[en] Advantages of the method are described, including the fact that the uranium and plutonium isotopes can be determined from the same mass spectrometric sample. Interferences are discussed. Experimental details are given: a triple indicator consisting of ¹⁵⁰Nd, ²⁴²Pu and ²³³U is added which should correspond as closely as possible to the sample in its composition and concentration of the of the principal isotopes ¹⁴⁸Nd, ²³⁹Pu and ²³⁸U. Results are presented and discussed. (U.K.)

[en] The determination of Pu(VI) in nitric acid solutions by spontaneous Laser Raman Spectrometry (LRS) was investigated and a calibration curve was established using U(VI) as internal standard. In addition, the concentrations of Pu(VI) and Pu(V) as a function of time were measured by this method in Pu(VI) solutions of different acidity containing H₂O₂ as the reducing agent. In solutions which are intensely coloured by the presence of Ru(NO) complexes Pu(VI) can also be determined by LRS using a Kr⁺ laser as excitation source. In future experiments, the study of the Pu(IV)-interaction with Ru using LRS and spectrophotometry as analytical techniques is therefore intended. (orig.)

[en] With a commercially available laser Raman spectrometer combined with a microscope (Raman microprobe) the applicability of this method to the analysis of liquid and solid samples from nuclear fuel reprocessing has been studied. Till now, the determination of U, TBP, and its degradation products in simulated organic and aqueous process solutions has been investigated and precipitation products containing zirconium and molybdenum have been analyzed with the Raman microprobe. The results obtained are described. (orig./HP)

[en] The suitability of laser Raman spectrometry in process control is demonstrated by comparing results obtained under standard measuring conditions and with special optical fibers. The applicability of capillary tubes which can improve sensitivity in remote sensing is investigated and possible distortions of Raman spectra sampled with optical fibers are described. In preliminary experiments with U(VI) solutions it could be shown that internal standardization using the 1650 cm^-1 water band is possible in the process control of aqueous solutions. (orig.)

[en] Mixtures of silver hydrosols and tributyl phosphate saturated diluted nitric acid exhibit an intense Stokes-Raman spectrum between 600 cm^-1 and 1700 cm^-1 which is possibly attributable to surface-enhanced Raman scattering but whose bands, however, cannot be assigned to tributyl phosphate. The observed effect which grows with increasing wavelength of the exciting light (Ar⁺ laser) depends on the acid concentration and attains a maximum for 1 M HNO₃, whereas in weakly acidic and neutral solutions it cannot be detected. Tributyl phosphate in diluted HClO₄ and H₂SO₄ gives the same spectrum. As the silver sol is rapidly destroyed by the acids the Raman bands can be observed for only about 1-3 h. No linear relationship between the Raman signal the tributyl phosphate concentration allowing quantitative work could be obtained which is possibly due to the strong instability of the hydrosol in the presence of acids. 13 references, 9 figures, 1 table

No abstract available

No abstract available

[en] Solids formed from synthetic nuclear fuel reprocessing solutions under process conditions containing Zr, Mo and Ru and additionally U and Pu have been characterized by use of emission, X-ray fluorescence, Raman and infrared spectroscopy, thermogravimetry, and X-ray diffraction techniques. In solutions containing an excess of Mo relative to Zr, the solid residues consist of a mixture of ZrMo₂O₇(OH)₂.2H₂O and MoO₃ while in the absence of Zr mainly UO₂Mo₂O₇.1.3H₂O and/or Pu(MoO₄)₂.H₂O are precipitated. Hydrated Zr and U molybdates from non-crystalline phases on dehydration and on further heating to above 500deg C result in the recrystallization of ZrMo₂O₈ and UO₂MoO₄ and MoO₃, respectively. Hydrated Pu molybdate is different from the known structures and the X-ray diffraction patterns and the Raman spectra of its hydrated and anhydrous forms are identical. The infrared and Raman spectra support the presence of MoO₆ octahedra in hydrated Zr and U molybdates and MoO₄ tetrahedra in their dehydrated structures. The advantages and the limitations of the Raman microprobe technique with regard to its applicability to the nuclear fuel cycle are discussed. (orig.)

[en] Published in summary form only

[en] Pu(IV) undergoes oxidation to Pu(VI) at an accelerated rate due to Ru(III) present as Ru(NO)-complexes in nitric acid solution. To be able to study this effect in more detail kinetic measurements were performed using Laser Raman Spectroscopy (LRS) and spectrophotometry as analytical methods. In these experiments the parameters temperature, Ru(III)-concentration, Pu(IV) concentration, HNO₃ concentration and F^- concentration were investigated. From the results obtained reaction orders were estimated as far as possible, using the method of initial rates according to van't Hoff. (orig.)