• 전기전자학회논문지
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• 제26권3호
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• pp.515-519
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• 2022

본 논문에서는 고감도 보급형 핵종 분석 모듈 개발을 제안한다. 제안하는 측정센서 모듈은 핵종 분석 분해능을 위한 전자부 구동회로, 핵종 분석 기능이 적용된 시제품 제작, 시제품에 적용되는 GUI 개발 등으로 구성된다. 핵종 분석 분해능을 위한 전자부 구동회로는 전자부 구동 회로 블록도에 의한 핵종 분석 분해능 과정, 방사선 측정에 사용되는 MCU 회로 설계, Spectrum 취득용 PC 프로그램 설계 등으로 나뉘어진다. 핵종 분석 기능이 적용된 시제품 제작은 128×128 픽셀의 OLED display, 조작을 위한 3개의 버튼, Li-ion 배터리, 배터리 충전을 위한 USB-C Type 포트의 구성을 추가하여 제작한다. 시제품에 적용되는 GUI 개발부는 현재시간, 측정 경과 시간, 토탈 카운트, 핵종 Spectrum 등의 화면구성으로 개발한다. 제안된 측정센서 모듈의 성능을 평가하기 위하여 공인기관 전문가 입회시험을 시행한 결과, 핵종 분석 장치에 Cs-137 표준선원을 이용하여 취득한 Spectrum(FWHM@662keV)으로 분해능 공식을 적용하여 계산한 결과가 17.77%의 분해능을 가짐이 확인되었다. 따라서, 제안된 본 논문에서 제안한 핵종 분석 분해능 방법이 기존의 상용의 핵종 분석 모듈보다 저렴하면서도 향상된 성능이 산출됨이 확인되었다.

• Nuclear Engineering and Technology
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• 제44권7호
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• pp.781-790
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• 2012

The HyperGam program was developed for the analysis of complex HPGe ${\gamma}$-ray spectra. The previous version of HyperGam was mainly limited to the analysis of ${\gamma}$-ray peaks and the manual logging of the result. In this study, it is specifically developed into a tool for the isotopic analysis of spectra. The newly developed features include nuclide identification and activity determination. An algorithm for nuclide identification was developed to identify the peaks in the spectrum by considering the yield, efficiency, energy and peak area for the ${\gamma}$-ray lines emitted from the radionuclide. The detailed performance of nuclide identification and activity determination was accessed using the IAEA 2002 set of test spectra. By analyzing the test spectra, the numbers of radionuclides identified truly (true hit), falsely (false hit) or missed (misses) were counted and compared with the results from the IAEA 2002 tests. The determined activities of the radionuclides were also compared for four test spectra of several samples. The result of the performance test is promising in comparison with those of the well-known software packages for ${\gamma}$-ray spectrum analysis.

• Nuclear Engineering and Technology
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• 제50권7호
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• pp.1120-1130
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• 2018

An analysis of a pyroprocessing safeguards methodology employing the Pu-to-$^{244}Cm$ ratio is presented. The analysis includes characterization of representative used nuclear fuel assemblies with respect to computed nuclide composition. The nuclide composition data computationally generated is appropriately reformatted to correspond with the material conditions after each step in the head-end stage of pyroprocessing. Uncertainty in the Pu-to-$^{244}Cm$ ratio is evaluated using the Geary-Hinkley transformation method. This is because the Pu-to-$^{244}Cm$ ratio is a Cauchy distribution since it is the ratio of two normally distributed random variables. The calculated uncertainty of the Pu-to-$^{244}Cm$ ratio is propagated through the mass flow stream in the pyroprocessing steps. Finally, the probability of Type-I error for the plutonium Material Unaccounted For (MUF) is evaluated by the hypothesis testing method as a function of the sizes of powder particles and granules, which are dominant parameters to determine the sample size. The results show the probability of Type-I error is occasionally greater than 5%. However, increasing granule sample sizes could surmount the weakness of material accounting because of the non-uniformity of nuclide composition.

• Nuclear Engineering and Technology
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• 제21권4호
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• pp.302-307
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• 1989

방사성폐기물 저장용기에 생긴 결함으로부터의 핵종유출을 분석하였다. 결함은 부식이나 균열으로부터 기인하며 저장용기의 재질이나 부식 부산물층을 관통하게 된다. 본 연구는 결함을 통한 핵종의 이동을 다루었으며 결함이 생기게 되는 방법에 관해서는 고려하지 않았다. 다수의 작은 결함으로부터의 핵종유출이 중요하며 저장용기가 없다고 가정한 폐기물고화체로부터의 핵종유출과 거의 비슷함을 보여준다. 비록 부분적으로 파손된 저장용기일지라도 핵종유출에 대하여서 장기간에 걸쳐 중요한 방벽의 역할을 하지만, 작은 결함의 수가 많아지면 방벽으로서의 효과가 줄어들게 된다.

• Nuclear Engineering and Technology
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• 제54권10호
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• pp.3878-3887
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• 2022

For the future energy-mix policy for carbon neutrality, demand for the capability of load-follow operation has emerged in nuclear power plants in order to accommodate the intermittency of renewable energy. The short-term decay heat analysis is also required to evaluate the decay heat level varied by the power level change during the load-follow operation, which is a very important parameter in terms of short-term decay heat removal during a grace time. In this study, the short-term decay heat level for 10 days after the shutdown was evaluated for both seasonal and daily load-follow cases. Additionally, the nuclide-wise contribution to the accumulated decay heat for 10 days was analyzed for further understanding of the short-term decay heat behavior. The result showed that in the seasonal case, the decay heat level was mainly determined by the power level right before the shutdown and the amount of each nuclide was varied with the power variation due to the long variation interval of 90 days. Whereas, in the daily case, the decay heat level was strongly impacted by the average power level during operation and meaningful mass variations for those nuclides were not observed due to the short variation interval of 0.5 days.

• 대한방사선기술학회지:방사선기술과학
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• 제44권4호
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• pp.351-358
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• 2021

This research project is a program promoted to seek diversification of domestic radioactive waste analysis institutions, and seeks public development, win-win cooperation, and cooperation between the entrusted institution and the entrusted institution. Accordingly, the entrusted institution established a standard analysis procedure for establishing a quality control system for radioactivity analysis, establishing a radiation control zone, obtaining KOLAS accreditation, and performing proficiency tests, which are the performance ranges requested by the entrusted institution, and intersecting the radioactive isotope waste generated at the actual site. Verification was performed to confirm the analysis quality. In addition, facilities and equipment for radioactivity analysis were supplemented and expanded, and the basic technology foundation and technical skills were secured through securing professional technicians and education/training. It is judged that the entrusted institution will contribute to securing radiation safety through the smooth execution of treatment, disposal, and transportation through value creation and analysis of radioactive waste generated by radioactive isotope-using institutions (research institutes, hospitals, industries, etc.) by succeeding in this research project do.

• 한국방사선학회논문지
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• 제5권1호
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• pp.5-10
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• 2011

검출한계에 대한 기본개념을 기초로 백그라운드 측정시간과 시료측정시간을 고려하였고, 환경시료중에서 육상시료(하천토, 표층토양, 식수, 지하수, 지표수, 솔잎, 쑥) 분석에서 백그라운드 계측시간과 시료 측정시간의 변화에 따른 MDA 값들을 비교하였다. 물시료 분석결과를 살펴보면 대부분 시료에서 불검출로 나타났으며, 육상시료 분석결과 대부분의 시료에서 "과학기술부고시 제 2008-28호"의 검출하한치 미만으로 측정되었으나, 일부 시료에서는 인공방사성핵종인 $^{137}Cs$이 검출되었다. 이는 과거 50.60년대 행해졌던 대기권 핵실험에 의한 낙진 및 소련의 체르노빌 원전사고 등에 의한 영향으로 우리나라뿐만 아니라 전 세계적으로 검출되고 있는 수준이다. 또한 $^{137}Cs$의 동위원소이며, 상대적으로 반감기가 짧은 $^{134}Cs$가 모든 시료에 대해서 검출되지 않는 것으로 보아 원전운영에 의한 영향이 아님을 알 수 있다.

• 대한방사선기술학회지:방사선기술과학
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• 제43권6호
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• pp.481-487
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• 2020

Radiation measurement technology has steadily improved and its usage is expanding in various industries such as nuclear medicine, security search, satellite, nondestructive testing, environmental industries and the domain of nuclear power plants (NPPs). Especially, the simultaneous measurements of gamma rays and neutrons can be even more critical for nuclear safety management of spent nuclear fuel and monitoring of the nuclear material. A semiconductor detector comprising cadmium, zinc, and tellurium (CZT) enables to detect gamma-rays due to the significant atomic weight of the elements via immediate neutron and gamma-ray detection. Semiconductor sensors might be used for nuclear safety management by monitoring nuclear materials and spent nuclear fuel with high spatial resolution as well as providing real-time measurements. We aim to introduce a portable nuclide-analysis device that enables the simultaneous measurements of neutrons and gamma rays using a CZT sensor. The detector has a high density and wide energy band gap, and thus exhibits highly sensitive physical characteristics and characteristics are required for performing neutron and gamma-ray detection. Portable nuclide-analysis device is used on NPP-decommissioning sites or the purpose of nuclear nonproliferation, it will rapidly detect the nuclear material and provide radioactive-material information. Eventually, portable nuclide-analysis device can reduce measurement time and economic costs by providing a basis for rational decision making.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 2004년도 추계학술발표회 발표논문집
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• pp.621-622
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• 2004

• Nuclear Engineering and Technology
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• 제46권3호
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• pp.313-342
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• 2014

A Nuclear Energy Agency (NEA), Organization for Economic Co-operation and Development (OECD) benchmark for Uncertainty Analysis in Modeling (UAM) is defined in order to facilitate the development and validation of available uncertainty analysis and sensitivity analysis methods for best-estimate Light water Reactor (LWR) design and safety calculations. The benchmark has been named the OECD/NEA UAM-LWR benchmark, and has been divided into three phases each of which focuses on a different portion of the uncertainty propagation in LWR multi-physics and multi-scale analysis. Several different reactor cases are modeled at various phases of a reactor calculation. This paper discusses Phase I, known as the "Neutronics Phase", which is devoted mostly to the propagation of nuclear data (cross-section) uncertainty throughout steady-state stand-alone neutronics core calculations. Three reactor systems (for which design, operation and measured data are available) are rigorously studied in this benchmark: Peach Bottom Unit 2 BWR, Three Mile Island Unit 1 PWR, and VVER-1000 Kozloduy-6/Kalinin-3. Additional measured data is analyzed such as the KRITZ LEU criticality experiments and the SNEAK-7A and 7B experiments of the Karlsruhe Fast Critical Facility. Analyzed results include the top five neutron-nuclide reactions, which contribute the most to the prediction uncertainty in keff, as well as the uncertainty in key parameters of neutronics analysis such as microscopic and macroscopic cross-sections, six-group decay constants, assembly discontinuity factors, and axial and radial core power distributions. Conclusions are drawn regarding where further studies should be done to reduce uncertainties in key nuclide reaction uncertainties (i.e.: $^{238}U$ radiative capture and inelastic scattering (n, n') as well as the average number of neutrons released per fission event of $^{239}Pu$).