• 한국압력기기공학회 논문집
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• 제10권1호
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• pp.44-50
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• 2014

There were many flaw issues of reactor vessel head penetration in USA fleets. USNRC issued 10CFR50.55a to implement reactor vessel head penetration ultrasonic examination performance demonstration(PD) in US for enhancement of inspection reliability. After September 2009, all US utilities inspected their RVHP with PD qualified system. Korea Hydro and Nuclear Power Company(KHNP) have developed reactor vessel head penetration performance demonstration system for ultrasonic test to apply for pressurized light-water reactor power plants in accordance with 10CFR50.55a since September 2011. RVHP configuration surveying and analysis, code requirement analysis, and performance demonstration specimen design were performed up to this day. Fingerprinting of manufactured specimen, development of test data management program, development of operation procedure, input of flawed data, and development of final report will be performed for the next step. This paper describes the development status of the performance demonstration system for reactor vessel head penetration ultrasonic examination in Korea.

• 한국신뢰성학회:학술대회논문집
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• 한국신뢰성학회 2006년도 학술발표대회 논문집
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• pp.3-19
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• 2006

The Status quo of the reliability in China is described in this paper, a reliability surge is now spreading in China, covering the fields such as hardware, software, machinery and electronics. The reliability work in China was firstly conducted by the CEPREI Lab as far as early in the 1950s, and the reliability engineering in China has developed from the reliability of electronic products to that of machinery and non-electronic products, from hardware reliability to software reliability, from the attention to the reliability statistical test to emphasis on the reliability engineering test. Concern of Chinese companies about the reliability is the complete import of reliability engineering, the reliability testing, the software reliability and the reliability of lead-free soldering. Demonstration of reliability cases is given.

• Journal of the Korean Data and Information Science Society
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• 제27권4호
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• pp.1067-1074
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• 2016

A start-up demonstration test is a mechanism that is usually used to determine the reliability of equipment, for example water pumps, car batteries and power generators. The simplest and oldest start-up demonstration tests are called CS (consecutive successes) which have been studied by Hahn and Gage (1983), Viveros and Balakrishnan (1993).At first Hahn and Gage (1983) discussed the start-up demonstration test. I was based on i.i.d (independently and identically distributed) binary outcomes with the specified number of consecutive successful start-ups. Oh (2016) studied CSNCF (consecutive successful, but not consecutive failures). In this paper, we investigated the CS and CSNCF models, also their applications to start-up demonstration tests. The numerical results showed that the expectations and variances of the total number of attempted start-ups until the acceptance of the unit are gradually increasing in all of the specified number of successes as the p (probability of a successful start-up in an single trial) decreases from 0.99 to 0.90. The difference between means of the CS mode and CSNCF model is small, but variances of the CS and CSNCF are big.

• 한국압력기기공학회 논문집
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• 제6권1호
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• pp.23-28
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• 2010

To enhance the reliability of ultrasonic testing system, MOST(Ministry of Science and Technology) bulletin 2004-13 was published in 2004.6 requiring performance demonstration in ultrasonic examination and MEST(Ministry of Education, Science and Technology) 2009-37 was published in 2009.9(formerly MOST bulletin 2004-13). In order to meet the MEST bulletin requirement and increase the reliability of ultrasonic testing, all the ultrasonic examination procedure and equipment should be performance demonstrated and qualified. In this paper, generic procedure for the ultrasonic examination of dissimilar metal welds are described and new technique are introduced.

• Journal of Electrical Engineering and Technology
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• 제7권1호
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• pp.103-108
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• 2012

The present study describes the considerations on the long-term reliability of the on-line partial discharge (PD) ceramic sensor for thermal power generators. Voltage acceleration aging tests were carried out under continuous and impulsive thermal aging at more than $100^{\circ}C$, considering the practical service environment. Experimental results show that the sensors have a life that could last for more than 100 years, excellent dielectric characteristics, and insulation strength. In addition, the ceramic on-line PD sensors were installed in a thermal power generator in Korea for demonstration. The results of the PD calibration and test voltage application prove that the on-line ceramic sensors have satisfactory performances for on-line PD measurement.

• 비파괴검사학회지
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• 제24권4호
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• pp.378-383
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• 2004

국내 원자력발전소의 Class1과 Class2 배관검사에 적용할 수 있는 초음파탐상 검사자, 장비 그리고 절차서에 대한 한국형 기량검증(KPD) 시스템을 구축하였다. PD 방법을 적용한 검사결과와 전통적인 dB-drop 방법을 이용한 검사결과를 상호 비교하기 위하여 Round Robin Test(RRT)를 수행하였다. RRT 결과는 PD 방법의 신뢰성이 dB Drop 방법보다 우수한 것으로 나타났다. 이러한 결과로부터 원자력발전소 가동중검사에 PD 방법을 적용함으로써 초음파탐상검사 결과의 신뢰성이 더욱 향상될 것으로 기대된다.

• 품질경영학회지
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• 제49권3호
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• pp.341-358
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• 2021

Purpose: After product development, a Reliability Demonstration Test(RDT) is performed to confirm that the target life has been achieved. In the RDT, there are cases where the test equipment cannot accommodate all samples. Therefore, this study considers a test method to most economically demonstrate the target life of the product at a certain confidence level when the sample size is larger than the capacity of the test equipment. Methods: If the sample size is larger than the capacity of the test equipment, test equipments may be added or the test time of individual samples may be increased. So the test method is designed to cover this situation with limited capacity. A zero-failure test method is applied as a test method to RDT. To minimize the cost, the test cost is defined and the cost function is obtained. Finally, we obtain the optimal test plan. Results: A zero-failure test method is designed when the sample size is larger than the capacity of the test equipment, and the expected total cost is derived. In addition, the process of calculating the appropriate sample size, test time, and number of test equipment is illustrated through an example, and the effects of model parameters to the optimal solutions are investigated numerically. Conclusion: In this paper, we study a zero-failure RDT with test equipment that has limited capacity. The expected total cost is derived and the optimal sample size, test time, and number of test equipment are determined to minimize the expected total cost. We also studied numerical examples and for further studies, we can relax some restrictions in the test model and optimize the test method.

• 한국신뢰성학회지:신뢰성응용연구
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• 제14권3호
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• pp.162-168
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• 2014

This paper discusses the application of Bayesian techniques with test data on similar products for performing the Economical Reliability Test of new one-shot device. Using the test data on similar products, reliability test required lower sample size currently being spent in order to demonstrate a target reliability with a specified confidence level. Furthermore, lower sample size reduces cost, time and various resources on reliability test. In this paper, we use similarity as calculating weight of similar products and analyze similarity between new and similar product for comparison of the essential function.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2009년도 제33회 추계학술대회논문집
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• pp.608-612
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• 2009

30톤급 액체로켓엔진 연소기 개발 기술을 바탕으로 75톤급 기술검증용 연소기 시제품을 제작하였다. 시제품 제작에서 검증하고자 하였던 일부 기계가공 공정 및 접합 기술들은 75톤급 연소기에서도 동일하게 적용할 수 있음을 확인하였다. 새롭게 설계된 연소기 헤드부는 새로운 공정을 적용하여 제작하였다. 기술검증용 시제품을 통해 확립된 공정 및 기술들은 대형 액체로켓엔진 연소기 제작 기술의 신뢰성을 향상 시킬 것이다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 춘계학술대회 논문집
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• pp.1-6
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• 2007

A train is subject to a series of reliability-related tasks through its entire life cycle. Among them the reliability demonstration is required for commercial trains and the test is performed during the commissioning period or the early stage of the commercial operation. On the other hands various test are carried out for prototype trains and hence their operational condition is quit different from that of the commercial trains. One should take account of these differences when reliability assessment is needed for the prototype trains. This paper presents a procedure and an analysis method to evaluate reliability of a prototype train. Reliability data have been obtained through test runs of the HSR-350x and operational conditions for the KTX and HSR-350x have been analyzed to compare the reliability targets of the prototype train.