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In this study, a method for selective separation of 63Ni and 55Fe with simultaneous wash-out of 60Co was developed. Purification of 63Ni and 55Fe was carried out using a chelating ion-exchange resin Chelex 100. The elaborated procedure was applied for aqueous and stainless steel matrices. Average recoveries were around 80% for both isotopes, confirmed by ICP-MS and LSC measurements. 60Co, interfering with the isotopes spectra in the same energy range, was washed-out from the system prior to 63Ni and 55Fe separation. The most important advantages over existing methods are short separation time (c.a. 8 h), application of a single chromatographic column and overall simplicity. [ABSTRACT FROM AUTHOR]

Radioactive wastes, such as concrete and soil, generated during the decommissioning of nuclear facilities contain radionuclides with varying levels of activity. Beta-emitting radionuclides can be identified after thoroughly decomposition and separation from the sample matrix. Among these radionuclides, Fe–55 and Ni–63 play vital roles in the management of radioactive waste from nuclear facilities owing to their pronounced incidence and high mobility in the environment. This study documents the results of the extraction efficiencies of Fe and Ni with a rapid pretreatment method within 2 h by wet digestion methods using hydrochloric acid and nitric acid (3:1, v/v). The average Fe and Ni extraction efficiencies for certified reference materials in soil and sediment matrix were evaluated to be 84–94% and 90–96% with analytical precision within 5%, respectively. [ABSTRACT FROM AUTHOR]

A pilot study to quantify 55Fe in steel from a reactor vessel of a nuclear power plant by accelerator mass spectrometry (AMS) without any chemical sample preparation was validated by liquid scintillation counting (LSC) and AMS after radiochemical separation. AMS reaches an uncertainty < 10% at the 1 kBq gFe−1 level within less than 10 min measuring time. The background was < 3 Bq gFe−1, presently limited by the short measurement time. The new instrumental AMS method for analysing 55Fe from neutron capture production is reasonable and fast compared to other analytical methods. [ABSTRACT FROM AUTHOR]

A radiochemical method was developed for the accurate 55Fe determination in various radioactive waste, in particular samples contaminated with 241Pu. It consisted of three purification steps based on first ammonium hydroxide precipitation, and then anion exchange separation followed by TRU®-based extraction chromatography. It was characterized by an iron recovery yield of about 80% for all the studied samples and a 60Co decontamination factor of 106. In comparison to a standard protocol based on iron cupferrate extraction in chloroform, an improvement of a 30-fold factor was achieved towards plutonium. The developed TRU®-based procedure was validated by participating in interlaboratory exercises. [ABSTRACT FROM AUTHOR]

We present the validation of a radiochemical procedure for the determination of 55Fe and 63Ni in water and steel samples from nuclear decommissioning activities. The in-house validation was an essential requirement of the accreditation to ISO/IEC 17025. A combination of co-precipitation, anion chromatography and extraction chromatography steps was used for separating and purifying both radionuclides. The activities were measured by liquid scintillation counting. Due to the lack of reference materials, the method was validated by analysing simulated samples and by the standard addition technique. The parameters precision/accuracy, repeatability/linearity, selectivity/specificity, decision threshold, detection limit and uncertainty of the method were evaluated. [ABSTRACT FROM AUTHOR]

A method for sequential determination of 55Fe and 63Ni in leaching solution of cement solidification using liquid scintillation counting (LSC) was developed. In this method, 55Fe and 63Ni were first precipitated in the form of hydroxide and subsequently purified by anion exchange chromatography and dimethylglyoxime precipitation. After the purification, 55Fe and 63Ni were determined by LSC. The performance of the method was examined, and minimum detectable activity concentration was determined to be 0.82 Bq L−1 for 55Fe and 0.42 Bq L−1 for 63Ni in leaching solution samples with a counting time of 1 h. High decontamination factors for 55Fe and 63Ni were also obtained. [ABSTRACT FROM AUTHOR]