[en] A method for precise determination of trace silver in plutonium by pulse anodic stripping voltammetry was developed. The experimental conditions were optimized. In solution of 0.1 mol/L HNO_3-0.1 mol/L KNO_3, silver was accumulated on the Nafion-modified glassy carbon electrode surface at -0.5 V (vs SCE) for 300 seconds and then a sensitive oxidation peak of Ag was observed by anodic stripping voltammetry. The peak current is proportional to the concentration of Ag"+ in the range of 10- 100 μg/L. The detection limit of Ag"+ is 5 ng/mL and the recovery for addition standard is 90%-109%. This is simple, sensitive and selective method. (authors)

[en] Various factors possibly influencing the measurement of sulfate in simulated high level liquid waste (HLLW) by Raman spectroscopy were studied, such as integration time, duplicate folds, laser power and so on, and then the optimum conditions for the determination of sulfate were obtained. A method for determination of sulfate in simulated HLLW by Raman spectroscopy was described. The concentration of sulfate could be determined based on detecting the relative intensity between sulfate and water. The measurement range of sulfate concentration is within 1-15 g/L, the linear correlation coefficient r is 0.9996, the relative error is less than ±5%, and the detection limit is 0.05 g/L. While the method is simple and rapid, it does not need much chemical reagents. Thus, it could be used for detecting sulfate in HLLW. (authors)

[en] A method for determination of uranium and nitric acid in uranyl nitrate system was established through combination measurement of density-conductivity-temperature. A mathematical model, which described the relationship between the concentration, temperature, density and conductivity, was obtained. This model was a set of non-linear dualistic quadratic equations. Once the temperature, density and conductivity of uranyl nitrate system were measured, the concentration of uranium and nitric acid could be calculated by computer. The method was used to determine the concentration of uranium and nitric acid in uranyl nitrate system. The results show that the relative errors are between ±5% to uranium and nitric acid. (authors)

[en] Radioisotope source excited X-ray fluorescence (XRF) has been widely used for determination trace elements in hair. The source excited XRF was once established in China Institute of Atomic Energy, it was used to analyze hair sample, the detection limit of Pb is about 10 μg This project took the ever work as the basis, by amending the parameters the background signal intensity was reduced, the sensitivity was improved especially for Pb, the detection limits of Ca, Fe, Cu, Zn, Pb are 19, 1.2, 1.1, 0.62, 1.1 μg respectively. Taking V as inner-standard and sample mass is 0.5 g, instrument short-term stability relative standard deviation (RSD) is 0.38%, long-term stability RSD is 0.98%. (authors)

[en] The conventional method for determination of thorium is established by EDTA complexometric titration in which xylenol orange is used to indicate the titration end point. This paper presents a novel technique to identify the complexometric titration end point. The technique is that Fe(Ⅲ)/Fe(Ⅱ) redox couple replaces the use of xylenol orange to detect the end point by potentiometry. Various factors possibly influencing the measurement of thorium by EDTA complexometric titration were studied, such as repeatability of titrated volume, pH value, the concentration of EDTA, buffer solution and so on. The optimum conditions for the determination of thorium by EDTA complexometric titration were obtained. A new methodology was established for precise and accurate determination of thorium with Fe(Ⅲ)/Fe(Ⅱ) detecting the titration end point by potentiometry. Under optimized conditions, 5 mg thorium can be determined precisely with a relative standard deviation of 0.1%(n = 6). (authors)

[en] Neptunium is the raw material for ²³⁸Pu preparation. The accurate determination method of neptunium with accurate and clear traceability is very important for the extraction process of neptunium and the preparation of neptunium standard material. A novel method for accurate and precise determination of neptunium was developed. First neptunium was oxidized to Np (VI) in 1.0 mol/L sulfuric acid solution by silver (II) oxide and excess silver (II) oxide was destroyed by sulfaminic acid, then Np (VI) was titrated to Np (IV) by Fe (II), finally excess Fe (II) was re-titrated by standard potassium dichromate solution. When neptunium is about 5.0 mg, a good precision is achieved with the relative standard division (RSD) of 0.04%. The method is clearly traceable, simple, precise, accurate and can be explored to prepare neptunium standard materials. (authors)

[en] A magnetically assisted sample preparation process for capturing and separating trace Np was established. With the application of TiOA paramagnetic capture, the sample can be prepared quickly while concentration and separation are all done. The influences of reacting time, the mass of capture, the volume and acidity of aqueous phase on the sample preparation were studied. The detection limit of this method for Np is 0.12 μg. The mass concentration detection limit is 0.04 mg/L, which meets the requirements of analyzing Np by XRF at 3EU in Purex. (authors)