No abstract available

[en] The influence of matrix elements that usually exist in spent nuclear fuel reprocessing, such as Na, Al, Ru, Cs, Pd, Nd, Fe, Ce, Sr, Y, Mo, and Zr, on the determination of uranium by highly oriented pyrolytic graphite (HOPG) pre-diffraction EDXRF is studied. The results show that the influence of matrix elements Na, Fe, Al, Ru, Cs, Pd, Nd, and Ce is negligibly small when their mass concentrations are lower than 1 000 mg/L. The influence of matrix elements Sr, Y, Mo and Zr is somewhat greater, and can be corrected to some degree by correction with scattered line of the silver target if their mass concentrations are lower than 1 000 mg/L. For higher mass concentration of these elements, their influence can be corrected by extrapolation of their mass fraction to zero by using the linear relationship between the logarithm of the uranium line intensity and the mass fraction of these elements. (authors)

[en] A quantitative method for determination of U and Ce in simulative MOX fuel samples by binary intensity ratio and X-ray fluorescence spectrometry is studied. Pressed powder pellet sample preparation is adopted. The pretreatment of the sample is fast and simple. The mutual interference of the two elements is eliminated efficiently by intensity ratio technique. The relative standard deviation (s_r) of U and Ce is 0.2% and 1.8%, respectively. (authors)

[en] By independent research L_Ⅲ--absorption edge densimeter, an analytical method for uranium sample with the concentration from 20 g/L to 200 g/L was developed. The fitting area for uranium measurement was determined through experiment. The left fitting area was 1659-1856 channel, and the right one was 2063-2280 channel. The uranium L_Ⅲ--absorption edge was at 1995 channel. The results show that the influence of HNO_3 concentration lower than 9 mol/L, Al and Fe concentration lower than 10 g/L was negligibly small. The uranium measurement precision is better than 0.5%, and the instrument stability is good. Some samples in bench test of uranium recovery were determined. The results are satisfactory. (authors)

[en] In order to determine the concentration of uranium and plutonium in 1AP of bench experiment in time, an on-line X-ray fluorescence spectrometer was designed and set up, and the angle between incident X-ray and emitted X-ray was 600. The spectrometer was airproofed in order to protect the X-ray tube and the detector. Based on the plotted working curve of uranium and plutonium, the analytical method was established to determine the concentration of uranium and plutonium in 1AP. The relative standard deviation of the measured concentration of uranium is 0.42%. The relative range for repeated measurement of uranium concentration in three hours is 1.6%. The results show that the device is stable enough. This spectrometer was applied in on-line determination of uranium. It can monitor the fluctuation of uranium concentration, and the results agree well with that of titration means. (authors)

[en] A method for determination of thorium i.e 23 trace elements in UF₄ is established. In this work, UF₄ was dissolved by HNO₃ and φ = 30% H₂O₂ with a volume ratio 1 : 1, then evaporated to dry repeatedly for the removal of F^-. By using a 15 mm × 105 mm CL-TBP column extraction chromatography, Al i.e 22 trace elements were separated with uranium in 3 mol/L HNO₃, the sixth to fifteenth mL eluent were collected for determination by ICP-AES. The recovery of these elements is between 97%-113%, and the relative standard deviation (sr) is better than 5%(n = 5) unless Al, Ca, Ba and Bi. In 6 mol/L HCl, the uranium was separated by TBP levextred resin chromatography, and the thorium was determined by ICP-MS. The recovery of Th is between 91%-94%, and the sr is within 5% (n = 5), and the detection limit of this separation method is 0.037 μg/g UF₄. (authors)

No abstract available

[en] An analytical instrument which can measure the concentration of technetium is developed. The Ag Cold Cathode which can excitated L series X-ray fluorescence of Tc is taken as excitation source. The X-Ray fluorescence is measured by Si-Pin detector. In order to determine high toxic and radio sample, a specific designation is adopted for sealing the sample cell in glove box. The X ray tube and detector are isolated with the sample by special windows. Such arrangement can provide convenience for measurement of high radioactive sample, as well as maintenance of the instrument. The basic performance of the instrument is tested. The linearity range of working curve for technetium is from 20 μg mL"-"1 to 200 μg/mL"-"1. The determination precision (RSD) of technetium with the concentration of 40 μg/mL"-"1 is l.2%. (authors)

[en] The first analytic device of graphite crystal diffract in advance X ray fluorescence in our country was developed. The device didn't suffer the influence of the radioactivity of the sample, didn't destroy sample, didn't produce wasted liquid etc, it was an ideal analytic method of micro U, Np, Pu in the high level waste liquid. (authors)

[en] Metal Zr tablet was used as quality control sample to monitor the long-term stability of L-edge densitometer, on which L-edge densitometer was used to measure the series of U reference solutions and Pu reference solutions in aqueous phase, and the U calibration curve and Pu calibration curve were drawn. The analytical methods for measuring U and Pu were established. The calibration curves were used to measure U and Pu reference solutions. The results show that the methods could measure both U and Pu in aqueous phase and organic phase. For the solution with U concentration above 10 g/L, the relative deviation of measurement results is less than 5%. For the solutions with Pu concentration above 5 g/L, the relative deviation of measurement results is less than 1.7%. It indicates that the method of measuring U and Pu with L-edge densitometer established in this paper has good accuracy and can be used for the measurement of U and Pu in practice. (authors)