Microwave Heating of Uranium Hexafluoride
Microwave Technique of Uranium Hexafluoride Heating for Safe Evaporation from Containers, Including Damaged Ones
Tech Area / Field
- FIR-FUE/Reactor Fuels and Fuel Engineering/Fission Reactors
8 Project completed
Senior Project Manager
Alexandrov K A
VNIIKhT (Chemical Technology), Russia, Moscow
- Pacific Northwest National Laboratory, USA, WA, Richland\nAdvance Research Chemicals, Inc., USA, Catoosa
Project summaryDepleted uranium (DU) is mostly stored in a form of uranium hexafluoride (UF6) in steel containers in the open air. Lifetime of some containers exceeds 40 years. There are defects (deformation, joint leakage, etc.) in some old containers. Removal of UH from such containers as well as storage may result in accident and pollution of sites. At the present time there are no technique and equipment for safe treatment of damaged containers. Standard techniques realize heating through container walls. It is obvious that it is unacceptable in case of damaged containers.
Project objective is the development of promising technique for safe evaporation of DU hexafluoride from containers, especially long-term stored and damaged ones.
The proposed technique is based on selective microwave heating of substance being placed on DU hexafluoride surface. This substance absorbs microwave energy and then transfers heat directly to DU hexafluoride and, therefore, there is no need for heating of container walls from outer sources.
Depending on technological flow sheet and process conditions in order to attain this goal there are three basic ways differentiated by type of microwave energy absorbing agent that used as inner heat source:
– bulk of granules or tablets;
– “cold plasma discharge”.
Uranium oxides (wastes) or iron oxides absorbing microwave energy and well transferring heat may be used as inner heat source.
By the project the following results are expected:
– theoretical study of microwave evaporation of uranium hexafluoride using solid, liquid and gaseous heat-absorbing agents;
– laboratory study of characteristics of heat-absorbing agents (absorption coefficient of microwave energy);
– construction, test and experimental study of the installation for microwave uranium hexafluoride evaporation;
– initial data for design of industrial module.
The basic advantages of a microwave heating for evaporation of DU hexafluoride are as follows:
– safe evaporation of damaged cylinders (no overheating container walls);
– an emergency container may be placed into the protective cover for a complete ecological pollution prevention;
– monitoring and technique control over the condition of the container wals, measuring of their temperature and heat-absorbing agent position (emptying level);
– non-inertia heating and easy control;
– this technique is applicable to any kinds of containers;
– preliminary estimation shows that evaporation rate is about five e times more as compared to the existing standard technique;
– the method is applicable to any types of containers with DU.
The above advantages allow to decrease emergency and environment pollution risk both at the expense of no overheating container walls and contraction of evaporation duration.
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