DECONTAMINATION OF HTGR REPROCESSING OFF-GASES.
OAK RIDGE NATIONAL LAB., TENN. MICHIGAN STATE UNIV., EAST LANSING. CYCLOTRON LAB., M Whatley, R. W. Glass, P Haas, A.B. Meservey, Karl J. Notz · 1972
The off-gas from the reprocessing of HTGR fuel elements is unique among reprocessing nuclear fuel reprocessing off-gases because of the large amount of CO produced by the burning of the fuel element which contains about ten times 4* as much graphite as heavy metals.The relatively high temperature of the burning process (i>800°C) releases virtually all of the volatile fission pro-ist£* ducts« and troublesome amounts of some which are normally solid.There filters to remove particulate solids and sorbtion methods for I and HO which have good potential for application to this off-gas, but no existing technology was found to remove and concentrate the Kr.The high concentration of CO in the filtered gas stream (^90% CO , 10% light gases, 10-20 ppm Kr), and the similarity of CO behavior to that of Kr preclude the use of commonly employed processes such as membrane permeation, sorption on charcoal or molecular sieves, and physical absorption by a third component.The removal of CO 2 before such an operation appears feasible, but undesirable.A process involving Kr absorption in liquid CO.(KALC), which exploits the fact that Kr is more soluble in liquid CO than.isO , N , or CO, appears to be a natural solution to this particular problem.The solubility of Kr in liquid CO_ has been experimentally determined by 85 an ill situ radioactive counting method using Kr.This method avoided the problems usually associated with sampling systems of highly volatile components.Kr (a total content of about 100 ppm) and CO ?were contained in a sealed stainless steel tube, brought to equilibrium by rocking in a constant temperature bath, and counted with the tube in a vertical position to measure the radioactivity in each phase.Data were obtained at various temperatures over almost the entire CO liquid range.-NOTICE-This report was prepared as an account of work sponsored by the United States Government.Neither the Umted States nor the