DISSOLUTION MONITOR FOR GRASPING DISSOLVING STATE OF NITRIC-ACID SOLUBLE ELEMENT OR COMPOUND

摘要

PURPOSE:To grasp the state of the dissolution of uranium in nitric acid in an atomic- nucleus reprocessing step with high reliability by converting nitrogen monoxide generat ed in dissolving reaction into nitrogen dioxide by oxidation, and remotely measuring the concentration. CONSTITUTION:When uranium oxide is dissolved with nitric acid, nitrogen oxide is generated. The most of the oxide is NO. The NO is mixed with oxygen and made to react. Thus NO2 is obtained. The obtained NO2 is guided into an optical cell. Visible light is sent into the cell through, e.g. optical fiber, from a light source which is pro vided at a remote place. The transmitted light is returned again to the same remote place by using the optical fiber. The light undergoes spectroscopic action with a diffrac tion grating, and the absorbance spectrum is obtained with a detector. The spectrum is compared with the absorbance spectrum which is measured by using the known amount of NO2 and operated beforehand, and the NO2 is obtained. Then, the amount of dissolution of the uranium oxide within a specified time and the data of the total dissolving time are obtained. The detecting sensitivity is improved by converting the NO into the NO2 as much as possible. The electronic equipment required for the detection is located at the position remote from the high radiation environment, and the reliability can be improved.