Isotopic composition of plutonium in the bottom deposits of the Norwegian Sea and Greenland Sea and identification of the sources of contaminationhearder

The results of measurements of the isotopic atomic ratios²³⁸Pu/²³⁹Pu,²⁴⁰Pu/²³⁹Pu,²⁴¹Pu/²³⁹Pu,²⁴²Pu/²³⁹Pu in samples of bottom deposits are presented. The role of the main sources of plutonium contamination of the region is examined. It is shown that the contribution of the α activity of industrial plutonium (^238–240Pu) in bottom sediments from the European reprocessing plants, mainly, Sellafield (Great Britain), on the background due to global fallouts is 20 to 55% of the total α activity and 70–95% for the β activity (²⁴¹Pu). No escape of reactor and weapons plutonium from the nuclear powered submarine “Komsomolets” into the environment was observed. The lower limit of sensitivity of the method is 10⁻¹⁴g of plutonium in a sample, which corresponds to a plutonium α activity of 0.02 mBq in a 10 g sample of bottom deposits, 4 tables, 26 references. Translated from Atomnaya énergiya, Vol. 87, No. 4, pp. 286–294. October, 1999.     

Isotopic uranium and plutonium analysis by alpha-particle spectrometry

An isotopic uranium analysis of environmental and man-made samples was performed by alpha-particle spectrometry. A fitting technique using blocks of peaks in the spectra measured with silicon detectors was developed. Samples of natural uranium from conventional mines and from the Bangombé natural nuclear reactor were analysed. The isotope composition of depleted and enriched uranium samples was also determined. The technique was applied to determining the isotope composition of plutonium samples, identifying whether the samples were reactor-grade or weapons-grade plutonium. Spectra of soil samples from Palomares and others from an inter-laboratory comparison exercise were analysed, yielding very good results.     

First application of plutonium in soil erosion research on terraces

<正>The spatial distributions of 239+240Pu and 137Cs in soils from Longji Rice Terraces were investigated to evaluate soil erosion.The activity concentrations of 239+240Pu and 137Cs in the surface soils of the paddy fields were in the range of 0.089–0.734 and1.80–7.88 mBq/g, respectively. The activities of 239+240Pu and 137Cs showed very similar distribution trends, first increasing and then decreasing with increasing elevation. The 240Pu/239Pu atom ratios in the surface soils ranged from 0...     

Determination of plutonium in soil and bottom sediments in the region of the scientific-research institute of atomic reactors

Scientific-Industrial Firm The Radium Institute. Scientific-Research Institute of Atomic Reactors, Dimitrovgrad. Translated from Atomnaya Énergiya, Vol. 75, No. 4, pp. 319-324, October, 1993.     

某铀成矿带地下水中同位素组成特征与铀矿找矿标志探讨

鄂尔多斯盆地北部某铀成矿带是近10年发现的大型可地浸砂岩型铀成矿带,诸多生产和研究部门对其成矿地质条件、成矿环境、控矿因素与成矿远景进行了研究,取得了可喜的找矿成果。由于此类矿床属盲矿,其找矿和矿体定位预测有较大的难度。为进一步扩大找矿成果,试图通过同位素水文学的应用,探索铀成矿环境和盲矿找矿的水文地球化学及同位素水文地球化学标志。     

137Cs vertical migration and contamination density in the soil of southern transbaikal

The mechanism of vertical migration of radionuclides along the soil profile is studied. For large averaging, the process can be described by the sum of the rates of effective diffusion and vertical advection of a radionuclide. The results of theoretical calculations of the¹³⁷Cs concentration profiles in light and heavy soils for actually observed atmospheric fallout in 1954–1999 are compared with the experimental profiles in mountain frozen-taiga and mountain frozen-forest tundra soils of southern Transbaikal. The rate of vertical migration is estimated and the reasons for the high¹³⁷Cs contamination density of soil in this region are discussed. 4 figures, 27 references. Scientific and Industrial Association “Taifun.” GP “Sosnovgeolservis.” Translated from Atomnaya énergiya, Vol. 88, No. 3, pp. 207–213, March, 2000.     

Analysis of soil contamination by137Cs in the USSR in 1988

Translated from Atomnaya Énergiya, Vol. 68, No. 4, pp. 262–264, April, 1990.     

Determination of the average137Cs contamination density of soil

Scientific and Industrial Association “Taifun.” Translated from Atomnaya énergiya, Vol. 76, No. 3, pp. 212–217, March, 1994.     

Analysis of the possibilities of the neutron-resonance method of determining the elemental composition of matter

Mathematical modeling of the neutron-resonance method analyzing the elemental and isotopic of matter is performed. The method is based on investigation of γ cascades, emitted by nuclei as a result of the radiative capture of neutrons. Gamma cascades of the determined element (effect) and elements of the matrix (background) are modeled and these cascades are detected with a γ-ray multisectional 4π detector. The response functions of the detector are presented for the case of an analysis of the gold content in a natural medium. It is shown that the introduction, performing together with neutron spectrometry, the spectrometry of γ cascades makes it possible to increase the effect/background ratio by a factor of 100. It is noted that this ratio can be further increased by improving the method used to detect γ cascades and analyzing the results of the measurements.     

Isotopic composition of boron secondary ions as a function of ion-beam fluence

We have examined the effects of target mass on sputtered material using 100 keV argon and neon to sputter an elemental target comprising the two naturally occurring isotopes of boron. At low beam fluences (≈ 1 × 10¹⁵ions/cm²) a light-isotope secondary enhancement is observed relative to steady-state secondary ion yields collected at higher beam fluences. The enhancement (46.1%o for Ne⁺ irradiation and 51.8%o for Ar⁺ irradiation) is large compared to the predictions of analytical theories and is independent of variations in surface potential, chemical effects, and surface impurities. This effect is consistent with an explanation based on an energy and momentum asymmetry in the collision cascade.