• Nuclear Engineering and Technology
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• v.49 no.4
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• pp.760-768
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• 2017

The transition temperature shift (TTS) of the reactor pressure vessel materials is an important factor that determines the lifetime of a nuclear power plant. The prediction of the TTS at the end of a plant's lifespan is calculated based on the equation of Regulatory Guide 1.99 revision 2 (RG1.99/2) from the US. The fluence factor in the equation was expressed as a power function, and the exponent value was determined by the early surveillance data in the US. Recently, an advanced approach to estimate the TTS was proposed in various countries for nuclear power plants, and Korea is considering the development of a new TTS model. In this study, the TTS trend of the Korean surveillance test results was analyzed using a nonlinear regression model and a mixed-effect model based on the power function. The nonlinear regression model yielded a similar exponent as the power function in the fluence compared with RG1.99/2. The mixed-effect model had a higher value of the exponent and showed superior goodness of fit compared with the nonlinear regression model. Compared with RG1.99/2 and RG1.99/3, the mixed-effect model provided a more accurate prediction of the TTS.

• Proceedings of the Korean Nuclear Society Conference
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• 2004.10a
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• pp.329-330
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• 2004

• Mass Spectrometry Letters
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• v.7 no.2
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• pp.50-54
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• 2016

Multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS) is currently used in our laboratory for isotopic and quantitative analyses of nuclear materials at ultra-trace levels in environmental swipe samples, which is a very useful for monitoring undeclared nuclear activities. In this study, to improve measurement precisions of uranium isotopes at ultratrace levels, we adopted a desolvating nebulizer system (Aridus-II, CETAC., USA), which can improve signal sensitivity and reduce formation of uranium hydride. A peristaltic pump was combined with Aridus-II in the sample introduction system of MC-ICP-MS to reduce long-term signal fluctuations by maintaining a constant flow rate of the sample solution. The signal sensitivity in the presence of Aridus-II was improved more than 10-fold and the formation ratio of UH/U decreased by 16- to 17- fold compared to a normal spray chamber. Long-term signal fluctuations were significantly reduced by using the peristaltic pump. Detailed optimizations and evaluations with uranium standards are also discussed in this paper.

• Proceedings of the Korean Nuclear Society Conference
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• 2004.10a
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• pp.1393-1394
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• 2004

• Proceedings of the Korean Nuclear Society Conference
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• 2004.10a
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• pp.1111-1112
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• 2004

• Proceedings of the Korean Nuclear Society Conference
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• 2005.05a
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• pp.1170-1171
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• 2005

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2016.05a
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• pp.167-168
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• 2016

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2017.05a
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• pp.383-384
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• 2017

• Journal of Radiation Protection and Research
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• v.26 no.3
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• pp.191-195
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• 2001

An accurate and simple analytical technique for low levels of fallout Pu in the environment was developed using an anion exchange resin. To develop the reliable determination of Pu isotopes in soil samples, decomposition of soil matrix, plutonium oxidation state adjustment on the anion exchange column and source preparation of Pu isotopes have been carried out. The optimum method of Pu isotopes with an anion exchange has been validated by application to IAEA-Reference soils.

• Journal of Radiation Protection and Research
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• v.26 no.3
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• pp.249-253
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• 2001

Neutron dose assessment in criticality accidents using Whole Body Counter (WBC) was proved to be an effective method as rapid neutron dose estimation at the JCO criticality accident in Tokai-mura. The 1.36MeV gamma-ray of $^{24}Na$ in a body can be detected easily by a germanium detector. The Minimum Detectable Activity (MDA) of $^{24}Na$ is approximately 50Bq for 10miniute measurement by the germanium-type whole body counter at JNC Tokai Works. Neutron energy spectra at the typical shielding conditions in criticality accidents were calculated and the conversion factor, whole body activity-to-organ mass weighted neutron absorbed dose, corresponding to each condition were determined. The conversion factor for uncollied fission spectrum is 7.7 $[(Bq^{24}Na/g^{23}Na)/mGy]$.