​​The Laboratory Directed Research and Development (LDRD) program is a vital resource for Idaho National Laboratory (INL) to achieve our mission to discover, demonstrate, and secure innovative nuclear energy solutions, clean-energy options, and critical infrastructure. Our LDRD investments stimulate high-impact research, sustain and amplify INL’s core capabilities, and recruit and retain world-class science and technology (S&T) talent for INL and the nation. 

LDRD Success Story:

Small-scale thermal and irradiation creep measurements accelerate advanced materials development.​

Advanced materials with enhanced resistance to irradiation at high temperatures benefit the life-extension and long-term operation of the current light water reactor fleet and the development of advanced nuclear reactor concepts. To qualify a material for reactor operation, many mechanical properties must be assessed, including thermal and irradiation creep. Creep is a time-dependent deformation process for a metal under the influence of stress, temperature, and irradiation. It is important to assess all aspects of the creep properties of new materials for reactor applications: thermal creep of as-manufactured materials, in-reactor/irradiation creep, and thermal creep of irradiated materials. 

Accelerated techniques to test nanoindentation creep, mesoscale thermal creep, and small-scale proton irradiation creep were developed to assist rapid qualification of new reactor materials. In the nanoindentation testing, the creep of oxide-dispersion-strengthened stainless steel was characterized and modeled with the Multiphysics Object-Oriented Simulation Environment (MOOSE). The novel mesoscale creep experiments on zirconiumniobium specimens with sizes of tens of micrometers were performed to extract bulk creep properties. The in situ irradiation creep of 304 stainless steel was characterized using proton irradiation facilities at Michigan Ion Beam Laboratory. This project paved a way to obtain creep properties of materials using only a small volume of specimen, facilitating efficient use of precious neutron-irradiated materials. 


Three accelerated small-scale creep ​​​measurement techniques: nanoindentation creep, mesoscale thermal creep, and combined thermal and proton irradiation creep.