Sn alloys corroded at water condition; (a), (d): Oxide surface, (b), (e): Middle and (c), (f) Oxide/Metal interface, none-hydride(a, b, c), 400ppm hydriing(d, e, f) 153

Fig. 74. Tetragonal phase volume fraction of Zr-1.5Nb-0.4Sn alloys corroded at water condition; (a), (d): Oxide surface, (b), (e): Middle and (c), (f) Oxide/Metal interface, none-hydride(a, b, c), 400ppm hydriing(d, e, f) 154

Fig. 75. Internal stresses at oxide in the Zr-0.4Nb-0.4Sn alloys(F.A. 580°C, Low Texture); (a) None-Hydriding: -802.5Ma, (b) 400ppm-Hydriding: -782.5MPa 155

Fig. 76. Internal stresses at oxide in the Zr-1.5Nb-0.4Sn alloys(F.A. 580°C, Low Texture); (a) None-Hydriding: -802.5Ma, (b) 400ppm-Hydriding: -812MPa 156