Laser Vibrometer PFC Health Monitoring System

The structural degradation of fusion reactor components within high temperature magnetically confined plasma environments is a well-known problem. The high heat flux associated with the plasma, in addition to sputtering and thermal cycling, leads to detrimental erosion and cracking of the plasma facing components (PFCs) which tile the reactor walls. At present, no evaluation method exists that will enable true in-situ structural health monitoring of PFCs. Current non-destructive systems suffer shortcomings in that they yield poor spatial resolution (~2mm) thus prohibiting erosion depth measurement and do not allow for true in-situ measurements since evaluation can only be performed during maintenance shutdowns, which happen only once a year. Therefore, there is clear need for a PFC non-destructive evaluation system that can operate at elevated temperatures in the presence of high magnetic fields and neutron fluence, is immune to RF noise and ultimately compatible with high performance plasma operation while offering legitimate in-situ monitoring. Luna Innovations is proposing to develop a revolutionary non-contact ultrasonic health monitoring system for plasma facing components used in fusion reactors. In phase I, Luna demonstrated non-contact defect detection of sample PFC components where simulated defect detection was demonstrated at relevant reactor first wall temperatures and included material thickness changes and crack defects. System development for phase II will address the particular aspects of laser NDE component/fusion interface and will ultimately demonstrate in-situ operation in actual plasma facing campaigns. Commercial Applications and Other Benefits: In-situ health monitoring of magnetically confined fusion reactor plasma facing components, enabled by the proposed non-contact ultrasonic solution, will facilitate commercialization of future tokamak designs (ITER) as well as increase reactor safety and lifetime in existing fusion reactors. The non-contact method is inherently environmentally insensitive and will therefore find potential application for health monitoring in other harsh environments including Gen-IV fission reactors.