Characteristics of Dicesium Plutonium(IV) Nitrate Formation in Separation System of Uranyl Nitrate Hexahydrate Crystal

There is a concerned that Cs and Pu double salt Cs2Pu(NO3)6 is formed under certain conditions in the course of U crystallization. The influence of the Cs concentration in a feed solution on Cs2Pu(NO3)6 formation was thus examined in the U crystallization process. Cesium and Pu were decontaminated after crystal washing with a decreasing Cs concentration in the feed solution. Although Cs remained in the mother liquor at a Cs concentration of 1.0 g/dm³ in the feed solution, Cs2Pu(NO3)6 precipitated at a Cs concentration of 2.2 g/dm³. There is, therefore, a lower limit for the Cs concentration in the feed solution at which Cs2Pu(NO3)6 precipitates, and this limit falls in the range from 1.0 to 2.2 g/dm³ Cs.     

Current levels and distribution of 137Cs and Pu isotopes in soil on the Kazakhstan territory of the Kazakhstan-Chinese border: Semipalatinsk and Lob Nor nuclear test sites detonation

More than 100 soil samples were collected from 46 sites along roads and some settlements connecting Alma-Ata to Semipalatinsk City of the Kazakhstan-Chinese border and analyzed for ¹³⁷Cs and Pu isotopes (²³⁸Pu, ²³⁹Pu and ²⁴⁰Pu). The mean ¹³⁷Cs inventory at each site was within the range of 1,000-3,000 Bq/m² for most of the sites. The ^239,240Pu concentration and its inventories were observed in the wide range of 0.18-2.6 Bq/kg and 28-677 Bq/m², respectively. At the most northern sites in the areas studied, higher^239,240Pu inventories were found corresponding to the increase of ^239,240Pu fraction which was not leached by hot digestion with conc. HNO₃+H₂O₂. The ^239,240Pu/¹³⁷Cs activity ratios for the soil samples from the southern areas lie in the narrow range of 0.016–0.039 (most of data being 0.02–0.03), probably indicative of global fallout origin. On the other hand, a little or several higher ratios (0.05 to 0.22) were found for soil samples from the northern areas. These higher ratios demonstrate strongly that there was additional Pu input of local fallout due to the atomic explosions. From ²⁴⁰Pu/²³⁹Pu atomic ratios measured, contribution of local fallout ^239,240Pu, probably from the SNTS, was found to be higher (60–86%) in the sites around the northern areas than the southern ones. The present data might serve not only as a current baseline information on distribution and contamination levels of the long-lived fallout radionuclides in the Kazakhstan areas of the Kazakhstan-Chinese border, but also as a aid of selection of control area for epidemiological projects.     

Plutonium isotopes and 137Cs in Dolon settlement near the Semipalatinsk Nuclear Test Site: About 50 years after the first nuclear weapon testing

Recent controversies concerning the radiation doses for populations living in the village of Dolon due to the nuclear explosions carried out at the Semipalatinsk Nuclear Test Site (SNTS) have encouraged us to evaluate in more detail the levels and distributions of residual long-lived radionuclides¹³⁷Cs and Pu isotopes (²³⁸Pu,^239,240Pu) in soils within the village. Soil core samples up to a depth of about 30 cm and/or 100 cm were collected at 25 sites and subjected to analysis of ¹³⁷Cs and Pu isotopes. The inventories of ¹³⁷Cs and ^239,240Pu were found to be in the wide range of 790-10,310 and 530-14,320 Bq/m², respectively. Sequential leaching of Pu from the soil showed that more than ca. 80% of the ^239,240Pu was not leached by hot digestion with conc. HNO³ + H₂O₂, indicating the presence of Pu associated with fused silicates. Further, the presence of hot-particles from the Pu contaminants by a-track radiography technique using CR-39 polycarbonate was confirmed in the soil, even at present, after about 50 years from the first nuclear weapon testing. This revised version was published online in July 2006 with corrections to the Cover Date.     

239+240Pu and137Cs concentrations in salmon (Oncorhynchus keta) collected on the Pacific coast of Japan

Salmon (Oncorhynchus keta) samples were collected on the Pacific coast of Japan and analyzed for their^239+240Pu and¹³⁷Cs concentrations in six places, i.e., muscle, viscera, gill, gonad, skin and spine. The^239+240Pu concentrations in muscle ranged from 0.07 to 0.14 mBq/kg (wet) and had the lowest value among the six regions. The mean^239+240Pu concentrations in viscera, gonad and spine were more than 1 mBq/kg (wet_ while those in muscle and skin were one order of magnitude lower. The largest amounts of^239+240Pu were accumulated in gonad. The^239+240Pu/¹³⁷Cs activity ratios in all positions were lower than that of the global fallout ratio of 0.022, suggesting that¹³⁷Cs could be accumulated with greater ease than^239+240Pu in all positions and ratios of uptake differed remarkably from position to position. The total accumulations of^239+240Pu and¹³⁷Cs in salmon were 1.32 and 328 mBq/individual, respectively.     

Distribution and behavior of some radionuclides associated with the Trinity nuclear test

The activities of ¹³³Ba, ¹³⁷Cs, ¹⁵²Eu, ¹⁵⁴Eu, ¹⁵⁵Eu, ²³⁹Pu, and ²⁴¹Am were determined by gamma spectroscopy on the largest sample set (n = 49) of bulk trinitite to date. The range in activity for all isotopes is large. For example, the activity of ²⁴¹Am (normalized to the time of detonation) ranges between 1 and 42 Bq/g. Comparison of activities for isotopes derived from the device, ²⁴¹Am versus ¹³⁷Cs, ¹⁵⁵Eu, and ²³⁹Pu, indicate positive trends. Correlations were not observed between the activities of the soil-derived activation products ¹⁵²Eu and ¹⁵⁴Eu and the radioisotopes from the device. The calculated ratio of fission products (¹⁵⁵Eu/¹³⁷Cs) is 0.012 ± .006 (1σ, n = 3), which is lower than predicted for the thermal neutron-induced fission of ²³⁹Pu (~0.03). This discrepancy may be attributed to the spontaneous fission of the natural U tamper resulting in mixing between fission products from ²³⁹Pu and ²³⁵U. The spatial distribution of the trinitite samples relative to ground zero has been modeled based on the activity of ¹⁵²Eu. The calculated distances do not correlate with any of the activities for the radioisotopes investigated here, and suggest a relatively homogeneous distribution. However, trinitite samples with the highest activities for ¹³⁷Cs, ²³⁹Pu, and ²⁴¹Am yield the shortest calculated distances of 50–60 m away from ground zero.     

Freshwater suspended particles: An intercomparison of long-term integrating sampling systems used for environmental radioactivity monitoring

Summary Sampling and sample preparation are known to carry large, but typically unknown uncertainty contributions to the final analytical data and there is a lack of qualitative and quantitative data on the comparability of results achieved by different sampling methods. To this end an intercomparison exercise was carried out to compare different methods for the collection of suspended material used for the monitoring of environmental radioactivity in freshwater bodies.This paper presents the results of this intercomparison exercise in which “in situ”particulate sampling devices were compared in field exercises performed in the Kiev Reservoir (Ukraine) and in the Po River (Italy). The main criterion for this intercomparison was the agreement among the¹³⁷Cs activity concentrations associated with the suspended particles expressed as Bq^. g^-1and among the (C/N) molar ratios measured on the suspended particles. In addition, an estimate of the uncertainties associated with each measuring method has been performed.     

Pu isotopes and137Cs in the surrounding areas of the former Soviet Union's Semipalatinsk nuclear test site

Field missions were sent to Semipalatinsk City and several settlements near the former Semipalatinsk nuclear test site to investigate the current radioactive contamination levels of the land coming from long-lived radionuclides. The soil was sampled at about 20 sites, including some settlements such as Mostik, Dolon and Chagan, forest and pasture areas, along the roads from Semipalatinsk City to Kurchatov City and to Korosteli settlement in the direction of the Altai District. The radioactivities of¹³⁷Cs,²³⁸Pu and^239,240Pu as well as²⁴⁰Pu/²³⁹Pu atomic ratios in the soil were determined by non-destructive γ-ray spectrometry and radiochemical separation followed by α-ray spectrometry and/or ICP-MS, respectively. The results showed a distinction of¹³⁷Cs and^239,240Pu inventories in soil depending on the site where we visited. While the overall¹³⁷Cs levels were as same as or slightly lower than the domestic global fallout level (3·10³–7·10³ Bq/m²),^239,240Pu levels at some sites were several to a few ten times higher than the domestic level (40–120 Bq/m²). The atomic ratios of²⁴⁰Pu/²³⁹Pu in the soil were in the range of 0.024–0.125, which were significantly lower than the value of 0.18 commonly accepted for global fallout Pu.     

Vertical Profiles, Inventories, and Activity Ratios of 239+240Pu and 137Cs in Sediments from Sagami Bay, Western Northwest Pacific Margin

Marine sediment cores were taken from Sagami Bay of the western Northwest Pacific and analyzed for ^239+240Pu and ¹³⁷Cs activities. A significant correlation was observed between ^239+240Pu and ¹³⁷Cs activities in sediment cores, i.e., their vertical profiles. The measured activities which were used to obtain the inventories of ^239+240Pu and ¹³⁷Cs in the sediment column, showed large variations, ranging from 36 to 474 MBq/km² for ^239+240Pu and 49 to 652 MBq/km² for ¹³⁷Cs. ^239+240Pu inventories in the sediment from one region in the Bay, Sagami Nada were 5–10 times greater than those predicted from atmospheric global fallout 42 MBq/km² at the same latitude. On the other hand, ¹³⁷Cs inventories, with a mean value of 297±168 MBq/km², were much less than predicted, 2040 MBq/km². The activity ratios of ^239+240Pu/¹³⁷Cs obtained, with a mean of 0.65±0.17, were significantly greater than the ratio predicted from fallout, 0.021. Furthermore, there was a clear relationship between both ^239+240Pu and ¹³⁷Cs inventories and the water content, indicating that higher inventories may be attributed principally to concentration in, and scavenging by, fine-grained particles.     

Studies of the vertical distribution of134Cs,137Cs,238Pu,239, 240Pu,241Pu,241Am and210Pb in ombrogenous mires at mid-latitudes

Six peat cores taken from three unmodified blanket and raised bogs in Ireland were sectioned and analyzed for a range of radionuclides including¹³⁴Cs,¹³⁷Cs,²³⁸Pu,²³⁹Pu,²⁴¹Am, and²¹⁰Pb.¹³⁴Cs and¹³⁷Cs were measured by high resolution gamma-spectrometry, while the transuranium nuclides were determined after chemical separation by alpha-spectrometry.²⁴¹Pu, present on the electroplated discs together with Pu(), was measured directly by low-level liquid scintillation counting. Core chronologies were established by measuring the unsupported²¹⁰Pb component using low energy photon spectrometry (LEPS). From the resulting profiles, relaxation depths and migration rates for the above mentioned radionuclides have been determined and differences in the values of these parameters interpreted.²³⁸Pu/^239,240Pu and²⁴¹Pu/^239,240Pu ratios have been examined carefully and are discussed in some detail. Finally, the contribution from Chernobyl to the total radiocaesium inventory in each core has been established using the¹³⁴Cs/¹³⁷Cs ratio observed in the initial fallout from Chernobyl.     

Depth distribution of239,240Pu and137Cs in soils of South Korea

Depth distribution of^239,240Pu and¹³⁷Cs in the soils of South Korea have been studied. The average accumulated depositions were estimated roughly to be 54.8±32.1 Bq·m^–2 for^239,240Pu, 1.6±1.0 Bq· ·m^–2 for²³⁸Pu and 1982.8±929.1 Bq·m^–2 for¹³⁷Cs. The activity ratios of^239,240Pu/¹³⁷Cs in soils were found to be in the narrow range of 0.0153 to 0.0364 with a mean value of 0.0230±0.006. The concentrations of^239,240Pu and¹³⁷Cs in soils decrease exponentially with increasing the soil depth. A significant correlation was found between the concentration of^239,240Pu and that of¹³⁷Cs. The activity ratios of^239,240Pu/¹³⁷Cs tend to increase slightly with increasing soil depth.     

238Pu, 239+240Pu, 241Am, 90Sr and 137Cs in mountain soil samples from the Tatra National Park (Poland)

Activity concentrations and inventory for ²³⁸Pu, ^239+240Pu, ²⁴¹Am, ⁹⁰Sr, and ¹³⁷Cs in soil from Tatra Mountains of Poland are presented. Soil samples were collected using 10 cm diameter cores down to 10 cm and sliced into 3 slices. Details of the applied procedure are described with the quality assurance program. The maximum activity concentrations found for various samples were: 1782±13 Bq/kg, 17.4±0.9 Bq/kg, 3.4±0.3 Bq/kg and 84±7 Bq/kg for ¹³⁷Cs, ^239+240Pu, ²⁴¹Am and ⁹⁰Sr, respectively. The maximum cumulated deposition of ^239+240Pu is 201±8 Bq/m². The origin of radionuclides is discussed, based mostly on the observed isotopic ratio of Pu. Significant correlations were found between ^239+240Pu, ²⁴¹Am and ¹³⁷Cs. The effective vertical migration rate seems to be in the order of: ⁹⁰Sr≫Pu>Am>Cs.     

Contents of238Pu,239,240Pu and137Cs in sediments and shore depositions of the Vltava river in 1995–1996

The²³⁸Pu,^239,240Pu and¹³⁷Cs concentrations in sediments and shore deposition samples of the Vltava river were determined.^239,240Pu and¹³⁷Cs concentrations in sediment samples (five locations) ranged from 19.6 to 124.8 mBq·kg⁻¹ and from 1.8 to 28.2 Bq·kg⁻¹, respectively. The²³⁸Pu,^239,240Pu and¹³⁷Cs concentrations in shore deposition samples (four locations) ranged from 2 to 16.8, from 26.8 to 477.2 mBq·kg⁻¹, and from 1.6 to 86.3 Bq·kg⁻¹, respectively. The superficial activity of studied radionuclides in shore deposition areas was determined and radionuclide origin at studied locations was discussed.     

Some aspects of environmental radioactivity around the former Soviet Union"""s Semipalatinsk nuclear test site: Local fallout Pu in Ust"""-Kamenogorsk district

The ¹³⁷Cs, ²³⁸Pu and ^239,240Pu activity concentrations were determined together with the atomic ratios of ²⁴⁰Pu/²³⁹Pu for the soil samples at 19 sites from the Ust"-Kamenogorsk district, located more than 300 km east of the Semipalatinsk nuclear test site (SNTS). The mean areal deposition of ¹³⁷Cs ranged from 1,500 to 4,100 Bq/m². However, some hot spot-like areas showing high concentrations of 5,500–7,700 Bq/m² were foundat some sites within the city. The ^239,240Pu levels ranged from <50 to 510 Bq/m², however most of them ranged between 120–200 Bq/m². These levels are nearly the same as those around the Semipalatinsk City. At most of the sites within the city and its adjacent areas, both nuclides were found in the soil layers up to a depth of 30 cm. A fraction of 20–50% of ^239,240Pu was not leached by hot digestion with concentrated HNO₃ containing a small amount of H₂O₂. Generally, such tightly bound fraction showed a trend to decrease with increasing distance from the SNTS. The fraction of these radionuclides that were deposited in Ust"-Kamenogorsk district from global and from SNTS fallouts have been determined using the ²⁴⁰Pu/²³⁹Pu atomic ratios in both Pu fractions: one which can be leached with hot HNO₃ + H₂O₂ and another that is a non-leacheable for each soil layer of core samples. As a result a fraction of 21–80% (mostly 30–60%) of total ^239,240Pu were found to be due to the local fallout of Pu from the SNTS debris. For ¹³⁷Cs, the contribution (mostly 10–20%) of local fallout from the SNTS were estimated to be far lower as compared to ^239,240Pu.     

A multi-method approach for determination of radionuclide distribution in trinitite

The spatial distribution of radiation within trinitite thin sections have been mapped using alpha track radiography and beta autoradiography in combination with optical microscopy and scanning electron microscopy. Alpha and beta maps have identified areas of higher activity, and these are concentrated predominantly within the surficial glassy component of trinitite. Laser ablation-inductively coupled plasma mass spectrometry (LA-ICP-MS) analyses conducted at high spatial resolution yield weighted average ²³⁵U/²³⁸U and ²⁴⁰Pu/²³⁹Pu ratios of 0.00718 ± 0.00018 (2σ) and 0.0208 ± 0.0012 (2σ), respectively, and also reveal the presence of some fission (¹³⁷Cs) and activation products (^152,154Eu). The LA-ICP-MS results indicate positive correlations between Pu ion signal intensities and abundances of Fe, Ca, U and ¹³⁷Cs. These trends suggest that Pu in trinitite is associated with remnants of certain chemical components from the device and surrounding Trinity test-related structures at ground zero. In contrast, negative correlations between Pu ion signals and SiO₂ and K₂O contents were observed within the glassy matrix of trinitite. This LA-ICP-MS result was corroborated by combined back-scattered electron imaging and alpha radiography, and indicates that Pu was not incorporated into unmelted crystalline grains of precursor minerals (i.e., quartz-SiO₂ and K-feldspar-KAlSi₃O₈) present within the desert sand at the Trinity site. The results from this study indicate that the device-related radionuclides were preferentially incorporated into the glassy matrix in trinitite.     

Distributions of Pu isotopes and 137Cs in soil from Semipalatinsk Nuclear Test Site detonations throughout southern districts

Soil samples collected mainly from the southern areas, including Kainar and Karaul settlements, around the Semipalatinsk Nuclear Test Site of the former USSR were analyzed for ¹³⁷Cs and Pu isotopes (²³⁸Pu,²³⁹Pu and ²⁴⁰Pu) by γ-ray and α-ray spectrometry and ICP-MS. The ¹³⁷Cs inventories varied widely from 170 to 13,600 Bq/m². The ^239,240Pu inventories, values of which are scare in the literature, also varied in the range of 34-2,050 Bq/m² (most of date being 100-300 Bq/m²). In the areas around Tailan, Sarzal and Karaul settlements where the radioactive cloud related to the first thermonuclear explosion passed through, higher inventories of these nuclides were observed and especially their ²³⁸Pu/^239,240Pu activity ratios (0.0064-0.0076) were markedly lower than those attributed to global fallout (0.03-0.04). The observed ratios might be used as a fingerprint to identify the Pu source of the first thermonuclear event. Most of the ²⁴⁰Pu/²³⁹Pu atomic ratios were lower than those of global fallout (0.18) commonly accepted. The contribution of local fallout ^239,240Pu was higher (more than 80-90%) in the areas around the Tailan, Sarzal and Karaul settlements than that (30-ca. 60%) in the other areas. This high Pu contribution was related to the Pu source from the first thermonuclear event. This revised version was published online in July 2006 with corrections to the Cover Date.     

Geochemical partitioning of actinides, 137Cs and 40K in a Tyrrhenian sea sediment sample: Comparison to stable elements

The knowledge of radioactive and stable elements partitioning to natural sediment systems is essential for modelling their environmental fate. A sequential extraction method consisting of six operationally-defined fractions has been developed for determining the geochemical partitioning of natural (U, Th, ⁴⁰K) and antropogenic (Pu, ²⁴¹Am, ¹³⁷Cs) radionuclides in a 10 cm deep sediment sample collected in the Tyrrhenian sea (Gaeta Gulf, Italy) in front of the Garigliano Nuclear Power Plant. ¹³⁷Cs and ⁴⁰K were measured by gamma-spectrometry. Extraction chromatography with Microthene-TOPO (U, Th), Microthene-TNOA (Pu) and Microthene-HDEHP (Am) was used for the chemical separation of the alpha-emitters: after electrodeposition alpha-spectrometry was carried out. Some stable elements (Fe, Mn, Al, Ca, Pb, Ba, Ti, Sr, Cu, Ni) were also determined in the different fractions to get more information about the chemical association of the radionuclides.     

Evaluation of the 153Sm-EDTMP radiochemical purity using three chromatographic methods

The knowledge of radioactive and stable elements partitioning to natural sediment systems is essential for modelling their environmental fate. A sequential extraction method consisting of six operationally-defined fractions has been developed for determining the geochemical partitioning of natural (U, Th, ⁴⁰K) and antropogenic (Pu, ²⁴¹Am, ¹³⁷Cs) radionuclides in a 10 cm deep sediment sample collected in the Tyrrhenian sea (Gaeta Gulf, Italy) in front of the Garigliano Nuclear Power Plant. ¹³⁷Cs and ⁴⁰K were measured by gamma-spectrometry. Extraction chromatography with Microthene-TOPO (U, Th), Microthene-TNOA (Pu) and Microthene-HDEHP (Am) was used for the chemical separation of the alpha-emitters: after electrodeposition alpha-spectrometry was carried out. Some stable elements (Fe, Mn, Al, Ca, Pb, Ba, Ti, Sr, Cu, Ni) were also determined in the different fractions to get more information about the chemical association of the radionuclides.     

Biosorptive behavior of some dead biomasses in the removal of Sr(85+89) from aqueous solutions

The knowledge of radioactive and stable elements partitioning to natural sediment systems is essential for modelling their environmental fate. A sequential extraction method consisting of six operationally-defined fractions has been developed for determining the geochemical partitioning of natural (U, Th, ⁴⁰K) and antropogenic (Pu, ²⁴¹Am, ¹³⁷Cs) radionuclides in a 10 cm deep sediment sample collected in the Tyrrhenian sea (Gaeta Gulf, Italy) in front of the Garigliano Nuclear Power Plant. ¹³⁷Cs and ⁴⁰K were measured by gamma-spectrometry. Extraction chromatography with Microthene-TOPO (U, Th), Microthene-TNOA (Pu) and Microthene-HDEHP (Am) was used for the chemical separation of the alpha-emitters: after electrodeposition alpha-spectrometry was carried out. Some stable elements (Fe, Mn, Al, Ca, Pb, Ba, Ti, Sr, Cu, Ni) were also determined in the different fractions to get more information about the chemical association of the radionuclides.     

Distribution of3H,137Cs and239,240Pu in the surface seawater around Korea

The concentrations of³H,¹³⁷Cs and^239,240Pu were determined in surface seawaters collected at 21 sampling stations around Korea from October of 1994 to May of 1995. The results were consistent with the past data observed in the North Pacific. The concentrations of³H and¹³⁷Cs did not show much difference no matter where the samples were taken. Due to the limited distribution of sampling points, no systematic change in³H and¹³⁷Cs levels with latitude was observed. On the other hand,^239,240Pu concentration in the East Sea (Japan Sea) was somewhat higher than that in the South and the Yellow Seas, although the data on^239,240Pu concentration were not enough to explain the reason. The activity ratios of^239,240Pu/¹³⁷Cs in surface seawater ranged from 0.13% to 0.44% with a mean of 0.25±0.08%. The activity ratios were lower than those of the global fall-out level, 1.1%. This result presumably arose from the different behavior of the two radionuclides in seawater.     

Determination of137Cs,90Sr and fallout Pu in the volcanic soil of Korea

The cumulative depositions of¹³⁷Cs,⁹⁰Sr and fallout Pu in the volcanic ash soil of Korea were determined. The average accumulated depositions of¹³⁷Cs,⁹⁰Sr and fallout Pu in the volcanic soil were much higher than those in other forest sites of Korea. From depth profiles, it was found that¹³⁷Cs,⁹⁰Sr and^239,240Pu in the volcanic soil are more mobile than those in other forest sites of Korea, and that the downward movement of⁹⁰Sr is faster than¹³⁷Cs and^239,240Pu. A significant correlation was found between the concentration of¹³⁷Cs and those of⁹⁰Sr and^239,240Pu. The activity ratios of²³⁸Pu/^239,240Pu and²⁴¹Pu/^239,240Pu in soils are close to those observed in the cumulative deposit from the global fallout of nuclear weapon testings.