共查询到20条相似文献,搜索用时 31 毫秒
1.
Sherrod L. Maxwell Brian A. Culligan Vernon D. Jones Sheldon T. Nichols Gary W. Noyes 《Journal of Radioanalytical and Nuclear Chemistry》2011,287(1):223-230
A new method that allows rapid preconcentration and separation of plutonium and neptunium in water samples was developed for the measurement of 237Np and Pu isotopes by inductively-coupled plasma mass spectrometry (ICP-MS) and alpha spectrometry. 238U can interfere with 239Pu measurement by ICP-MS as 238UH+ mass overlap and 237Np via peak tailing. The method provide enhanced removal of uranium by separating Pu and Np initially on TEVA Resin, then moving Pu to DGA resin for additional removal of uranium. The decontamination factor for uranium from Pu is almost 100,000 and the decontamination factor for U from Np is greater than 10,000. This method uses stacked extraction chromatography cartridges and vacuum box technology to facilitate rapid separations. Preconcentration is performed using a streamlined calcium phosphate precipitation method. Purified solutions are split between ICP-MS and alpha spectrometry so that long and short-lived Pu isotopes can be measured successfully. The method allows for simultaneous extraction of 20 samples (including QC samples) in 4?C6 h, and can also be used for emergency response. 239Pu, 242Pu and 237Np were measured by ICP-MS, while 236Pu, 238Pu, and 239Pu were measured by alpha spectrometry. 相似文献
2.
J. La Rosa J. Gastaud L. Lagan S.-H. Lee I. Levy-Palomo P. P. Povinec E. Wyse 《Journal of Radioanalytical and Nuclear Chemistry》2005,263(2):427-436
Summary A procedure is described to extend the current radiochemical method of seawater analysis for Pu and Am including Np. Short-lived 239Np tracer was prepared by separation from its 243Am parent. Irish Sea Water reference material (IAEA-381) containing known concentrations of 237Np, Pu isotopes and 241Am was used to test the procedure for small water volumes. Inductively-coupled plasma mass spectrometry (ICP-MS) was used in addition to alpha spectrometry for measurement of 237Np in the purified final Np fractions. 相似文献
3.
Sz. Osváth N. Vajda Zs. Molnár É. Széles Zs. Stefánka 《Journal of Radioanalytical and Nuclear Chemistry》2010,286(3):675-680
The majority of long-lived radionuclides produced in the nuclear fuel cycle can be regarded as “difficult-to-measure” nuclides,
hence chemical separation is needed before the nuclear measurement of them. A combined radiochemical procedure that enables
the simultaneous determination of some “difficult-to-measure” nuclides in medium and low level radioactive wastes has been
developed in our laboratory. Recently, this method has been extended for determination of 237Np and 93Zr. 237Np and 93Zr are pre-concentrated by co-precipitation on iron(II) hydroxide and zirconium oxide, separated by extraction chromatography
using UTEVA, and measured by inductively coupled plasma mass spectrometry (ICP-MS). As even traces of polyatomic ions and
isotopes at m/z 237 or 93 cause considerable interferences during ICP-MS detection, a purification step by extraction chromatography
was needed. Analyzing real samples (evaporation concentrates of a nuclear power plant) 66–99% and 31–99% chemical yields were
achieved for Np and Zr, respectively. 相似文献
4.
S. Salminen J. Paatero P. Roos K. Helariutta 《Journal of Radioanalytical and Nuclear Chemistry》2009,281(3):405-413
Activity concentrations of 237Np in peat and lichen samples in Finland were determined and contributions from nuclear weapons testing in 1950–1960s and
the Chernobyl accident were estimated. 237Np was determined with ICP-MS using 235Np as a tracer. Activity concentrations of 237Np in peat samples varied between 1.98 ± 0.05 and 14.1 ± 0.3 mBq/m2. The contribution from the Chernobyl accident to the total 237Np deposition in peat was 0.1–13%, the Chernobyl-derived fraction of total 237Np in peat being much lower than the previously determined corresponding Chernobyl-derived fractions of 239+240Pu, 241Pu, 241Am and 244Cm. 相似文献
5.
Jerome J. La Rosa Jerzy W. Mietelski Eric Wyse 《Journal of Radioanalytical and Nuclear Chemistry》2010,283(2):385-387
Described are results and the procedure for a pilot study on 237Np content in forest litter samples from Poland in relation to their plutonium activity. Neptunium was determined by inductively
coupled plasma mass spectrometry (ICP-MS) and Pu by alpha spectrometry. Two samples originated from a location with pure global
fallout and two others from a place with about 65% of the plutonium from Chernobyl. Plutonium activities were determined twice:
at Krakow and in Monaco. The two results were consistent and 239 + 240Pu activities ranged from about 1 to about 7 Bq/kg dry weight (dw). The chemical recovery for Np was between 27 and 89%. Results
for 237Np activity concentrations were between 0.099 ± 0.005 and 2.21 ± 0.076 mBq/kg dw. Observed activity ratios were lower than
expected and could be explained by fractionation of Np against Pu in forest litter. 相似文献
6.
N. Xu D. Gallimore A. Martinez L. Townsend 《Journal of Radioanalytical and Nuclear Chemistry》2013,297(1):127-132
An ICP-MS analytical method as an alternative to the current radiochemical method was developed to analyze trace level 237Np in bulk plutonium materials. In this method, 237Np is determined together with a suite of trace elements during a single analysis using one dissolution solution. Method validation was achieved through precision examination, spike recovery study, detection limit determination, comparison of results with the radiochemical method, and laboratory intercomparison studies on Pu metals. The ICP-MS method significantly reduced the analysis cost, the sample amount, consumption of chemicals and waste generation, as well as the sample turnaround time. 相似文献
7.
C. K. Kim S. Morita R. Seki Y. Takaku N. Ikeda D. J. Assinder 《Journal of Radioanalytical and Nuclear Chemistry》1992,156(1):201-213
Intertidal coastal and estuarine sediments from 24 sites in the Irish Sea have been analyzed for99Tc,237Np,238Pu,239,240Pu and241Am. The237Np activity and239Pu/240Pu ratio were measured simultaneously by ICP-MS, and99Tc was determined by HR-ICP-MS which is ten times more sensitive than Q-ICP-MS.The activities of99Tc,237Np,239,240Pu and241Am were distributed over a wide range of 1.5–70.5, 0.01–13.3, 2.3–1589, 2.6–1894 Bq/kg, respectively. Activities of these radionuclides decreased exponentially with distance from the Sellafield source. The241Am/239,240Pu and237Np/239,240Pu ratios were almost constant with distance from the Sellafield. This result suggests that the distribution and behavior of Np and Pu are controlled by complicated factors such as the influence of transport, the variation with time of Np/Pu ratio in the Sellafield discharges and sedimentary mixing processes in the Irish Sea. 相似文献
8.
A. S. Hursthouse M. S. Baxter K. McKay F. R. Livens 《Journal of Radioanalytical and Nuclear Chemistry》1992,157(2):281-294
Inductively coupled plasma mass spectrometry (ICP-MS) and neutron activation analysis (NAA) have been investigated as alternatives to alpha-spectrometry for the low-level determination of237Np and other actinides in environmental matrices. ICP-MS in particular, has been shown here to offer suitable sensitivity, precision and accuracy compared to the other techniques, with considerably faster sample throughput relative to radiometric and activation approaches. Added advantages of ICP-MS are found to include the abilities to determine other long-lived actinides simultaneously and to quantify239Pu:240Pu ratios. The neutron activation analysis approach was found to be particularly prone to interference especially from uranium nuclides. 相似文献
9.
Zsolt Varga Adrian Nicholl Erich Hrnecek Maria Wallenius Klaus Mayer 《Journal of Radioanalytical and Nuclear Chemistry》2018,318(3):1565-1571
The paper describes the age (production date) determination of uranium reference materials using the 231Pa/235U ratio. Direct addition of 237Np in secular equilibrium with its 233Pa daughter was chosen instead of the regular milking of 237Np to avoid possible loss of Pa. Sample preparation consists of a fast, one-step procedure. The developed method using ICP-MS for the measurement of 231Pa is more precise than alpha spectrometry and is applicable for freshly produced low-enriched uranium materials. The measured ages are in good agreement with the reported production dates, thus the 231Pa/235U chronometer can be applied for validation of 230Th/234U in nuclear forensics and safeguards. 相似文献
10.
Xiaowei Yi Yanmei Shi Jiang Xu Xiaobing He Haitao Zhang Jianfeng Lin 《Journal of Radioanalytical and Nuclear Chemistry》2013,298(3):1757-1761
A radiochemical procedure is developed for the determination of 237Np in soil with multi-collector inductively-coupled plasma mass spectrometry (MC-ICP-MS) and gamma-spectrometry. 239Np (milked from 243Am) was used as an isotopic tracer for chemical yield determination. The neptunium in the soil is separated by thenoyl-trifluoracetone extraction from 1 M HNO3 solution after reducing Np to Np(IV) with ferrous sulfamate, and then purified with Dowex 1 × 2 anion exchange resin. 239Np in the resulting solution is measured with gamma-spectrometry for chemical yield determination while the 237Np is measured with MC-ICP-MS. Measurement results for soil samples are presented together with those for two reference samples. By comparing the determined value with the reference value of the 237Np activity concentration, the feasibility of the procedure was validated. 相似文献
11.
M. Yamamoto Y. Yamauchi K. Chatani S. Igarashi K. Komura K. Ueno M. Sakanoue 《Journal of Radioanalytical and Nuclear Chemistry》1991,147(1):165-176
In order to investigate the sedimentary behaviour of neptunium,237Np together with Pu isotopes and241Am have been measured for the sediment cores collected from Lake Mikata (freshwater) and from Lake Kugushi (brakish water) both belonging to the Mikata Five Lakes, and from Nyu Bay (sea water). In all sediment core samples237Np was detected, and its concentrations were far below those of239,240Pu and241Am measured for the same samples. Inventories of237Np in Lake Mikata, Lake Kugushi and Nyu Bay were estimated to be 0.53, 0.29 and 0.34 MBq/km2, respectively. The activity ratio of237Np/239,240Pu calculted from the inventories in each sediment core was 0.29% for Lake Mikata, 0.15% for Lake Kugushi and 0.10% for Nyu Bay. These values except for the value for Lake Mikata are two or three times lower than the value of 0.3–0.4% observed for surface soils of 0–20 cm depth, suggesting that Np is more soluble compared with Pu. 相似文献
12.
M. Yamamoto S. Igarashi K. Chatani K. Komura K. Ueno 《Journal of Radioanalytical and Nuclear Chemistry》1990,138(2):365-376
This paper describes the analytical methods for the determination of237Np, Pu isotopes, and241Am, with particular emphasis on237Np by alpha-ray spectrometry and241Pu by liquid scintillation technique. Results are also presented for the sediment cores collected from Mikata Five Lakes in Fukui Prefecture, Japan. 相似文献
13.
Donatella Desideri Laura Feduzi Maria Assunta Meli Carla Roselli 《Microchemical Journal》2011,97(2):264-268
Environmental contamination by artificial radionuclides and the evaluation of their sources require precise isotopic analysis and accurate determination of actinide elements above all plutonium and americium. These can be achieved by alpha spectrometry or by inductively coupled plasma mass spectrometry (ICP-MS) after chemical separation. In the present work, a simple, rapid method has been developed for the sequential separation of actinide elements from aqueous solutions and their determination by alpha spectrometry. Extraction chromatography was applied to the separation of 241Am, 244Cm, 239 + 240,238Pu, 237Np and 238,235,234U using microporous polyethylene supporting tri-n-octylamine as the stationary phase and hydrochloric acid with and without reducing agents as the mobile phase. Actinide in 9 M HCl solution is introduced into the anion exchange column; Pu (IV), Np (IV) and U(VI) are retained on the column while Am (III) and Cm passed through. Pu is eluted first, reductively, after which, Np and then U are eluted. The method can be applied to all aqueous solutions which do not contain strong complexing or precipitation agents for the elements considered. 相似文献
14.
A procedure for the analysis of90Sr,154Eu,237Np,239Pu,241Am and242−244Cm was developed. Separation was done with the separating agent, di-2(ethyl hexyl)-phosphoric acid (HDEHP), and results in
fractions containing the different elements to be analysed.90Sr analysis was done by analysing its daughter nuclide90Y, detected through the Cherenkov radiation emitted by this high energy β−-emitter.154Eu was detected using γ-spectrometry with a lower Compton background as a result of the removal of other fission products.241Am could also be detected with γ-spectrometry or together with242−244Cm with α-spectrometry. The long-lived radionuclides237Np and239Pu were detected using inductively coupled plasma mass spectrometry (ICP-MS). 相似文献
15.
Maxwell SL Culligan BK Jones VD Nichols ST Bernard MA Noyes GW 《Analytica chimica acta》2010,682(1-2):130-136
A new method for the determination of (237)Np and Pu isotopes in large soil samples has been developed that provides enhanced uranium removal to facilitate assay by inductively coupled plasma mass spectrometry (ICP-MS). This method allows rapid preconcentration and separation of plutonium and neptunium in large soil samples for the measurement of (237)Np and Pu isotopes by ICP-MS. (238)U can interfere with (239)Pu measurement by ICP-MS as (238)UH(+) mass overlap and (237)Np via (238)U peak tailing. The method provides enhanced removal of uranium by separating Pu and Np initially on TEVA Resin, then transferring Pu to DGA resin for additional purification. The decontamination factor for removal of uranium from plutonium for this method is greater than 1×10(6). Alpha spectrometry can also be applied so that the shorter-lived (238)Pu isotope can be measured successfully. (239) Pu, (242)Pu and (237)Np were measured by ICP-MS, while (236)Pu and (238)Pu were measured by alpha spectrometry. 相似文献
16.
Yoon Yeol Yoon Chul Soo Kim Dong Yoon Yang Wook Hyun Nahm Soo Young Cho Kil Yong Lee 《Journal of Radioanalytical and Nuclear Chemistry》2008,276(1):187-191
Sediment core samples taken from the Jinheung catchment located in the middle of the Korean Peninsula were used to know environmental
radionuclide distribution. The grain sizes of the sediment cores were found at depth of about 17 cm suggesting that it might
have occurred during a dry period of 1969. The radionuclides, 137Cs, 237Np, 239Pu, 240Pu, 234U, 238U, 228Th, 230Th, 232Th, were analyzed by sector type ICP-MS and gamma-spectrometry. The Cs and Pu distribution changed with the depth, in which
the maximum ranged from 14 to 22 cm. This was due to the high activity of the results of nuclear bomb tests in the air from
1960s and showed different distribution pattern on the soil surface. The average activity ratio of 240Pu/239Pu and 237Np/239Pu was 0.173 and 0.45, respectively. These values were similar to the north hemisphere global fallout ratio of 240Pu/239Pu (0.18) and 237Np/239Pu (0.45). The 237Np/239Pu ratio showed a higher value than the global fallout ratio above 14 cm depth. The U, Th and their daughter radionuclides
kept secular equilibrium in the sediment core because the average activity ratios were nearly 1. 相似文献
17.
A simple, rapid, cost-efficient, and robust method for separation of 237Np with an extraction chromatographic column (TOA: tri-n-octylamine on Teflon powder) is outlined in detail and further improved for direct ICP-MS analysis. The column efficiently retained 237Np in 2 mol L(-1) HNO3 medium and all of the 237Np was easily eluted with 0.02 mol L(-1) oxalic acid in 0.16 mol L(-1) HNO3 at 95 degrees C. The separated solutions were free from most matrix elements and were aspirated into the ICP-MS directly. The decontamination factor for 238U is more than 10(4). The instrumental detection limit for 237Np was 0.46 pg mL(-1), which corresponds to 1.2 x 10(-5) Bq mL(-1). The method is more rapid than traditional radiometric techniques. It is also considered to be more suitable for environmental monitoring than existing methods based on TOA. 相似文献
18.
N. Shinohara N. Kohno T. Suzuki S. Usuda 《Journal of Radioanalytical and Nuclear Chemistry》1989,130(1):3-12
A method for analyzing the content of237Np in spent fuel has been developed using inherent239Np as a chemical yield monitor. After ion-exchange separations for the dissolved fuel solution, the237Np content in the neptunium fraction was determined from the activity of237Np or of233Pa, which is in radioactive equilibrium with237Np. The chemical yield in the separations was determined both from the content of243Am which is in radioactive equilibrium with239Np before the separations and from the239Np content in the neptunium fraction after the separations by alpha- and gamma-ray spectrometry. 相似文献
19.
A method is described for the determination of 239Np in natural uranium metal foils irradiated in a zero-energy reactor. The foils are dissolved in nitric acid in the presence of 237Np used for the determination of the yield of 239Np. Neptunium is co-precipitated with lanthanum fluoride; lanthanum and thorium are removed by anion exchange in hydrochloric acid solution, and the neptunium is further purified by anion exchange in nitric acid solution. Sources for counting are prepared by direct evaporation of an aqueous solution onto a stainless steel disc. No corrections are necessary to the 237Np α-count for absorption in the source. The method does not necessitate prior separation of daughter 233Pa from the 237Np tracer and gives sources of high purity in good yield. 相似文献
20.
R. J. Rosenberg 《Journal of Radioanalytical and Nuclear Chemistry》1993,171(2):465-482
The results of a literature survey on non-radiometric analytical techniques for the determination of long-lived radionuclides are described. The methods which have been considered are accelerator mass spectrometry, inductively coupled plasma mass spectrometry, thermal ionization mass spectrometry, resonance ionization spectrometry, resonance ionization mas spectrometry and neutron activation analysis. Neutron activation analysis has been commonly used for the determination of129I and237Np in environmental samples. Inductively coupled mass spectrometry seems likely to become the method of choice for the determination of99Tc,237Np and Pu-isotopes. The methods are discussed and the chemical separation methods described. 相似文献