• The Journal of the Petrological Society of Korea
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• v.23 no.3
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• pp.249-259
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• 2014

Proxies for paleo-circulation are drawing much interest with the recognition that ocean circulation plays an important part in the redistribution of heat and climate change on orbital and millennial timescales. In this review, we will introduce how neodymium isotope ratios of the authigenic fraction of marine sediments can be used as a proxy for ocean circulation along with analytical methods and two case studies. The first case study shows how the North Atlantic Deep Water (NADW) has varied over the glacial-interglacial and stadial-interstadial periods. The second case study shows how the freshwater budget and water circulation within the Arctic Ocean can be reconstructed for the last glacial period.

• Nuclear Engineering and Technology
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• v.47 no.7
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• pp.924-933
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• 2015

The correlation of the isotopic composition of uranium, plutonium, neodymium, and cesium with the burnup for high burnup pressurized water reactor fuels irradiated in nuclear power reactors has been experimentally investigated. The total burnup was determined by Nd-148 and the fractional $^{235}U$ burnup was determined by U and Pu mass spectrometric methods. The isotopic compositions of U, Pu, Nd, and Cs after their separation from the irradiated fuel samples were measured using thermal ionization mass spectrometry. The contents of these elements in the irradiated fuel were determined through an isotope dilution mass spectrometric method using $^{233}U$, $^{242}Pu$, $^{150}Nd$, and $^{133}Cs$ as spikes. The activity ratios of Cs isotopes in the fuel samples were determined using gamma-ray spectrometry. The content of each element and its isotopic compositions in the irradiated fuel were expressed by their correlation with the total and fractional burnup, burnup parameters, and the isotopic compositions of different elements. The results obtained from the experimental methods were compared with those calculated using the ORIGEN-S code.

• Nuclear Engineering and Technology
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• v.29 no.4
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• pp.327-335
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• 1997

The correlation of isotope composition of uranium, plutonium and neodymium with the burnup in M uranium dioxide fuel has been investigated experimentally. The total and fractional($^{235}$ U) burnup were determined by Nd-148 and, U and Pu mass spectrometric method respectively. The isotope compositions of these elements, after their separation from the fuel samples were measured by mass spectrometric. The content of the elements in the irradiated fuel ore determined by isotope dilution mass spectrometric method using $^{233}$ U, $^{242}$ Pu and $^{150}$ Nd as spikes. The content of plutonium in the irradiated fuel was expressed by the correlation with uranium isotopes. The correlations between isotope compositions themselves and the total and fractional burnup ore compared with those calculated from ORIGEN2 code.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2017.05a
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• pp.67-68
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• 2017

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2017.10a
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• pp.373-374
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• 2017

• Proceedings of the Korean Nuclear Society Conference
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• 2005.05a
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• pp.321-322
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• 2005

• Ocean and Polar Research
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• v.45 no.2
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• pp.89-102
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• 2023

Climate and environmental changes in the Arctic Ocean due to global warming have been linked to extreme climate change in mid-latitude regions, including the Korean Peninsula, requiring a better understanding of the Arctic climate system based on the paleo-analog. This review introduces three paleoenvironmental research cases using neodymium isotopes (¹⁴³Nd/¹⁴⁴Nd, ε_Nd) measured on two different fractions of marine sediments: silicate-bound 'detrital' and Fe-Mn oxide-dominated 'authigenic' fractions. In the first case, detrital ε_Nd in core HH17-1085-GC on the continental shelf off northern Svalbard was used for tracing changes in sediment provenance and associated glacier behavior over the last 16.3 ka. The second case showed the potential use of authigenic ε_Nd as a quasi-conservative water mass tracer. Three prominent ε_Nd peaks and troughs observed in core PS72/410-1 from the Mendeleev Ridge in the western Arctic Ocean over the past 76 ka suggested episodic meltwater discharge events during 51~46, 39~35 and 21~13 ka BP. The last case proposed the use of the difference between authigenic and detrital ε_Nd as a proxy for reconstructing glacier fluctuation. The idea is based on the assumption that enhanced glacial erosion during glacier advances can supply sufficient freshly-exposed rock substrate for incongruent weathering, potentially leading to greater isotopic decoupling between bedrock and dissolved weathering products as recorded in detrital and authigenic ε_Nd, respectively. Thus, it would be worthwhile to take advantage of sedimentary ε_Nd to improve our understanding of past environmental changes in polar regions.

• Nuclear Engineering and Technology
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• v.33 no.4
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• pp.375-385
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• 2001

The total burnup in the spent U$_3$Si/Al fuel samples from Hanaro reactor was determined by destructive methods using $^{148}$ Nd, the sum of $^{143}$ Nd and $^{144}$ Nd, the sum of $^{145}$ Nd and $^{146}$ Nd, and the sum of total Nd isotopes($^{143}$ Nd, $^{144}$ Nd, $^{145}$ Nd, $^{146}$ Nd, $^{148}$ Nd and $^{150}$ Nd) monitors. The fractional($^{235}$ U) turnup in the spent fuel samples was also determined by U and Pu mass spectrometric method. The samples were dissolved in a mixture of 4 M HCI and 10 M HNO$_3$ without any catalyst. The separation of U, Pu and Nd from the spiked and unspiked sample solutions was achieved by two sequential anion exchange separation methods. The isotope compositions of these elements, after their separation from the fuel samples were measured by mass spectrometry. The contents of the elements in the spent fuel samples were determined by isotope dilution mass spectrometric method(IDMS) using $^{233}$ U, $^{242}$ Pu and $^{150}$ Nd as spikes. The effective fission yield was calculated from the weighted fission yields averaged over the irradiation period. The difference between total turnup values determined by various Nd monitors were in the range of 1.8%.

• Nuclear Engineering and Technology
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• v.25 no.2
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• pp.259-264
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• 1993

Ion chromatographic method has been applied for burnup measurement of irradiated nuclear fuel by dynamic system using 1-octanesulfonate as a cation exchanger and $\alpha$-hydroxyisobutyric acid as an eluant. A number of elution techniques were evaluated for the optimum separation of plutonium, uranium and neodymium. These elements were individually separated and collected by gradient elution between 0.05 M and 0.40 M of $\alpha$-hydroxyisobutyric acid in a single column, and finally determined by isotope dilution mass spectrometry. The burnup data from this method were compared with those from conventional anion exchange method. The results showed a good agreement within 3.5 % of difference between two methods.

• Economic and Environmental Geology
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• v.41 no.3
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• pp.315-326
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• 2008

Recently, the occurrence and intensity of Asian Dust have dramatically increased in Korean peninsula, resulting in severe damages to the domestic social and economic field. The most useful way to prevent the damage of Asian Dust is the restraint of the occurrence of Asian Dust itself. However, Asian dust is the one of the natural phenomena, thus there is a basic limit to manage the Asian Dust. Though it is impossible to restrain the occurrence of Asian Dust in short time at present, it is a urgent matter to minimize the damage of Asian Dust. It is necessary to construct the basic data for understanding the harmfulness of Asian Dust, and to elucidate the source area of Asian Dust in connection with the maleficence of itself. In this study, the source area of Asian Dust in spring, 2007, is investigated using the Sr-Nd isotopic ratios which is the most common method to trace the source of geological materials. The relationships of Sr-Nd isotope ratios indicate that Asian Dust was originated from Central Loess Plateau and/or Ordos desert in spring, 2007.