Traditional options to remove dangerous contaminants — such as abrasive blasting — have been used for many years. But, our laser solutions are designed to safely and effectively remove hazardous contaminants — leaving behind a pristine surface that media blasting options can’t produce. So, what makes the two options different?
Traditional options use media to handle contaminants and they often damage the base metal, require secondary cleanup, and are costly to dispose of. In comparison, laser ablation uses only focused light, requires no media or secondary cleanup process, and produces little to no additional waste to dispose of. That’s why a nuclear power plant requested the testing of our laser solutions on their applications.
TESTING LASER SOLUTIONS
In 2012, Adapt Laser conducted decontamination testing at a service provider for commercial nuclear power plants. Our goal was to identify the effectiveness of high-powered laser systems for removing fixed low-level radiological contaminants from plant components. The first test involved using laser ablation on unpainted steel surfaces that had been unsuccessfully decontaminated with abrasive grit blasting — multiple times.
TESTING VARIABLES
EQUIPMENT PROTECTION
The laser optic and fiber optic cable package were the only parts of the system brought into the Radiation Control (RC) area used for the testing. During the test, the fiber optic package entered the RC through a sealed opening while the laser source remained outside in a clean area. The laser optic was bagged/taped‐up, and the fiber optic package was wrapped with a protective plastic sleeve. A low volume compressed airline was applied to the optic to provide positive pressure inside the protective covering.
TESTING LOCATION
The location selected for laser testing was a secure RC area consisting of a room used for the decontamination of components by grit blasting. The room was maintained with negative air and ventilated with fresh air. The air in the RC was continuously monitored for contamination. Two laser operators wore personal air monitors and dose monitors, along with the required PPE, while working in the RC.
FUME EXTRACTION
A HEPA vacuum in the RC was used to capture contaminated dust and vapors from the laser cleaning process. This was accomplished using a flexible hose from a HEPA vacuum to an externally-mounted suction nozzle on the laser optic.
Initially, safety personnel required the laser operators to wear respirators while operating the equipment. After working with the laser for a few hours, the personal air monitors were checked for airborne contamination. Based on the findings, safety personnel determined the technicians did not need to use respirators. The technicians removed their respirators and resumed operating the laser — with air and radiation dosage monitors continuing to be worn.
FINAL RESULTS
Testing showed that laser ablation reduced the contamination level from ~40,000 CPM down to ~100-200 CPM. The results from laser treating an unpainted steel component proved to be very fast and effective, and laser ablation completely removed contaminants from surfaces that had not been previously grit blasted.
Upon completion of testing, the laser optic and fiber optic cable were removed from the RC area. The temporary protective coverings were removed and thoroughly frisked by safety personnel to check for possible contamination. All laser components used in the RC were declared clean without any issues. And, when the laser operators were thoroughly screened and scanned for radiation exposure, neither operator was found to have experienced unhealthy exposure levels.