NSUF 20-4166: Study of Irradiation Effects on Tantalum Alloys for Fast-Spectrum Self-Powered Neutron Detectors

Four samples of ASTAR-811C tantalum alloy and three samples of T-111 tantalum alloy were irradiated in the High Flux Isotope Reactor (HFIR) in 2005. All samples were irradiated in the same capsule at 1100 oC to 0.4 dpa. Because void swelling in neutron-irradiated tantalum alloys is likely to occur between 500 oC to 1100 oC, these samples will serve as an excellent pinpoint to guide our future efforts to map the void-swelling coefficient in tantalum. This specific irradiation temperature is at the higher end of the radiation-hardening temperature regime (0.33TM, where TM is the melting temperature of tantalum), so these neutron irradiated specimens provide the added value of being able to map multiple irradiation-induced defects for future comparisons to damage simulated using charged particle irradiations. Radiation-induced void swelling is a critical consideration in the design of future tantalum-based fast-spectrum self-powered neutron detectors as this it could be a source of catastrophic detector failure. All seven tantalum alloy samples are in SS-3 type tensile specimen format. The specimens are accompanied by six silicon carbide thermometry samples irradiated in the same capsule. We will move all samples to LAMDA following the award date in July of 2020. We plan to perform tensile strength and electrical resistivity measurements on all four samples of ASTAR-811C tantalum and all three samples of T-111 tantalum following this in July/August of 2020. Upon completion of the electrical resistivity measurements we will perform at least two focused ion beam (FIB) liftouts on one SS-3 tensile specimen for each alloy since the irradiation conditions were identical for all samples and follow that with transmission electron microscopy (TEM) measurements in order to image void creation in each sample. Additionally, we will perform dilatometry measurements on the six silicon carbide samples in order to obtain a more accurate irradiation temperature. We expect all measurements to require 14 – 15 days of LAMDA facility time and to be completed by September of 2020, pending facility availability.

Additional Info

Field	Value
Abstract	Four samples of ASTAR-811C tantalum alloy and three samples of T-111 tantalum alloy were irradiated in the High Flux Isotope Reactor (HFIR) in 2005. All samples were irradiated in the same capsule at 1100 oC to 0.4 dpa. Because void swelling in neutron-irradiated tantalum alloys is likely to occur between 500 oC to 1100 oC, these samples will serve as an excellent pinpoint to guide our future efforts to map the void-swelling coefficient in tantalum. This specific irradiation temperature is at the higher end of the radiation-hardening temperature regime (0.33TM, where TM is the melting temperature of tantalum), so these neutron irradiated specimens provide the added value of being able to map multiple irradiation-induced defects for future comparisons to damage simulated using charged particle irradiations. Radiation-induced void swelling is a critical consideration in the design of future tantalum-based fast-spectrum self-powered neutron detectors as this it could be a source of catastrophic detector failure. All seven tantalum alloy samples are in SS-3 type tensile specimen format. The specimens are accompanied by six silicon carbide thermometry samples irradiated in the same capsule. We will move all samples to LAMDA following the award date in July of 2020. We plan to perform tensile strength and electrical resistivity measurements on all four samples of ASTAR-811C tantalum and all three samples of T-111 tantalum following this in July/August of 2020. Upon completion of the electrical resistivity measurements we will perform at least two focused ion beam (FIB) liftouts on one SS-3 tensile specimen for each alloy since the irradiation conditions were identical for all samples and follow that with transmission electron microscopy (TEM) measurements in order to image void creation in each sample. Additionally, we will perform dilatometry measurements on the six silicon carbide samples in order to obtain a more accurate irradiation temperature. We expect all measurements to require 14 – 15 days of LAMDA facility time and to be completed by September of 2020, pending facility availability.
Award Announced Date	2020-07-14T14:11:45.367
Awarded Institution	None
Facility	None
Facility Tech Lead	Kory Linton
Irradiation Facility	None
PI	Kathleen (Callie) Goetz
PI Email	[email protected]
Project Type	RTE
RTE Number	4166