• Nuclear Engineering and Technology
• /
• 제49권3호
• /
• pp.651-661
• /
• 2017

The Korea Institute of Nuclear Safety, as a representative organization of Korea, in February 2012 participated in an international Program to Assess the Reliability of Emerging Nondestructive Techniques initiated by the U.S. Nuclear Regulatory Commission. The goal of the Program to Assess the Reliability of Emerging Nondestructive Techniques is to investigate the performance of emerging and prospective novel nondestructive techniques to find flaws in nickel-alloy welds and base materials. In this article, Korean round-robin test results were evaluated with respect to the test blocks and various nondestructive examination techniques. The test blocks were prepared to simulate large-bore dissimilar metal welds, small-bore dissimilar metal welds, and bottom-mounted instrumentation penetration welds in nuclear power plants. Also, lessons learned from the Korean round-robin test were summarized and discussed.

• 비파괴검사학회지
• /
• 제21권6호
• /
• pp.642-649
• /
• 2001

정밀부품이나 기기는 개발과정이나 완료단계에서 부적절한 설계에 의하여 발생할지도 모르는 잠재적인 결함을 방지하기 위하여 시험평가를 실시하게 된다. 본 논문에서는 신뢰성 기술 분야의 기초가 되는 환경시험기술을 소개하였으며 엔코더, 교통신호제어기, 계측기기 및 위성항법 수신기 등 제품단위의 대상품에 대한 시험조건 및 방법 등을 기술하고 시험사례를 보고하였다. 이러한 사례를 통하여 제품의 신뢰성 향상을 위한 복합환경시험의 중요성을 강조하였고 최근 환경시험기술에 대한 인식이 날로 증대되면서 시험기술자 양성, 지그설계기술 그리고 고장해석 및 대책기술의 확보가 매우 필요함을 제안하였다.

• Architectural research
• /
• 제20권4호
• /
• pp.137-145
• /
• 2018

The nondestructive test is widely used in the field of diagnosis and maintenance to evaluate the degree of damaging of structures caused by aging, and the demand for this test method is expected to continue increasing. However, there is a lack of standards related to the nondestructive test, and South Korea is relying heavily on developed nations for original technologies related to diagnosis. It is an urgent task to establish a nondestructive test method appropriate for the circumstance of South Korea. The purpose of this study is to compare and analyze estimated error of compressive strength in single-story structures comprised of vertical and horizontal reinforced concrete members using the impact testing method and rebound hardness method, which are nondestructive test methods, and to review on-site applicability of these methods. Based on compressive strength of the structures estimated, overall mean error was 21.2% for the impact testing method and 15.6% for the rebound hardness method. The necessity of a reliable diagnostic method based on compound nondestructive test methods to increase accuracy of estimation was confirmed.

• 비파괴검사학회지
• /
• 제30권6호
• /
• pp.527-538
• /
• 2010

This paper presents a nondestructive evaluation approach for system identification (SID) of real railway bridges using field vibration test results. First, a multi-phase SID scheme designed on the basis of eigenvalue sensitivity concept is presented. Next, the proposed multi-phase approach is evaluated from field vibration tests on a real railway bridge (Wondongcheon bridge) located in Yangsan, Korea. On the steel girder bridge, a few natural frequencies and mode shapes are experimentally measured under the ambient vibration condition. The corresponding modal parameters are numerically calculated from a three-dimensional finite element (FE) model established for the target bridge. Eigenvalue sensitivities are analyzed for potential model-updating parameters of the FE model. Then, structural subsystems are identified phase-by-phase using the proposed model-updating procedure. Based on model-updating results, a baseline model and a nondestructive evaluation of test bridge are identified.

• 전기학회논문지P
• /
• 제57권4호
• /
• pp.424-430
• /
• 2008

A new active vibration measurement system in electric power transmission line is presented, using in the nondestructive test. With a permanent magnet and a couple of coils, the system exerts impact force to a test object and in turn picks up the vibration of the object. The natural frequency with the amplitude obtained from the system are used as a basis for the detection of defects in the object. The system is controlled by an electronic device designed to facilitate the fully automated testing process with consistent repeatability and reliability which are essential to the nondestructive test. The system is expected to be applied to the wide area of defect detection including the classification of mechanical parts in production and inspection processes.

• 비파괴검사학회지
• /
• 제29권3호
• /
• pp.230-234
• /
• 2009

As concrete ages, the surrounding environment is expected to have growing influences on the concrete. As all the impacts of the environment cannot be considered in the strength-estimating model of a nondestructive concrete test, the increase in concrete age leads to growing uncertainty in the strength-estimating model. Therefore, the variation of the model error increases. It is necessary to include those impacts in the probability model of concrete strength attained from the nondestructive tests so as to build a more accurate reliability model for structural performance evaluation. This paper reviews and categorizes the existing strength-estimating statistical models of nondestructive concrete test, and suggests a new form of the strength-estimating statistical models to properly reflect the model uncertainty due to aging of the concrete. This new form of the statistical models will lay foundation for more accurate structural performance evaluation.

• 동력기계공학회지
• /
• 제3권4호
• /
• pp.51-56
• /
• 1999

The ultrasonic method, which is well known as nondestructive test method, is widely used to evaluate the material damage due to degradation. However, this method is just used for measuring the crack size and the thickness loss of the tube. The purpose of this study is to investigate the applicability of the ultrasonic technique for the evaluation of marine diesel engine exhaust valve and to suggest the correlations between the ultrasonic characteristics and valve degradation. From the evaluation of the results obtained, the technique of using the ultrasonic property was founds to be a efficient method to evaluate the degree of marine diesel engine exhaust valve by nondestructive test.

• 비파괴검사학회지
• /
• 제15권4호
• /
• pp.561-567
• /
• 1996

원자력산업이 발전함에 따라 우리나라에서도 방사성동위원소 및 방사선발생장치를 사용하는 시설이 매년 증가하고 있으며 그에 따라 방사선 차폐시설에 대한 방사선 안전성 문제도 크게 대두되기 시작하였다. 그러므로 안전성 확보의 일환으로 방사선 차폐체 건전성검사는 매우 중요하다고 할 수 있다. 본 연구에서는 이러한 방사선 차폐체 건전성검사를 위한 비파괴검사방법중의 하나인 감마스케닝검사법 (gamma scanning test, GST)의 검사 방법에 대한 평가와 실제 현장에서의 적용 예를 비교 고찰하였다. 또한 본 연구에서는 사용된 감마스케닝검사방법에서 정확성을 위해 검사시 갖추어야 할 기본 장치와 개선해야 할 사항 등을 제시하였다. 이러한 기술을 국내 관련기관 및 산업체에서 널리 보급하여 보다 효율적이고 정확한 검사 방법을 수행한다면 앞으로 구조물의 건전성검사시 비파괴검사방법의 한 수단으로 정착하여 유용하게 사용될 수 있을 것이다.

• Transactions on Electrical and Electronic Materials
• /
• 제7권5호
• /
• pp.262-266
• /
• 2006

The insulation diagnostic test and the AC breakdown test were performed under off-line using the 3.3 kV class induction motor which have been served for 10 years. These tests were conducted in means of nondestructive and destructive test. In this paper, we compared the correlation between the nondestructive and destructive test. Furthermore we setup an experimental condition with moisture and compared the insulation characteristics between moist and dry sample. From the results of the nondestructive and destructive test, it was found that the second AC current, which is the previous step of insulation breakdown, suddenly increased at a point of around 8.5 kV. The insulation breakdown of moist sample occurred at 12-14 kV, which is 4-5 kV lower than dry sample.

• 한국철도학회논문집
• /
• 제8권5호
• /
• pp.419-424
• /
• 2005

This paper has performed fatigue and nondestructive test of bogie frame for Korean tilting train. Before the fatigue test, static tests were carried out. From the test, the structural safety was investigated using Goodman diagram. After the static test, the fatigue test were conducted under tilting load conditions. The fatigue test was conducted for $10{\times}10^6$ cycles. During the fatigue test, the nondestructive tests using magnetic particle and liquid penetrant were performed at $6{\times}10^6$ cycle and $10{\times}10^6$cycle. From the crack detection tests, it was known that there was no fatigue crack in the bogie frame.