Confirmation of the availability of an analytical technique, Pu(VI) spectrophotometry for HALW; Technical Support for the Joint IAEA/Japan On-site Analytical Laboratory at the Rokkasho Reprocessing Plant (JASPAS JU-01-01)

Kitao, Takahiko ; Sato, Soichi ; Kuno, Takehiko ; Keiji, Yamada,; Watahiki, Masaru; Kamata, Masayuki

The Agency requested the Tokai Reprocessing Plant(TRP) to confirm the applicability of three kinds of analytical procedure for Pu(VI) spectrophotometry in On-Site Analytical Laboratory (OSL) at Rokkasho, in order to obtain accurate plutonium(Pu) concentration in High Active Liquid Waste (HALW). Three analytical procedures, (1) Calibration method, (2) Nd internal standard method and (3) Reduction method, were tested. The measurement sample was prepared by adding the known amount of plutonium in the actual HALW after removing original Pu by solid extraction. We measured the Pu concentration in the sample by three methods and calculated the accuracy and precision. The results of each method are summarized as follows:(1) Calibration method Plutonium concentration calculated by the calibration method agreed with that by adjusted concentration. (2) Nd internal standard method Accurate results were obtained by this method. The error of pretreatment, especially dilution, has not influenced on the Pu measurements. (3) Reduction method The measured Pu concentrations were higher than those by adjusted. From the comparison with these results, the calibration method is the most simple and rapid in the three methods. Analysis time was within 1 hour including sample preparation. The detection limit, with the calibration method, was 1.3 mgPu/L in the actual HALW measurements.