Page 1 Page 2 Page 3 Page 4 Page 5 Page 6 Page 7 Page 8 Page 9 Page 10 Page 11 Page 12 Page 13 Page 14 Page 15 Page 16 Page 17 Page 18 Page 19 Page 20 Page 21 Page 22 Page 23 Page 24 Page 25 Page 26 Page 27 Page 28 Page 29 Page 30 Page 31 Page 32 Page 33 Page 34 Page 35 Page 36 Page 37 Page 38 Page 39 Page 40 Page 41 Page 42 Page 43 Page 44 Page 45 Page 46 Page 47 Page 48 Page 49 Page 50 Page 51 Page 52 Page 53 Page 54 Page 55 Page 56 Page 57 Page 58 Page 59 Page 60 Page 61 Page 62 Page 63 Page 64 Page 65 Page 66 Page 67 Page 68 Page 69 Page 70 Page 71 Page 72 Page 73 Page 74 Page 75 Page 76 Page 77 Page 78 Page 79 Page 80 Page 81 Page 82 Page 83 Page 84 Page 85 Page 86 Page 87 Page 88 Page 89 Page 90 Page 91 Page 92 Page 93 Page 94 Page 95 Page 96 Page 97 Page 98 Page 99 Page 100 Page 101 Page 102 Page 103 Page 104 Page 105 Page 106 Page 107 Page 108 Page 109 Page 110 Page 111 Page 112 Page 113 Page 114 Page 115 Page 116 Page 117 Page 118 Page 119 Page 120 Page 121 Page 122 Page 123 Page 124Nuclear Science User Facilities 112 INL-AECL Joint Project for Active FIB and TEM analysis of Irradiated X‑750, CRADA 11‑CR‑16 John H. Jackson – Idaho National Laboratory – john.jackson@inl.gov Project Description This joint project examines the micro- structural changes of alloy X‑750 as a function of neutron irradiation and temperature. Several garter spring sections that had been used in service as fuel channel spacers in Canada Deuterium Uranium (CANDU) reactors were provided to INL by the Atomic Energy of Canada’s (AECL) Chalk River Laboratory (now Canadian Nuclear Laboratories Limited [CNL]). These spring sections had exhibited extreme loss of ductility during service inspections and have become the subject of fitness for service investigations by the CANDU reactor industry. Preliminary field inspections indicated a potential relationship between loss of ductility and loca- tion of spring sections; a thorough microstructural analysis was deemed necessary to understand the behavior of these spring materials. Alloy X‑750 is a nickle-based super alloy that is commonly used in light water reactor internal components as well as the CANDU reactor. Embrittlement caused by a neutron environment is of interest for lifetime prediction in the current fleet of reactors in the United States and the rest of the world.This work directly relates to relicensing efforts for light water reactors. This work will provide much needed microstructural information toward understanding the evolution of material microstructure as a function of temperature and very high neutron fluence. The work will lead to a better understanding of the role of helium formation in nickel alloys as neutron damage accumulates. Figure 1. Temperature profile in an X-750 spacer spring.