Establishing rapid analysis of Pu isotopes in seawater to study the impact of Fukushima nuclear accident in the Northwest Pacific

Abstract

In order to assess the impact of the Fukushima derived Pu isotopes on seawater, a new analytical method to rapidly determine Pu isotopes in seawater by SF-ICP-MS including Fe(OH)2 primary co-precipitation, CaF2/LaF3 secondary co-precipitation and TEVA+UTEVA+DGA extraction chromatographic separation was established. High concentration efficiency (~100%) and high U decontamination factor (~107) were achieved. The plutonium chemical recoveries were 74–88% with the mean of 83 ± 5%. The precisions for both 240Pu/239Pu atom ratios and 239+240Pu activity concentrations were less than 5% when 15 L of seawater samples with the typical 239+240Pu activity of the Northwest Pacific were measured. It just needs 12 hours to determine plutonium using this new method. The limit of detection (LOD) for 239Pu and 240Pu were both 0.08 fg/mL, corresponding to 0.01 mBq/m3 for 239Pu and 0.05 mBq/m3 for 240Pu when a 15 L volume of seawater was measured. This method was applied to determine the seawater samples collected 446–1316 km off the FDNPP accident site in the Northwest Pacific in July of 2013. The obtained 239+240Pu activity concentrations of 1.21–2.19 mBq/m3 and the 240Pu/239Pu atom ratios of 0.198–0.322 suggested that there was no significant Pu contamination from the accident to the Northwest Pacific.

Legal aspects of capturing killer whales (Orcinus orca) for educational and cultural purposes in 2018

“…In June 2012, 134 Cs activity reached a maximum of 6.12±0.50 Bq/m at 151m depth at 29ºN, 165ºE, and higher in the central mode waters than in any of surrounding waters of the North Pacific Ocean. The mean value of 137 Cs and 239+240 Pu in the surface waters in the Northwestern Pacific was 0.04±0.28 Bq/L (Honda et al, 2012) and 1.86±0.17 mBq/L (Men et al, 2018).…”

Plutonium (IV) Quantification in Technologically Relevant Media Using Potentiometric Sensor Array

“…The second set was employed to explore the sensitivity of the sensors to Pu 4+ in the presence of technologically relevant uranium concentrations. This set contained 10-50 mg/L Pu 4+ in 1.5 M HNO 3 and 500 mg/L of uranium. The third set was employed as a simulation of the real industrial PUREX conditions.…”

“…In order to decrease the radiation burden for personnel and to ensure appropriate functioning of the analytical instrumentation, the samples taken from PUREX are normally diluted multiple times. The methods currently in use for plutonium quantification in process streams are mainly inductively coupled plasma atomic emission spectrometry (ICP-AES) [2] and mass spectrometry (ICP-MS) [3]. While providing perfect sensitivity and selectivity, these methods are rather time-consuming and can hardly be implemented in on-line mode.…”

Rapid Method To Determine 137Cs, 237Np, and Pu Isotopes in Seawater by SF-ICP-MS

“…In the open ocean, the activity concentration of 237 Np is at the sub-μBq L –1 level, which is approximately 10 times lower than the level of 239, 240 Pu. ,,, The reported methods for determining 237 Np can be divided into radiometric counting and mass spectrometric methods. ,,− Conventional alpha spectrometry techniques for the analysis of 237 Np in seawater require large amounts of seawater (1000–2000 L) owing to their low sensitivity, resulting in great inconvenience for sample collection and chemical separation . With the optimization of chemical separation processes and the development of mass spectrometric technologies for 237 Np analysis, the seawater volume has been reduced to 10–20 L by the accelerator mass spectrometry (AMS) method and to 100–200 L by the inductively coupled plasma mass spectrometry (ICP-MS) method .…”