Investigation of Spectral Characteristics of Pulsed Xenon Lamps for Combined Photochemical Degradation of Organometallic Compounds in Liquid Radioactive Waste

Abstract

The paper considers the composition of liquid radioactive wastes from the nuclear plants. Using traditional ways to extract organometallic compounds formed, when using the deactivation solutions to clean the surfaces of nuclear plant rooms, are complicated. The paper studies the edge-cutting methods of solving this problem. Its proposal is to use a combined ultraviolet treatment for organometallic compounds degradation based on ethylenediaminetetraacetic acid (EDTA) via pulsed xenon lamps. A potential use of the tubular and spherical geometry lamps is examined and advantages, disadvantages and features of these lamps are described. Instead of the pure EDTA the experiments used its disodium salt ( Na 2 -EDTA). The hydrogen peroxide was used as an extra oxidizer. Absorption spectrums of solutions with various Na 2 -EDTA - hydrogen peroxide ratio were measured. It is found that the absorbance curve maximum is in the shortwave spectrum region (λ < 210 nm). The use of amalgam lamps of monochromatic radiation at wavelength λ = 254 nm will result only in formation of hydroxyl radicals but direct destruction processes of EDTA molecules due to radiation will be rare, and this decreases efficiency of their use. The spectral radiation characteristics of various continuum spectrum pulsed xenon lamps was measured. The experimental data expressed in relative units were compared with the emission spectrum of an absolutely black body. The paper shows that in spherical lamps high brightness temperature can be reached. Thus, in spherical lamps it is possible to obtain a spectrum, which is in maximum correlation with the absorption spectrum of the solutions under study, thereby making them a prospective radiation source for photo-degradation of EDTA compounds. For drawing a final conclusion it is necessary to conduct researches in order to compare Na 2 -EDTA degradation via tubular and spherical xenon lamps.