Toshiaki Hiyama

Determination of nitrogen in uranium-plutonium mixed oxide fuel by gas chromatography after fusion in an inert gas atmosphere

Abstract A gas chromatographic technique has been developed for the determination of nitrogen in uranium-plutonium mixed oxide fuel after fusion in an inert gas atmosphere. When the sample and pure iron powder in a graphite crucible were heated to approximately 2500 °C by a resistance heating furnace, a large amount of carbon monoxide was evolved with a small amount of nitrogen and hydrogen. A gas chromatograph equipped with a pre-cut system was used for the separation of nitrogen from the carbon monoxide. Nitrogen separated by the gas chromatograph was determined by means of a thermal conductivity detector. Only 100 mg of the sample was used, and the analysis requires about 10 min. No specific skills for glove-box work are necessary. The relative standard deviation and detection limit (3σ-criterion) were less than 5% and 9μg g −1 , respectively. The present method is not only applicable to the analysis of research samples but also to the quality control of uraniumplutonium mixed oxide fuel production lines.

Determination of occluded gases in mixed oxide fuel pellets using gas sampling unit and gas chromatography

Abstract A new technique for the determination of occluded gases in sintered plutonium-uranium mixed oxide (MOX) fuel pellets was developed. The gases extracted from the sample at vacuum condition were injected into a gas chromatograph through an originally developed gas sampling unit. The gases were simultaneously determined using the improved gas chromatograph equipped with several separation columns and a photoionization detector. The relative standard deviations ( n = 10) were 1.0, 3.4, 0.6, 1.0, 1.4, 0.8 and 0.9% for H 2 , O 2 , N 2 , CH 4 , CO 2 , CO and C 2 H 6 , respectively. The gases H 2 , O 2 , N 2 , CH 4 , CO 2 and CO from the MOX fuel pellets were simultaneously determined in this study. The results of gas analysis using this method were in agreement with that of high temperature vacuum extraction method in the range less than 300 μl of extracted gas.