Method and device for dissolving particulate nuclear fuels out of high-temperature fuel elements

摘要

Methods and devices which can achieve high dissolution rates are required to use flowing nitric acid to dissolve particulate nuclear fuels, in particular, out of spent HTR fuel elements contained in a dissolving basket along with their mechanically crushed, hemispherical silicon carbide claddings after the carbon has been removed. For this purpose, the flow of the acid is chosen in such a way that the silicon carbide claddings are rinsed out of the dissolving basket but the heavy cores are left behind. This is achieved if the cross-section of the outlet connecting pipe (9) underneath the dissolving basket (4) is made at least 1.5 times as large as the overflow connecting pipe (8) used as connection to the shallow tank (2) serving as acid reservoir.