Laser cuts nuclear plant ice buildup in minutes in tests

More than 40 feet below the surface, between baskets packed with borated ice, a narrow tool is being asked to do a precise job: cut ice without disturbing the safety system around it. Engineers Ahmad Vaselbehagh and Ty Hagan at the University of South Florida have tested a laser de-icing system at two Tennessee Valley Authority nuclear plants after four years of research, design and testing.

The problem begins during routine inspections. Workers must lift and weigh thousands of individual baskets. When fresh ice is added, neighboring baskets can freeze together, blocking that one-by-one inspection. The laser fits into the narrow gaps and cuts the sheets of ice connecting the baskets, allowing workers to separate them without damaging the equipment or relying on extensive manual labor.

The choice to cut rather than melt is the practical heart of the design. Fully melting the ice would create larger volumes of water, which could refreeze in other areas or collect at lower elevations. The system can clear several feet of ice buildup in minutes, according to the University of South Florida and reports of the TVA tests.

Getting from an engineering concept to a tool plant workers could use required mechanical and electrical engineering, optics, controls, manufacturing and safety work. The team tested the equipment in freezing environments and contamination-controlled areas, completed radiation-worker and laser-safety certifications, and built a system with hundreds of components for tight nuclear spaces.

So what changes in practice? Plant personnel can separate frozen baskets faster and complete inspections of a critical containment safety system with less manual effort. USF also prepared operating procedures, technical documentation and training so workers can operate and maintain the equipment without the researchers on site. The reported milestone is a successful test at two plants; similar ice condenser systems are used in nuclear facilities in the United States, Japan and Finland.