Dary-to-day variation of urine 90Sr may produce error in the assessment of body 90Sr by urinalysis. Based on the good correlation between urine 90Sr and Ca, the range of the day-to-day variation of urine 90Sr was inferred from that of calcium, which was obtained from the analysis of about 50 to 100 urine samples per person in seven volunteers. From the frequency dstribution curves of urine calcium, it was concluded that 90per cent of the daily urine 90Sr would be involved in the range from 0.4 to 2.0 times the mean value. Therefore, if the assessment of body 90Sr is made from only one urinary excretion level, the estimated body burden will probably be in the range between 0.4 and 2 times the correct value.
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.