• Nuclear Engineering and Technology
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• 제54권6호
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• pp.1982-1990
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• 2022

The purpose of this study was to verify the possibility of fuel rod pattern analysis in a fresh fuel assembly using the Yonsei single-photon emission computed tomography (YSECT) system. The YSECT system consisted of three main parts: four trapezoidal-shaped bismuth germanate scintillator-based 64-channel detectors, a semiconductor-based multi-channel data acquisition system, and a rotary stage. In order to assess the performance of the prototype YSECT, tomographic images were obtained for three representative fuel rod patterns in the 6 × 6 array using two representative image-reconstruction algorithms. The fuel-rod patterns were then assessed using an in-house fuel rod pattern analysis algorithm. In the experimental results, the single-directional projection images for those three fuel-rod patterns well discriminated each fuel-rod location, showing a Gaussian-peak-shaped projection for a single 10 mm-diameter fuel rod with 12.1 mm full-width at half maximum. Finally, we successfully verified the possibility of the fuel rod pattern analysis for all three patterns of fresh fuel rods with the tomographic images obtained by the rotational YSECT system.

• Nuclear Engineering and Technology
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• 제55권12호
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• pp.4591-4596
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• 2023

Single-photon emission computed tomography SPECT image reconstruction methods have a significant influence on image quality, with filtered back projection (FBP) and ordered subset expectation maximization (OSEM) being the most commonly used methods. In this study, we proposed newly-designed adaptive non-blind deconvolution with a structural similarity (SSIM) index that can take advantage of the FBP and OSEM image reconstruction methods. After acquiring brain SPECT images, the proposed image was obtained using an algorithm that applied the SSIM metric, defined by predicting the distribution and amount of blurring. As a result of the contrast to noise ratio (CNR) and coefficient of variation evaluation (COV), the resulting image of the proposed algorithm showed a similar trend in spatial resolution to that of FBP, while obtaining values similar to those of OSEM. In addition, we confirmed that the CNR and COV values of the proposed algorithm improved by approximately 1.69 and 1.59 times, respectively, compared with those of the algorithm involving an inappropriate deblurring process. To summarize, we proposed a new type of algorithm that combines the advantages of SPECT image reconstruction techniques and is expected to be applicable in various fields.

• 한국콘텐츠학회논문지
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• 제14권11호
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• pp.355-361
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• 2014

본 연구의 목적은 필름/증감지 방식에서 사용된 비감도 측정 방식을 이용하여 컴퓨터 방사선영상에서 영상판의 상대적 발광량을 평가하고자 하였다. 비감도 측정을 위한 특성곡선은 균일한 알루미늄으로 구성된 11 계단의 투과도계를 이용하였다. 디지털 방사선영상을 획득하기 위한 X선 조사조건은 50 kVp, 10 mAs로 조절했다. 영상후처리 알고리즘(MUSICA)의 모든 파라메터들은 제로화하여 원본 데이터에 근사화하였고 레이저 조사분류(exposure class)는 200으로 고정하였다. 영상판의 상대적 발광량 모델링은 X선 조사후 0, 4, 8, 12, 24 시간 보관한 영상판을 이용하였다. 그 결과, 컴퓨터 방사선영상시스템의 영상판 비감도 측정에 필요한 감도점 농도는 모든 특성곡선을 상대적으로 측정하기 용이한 2000 픽셀(pixel) 값이 적합하였다. 또한 영상판의 비감도가 저하될 때 영상신호를 생성하기 위한 빛 발광량도 감소하였다. 본 연구에서 제시한 비감도 평가방법은 컴퓨터 방사선영상시스템에서 영상판의 상대적 발광량을 평가할 수 있는 기술로 활용될 수 있을 것이다.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• 제3B권3호
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• pp.115-121
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• 2003

This paper proposes a radiation model, which considers radiation transport as an important component in hot gas analysis. This radiation model is derived from combining the method of partial characteristics (MPC) with net emission coefficient (NEC), and it covers the drawbacks of existing models. Subsequently, using this proposed model, the arc-flow interaction in an arcing chamber can be efficiently computed. The arc is represented as an energy source term composed of ohmic heating and the radiation transport in the energy conservation equation. Ohmic heating term was computed by the electric field analysis within the conducting plasma region. Radiation transport was calculated by the proposed radiation model. Also, in this paper, radiation models were introduced and applied to the gas circuit breaker (GCB) model. Through simulation results, the efficiency of the proposed model was confirmed.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2012년도 춘계 학술논문 발표대회
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• pp.43-45
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• 2012

As a part of recent CO₂ emission reduction studies in the concrete industry with active use of concrete admixtures with low basic unit of CO₂ emission such as blast furnace slag (BFS), basic unit of CO₂ emission by SBFS was computed in order to assess CO₂ emission by reinforced concrete building with smart blast furnace slag (SBFS). In addition, SBFS concrete was applied to the subject building for assessment of CO₂ emission during material production step among construction steps. Life cycle CO₂ emission assessment on the subject building was classified into 7cases according to mix ratio of BFS and SBFS.

• Journal of Radiation Protection and Research
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• 제49권1호
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• pp.29-39
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• 2024

Background: The gamma emission tomography (GET) device has been reported a reliable technique to inspect partial defects within spent nuclear fuel (SNF) of pin-by-pin level. However, the existing GET devices have low accuracy owing to the high attenuation and scatter probability for SNF inspection condition. The purpose of this study is to design and optimize a Yonsei single-photon emission computed tomography version 2 (YSECT.v.2) for fast inspection of SNF in water storage by acquisition of high-quality tomographic images. Materials and Methods: Using Geant4 (Geant4 Collaboration) and DETECT-2000 (Glenn F. Knoll et al.) Monte Carlo simulation, the geometrical structure of the proposed device was determined and its performance was evaluated for the ¹³⁷Cs source in water. In a Geant4-based assessment, proposed device was compared with the International Atomic Energy Agency (IAEA)-authenticated device for the quality of tomographic images obtained for 12 fuel sources in a 14 × 14 Westinghouse-type fuel assembly. Results and Discussion: According to the results, the length, slit width, and septal width of the collimator were determined to be 65, 2.1, and 1.5 mm, respectively, and the material and length of the trapezoidal-shaped scintillator were determined to be gadolinium aluminum gallium garnet and 45 mm, respectively. Based on the results of performance comparison between the YSECT.v.2 and IAEA's device, the proposed device showed 200 times higher performance in gamma-detection sensitivity and similar source discrimination probability. Conclusion: In this study, we optimally designed the GET device for improving the SNF inspection accuracy and evaluated its performance. Our results show that the YSECT.v.2 device could be employed for SNF inspection.

• 한국대기환경학회지
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• 제23권4호
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• pp.440-448
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• 2007

Although the anthracite power plant is an important source of greenhouse gas, research on this type of power plant has not been conducted much. The present study investigated the entire anthracite power plants in Korea and analyzed the emitted gas in connection with GC/FD and a methanizer in order to develop $CO_2$ emission factors. The study also sampled the anthracite to analyze the amount of carbon and hydrogen using an element analyzer, and to measure the calorie using an automatic calorie analyzer. The emission factors computed through the fuel analysis was 30.45 kg/GJ and that computed through the $CO_2$ gas analysis was 26.48 kg/GJ. The former is approximately about 15% higher than the latter. When compared the carbon content factors of anthracite with that of bituminous coal, the value of anthracite was 24% higher Compared with IPCC values, the emission factors by the fuel was 14% higher, and that by the emitted $CO_2$ gas was about 1.2% lower. More research is needed on our own emission factors of various energy-consuming facilities in order to stand on a higher position in international negotiations regarding the treaties on climate changes.

• 대한수의학회지
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• 제52권3호
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• pp.205-208
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• 2012

Endocrine test data from a 13-year old intact female Maltese was indicative of the presence of an insulinoma, however ultrasonography identified a pancreatic mass only after 10 months after the first admission. Following identification of both pancreatic tumor and hepatic metastasis on computed tomography (CT), surgical excision of the mass was attempted. However, total excision failed because of tumor adhesion to adjacent large vessels. The pancreatic mass was monitored over the next 25 months via ultrasonography, CT, and positron emission tomography-computed tomography (PET-CT). Histopathological and immunohistochemical data confirmed the diagnosis of insulinoma with hepatic metastasis.

• Investigative Magnetic Resonance Imaging
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• 제20권4호
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• pp.259-263
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• 2016

Primary diffuse large B-cell lymphoma of the seminal vesicle is an extremely rare disorder, with only two cases reported in the English literature. Here, we present imaging findings of a case of primary diffuse large B-cell lymphoma of the seminal vesicle. On transrectal ultrasonography, the mass presented as a 3.0-cm-sized heterogeneous, hypoechoic lesion in the right seminal vesicle. Computed tomography (CT) revealed a mass with rim-like enhancement in the right seminal vesicle. On magnetic resonance imaging (MRI), the tumor showed iso-signal intensity on T1-weighted images and heterogeneously intermediate-high signal intensity on T2-weighted images. The tumor showed rim-like and progressive enhancement with non-enhancing portion on dynamic scanning. Diffusion restriction was observed in the mass. On fluorodeoxyglucose positron emission tomography-computed tomography (FDG PET/CT) imaging, a high standardized uptake value (maxSUV, 23.5) by the tumor was noted exclusively in the right seminal vesicle.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 1998년도 춘계학술발표회논문집(2)
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• pp.705-710
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• 1998

We describe a multigrid wavelet-based natural pixel (WNP) method for image reconstruction in emission computed tomography (ECT). The ECT is used to identify the tagged radioactive material's position in the body for detection of abnormal tissue such as tumor or cancer, as in SPECT and PET. With ECT methodology in parallel beam mode, we formulate a matrix-based reconstruction method for radionuclide sources in the human body. The resulting matrix for a practical problem is very large and nearly singular. To overcome this ill-conditioning, wavelet transform is considered in this study. Wavelets have inherent de-noising and multiscale resolution properties. Therefore, the multigrid wavelet-based natural pixel (WNP) method is very efficient to reconstruct image from projection data that is noisy and incomplete. We test this multigrid wavelet natural pixel (WNP) reconstruction method with the MCNP generated projection data for diagnosis of the simulated cancerous tumor.