• Nuclear Engineering and Technology
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• 제43권6호
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• pp.583-592
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• 2011

The radiological characteristics for waste classification were assessed for neutron-activated decommissioning wastes from a CANDU reactor. The MCNP/ORIGEN2 code system was used for the source term analysis. The neutron flux and activation cross-section library for each structural component generated by MCNP simulation were used in the radionuclide buildup calculation in ORIGEN2. The specific activities of the relevant radionuclides in the activated metal waste were compared with the specified limits of the specific activities listed in the Korean standard and 10 CFR 61. The time-average full-core model of Wolsong Unit 1 was used as the neutron source for activation of in-core and ex-core structural components. The approximated levels of the neutron flux and cross-section, irradiated fuel composition, and a geometry simplification revealing good reliability in a previous study were used in the source term calculation as well. The results revealed the radioactivity, decay heat, hazard index, mass, and solid volume for the activated decommissioning waste to be $1.04{\times}10^{16}$ Bq, $2.09{\times}10^3$ W, $5.31{\times}10^{14}\;m^3$-water, $4.69{\times}10^5$ kg, and $7.38{\times}10^1\;m^3$, respectively. According to both Korean and US standards, the activated waste of the pressure tubes, calandria tubes, reactivity devices, and reactivity device supporters was greater than Class C, which should be disposed of in a deep geological disposal repository, whereas the side structural components were classified as low- and intermediate-level waste, which can be disposed of in a land disposal repository. Finally, this study confirmed that, regardless of the cooling time of the waste, 15% of the decommissioning waste cannot be disposed of in a land disposal repository. It is expected that the source terms and waste classification evaluated through this study can be widely used to establish a decommissioning/disposal strategy and fuel cycle analysis for CANDU reactors.

• Nuclear Engineering and Technology
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• 제54권3호
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• pp.959-964
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• 2022

Lead is an important material, both for fusion or fission reactors. The cross sections of natural lead should be validated because lead is a main component of lithium-lead modules suggested for fusion power plants and it directly affects the crucial variable, tritium breeding ratio. The presented study discusses a validation of the lead transport libraries by dint of the activation of carefully selected activation samples. The high emission standard ²⁵²Cf neutron source was used as a neutron source for the presented validation experiment. In the irradiation setup, the samples were placed behind 5 and 10 cm of the lead material. Samples were measured using a gamma spectrometry to infer the reaction rate and compared with MCNP6 calculations using ENDF/B-VIII.0 lead cross sections. The experiment used validated IRDFF-II dosimetric reactions to validate lead cross sections, namely ¹⁹⁷Au(n, 2n)¹⁹⁶Au, ⁵⁸Ni(n,p)⁵⁸Co, ⁹³Nb(n, 2n)^92mNb, ¹¹⁵In(n,n')^115mIn, ¹¹⁵In(n,γ)^116mIn, ¹⁹⁷Au(n,γ)¹⁹⁸Au and ⁶³Cu(n,γ)⁶⁴Cu reactions. The threshold reactions agree reasonably with calculations; however, the experimental data suggests a higher thermal neutron flux behind lead bricks. The paper also suggests ²⁵²Cf isotropic source as a valuable tool for validation of some cross-sections important for fusion applications, i.e. reactions on structural materials, e.g. Cu, Pb, etc.

• Analytical Science and Technology
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• 제16권5호
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• pp.1041-1051
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• 2003

Neutron induced prompt gamma activation analysis (PGAA) offers a nondestructive, sensitive and relatively rapid method for the determination of trace and major elements and is proven to be convenient for online analysis of minerals, metals, coal, cement, petrochemical, coating, paper as well as many other materials and products. The technique has found many uses in medicine, industry, research, security and the detection of contraband items. This report reviews the present status and future trends of the PGAA techniques. Requirements for the system are neutron source, high resolution HPGe detectors with a high-voltage power supply, an amplifier, analog-to-digital converter, and a multichannel analyzer for the detection and measurement of prompt ${\gamma}$-ray emit form the neutron capture elements. Introducing a ${\gamma}$-${\gamma}$ coincidence system also improves the quality of the ${\gamma}$-ray spectrum by suppressing the background created from the Compton scattering of high energy prompt ${\gamma}$-rays. A PGAA system using a $^{252}Cf$ neutron source is currently under construction for the on-line measurement of several elements in aqueous samples at KAERI. The system can be applied for the detection of chemical weapons and explosives as well as various narcotics.

• Journal of Radiation Protection and Research
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• 제24권4호
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• pp.231-233
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• 1999

This report will introduce the epitome about the subject, HANARO (Hi-flux Advanced Neutron Application Reactor designed by KAERI in early 1995) Utilization Education Training Program Development and Operation, which is one of the nuclear research basic expansion businesses executed from 1999. 12. to strengthen the usage of HANARO. This program consists of the basic reactor experiments program for university students who have specialty of nuclear and other engineering, and the special research education program for faculties from universities and researchers from industrial fields. Principle lessons are reactor operation, radioisotope production, neutron activation analysis, neutron radiography, radiation shield (health physics), nuclear fuel combustion measurement by gamma scanning arrangement, and CNS (Compact Nuclear Simulator) and so on.

• Nuclear Engineering and Technology
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• 제2권2호
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• pp.85-95
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• 1970

An attempt has been made to do interpretation of the fast neutron dose with two threshold detectors incorporated with the Harwell criticality locket. This method is based on the assumption that the spectral distribution of fission neutrons in criticality accidents may be governed by one spectral parameter. The surface-absorbed dose for a unit fission neutron fluence seems to be insensitive to spectral shifts of the fission neutron spectrum. The average cross-sections for the activation detectors, however, are considerably changed with the neutron spectral shape, which may lead to a large error in calculating the dose from the reaction rate if one uses a fixed value for the average cross sections regardless of the neutron spectral distribution. Besides, the doses calculated from three representative formulae for fission neutron spectra have been compared : these formulae are Watt, Cranberg at al. and Maxwellian forms. The results obtained front the Maxwellian formula show a departure from the Watt and Cranberg's, both being similarly close.

• Journal of the Korean Vacuum Society
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• 제14권3호
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• pp.132-137
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• 2005

Neutron reflectometer has been installed at HANARO, research reactor in Korea. It has vertical sample geometry and the wavelength of incident neutron beam is $2.459\;\AA$ Neutron fluxes at monochromator and sample position were $4.5\times10^9\;n/cm^2/sec,\;6.64\times10^6\;n/cm^2/sec4 those were measured by gold wire activation method. Also, some reference thin films such as d-PS, $SiO_2$ were measured and analyzedwith HANARO neutron reflectometer. As result of the work, it was certified that minimum reflectivity and available Q range were $10^{-6},\;and\;0.003\sim0.3\;\AA^{-1}$ respectively.

• 한국문화재보존과학회:학술대회논문집
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• 한국문화재보존과학회 2006년도 제24회 학술대회발표 논문집
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• pp.73-80
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• 2006

• Proceedings of the Korean Nuclear Society Conference
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• 한국원자력학회 2004년도 추계학술발표회 발표논문집
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• pp.1465-1466
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• 2004

• Proceedings of the Korea Air Pollution Research Association Conference
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• 한국대기환경학회 2004년도 추계학술대회 논문집
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• pp.345-346
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• 2004

• Proceedings of the Korean Nutrition Society Conference
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• 한국영양학회 2002년도 추계학술대회 및 총회
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• pp.103-103
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• 2002