https://orbit.dtu.dk/files/3249858/2007_333.pdf

Critical comparison of radiometric and mass spectrometric methods for the determination of radionuclides in environmental, biological and nuclear waste samples.

Determination of 63Ni and 55Fe in nuclear waste samples using radiochemical separation and liquid scintillation counting

Liquid scintillation counting (LSC) is a major technique not only for measurement of pure beta emitting radionuclides, but also radionuclides decay by electron capture and alpha emission. Although it is a conventional radiometric technique, but still a competitive techniques for the measurement of many radionuclides. This paper summaries the major development of this measurement technique in instrumentation, methodology and applications in the past decades. The progresses in the instrumentation and methodology mainly focus on the commercialization of triple-to-double coincidence ratio based LSC techniques and its application in the determination of different radionuclides. An overall review and discussion on the LSC based analytical methods for the determination of major radionuclides in environmental researches, decommissioning of nuclear faculties and nuclear application are presented, in both measurement techniques and sample preparation using radiochemical separation. Meanwhile the problems and challenges in the development and application of the LSC are also discussed.

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Liquid scintillation counting for determination of radionuclides in environmental and nuclear application

Principles of ultralow-level liquid scintillation spectrometers are introduced in this chapter. The sources of background signals and the means to reduce background are discussed. Electronic pulse discrimination and anticoincidence counting allow the determination of low radioactivities and the separation of α- and β-events into their respective spectra. These features make liquid scintillation counting (LSC) methods practical for simultaneous detection of low α and β activities in environmental samples, which are described. LSC methods are presented and discussed for 3 H, 14 C, 63 Ni, 89 Sr, 90 Sr/ 90 Y, and 99 Tc, transuranium elements including plutonium and for most important natural radionuclides, 222 Rn, Ra, U and Th isotopes, and 210 Pb and 210 Po. Because the radiation exposure from environmental radioactivity arises largely from natural radionuclides, the importance of their analyses is discussed along with the sensitive methods used for their analysis. A section is devoted to radiometric methods to differentiate between biogenic and fossil 14 C in fuels. Spectrum unfolding or deconvolution of low-activity α-spectra is discussed.

Environmental Liquid Scintillation Analysis

Isolation and quantification of 55Fe and 63Ni in reactor effluents using extraction chromatography and liquid scintillation analysis

A method has been developed for the determination of63Ni in environmental samples. The samples are ashed and leached with aqua regia whereafter hydroxides are precipitated with ammonia, leaving Ni in the aqueous phase. Nickel is extracted as dimethyl glyoxime complex by chloroform and back-extracted with HCl. Finially, Ni is electroplated onto a copper disc from an ammonium sulphate medium at high pH. The radiochemical yield is determined by atomic absorption measurements of stable Ni before and after electrodeposition.

U. Nilsson

Papers

Nickel-63: radiochemical separation and measurement with an ion implanted silicon detector