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Abstract  

A procedure has been developed using 242Pu as tracer for simultaneous determination of 237Np and 239,240Pu in environmental samples. The validity of the method has been demonstrated by ICPMS and a-spectroscopy for up to 10 gram soil and sediment, seawater up to 200 litres. The paper describes a suitable chemical procedure for Np and Pu including a quantitative pre-concentration of neptunium and plutonium, preparation of Np4+ and Pu4+, Np(NO3)6 2- and Pu(NO3)6 2-. The ratio of 237Np/242Pu (or 237Np/239Pu) before and after the procedure has been determined using 10 g soil (free from Np and Pu) R before/R after = 1.004±3.3% (S.D n = 20) and 1 litre seawater R before/R after = 1.019±1.9% (S.D., n = 12). Results from the intercomparison samples IAEA-135, IAEA-381 and from environmental samples are presented.

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Abstract  

Neutron activation analysis combined with a simple exchange pre-separation is described for the determination of iodide and iodate in liquid samples. Iodide and iodate in seawater were separated by passing natural seawater through a small AGI-x4 ion exchange column. The effluent and washings of water were collected, acidified to pH 1.0, KHSO3 was added to the effluent to reduce IO3 to I, and the effluent was passed through a new column. By eluting with diluted KNO3 solution and de-ionized water to remove Br, Cl and other ions, the columns were directly irradiated for the determination of iodide and iodate. For urine and milk, inorganic iodide was separated and determined by directly passing sample through the exchange column and washing. Under these experimental conditions, 10 ng is the detection limit for iodine.

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Abstract  

The title method was successfully used for collecting239,249Pu from 200 litres of seawater by coprecipitation with 16 g FeSO4·7H2O under redcing conditions witout filtering. The plutonium is leached by concentrate HNO3+HCl from the coprecipitate and the solid particles. The precipitate is heated at 400°C and digested in aqua regia. Na2SO3 and NaNO2 have been applied to obtain the Pu4+ valence state in 0.5–1N HNO3 for different samples. Plutonium and thorium are coadsorbed on anionic resin from 8N HNO3. The column is eluted with 8N HNO3 containing fresh NaNO2 to keep the Pu4+ state for uranium decontaination. The system of the column is changed from 8N HNO3 to concentrated HCl with 50 ml concentrated HCl containing a few milligrams of NaNO2. Furtheer decontaimination of torium was achieved by elution with concentrated HCl instead of 9N HCl. The plutonium is successfully stripped by H2O, NaOH, 2N HNO3 and 0.5N HNO3 containign 0.01M NaNO3. The chemica yield of plutonium for a 2001 seawate sample is 60–80%. The resolution of the electroplated thin source is very good.

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Abstract  

Distribution coefficients of technetium and ruthenium are determined under different conditions with CCl4, cyclohexanone, and 5% tri-isooctylamine (TIOA)/xylene. A method for analyzing99Tc in environmental samples has been developed by solvent extraction in which the valences of technetium and ruthenium are controlled with H2O2 and NaClO. Technetium and ruthenium which are oxidized to TcO 4 and RuO 4 by NaClO are separated by extraction with CCl4 at pH 4. The RuO 4 is reduced to low valence and technetium is kept in the TcO 4 state with H2O2. Technetium, ruthenium, and other nuclides are subsequently separated by solvent extraction with cyclohexanone and 5% TIOA/xylene. The decontamination of the procedure is 1.35·105 for103Ru and 1.66·105 for110mAg. The chemical yield of technetium-99 is 55%.

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Abstract  

In 1968 a U.S. B-52 bomber from USA with four nuclear weapons crashed on the sea ice near the Thule air base and contaminated the surroundings. Most of contamination was recovered during the cleanup program. However, some of the plutonium still remains in the bottom sediments of the area. In 1997 an international expedition with a comprehensive sampling program was performed. A lot of sediment samples were taken with a Finnish Gemini corer. Sediment samples from 5 sampling stations, 80 samples altogether, were pretreated in Ris, Denmark, and analysed for transuranic elements at STUK, Finland. The samples were analysed primarily for Pu, but gamma-spectrometric measurements of 241Am were also made. Generally, the Pu concentrations in the area studied were from 1 to 3 magnitudes higher than the fallout level in the Arctic sea area. None of the vertical profiles of Pu at the various stations showed a typical Pu peak originating from the accident in 1968, but the sediments were mixed down and contaminated to the depths studied (20 cm). The presence of large quantities of hot particles distorted the estimations of mean concentrations and inventories. Samples with plutonium from the accident show significant variations of nuclide ratios, 238Pu/239,240Pu, 241Pu/239,240Pu and 241Pu/241Am. This indicates that Pu at Thule may be from more than one source of different quality.

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Journal of Radioanalytical and Nuclear Chemistry
Authors:
A. Aarkrog
,
S. Boelskifte
,
H. Dahlgaard
,
S. Duniec
,
E. Holm
, and
J. Smith

Abstract  

Since the accidental loss of four nuclear weapons by a B-52 at Thule Airbase, Greenland in 1968, the marine environment at Thule has showed enhanced levels of Pu and Am. Most of the activity is confined to the benthic environment within a distance of 50 km from the crash site of the B-52. Samplings of sediments, benthos, seaplants, fish, and water have been carried out in 1968, 1970, 1974, 1979, and in 1984. The study presented herein intends to answer the following questions: What is the mean residence time of these transuranics in the benthic communities? Do Pu and Am behave differently in the environment?

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Journal of Radioanalytical and Nuclear Chemistry
Authors:
P. Povinec
,
M. Pham
,
J. Sanchez-Cabeza
,
G. Barci-Funel
,
R. Bojanowski
,
T. Boshkova
,
W. Burnett
,
F. Carvalho
,
B. Chapeyron
,
I. Cunha
,
H. Dahlgaard
,
N. Galabov
,
L. Fifield
,
J. Gastaud
,
J. Geering
,
I. Gomez
,
N. Green
,
T. Hamilton
,
F. Ibanez
,
M. Ibn Majah
,
M. John
,
G. Kanisch
,
T. Kenna
,
M. Kloster
,
M. Korun
,
L. Liong Wee Kwong
,
J. La Rosa
,
S. Lee
,
I. Levy-Palomo
,
M. Malatova
,
Y. Maruo
,
P. Mitchell
,
I. Murciano
,
R. Nelson
,
A. Nouredine
,
J. Oh
,
B. Oregioni
,
G. Le Petit
,
H. Pettersson
,
A. Reineking
,
P. Smedley
,
A. Suckow
,
T. van der Struijs
,
P. Voors
,
K. Yoshimizu
, and
E. Wyse

Abstract  

A reference material designed for the determination of anthropogenic and natural radionuclides in sediment, IAEA-384 (Fangataufa Lagoon sediment), is described and the results of certification are presented. The material has been certified for 8 radionuclides (40K, 60Co, 155Eu, 230Th, 238U, 238Pu, 239+240Pu and 241Am). Information values are given for 12 radionuclides (90Sr, 137Cs, 210Pb (210Po), 226Ra, 228Ra, 232Th, 234U, 235U, 239Pu, 240Pu and 241Pu). Less reported radionuclides include 228Th, 236U, 239Np and 242Pu. The reference material may be used for quality management of radioanalytical laboratories engaged in the analysis of radionuclides in the environment, as well as for the development and validation of analytical methods and for training purposes. The material is available from IAEA in 100 g units.

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