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Thickness evaluation of Cr coating fuel rod using encircle ECT sensor
박정원,하종문,승홍민,장훈,최원재 한국원자력학회 2022 Nuclear Engineering and Technology Vol.54 No.9
To improve the safety and life extension qualities of nuclear fuel rods which is currently made of zirconium (Zr) alloy, research on the application of chromium (Cr) coating was conducted. Cr coating has advantages such as increased corrosion resistance and reduced oxidation rate, but non-destructive thickness evaluation studies are needed to ensure the reliability of the steps taken to provide uniform coating thickness. Eddy current testing (ECT) is a representative non-destructive technique for such as thickness evaluation and surface defect inspection. To inspect changes in thickness at micron scale, the Swept Frequency Eddy Current Testing (SFECT) method was applied to select a frequency range sensitive to changes in thickness. The coating thickness was evaluated using changes in signals, such as that for impedance. In this study, basic research was performed to evaluate the thickness of the Cr coating on a rod using an encircling sensor and the SFECT technique. The sensor design parameters were determined through simulation, after which the new sensor was manufactured. A sensor capable of measuring the thickness of a non-uniformly Cr-coating rod was selected through an experiment evaluating the performance of the manufactured sensor. This was done using the impedance-difference of a Cr-coating rod and a Zr alloy rod. The possibility of evaluation of the Cr coating thickness was confirmed by comparing the experimental results with the selected sensor and the signals of the measured Cr-coating rod. All simulation results were verified experimentally.
스마트워터그리드를 위한 LoRa IoT 원격검침 및 계량데이터 시스템 개발
박정원,박재삼 한국항행학회 2022 韓國航行學會論文誌 Vol.26 No.3
In this paper, water meter AMR(automatic meter reading), one of the core technologies of smart water grid, using LoRa IoT network is studied. The main content of the research is to develop the network system and show the test results that one PC server receives the readings of water meters from multiple households through LoRa communication and stores them in the database, and at the same time sends the data to the web server database through internet. The system also allows users to monitor the meter readings using their smartphones. The hardware and firmware of the main board of the digital water meter are developed. For a PC server program, MDMS(meter data management system) is developed using Visual C#. The app program running on the user's smartphone is also developed using Android Studio. By connecting each developed parts, the total network system is mounted on a flow test bench in the laboratory and tested. For the fields test, 5 places around the university are selected and the transmission distances are tested. The test result show that the developed system can be applied into the real field. The developed system can be expanded to various social safety nets such as monitoring the living alone or elderly with dementia.
박정원,김동원,엄기연,이장근,김흥구,박종수,이신근 한국화학공학회 2007 화학공학의이론과응용 Vol.10 No.2
연료전지의 원료로 사용되는 수소 가스를 생성하기 위한 수소 가스 분리막의 연구가 최근 많이 이루어 지고있다. 그에 따라 분리막의 지지체 연구 또한 이루어 지고 있는데 본 연구에서는 기존의 다공성 스테인레스 스틸 지지체나 다공성 세라믹 지지체등의 문제점을 인식하고 그를 극복하기 위하여 니켈를 이용하여 다공성 지지체를 제작하였다. 수소취성의 내성이 있는 다공성니켈 지지체를 사용함으로 수소 분위기 플라즈마 표면 개질 공정과 도금액내 이물질 제거를 위한 진공 열처리가 가능하게 되었으며 이를 통하여 코팅층간의 접착력이 우수하면서 지지체 표면기공의 완전 매립과 표면 평탄화를 가져오는 니켈 전해 도금 코팅층을 형성하게 되었다. 또한 건식 스퍼터 팔라듐 박막공정을 통해 적은 팔라듐양으로 치밀하면서도 열적 안정화된 Pd-Ni 합금 분리막을 형성하여 수소/질소 혼합 기체에서 수소기체의 분리도를 측정하여 수소기체의 높은 투과 및 분리 성능 결과를 얻을 수 있었다.