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1.
《中国化学快报》2022,33(7):3516-3521
Plutonium (Pu) is an anthropogenic radionuclide which mainly derived from atmospheric nuclear tests in the environment. In this study, the Pu isotopes (239Pu and 240Pu) in aerosol samples collected during the sandstorm and non-sandstorm period were measured by accelerator mass spectrometry (AMS) and the behavior of Pu was studied. The activity concentrations of 239Pu and 240Pu in the aerosol samples of Beijing were ranged from 0.62 nBq/m3 to 99.6 nBq/m3 for 239Pu and 3.51 nBq/m3 to 60.23 nBq/m3 for 240Pu, respectively. 239Pu and 240Pu concentrations exhibited a remarkable seasonal variation trend, with the higher results showed in spring, and the relatively lower concentrations in winter. The observed higher concentration of 239Pu and 240Pu detected in sandstorm samples further indicated Pu was closely related to the occurrence of sandstorms. The global fallout characteristics of 240Pu/239Pu atom ratios (average 0.20, ranging from 0.16 to 0.27) in aerosol samples indicating that global fallout was the major source of Pu in the atmosphere. Using aluminum (Al) as an indicator of soil resuspension, significant positive correlation between 239Pu and Al (r2 = 0.934), 240Pu and Al (r2 = 0.525) revealed that soil resuspension was a primary source of atmospheric Pu in Beijing. These results implied that the combination of 239Pu, 240Pu and Al could be used as the potential tracer of sandstorm.  相似文献   

2.
IAEA reference materials (radionuclides in the marine environment) collected in areas affected by nuclear reprocessing plants and nuclear weapons tests have been analysed by semiconductor alpha-spectrometry (SAS), liquid scintillation spectrometry (LSS) and mass spectrometric techniques (high resolution ICP-MS and AMS) with the aim of developing analytical procedures and to study the geochemical behavior of plutonium in the marine environment. The Pu results obtained by SAS, ICP-MS and AMS were in reasonably good agreement (R 2 = 0.99). The mean atom ratios of 240Pu/239Pu in IAEA reference materials, IAEA-134, 135 and 381 were (0.212±0.010), (0.211±0.004) and (0.242±0.004), respectively. IAEA-384 (Fangataufa Lagoon Sediment) gave a 240Pu/239Pu mean atom ratio of 0.051±0.001. The results of 241Pu obtained by ICP-MS and LSS also show reasonable agreement (R 2 = 0.91). Pu isotopic signatures were useful in tracing Pu origin and in interpreting biogeochemical processes involving Pu in the marine environment.  相似文献   

3.
The paper summarizes the results of the 240Pu/239Pu atomic ratio studies in atmospheric fallout samples collected in 1986 over Gdynia (Poland) as well as three Baltic fish species collected in 1997 using the accelerator mass spectrometry. A new generation of AMS has been developed during last years and this method is an efficient and good technique to measure long-lived radioisotopes in the environment and provides the most accurate determination of the atomic ratios between 240Pu and 239Pu. The nuclide compositions of plutonium in filter samples correspond to their means of production. AMS measurements of atmospheric fallout collected in April showed sufficient increase of the 240Pu/239Pu atomic ratio from 0.28 from March to 0.47. Also such high increase of 240Pu/239Pu atomic ratio, close to reactor core 240Pu/239Pu atomic ratio, was observed in September and equaled 0.47.  相似文献   

4.
Plutonium isotopes were measured by alpha-spectrometry and ICP-MS in sediment samples from two European lakes: Blelham Tarn in U.K. and Stechlin lake in Germany. The ICP-MS measurements were made after alpha-spectrometry counting of the planchets. The planchets were prepared by traditional electrodeposition method after radiochemical extraction, separation and purification of the Pu fraction. A short radiochemical separation using plutonium selective resin, between the two spectrometry measures, is presented. The results show that these two complementary methods are in good agreement, the plutonium activity concentrations are the same. Alpha-spectrometry allows the 238Pu determination and ICP-MS individual measurement of 239Pu and 240Pu. 238Pu/239+240Pu and 240Pu/239Pu ratios are calculated to determine the plutonium contamination source. With the results of these two techniques, it could be demonstrate that the plutonium is of global fallout origin.  相似文献   

5.
Plutonium and other actinides were determined in human autopsy tissues of occupationally exposed workers who were registrants of the United States Transuranium and Uranium Registries (USTUR). In this study, Pu was purified and isolated from Am, U and Th, after drying and wet-ashing of the tissues, and the addition of238Pu as a radiotracer. After electrodeposition onto vanadium planchets the239+240Pu activity was determined by alpha-spectrometry. A fission track method was developed to determine239Pu in the presence of238Pu and240Pu, using LexanTM polycarbonate detectors. Combining the two techniques allowed the determination of the240Pu/239Pu activity and atom ratios. Data from selected USTUR cases are presented.  相似文献   

6.
Summary Accelerator mass spectrometry (AMS) is a sensitive and robust technique typically applied to the quantification of long-lived radioisotopes in samples too small to be decay-counted. AMS is characterized by a high rejection of interferences and a low susceptibility to matrix components, which reduce the demands on sample preparation chemistry. At Lawrence Livermore National Laboratory (LLNL), Center for Accelerator Mass Spectrometry (CAMS), we have developed an AMS capability for the measurement of actinide concentrations and isotopic ratios. To date, this capability has been primarily devoted to the measurement of 239Pu and 240Pu in bioassay and environmental samples including soils, sediments, waters, and human urine. For these analyses, a known amount of 242Pu is added to the samples as a reference isotope for normalization. Measurements of standard and intercomparison samples have shown that quantification is accurate and precise from at least 106 to 1011 atoms/sample. Recently, the ratios of 240Pu, 241Pu, 242Pu, and +Pu to intrinsic 239Pu have been successfully measured in soil samples from nuclear test sites. In addition, initial measurements of U and Np isotopes have yielded results consistent with the Pu measurements with respect to sensitivity, accuracy, precision, and linear range.  相似文献   

7.
Analysis of plutonium isotopes by Semiconductor Alpha Spectrometry (SAS), ICP-sector field mass spectrometry (ICP-MS) and Accelerator Mass Spectrometry (AMS) was carried out in seawater samples collected from the Northeast Atlantic Ocean (nuclear waste dumping sites) and Northwest Pacific Ocean. No particularly elevated levels of the atom ratios of 240Pu/239Pu compared to global fallout ratio (0.18) were found in the Northeast Atlantic Ocean seawater samples. The higher levels of atom ratios of 240Pu/239Pu were found in the Northwest Pacific Ocean. This is mainly due to contribution from the local fallout from nuclear weapon tests carried out at the Pacific Proving Grounds at the Marshall Islands.  相似文献   

8.
It is well known that ammunition containing depleted uranium (DU) was used by NATO during the Balkan conflict. To evaluate the origin of DU (the enrichment of natural uranium or the reprocessing of spent nuclear fuel) it is necessary to directly detect the presence of activation products ((236)U, (239)Pu, (240)Pu, (241)Am, and (237)Np) in the ammunition. In this work the analysis of actinides by alpha-spectrometry was compared with that by inductively coupled plasma mass spectrometry (ICP-MS) after selective separation of ultratraces of transuranium elements from the uranium matrix. (242)Pu and (243)Am were added to calculate the chemical yield. Plutonium was separated from uranium by extraction chromatography, using tri- n-octylamine (TNOA), with a decontamination factor higher than 10(6); after elution plutonium was determined by ICP-MS ((239)Pu and (240)Pu) and alpha-spectrometry ((239+240)Pu) after electroplating. The concentration of Pu in two DU penetrator samples was 7 x 10(-12) g g(-1) and 2 x 10(-11) g g(-1). The (240)Pu/(239)Pu isotope ratio in one penetrator sample (0.12+/-0.04) was significantly lower than the (240)Pu/(239)Pu ratios found in two soil samples from Kosovo (0.35+/-0.10 and 0.27+/-0.07). (241)Am was separated by extraction chromatography, using di(2-ethylhexyl)phosphoric acid (HDEHP), with a decontamination factor as high as 10(7). The concentration of (241)Am in the penetrator samples was 2.7 x 10(-14) g g(-1) and <9.4 x 10(-15) g g(-1). In addition (237)Np was detected at ultratrace levels. In general, ICP-MS and alpha-spectrometry results were in good agreement.The presence of anthropogenic radionuclides ((236)U, (239)Pu,(240)Pu, (241)Am, and (237)Np) in the penetrators indicates that at least part of the uranium originated from the reprocessing of nuclear fuel. Because the concentrations of radionuclides are very low, their radiotoxicological effect is negligible.  相似文献   

9.
The simultaneous determination of multiple actinide isotopes in samples where total quantity is limited can sometimes present a unique challenge for radioanalytical chemists. In this study, re-determination of 238Pu, 239+240Pu, and 241Am for soils collected and analyzed approximately three decades ago was the goal, along with direct determination of 241Pu. The soils had been collected in the early 1970’s from a shallow land burial site for radioactive wastes called the Subsurface Disposal Area (SDA) at the Idaho National Lab (INL), analyzed for 238Pu, 239+240Pu, and 241Am, and any remaining soils after analysis had been archived and stored. We designed an approach to reanalyze the 238Pu, 239+240Pu, and 241Am and determine for the first time 241Pu using a combination of traditional and new radioanalytical methodologies. The methods used are described, along with estimates of the limits of detection for gamma-and alpha-spectrometry, and liquid scintillation counting. Comparison of our results to the earlier work documents the ingrowth of 241Am from 241Pu, and demonstrates that the total amount of 241Am activity in these soil samples is greater than would be expected due to ingrowth from 241Pu decay.  相似文献   

10.
Summary As a follow up to the initial 1998 intercomparison study, a second study was initiated in 2001 as part of the ongoing evaluation of the capabilities of various ultra-sensitive methods to analyze 239Pu in urine samples. The initial study1 was sponsored by the Department of Energy, Office of International Health Programs to evaluate and validate new technologies that may supersede the existing fission tract analysis (FTA) method for the analysis of 239Pu in urine at the µBq/l level. The ultra-sensitive techniques evaluated in the second study included accelerator mass spectrometry (AMS) by LLNL, thermal ionization mass spectrometry (TIMS) by LANL and FTA by the University of Utah. Only the results for the mass spectrometric methods will be presented. For the second study, the testing levels were approximately 4, 9, 29 and 56 µBq of 239Pu per liter of synthetic urine. Each test sample also contained 240Pu at a 240Pu/239Pu atom ratio of ~0.15 and natural uranium at a concentration of 50 µBq/ml. From the results of the two studies, it can be inferred that the best performance at the µBq level is more laboratory specific than method specific. The second study demonstrated that LANL-TIMS and LLNL-AMS had essentially the same quantification level for both isotopes. Study results for bias and precision and acceptable performance compared to ANSI N13.30 and ANSI N42.22 have been compiled.  相似文献   

11.
Summary Studies on the environmental behavior of plutonium in the marine environment require an analytical method with high sensitivity and capability to provide the isotopic composition of Pu in marine samples. In this work, as part of our on-going project on Pu environmental behavior in the Pacific Ocean, a sector field ICP-MS method combined with an off-line anion-exchange chromatography system was optimized for the determination of Pu and its atomic ratio of 240Pu/239Pu in sediment core samples. Using a conical concentric nebulizer and 150-second counting time, we were able to lower the detection limit of Pu down to 0.35 fg. The mass discrimination effect was evaluated using a mixed Pu isotope standard solution with certified a 240Pu/239Pu isotope ratio (NBS-947). The overall performance of the analytical method was validated by the determination of Pu and its isotope composition in an ocean sediment reference material (IAEA-368). Both the 239+240Pu activity and 240Pu/239Pu atomic ratio were found to be in good agreement with the certified and/or literature values. As an important application, we employed the analytical method to investigate the vertical profiles of 239+240Pu activity and 240Pu/239Pu atomic ratio in sediment cores in the Sea of Okhotsk and the NW Pacific. It was found that the Bikini close-in fallout Pu could be transported as far as the Sea of Okhotsk. The results provided evidence to support our hypothesis on the oceanic current transportation of Bikini close-in fallout Pu in the NW Pacific and its marginal seas.  相似文献   

12.
A rapid and simple sample preparation method for plutonium determination in environmental samples by inductively coupled plasma sector field mass spectrometry (ICP-SFMS) and alpha-spectrometry is described. The developed procedure involves a selective CaF2 co-precipitation for preconcentration followed by extraction chromatographic separation. The proposed method effectively eliminates the possible interferences in mass spectrometric analysis and also removes interfering radionuclides that may disturb alpha-spectrometric measurement. For 239Pu, 240Pu and 241Pu limits of detection of 9.0 fg·g−1 (0.021 mBq), 1.7 fg·g−1 (0.014 mBq) and 3.1 fg·g−1 (11.9 mBq) were achieved by ICP-SFMS, respectively, and 0.02 mBq by alpha-spectrometry. Results of certified reference materials agreed well with the recommended values.  相似文献   

13.
In order to know the distribution of plutonium derived from the Nagasaki atomic bomb, soil samples were measured to determine the 240Pu/239Pu isotope ratio of and concentrations of 239+240Pu and 137Cs. The 239+240Pu concentrations in soils, except for Nishiyama area, were close to the average concentration of soil collected in Japan. In soils collected at the Nishiyama area and at the eastern area of Nagasaki Prefecture and at part of northern area in Kumamoto Prefecture, the 240Pu/239Pu ratios were lower than the global fallout values. This suggests that plutonium from the atomic bomb was deposited in the eastern area from the hypocenter reaching up to 100 km eastwards.  相似文献   

14.
Radiochemical separation of Pu, Am and U was tested from synthetic solutions and evaporator concentrate samples from nuclear power plants for isolation of each of them for alpha-spectrometry analysis. The separation was performed by anion-exchange chromatography, extraction chromatography, using TRU resin, and precipitation techniques. The aim of the study was to develop a sensitive analytical procedure for the sequential determination of 242Pu, 238Pu, 239+240Pu, 241Am and 235, 238U in radioactive wastes. 238Pu, 242Pu, 243Am and 232U were used as tracers. The measurements of α emitting radionuclides were performed by semiconductor detector that is used especially when spectrometric information is needed. For synthetic solutions the chemical recovery was based on associated iron concentration and was about 93%.  相似文献   

15.
We applied three techniques (DF-ICP-MS, PERALS and alpha-spectrometry) for the determination of minor actinides at environmental levels. For each method the limit of detection and the resolution were estimated in order to study the content and isotopic composition of the actinides. Two international reference materials, IAEA-135 (Irish Sea Sediment) and IAEA-300 (Baltic Sea sediment) were analyzed for activity concentrations of 238Pu, 239Pu, 240Pu, 241Pu and 241Am. The sensitivities of the three determination techniques were compared.  相似文献   

16.
A simple, rapid and reliable method was developed for the simultaneous determination of uranium and plutonium isotopes by alpha-spectrometry using a single source. A new uranium tracer230U was applied as well as the236Pu tracer to determine overall yields of uranium and plutonium isotopes throughout the entire procedure employed. The analytical procedure consists of sample leaching with 8N HNO3 solution, purification by solvent extraction, simultaneous electrodeposition of U and Pu, and subsequent alpha-spectrometry with a silicon detector. In the solvent extraction using TOA/xylene from 8N HNO3 solution, the preferential extractability of Pu rather than U permits to purify simultaneously the trace amounts of Pu and the macro amounts of U, as in the case of ordinary soil samples, resulting in favourable peak heights for both isotopes. From a single alpha-spectrum, the determinations of238U,234U (and their ratio of234U/238U),239+240Pu, and238Pu contents were conveniently carried out after correcting the overall yields obtained from230U and236Pu activities in the same spectrum. This analytical method was satisfactorily applied to the determination of U and Pu isotope contents in some soils.  相似文献   

17.
An analytical procedure for the determination of activation products 238Pu, 241Pu, 239Pu/240Pu, 241Am, 237Np, and a fission product 90Sr in radioactive wastes is presented. Samples were decomposed using Fenton’s reaction. The separation was performed by anion-exchange chromatography, extraction chromatography, using TRU and Srresin, and precipitation techniques, followed by α-spectrometry and LSC counting. Tracer solutions and pure ion exchange resins were used to prepare artificial samples and trace nuclides during the analytical procedure. Some real samples of spent ion-exchange resins originating from our TRIGA Mark II research reactor were analyzed.  相似文献   

18.
During the last ten years, the Italian Universities of Parma and Urbino collaborated on a special radioecological program having the aim to study the levels and the distribution of long-lived radionuclides in different marine and terrestrial matrixes. This paper summarizes the results concerning the concentrations of 239+240Pu and 238Pu, 241Am and 137Cs in sediments collected in the Ligurian and South Tyrrhenian Seas (Rapallo Harbour, Vado Ligure Canyon, Eolie Islands). Superficial sediments and sediment cores were collected. For cores the vertical distribution was calculated and the sedimentation rate obtained. 137Cs was determined directly by gamma-spectrometry, while 239+240Pu, 238Pu and 241Am were separated by extraction chromatography, electroplating and determined by alpha-spectrometry. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   

19.
An analytical method for determining 239Pu and 240Pu in marine sediment samples, which uses quadrupole ICP-MS, was developed in this work. A simple anion-exchange chromatography system was employed for the separation and purification of Pu from the sample matrix. A sufficient decontamination factor of 1.4×104 for U, which interferes with the determination of 239Pu, was achieved. High sensitivity Pu determination was obtained, which led to an extremely low concentration detection limit of ~8 fg/ml (0.019 mBq/ml for 239Pu; 0.071 mBq/ml for 240Pu) in a sample solution, or an absolute detection limit of 42 fg in a 5 ml sample solution, by using the shield torch technique. Analytical results for the determination of the 239+240Pu and the 240Pu/239Pu ratio in IAEA 368 (ocean sediment) reference material indicated that the accuracy of the method was satisfactory. The method developed was successfully applied to a study of Pu behavior in the sediments from Sagami Bay, Japan. The observed high 240Pu/239Pu ratio in the sediment core indicated that there was additional Pu input derived from close-in fallout in addition to the global fallout.  相似文献   

20.
Summary A new high-sensitivity plutonium bioassay program employing thermal ionization mass spectrometry (TIMS) has been developed to monitor Savannah River Site employees for intakes of PuO2. The U.S. Department of Energy requires bioassay laboratories which have the ability to detect a 100 mRem, 50-year committed effective dose equivalent (CEDE) intake of radioactive material. For PuO2, traditional alpha-spectrometry methods are not sensitive enough to meet this specification. To comply with this requirement, a radiochemical TIMS method was developed to determine Pu in urine bioassay samples. Four radiochemical separation steps were used to purify Pu from urine to ensure samples were free from matrix effects that interfere with TIMS analysis. These included precipitation, ion-extraction chromatography, electrodeposition, and ion-exchange chromatography. A batch of reagent blanks determined the detection limit for this method was 0.59 fg 239Pu/l (1.3 µBq 239Pu/l). The 239Pu concentration was also measured in 20 urine blank samples to determine the minimum 239Pu concentration that would indicate an occupational intake. A Probit plot was constructed for the results and the 99 th percentile of the urine blanks showed that the minimum 239Pu concentration that would indicate an uptake was 2.4 fg/l (5.5 µBq/l).  相似文献   

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