Development of Laser Induced Breakdown Spectroscopy Systems for Nuclear Power Plants

Abstract

We report the development of laser induced breakdown spectroscopy (LIBS) techniques and systems for the applications in the nuclear power plants [1] . The plasma behaviors and their spectral properties of the fiber-delivery laser-induced plasma are compared with the conventional LIBS. The use of fiber-delivery would decrease the laser's peak irradiance, and results in weak plasma radiation and insufficient detection sensitivity [2] , [3] . Then spectral enhancement methods including dual-pulse excitation and spatial confinement are investigated to increase the sensitivity of trace elements. Calibration-based methods, including internal standardization, partial least square regression and random forest regression, are established to quantify concentration of Cr, Cu in steels and Cl in cements. In addition, the relationship between the spectral characteristics of the reactor pressure vessel samples under different thermal aging time with their vickers hardness is also established. Based on the researches above, several LIBS instruments have been developed for the measurements of different objects, including a FO-LIBS, and a telescope LIBS for the elemental analysis of the instruments such as the reactor pressure vessel and main pipes inside the containment vessel, and a dual-pulse LIBS system for the evaluation of the chlorine corrosion of the reactor containment. Recently, the developed system has been applied in the nuclear power plant for the identification of materials in nuclear environments.