Rapid Dissolution Techniques with Microwave Heating Devices for Solidified Products Made from Non-Metallic Wastes by Plasma Melting

Abstract

A relatively large quantity of sample solutions have to be prepared for the radiochemical analysis of solidified products yielded by a plasma melting treatment of non-metallic radioactive wastes. In order to dissolve a sample of solidified products rapidly, a dissolution method with microwave heating devices was applied. In a conventional method involving only external heating with various mixtures of acids (HNO3, HF, HClO4 and H2SO4), a 0.1 g amount of the sample was dissolved with difficulty. However, upon applying the microwave-assisted dissolution method, a 1 g amount of the sample was completely dissolved in a shorter time. Thereby the time for dissolution procedures was shortened to less than one-tenth. The present dissolution method was successfully applied to blast furnace slag as a reference material to determine the main elements with good precision.

A New Method to Analyze 242mAm in Low-Level Radioactive Waste Based on Extraction Chromatography and β-ray Spectrometry

“…A solidified product of simulated LLW was made from FeO (12%) and concrete (88%) via a plasma melting treatment . The solidified product was then digested using the procedure described in previous studies. , The radionuclides (i.e., 152 Eu, 242 Pu, 241+242m+243 Am, and 244 Cm) were added to the digested solution of the solidified products (corresponding to 0.2 g solidified products), and the solution was evaporated to dryness. The sample solution was prepared by dissolving the residue in 2 M HNO 3 containing 0.5 M Al(NO 3 ) 3 and 0.3 M ascorbic acid.…”