Using laser induced plasma to characterize performance of HTGR advanced alloys

New advanced alloys for fission and potential fusion reactor designs are gaining traction while systems in place to analyze the inevitable material degradation via irradiation, high temperature, and corrosive environments have not changed. At the center for materials under extreme environments (CMUXE), Purdue University, we are developing methods using laser induced plasmas to further analyze Alloy 617, recommended for new HTGR cooling loops for its superior high temperature mechanical strengths. Recent studies have shown that impurity gases in the helium loop can cause significant oxide formation on the surface affecting various mechanical properties, including hardness during the high temperature operation. At CMUXE, methods to perform mechanical testing and diagnose oxide layer formation are currently being conducted using laser induced breakdown spectroscopy (LIBS). A variety of extreme environments are being tested in our facility to simulate different cooling loop environments in HTGRs with possible fusion reactor applications. Current work investigates spectral variations seen during high temperature LIBS testing to analyze material composition, spatial distribution, and mechanical properties during reactor operations with high accuracy. The goal is to further investigate LIBS at high temperatures to better understand its viability for in-situ measurements in nuclear reactor environments.