Determination of 135Cs and 137Cs in environmental samples: A review

Abstract

Radionuclides of caesium are environmentally important since they are formed as significant high yield fission products ( 135 Cs and 137 Cs) and activation products ( 134 Cs and 136 Cs) during nuclear fission. They originate from a range of nuclear activities such as weapons testing, nuclear reprocessing and nuclear fuel cycle discharges and nuclear accidents. Whilst 137 Cs, 134 Cs and 136 Cs are routinely measurable at high sensitivity by gamma spectrometry, routine detection of long-lived 135 Cs by radiometric methods is challenging. This measurement is, however, important given its significance in long-term nuclear waste storage and disposal. M A N U S C R I P T A C C E P T E D ACCEPTED MANUSCRIPTseparation using an ICP-MS equipped with a reaction cell. The removal of the peak tailing interference is dependent on the instrument used for final measurement. This review summarizes and compares the analytical procedures developed for determination of 135 Cs/ 137 Cs, with particular focus on ICP-MS detection and the methods applied to interference separation. Sources and properties of caesium isotopesHigh yield fission products 135 Cs and 137 Cs (Table 1) are present in environmental samples as a result of releases from nuclear power plants and reprocessing sites, nuclear accidents, and fallout from atmospheric weapons testing [1]. Caesium-137 is established as an important radionuclide in radiation protection, environmental monitoring, sediment dating, land erosion and waste disposal [2]. By comparison, 135 Cs is a long-lived radioisotope with a comparatively low radiation risk; however it is a significant contributor to the long term radiological risk associated with deep geological disposal [3]. Furthermore, the 135Cs/ 137 Cs ratio varies with reactor, weapon and fuel type, and therefore can be used as a forensic tool to identify the source of radioactive contamination [1,[4][5][6]. Other isotopes of caesium include the activation products ( 134 Cs and 136 Cs, Table 1). These shorter-lived activation products (2.06 years and 13.2 days, respectively) provide information on fuel irradiation history and have importance in health physics terms but are not considered further here.( Table 1) Caesium-137 decays by beta emission to short-lived metastable isomer Cs is therefore achievable using beta counting or gamma spectrometry. Gamma spectrometry is generally favoured because it exploits the high gamma intensity of the 662 keV energy that is not susceptible to significant absorption. The ability to directly count most samples without the need for any chemical separation is also beneficial, and a high-purity germanium (HPGe)well detector can readily achieve a detection limit of ~2.5 mBq g -1 (for a 20 g sample counted for half a day), which is suitable for many environmental samples [3]. By comparison, 137 Cs measurement by beta counting in environmental samples requires chemical separation from other beta-emitting nuclides prior to measurement.Caesium-135 decays with a maximum beta particle energy of 2...

Studies on Isotope Ratio Measurement of Cl by Inductively Coupled Plasma Triple-quad Mass Spectrometry

“…As can be seen in Fig. 1, similar Cl isotope ratios were observed for 1 -10 mg kg -1 Cl standard solution and their relative standard deviations (%RSDs) obtained were 0.2 -0.5% which provided enough precisions for such studies as stable isotope tracers, 2,5,6 nuclear chemistry 7,8,10 and quantitative analysis of elements by IDMS. [23][24][25][26][27][28][29] The observed isotope ratios of ca.…”

“…[23][24][25][26][27][28][29] Isotope ratio measurements have traditionally been carried out by isotope ratio mass spectrometry (IRMS) 3,12,13,20,22 and by thermal ionization mass spectrometry (TIMS). 4,8,14,20 Disciplines of IRMS are the ability to accurately and precisely measure variations in the abundance of isotope ratios of light elements such as H, C, N, O and S. On the other hand, TIMS can cover the whole range of elements from Li to U except for the gaseous elements measured by IRMS. An inductively coupled plasma mass spectrometry (ICPMS) has also been more and more involved in isotope ratio measurements, especially for heavy elements such as Fe, Cu, Mo, Cd, Cs, Nd, Hf, W, Tl, Pb, U, and so on.…”

“…An inductively coupled plasma mass spectrometry (ICPMS) has also been more and more involved in isotope ratio measurements, especially for heavy elements such as Fe, Cu, Mo, Cd, Cs, Nd, Hf, W, Tl, Pb, U, and so on. 2,[5][6][7][8][9][10][15][16][17][18][19][20][21][30][31][32][33][34] However, the subjects still remain with respect to the analysis of light elements such as H, C, N, and O as well as Si, S and Cl, that suffer from the huge background signals from H2O, air entrainment (N2, O2, CO2) and Ar plasma gas.…”

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isotope abundance measurements in nuclear chemistry 7,8,10 and the accurate determination by IDMS, [23][24][25][26][27][28][29] which require the precision of ca.

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Progress towards the development of a rapid analytical approach for separation of 226 Ra using dibenzo-18-crown-6 ether functionalised silica (SiO 2 ) disks

“…Russell et al, 2015). The instrument was fitted with quartz double-pass spray chamber and a MicroMist nebuliser (Glass Expansion, Melbourne, Australia) and nickel sample and skimmer cones (Crawford Scientific, South Lanarkshire, UK).…”