Instituto de Instrumentación para Imagen Molecular

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Fecha de finalización: 1999 × Fecha de inicio: 1995 ×

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  • Miniatura
    Publicación
    Behaviour of uranium along Jucar River (Eastern Spain) Determination of 234U/238U and 235U/238U ratios
    (Springer Verlag, 1995-02) Rodríguez Álvarez, María José; Sanchez, F.; Departamento de Matemática Aplicada; Escuela Técnica Superior de Ingeniería Informática; Instituto de Instrumentación para Imagen Molecular
    The uranium concentration and the U-234/U-238, U-235/U-238 activity ratios were studied in water samples from Jucar River, using low-level alpha-spectrometry. The effects of pH, temperature and salinity were considered and more detailed sampling was done in the neighbourhood of Cofrentes Nuclear plant (Valencia, Spain). Changes were observed in the uranium concentration with the salinity and the U-234/U-238 activity ratio was found to vary with pH. Leaching and dilution, which depend on pH and salinity, are the probable mechanisms for these changes in the concentration of uranium and the activity ratios.
  • Miniatura
    Publicación
    Measurement of radium and thorium isotopes in environmental samples by alpha-spectrometry
    (Akadémiai Kiadó, 1995-03) Rodríguez Álvarez, María José; Sánchez, F.; Departamento de Matemática Aplicada; Escuela Técnica Superior de Ingeniería Informática; Instituto de Instrumentación para Imagen Molecular; Institución Valenciana de Estudios e Investigación
    [EN] A new method for the determination of low-level radium and thorium isotopes in environmental samples by α-spectrometry is described. Thorium and radium isotopes were chemically separated from the same sample, by using the same tracer (229Th). Two different ways were explored for the concentration process in water samples, obtaining a chemical yield for Ra isotopes between 70–90% in both cases using KMnO4 as carrier and BaCl2 and FeCl3, respectively. The method can also be directly applied for uranium measurements, but in this case there is a limitation on the range of uranium isotopes that can be analyzed.