NSUF 21-4345: A first Investigation in Lanthanide-induced Grain Boundary Embrittlement in HT9 Cladding via In-situ Micro-tensile Testing

Fuel cladding chemical interaction (FCCI) between HT9 cladding and UZr based metallic fuel often leads to significant change of the composition and microstructure in the inner cladding. Existing STEM-EDS mapping data clearly shows, for the first-time, the infiltration of lanthanide fission product (Represented by Ce) into HT-9 cladding along grain boundaries. How the migration of lanthanide at α-Fe grain boundary will affect the formation of cracks, mechanical integrity of cladding, and service lifetime of fuel elements in reactors remains an open question. Currently understanding is based on indirect estimation out of nano indentation results. Therefore, a direct tensile strength measurement of grain boundary penetrated with lanthanides in HT-9 cladding is critical for a better understanding on the effect of FCCI and rationalizing future cladding design. In this RTE project, in-situ push-to-pull mechanical tensile testing will be used to measure the grain boundary strength in different FCCI sublayers of HT9 inside a SEM/FIB instrument. The data will fill the knowledge gap between embrittlement of HT9 cladding and actual grain boundary strength of cladding. The HT9 sample (sample ID: 83T) is in IMCL ready for experiment. It is estimated to take around 3~5 months for accomplishing data collection, including in-situ tensile testing and TEM characterization. And another 3~4 months for data analysis, report draft, and journal publication.

Additional Info

Field	Value
Abstract	Fuel cladding chemical interaction (FCCI) between HT9 cladding and UZr based metallic fuel often leads to significant change of the composition and microstructure in the inner cladding. Existing STEM-EDS mapping data clearly shows, for the first-time, the infiltration of lanthanide fission product (Represented by Ce) into HT-9 cladding along grain boundaries. How the migration of lanthanide at α-Fe grain boundary will affect the formation of cracks, mechanical integrity of cladding, and service lifetime of fuel elements in reactors remains an open question. Currently understanding is based on indirect estimation out of nano indentation results. Therefore, a direct tensile strength measurement of grain boundary penetrated with lanthanides in HT-9 cladding is critical for a better understanding on the effect of FCCI and rationalizing future cladding design. In this RTE project, in-situ push-to-pull mechanical tensile testing will be used to measure the grain boundary strength in different FCCI sublayers of HT9 inside a SEM/FIB instrument. The data will fill the knowledge gap between embrittlement of HT9 cladding and actual grain boundary strength of cladding. The HT9 sample (sample ID: 83T) is in IMCL ready for experiment. It is estimated to take around 3~5 months for accomplishing data collection, including in-situ tensile testing and TEM characterization. And another 3~4 months for data analysis, report draft, and journal publication.
Award Announced Date	2021-06-07T16:03:40.76
Awarded Institution	None
Facility	None
Facility Tech Lead	Alina Zackrone
Irradiation Facility	None
PI	Yachun Wang
PI Email	[email protected]
Project Type	RTE
RTE Number	4345