• 생명과학회지
• /
• 제8권4호
• /
• pp.449-456
• /
• 1998

태생 13일된 토끼의 발생기 신장에서 뇨세관과 사구체 세포들의 크기와 형태를 관찰하여 성숙한 토끼의 신장과 형태계측학적으로 비교한 결과 다음과 같은 결과를 얻었다. 1. 태생 13일의 발생기 뇨세관 단면적은 성숙한 토끼의 근위세관 단면적보다 훨씬 넓고 평균직격이 길었으며 내강이 거의 없었다. 뇨세관 상피세포의 솔모양 가장자리는 발달되지 않았고 핵 위쪽에 둥근 사립체가 발달되었으며 기저막부분에는 사립체가 적었다. 2. 발생기 사구체내에는 벽측세포, 족세포, 내피세포들로 구별되었으며 성숙한 토끼보다 내피세포와 벽측세포의 세포핵 단멱적이 훨씬 컸고 성숙한 토끼의 사구체에서는 족세포가 가장 컸으나 발생기에는 내피세포의 크기가 가장 컸다.

• 한국음향학회:학술대회논문집
• /
• 한국음향학회 1998년도 학술발표대회 논문집 제17권 2호
• /
• pp.247-250
• /
• 1998

The scattering of plane ultrasonic waves by the nuclear fuel pin of liquid metal reactor in sodium is studied. According to the internal composition in the cladding tube, the fuel pin has three cross sections, i.e. helium gas plenum, sodium-filled section, and fuel insertion section. The scattering spectra for each section of the fuel pin are different. The circumnavigating ultrasonic waves of each section are analyzed by the resonance scattering method. The whispering gallery wave modes are generated in the sodium-filled plenum section and the fuel rod insertion section with a sodium-gap. The circumferential wave modes are propagated in the cladding tube of the helium gas plenum section. The annular gap between the cladding tube and metal uranium pellet rod affects the scattering spectra. The different propagation characteristics can be utilized for the nondestructive method of detecting the unbonded area and measuring the level of the sodium-filled section of the fuel pin.

• Nuclear Engineering and Technology
• /
• 제54권3호
• /
• pp.849-859
• /
• 2022

Feed-water valves (FWVs) are used to regulate the flow rate of water entering steam generators, which are very important devices in nuclear power plants. Due to the working environment of relatively high pressure and temperature, there is strength failure problem of valve body in some cases. Based on the thermo-fluid-solid coupling model, the valve body stress of the feed-water valve in the opening process is investigated. The flow field characteristics inside the valve and temperature change of the valve body with time are studied. The stress analysis of the valve body is carried out considering mechanical stress and thermal stress comprehensively. The results show that the area with relatively high-velocity area moves gradually from the bottom of the cross section to the top of the cross section with the increase of the opening degree. The whole valve body reaches the same temperature of 250 ℃ at the time of 1894 s. The maximum stress of the valve body meets the design requirements by stress assessment. This work can be referred for the design of FWVs and other similar valves.

• Nuclear Engineering and Technology
• /
• 제48권2호
• /
• pp.360-367
• /
• 2016

A windowless spallation target can provide a neutron source and maintain neutron chain reaction for a subcritical reactor, and is a key component of China's nuclear waste transmutation of coupling accelerator and subcritical reactor. The main issue of the windowless target design is to form a stable and controllable free surface that can ensure that energy spectrum distribution is acquired for the neutron physical design when the high energy proton beam beats the lead-bismuth eutectic in the spallation target area. In this study, morphology and flow characteristics of the free surface of the windowless target were analyzed through the volume of fluid model using computational fluid dynamics simulation, and the results show that the outlet cross section size of the target is the key to form a stable and controllable free surface, as well as the outlet with an arc transition. The optimization parameter of the target design, in which the radius of outlet cross section is $60{\pm}1mm$, is verified to form a stable and controllable free surface and to reduce the formation of air bubbles. This work can function as a reference for carrying out engineering design of windowless target and for verification experiments.

• Nuclear Engineering and Technology
• /
• 제51권1호
• /
• pp.155-162
• /
• 2019

To reduce the secondary damage caused by leakage accidents in plant piping systems, a constant surveillance system is necessary. To ensure leaks are promptly addressed, the surveillance system should be able to detect not only the leak itself, but also the location of the leak. Recently, research to develop new methods has been conducted using cameras to detect leakage and to estimate the location of leakage. However, existing methods solely estimate whether a leak exists or not, or only provide two-dimensional coordinates of the leakage location. In this paper, a method using multiple cameras to detect leakage and estimate the three-dimensional coordinates of the leakage location is presented. Leakage is detected by each camera using MADI(Moving Average Differential Image) and histogram analysis. The two-dimensional leakage location is estimated using the detected leakage area. The three-dimensional leakage location is subsequently estimated based on the two-dimensional leakage location. To achieve this, the coordinates (x, z) for the leakage are calculated for a horizontal section (XZ plane) in the monitoring area. Then, the y-coordinate of leakage is calculated using a vertical section from each camera. The method proposed in this paper could accurately estimate the three-dimensional location of a leak using multiple cameras.

• Nuclear Engineering and Technology
• /
• 제54권3호
• /
• pp.926-939
• /
• 2022

The area of this study will cover the location-wise seismic response variation of an electrical cabinet in nuclear power point (NPP) based on classical reliability analysis. The location-based seismic ground motion (GM) selection is carried out with the help of probabilistic seismic hazard analysis using PSHRisktool, where the variation of reliability analysis can be understood from the relation between the reliability index and intensity measure. Two different approaches such as the first-order second moment method (FOSM) and Monte Carlo Simulation (MCS) are helped to evaluate and compare the reliability assessment of the cabinet. The cabinet is modeled with material uncertainty utilizing Steel01 as the material model and the fiber section modeling approach is considered to characterize the section's nonlinear reaction behavior. To verify the modal frequency, this study compares the FEM result with recorded data using Least-Squares Complex Exponential (LSCE) method from the impact hammer test. In spite of a few investigations, the main novelty of this study is to introduce the reader to check and compare the seismic reliability assessment variation in different seismic locations and for different earthquake levels. Alongside, the betterment can be found by comparing the result between two considered reliability estimation methods.

• 한국BIM학회 논문집
• /
• 제6권1호
• /
• pp.1-8
• /
• 2016

This paper provides a method for generating flight path of Unmanned Aerial Vehicle (UAV) that is intended to be used in visual inspection of dome-type nuclear containment building. The method basically employs 3-D model to extract accurate location coordinates. Two basic route patterns that provide guide lines in defining moving locations were defined for each side wall and dome section of the containment. The route patterns support sequential capturing of images as well. In addition, several simple equations and an algorithm for calculation of the moving location on the route were developed on the basis of 3-D geometric characteristics of the containment building. A prototype computer program has been implemented to validate the proposed method, and a case study shows the method can visualize covering area in 3-D model as well.

• 방사성폐기물학회지
• /
• 제11권4호
• /
• pp.303-309
• /
• 2013

사용후핵연료의 지층처분의 대안으로 심부시추공을 설치하여 지하 3-5 km 구간에 사용후핵연료를 처분하는 개념이 여러나라에서 제시된 바 있다. 특히 미국 샌디아국립연구소의 최근 연구 결과를 분석하고, 국내 적용을 위한 한국형 캐니스터 디자인과 심부시추공 디자인 개념을 처분 소요 면적과 함께 제시하였다.

• 한국정밀공학회지
• /
• 제28권2호
• /
• pp.233-238
• /
• 2011

In piping design of nuclear power plant facilities, the load stress according to self-weight is important for design values in test run(shutdown and starting). But sometimes it needs more studies, such as seismic analysis of an earthquake of power plant area and fatigue life and stress of thermal expansion and anchor displacement in operating run. In this paper, seismic evaluations were performed to nuclear piping system of Shin-Kori NO. 3&4 being built in Pusan lately. Results of seismic analysis are evaluated on basis of KEPIC MN code. The structural integrity on RCB piping system was proved.

• Nuclear Engineering and Technology
• /
• 제54권6호
• /
• pp.2334-2337
• /
• 2022

Deuterium-tritium reaction is the most promising one in term of the highest nuclear fusion cross-section for the reactor. So it is one of urgent issues to develop materials and components that are simultaneously resistant to high heat flux and high energy neutron flux in realization of the fusion energy. 2.45 MeV neutron production was reported in D-D reaction in KSTAR and regarded as beam-target is the dominant process. The feasibility study of KSTAR to wide area neutron source facility is done in term of D-D and D-T reactions from the empirical scaling law from the mixed fast and thermal stored energy and its projection to cases of heating power upgrade and DT reaction is done.