UF6 plasma chemistry reconstitution experiments using high-temperature fluorine

Abstract

Prior results indicate techniques have been developed for fluid mechanical confinement of high-temperature uranium hexafluoride (UF6) plasma for long test times while simultaneously minimizing uranium compound deposition on the walls. Follow-on investigations were conducted to demonstrate a UF6/argon injection, separation, and reconstitution system for use with rf-heated uranium plasma confinement experiments applicable to UF6 plasma core reactors. A static fluorine batch-type regeneration test reactor and a flowing preheated fluorine/UF6 regeneration system were developed for converting all the nonvolatile uranium compound exhaust products back to pure UF6 using a single reactant. Pure fluorine preheat temperatures up to 1000 K resulted in on-line regeneration efficiencies up to about 90%; static batch-type experiments resulted in 100% regeneration efficiencies but required significantly longer residence times. A custom-built, ruggedized time-of-flight (T.O.F.) mass spectrometer, sampling, and data acquisition system permitted on-line quantitative measurements of the UF6 concentrations down to 30 ppm at various sections of the exhaust system; this system proved operational after long-time exposure to corrosive UF6 and other uranium halides.