ESM researchers awarded fellowship for robot-delivered laser ultrasonics system
UNIVERSITY PARK, Pa. Ė A research group in Penn Stateís Department of Engineering Science and Mechanics, led by Cliff Lissenden, recently received a 2016 American Society for Nondestructive Testing (ASNT) Fellowship Award to support its research on nondestructive inspection (NDI) of materials and structures in harsh environments.
There are many applications where NDI is required in harsh environments, such as chemical processing, material manufacturing, power generation and waste management. One particular example of a harsh environment, that also has significant geometric constraints, is dry cask storage of used nuclear fuel.
Spent fuel rods are confined in a welded stainless steel canister that is shielded and protected by a concrete and steel overpack drum. Aging management plans require periodic inspection of the canister, and stress corrosion cracking is one of the potential degradation modes because of the longer storage periods now required due to a lack of repositories for disposal.
Due to high temperatures, a gamma radiation environment and extremely limited access to structural components susceptible to degradation, dry storage casks necessitate distinctive nondestructive testing (NDT) methods.
Lissenden, along with Sungho Choi, research associate, and Mostafa Hasanian, doctoral candidate, are working to characterize surface degradation, specifically pitting and SCC, through the development of a robot-delivered laser ultrasonics system for dry storage casks.
Laser ultrasonics provide noncontact transduction for NDT that can be easily implemented into robotic inspection systems. By using a pulse laser coupled to an optical fiber and an innovative lens, Lissenden and his group aim to develop a system with the ability to operate in harsh, hazardous environments and confined spaces, providing an alternative to conventional contact or immersion-type techniques.
The robot-delivered laser ultrasonics system will also be suitable for other applications including pressure vessels, piping and structural components for power plants, to name a few. In particular, the system will be well adapted for inspection of defects in harsh environments such as inspection of pipelines exposed to high temperatures and radiation inside nuclear power plants and inspection of inaccessible, cramped and hazardous areas for preventive maintenance.
The ASNT Fellowship Award is granted to an ABET-accredited educational institution to fund specific research in NDT at the graduate level, either masterís or doctoral. The ASNT will provide $20,000 in funding to Lissendenís group in July 2016, and will require a written report of the completed study within 24 months, which will be published in a future edition of Materials Evaluation. In addition, Hasanian, the fellowship student recipient, will present the groupís findings at an ASNT annual conference following completion of the research.
Recipients of the ASNT Fellowship Award will be recognized at the annual awards banquet at the societyís annual conference, Oct. 24-27, in Long Beach, California.