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The Fuel Reprocessing Test Plant at JAERI was operated during the period of 1968-1969 to gain experiences of the fuel reprocessing.Fuel elements reprocessed were irradiated in the JRR-3 reactor up to about 700MWD/ton and cooled for 87-300 days.The purpose of this paper is to discribe the measured results of airborne radioiodine released in each stage of chemical processing and discuss collection efficiency of the charcoal impregnated filter paper for radioiodine in the presence of process off gas such as NO, NO2, NH3, HNO3 and solvent encountered during the fuel reprocessing.

The Fuel Reprocessing Test Plant at JAERI was operated during the period of 1968-1969 to gain experiences of the fuel reprocessing.Fuel elements reprocessed were irradiated in the JRR-3 reactor up to about 700MWD/ton and cooled for 87-300 days. Therefore, krypton-85 is the most dominant radionuclide in the long lived gaseous fission products and the major part of krypton-85 in the fuel is discharged from the stack to atmosphere in the process of uranium dissolution.The purpouse of the paper is to describe the measured results of gaseous krypton-85 released in each chemical processing and also to discuss the performance of krypton-85 gas monitor, in particular the relationship of counting rate and the inner pressure of the krypton-85 sampler. The measured activity of krypton-85 released was in fairly good agreement with the calculated inventory.

The Fuel Reprocessing Test Plant in JAERI was operated during the period of 1968-1969 to gain experiences of the fuel reprocessing. The fuel elements reprocessed were irradiated in the JRR-3 up to about 700MWD/ton and cooled for 87-300 days.Tritium is produced by ternary fission and is one of the important nuclides to be monitored during the reprocessing of the highly irradiated fuels, because it is easily released into the off-gas line and difficult to be trapped before discharging to the atmosphere.In this paper, the results of tritium monitoring at the stack are described. It was found that tritium discharged from the stack during the reprocessing was about 1% of the total inventory and its concentration in air was about 1×10-8μCi/cm3.