• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.15 no.1
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• pp.46-52
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• 2019

This work proposes a noncontact ultrasonic transducer for detecting wall-thinning of containment liner plates of nuclear power plants by measuring their thickness without physical contact. Because the containment liner plate is designed to prevent atmospheric leakage of radioactive substances under severe nuclear accident, its wall-thinning inspection is important for safety of nuclear power plants. Wall-thinning investigation of containment liner plates have been carried out by measuring their thickness with contact-type ultrasonic thickness gauge by inspectors and needs a lot of time and cost. As an alternative, an electromagnetic acoustic transducer measuring precisely thickness of containment liner plates without any physical contact or couplant was suggested in this research. A transducer generating and measuring shear ultrasonic waves in thickness direction was designed and wave field produced by the transducer was analyzed to verify the design. The working performance of the suggested transducer was tested with carbon steel plate specimens with various thicknesses. The test result shows that the proposed transducer can measure thickness of the specimens precisely without any couplant and implies that swift scanning of wall-thinning of containment liner plates will be possible with the proposed transducer.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.20 no.1
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• pp.16-24
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• 2024

Denting of steam generator (SG) tube is defined as the reduction in tube diameter due to the stresses exerted by the corrosion products formed on the outer diameter surface. This phenomenon is mostly observed in the crevices between SG tube and the top-of tubesheet or tube support plate. Despite the replacement of SG tube with Alloy 690, which has better corrosion resistance than Alloy 600, the denting of SG tube still remains a potential problem that could decrease the SG integrity. Deformation of SG tube by denting phenomenon can affect the surface properties and microstructure of SG tube. In this study, the effects of plastic deformation on surface properties and microstructure of Alloy 690 thermally treated (TT) tube was investigated by using the various analysis techniques. The plastic deformation of Alloy 690 increased the surface roughness and area. Many surface defects such as ripped surface and micro-cracks were observed on the deformed Alloy 690TT specimen. Based on the electron backscatter diffraction analysis, the dislocation density of deformed SG tube increased compared to non-deformed SG tube. In addition, the effects of changes in surface properties and microstructure of SG tube on general corrosion behavior were discussed.

• Journal of the Korean Institute of Gas
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• v.28 no.2
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• pp.24-31
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• 2024

In the chemical industry, fires and explosions constantly occur due to runaway reactions during the production of various chemical products. To prevent this, much research has been conducted, and the possibility of runaway reactions for each substance is reviewed and interlocking devices are installed to prepare for adverse reactions to prepare for fires and explosions. However, despite legal and technical safety measures, accidents due to runaway reactions still occur every year. Accordingly, in this study, based on cases of fire and explosion accidents in styrene monomer reactors, the discharge capacity during runaway reactions was examined through experiments and graphs. Unlike the commonly calculated fire equation, in the case of a runaway reaction where pressure and temperature increase rapidly, discharge is made in two phases rather than a single phase, so the size of the rupture disk must also increase, and the orientation must be adjusted before the rupture disk is installed at the top of the pressure vessel. It was found that position adjustment was necessary.

• Journal of the KSME
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• v.34 no.11
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• pp.859-866
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• 1994

석유화학플랜트에서 운용되는 반응로, 저장탱크, 열교환기 등의 압력용기 그리고 배관 등의 시 설물은 장기간 사용함에 따라 고온, 고압, 부식성 분위기, 열응력, 피로 등 여러 가지 요인으로 경년열화되어 노후화 된다. 일반적으로 이들 설비들에서 작용하는 유체나 가스의 누출은 화재나 폭발과 같은 재해 뿐만아니라 주위 환경을 오염시켜 공해를 유발하게 되며, 이들 시설물에 대한 신뢰성 및 안전성 확보는 국가기간 산업에서 매우 중요하며 이와 관련된 장치의 설계, 시공 뿐만 아니라 시험검사 및 평가기술 측면에서도 중요시되고 있다. 플랜트 시설물에 대한 가동중 주기적인 안전진단은 현상의 파악 뿐만 아니라 인명과 재산의 손실을 미연에 예방하고 경제적 이고 효율적인 운영계획 수립에 필수적인 것이다. 이 글에서는 국내 석유화학플랜트의 검사현 황을 알아보고 앞으로 플랜트의 효율적 운영 및 안전 운전을 위한 가동중검사 기술 및 개선대 책에 대하여 기술하고자 한다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.9
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• pp.3864-3868
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• 2012

In this paper, a safety valve was modeled by using 3-dimensional designing program, Solidsworks after it was dismantled and measured. And 3-dimensional finite element analysis code, ANSYS was used to FEM analysis. Stress, strain and deformation were obtained when some amount of pressure was applied to the safety valve through FEM analysis.

• Nuclear industry
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• v.4 no.1 s.17
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• pp.70-71
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• 1984

지난해 11월 4일 국내 각 신문은 캐나다의 토론토발 연합통신의 기사를 연재, $\ulcorner$캐나다 정부는 캔두(CANDU)형 원자로 압력관의 안전도에 대한 우려가 고조되고 있는 가운데 고위관계자들로 구성된 긴급기술조사단을 구성, 캐나다와 한국을 비롯한 외국에 설치된 모든 캔두형 원자로의 안전여부를 조사하기로 했다$\cdots$$\cdots$$\lrcorner$고 크게 보도하여 물의를 일으킨바 있다. 이에 대하여 당사자인 캐나다 원자력공사는 같은 11월 17일자로 해명서를 발표, $\ulcorner$동기사는 월성원자력 발전소의 안전성을 진단하기 위하여 캐나다로부터 조사반을 파견하는 것으로 되어 있으나 이는 전혀 사실과 다르다. 캐나다 원자력공사는 $\ulcorner$픽커링$\lrcorner$원자력발전소의 사고와 관련하여 캔두원자로 보유국에 그 사고내용을 설명하고 최신 원자로의 안전성을 설득시키기 위하여 관계자를 파견할 계획이었으며 이번 우리들의 방한은 그 목적을 위해서 이루어진 것이다$\lrcorner$라고 말하고 다음과 같이 해명하고 있는데 그 요지는 다음과 같다.

• Journal of Korea Ship Safrty Technology Authority
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• s.36
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• pp.2-14
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• 2014

수중관람창의 판 두께산정식의 유효성을 판단하기 위하여 ISO기준과 일본기준을 비교하고 쌍동선에 설치되는 관람창의 안전성을 평가하기 위해 상용 유한요소해석 프로그램인 ABAQUS를 이용하여 Plexiglass의 두께를 산정하였다. 그 결과를 KS V ISO 12216:2005에 제시된 응력과 처짐에 의한 두께 산정 기준에 따라 관람창의 압력시험을 실시하여 유한요소해석의 적합성을 판단하였다. 또한, 선박과 관람창 연결부(Framing부)는 ISO 11336-1:2012(E)에서 제시된 6가지의 Type중 볼트가 체결된 4가지 경우에 대한 구조해석을 실시하여 연결부의 타입을 결정하였다.

• Journal of the Korean Society of Marine Environment & Safety
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• v.25 no.6
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• pp.772-779
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• 2019

The subsea pipeline has received considerable attention as a high-value-added industry linked to the energy and steel industries including natural resource development. The design and installation of the subsea pipeline require a variety of key technologies to carry out the project. In particular, a thorough pre-verification process through pre-commissioning is essential for the safe operation of the subsea pipeline. The hydrotesting stage in the pre-commissioning process of the subsea pipeline is known to be affected significantly by the ambient temperature change; however, there is a little study based on the theoretical and numerical approach. In this study, the method of predicting the internal temperature change using the transient heat transfer method for the stage of hydrotesting during the pre-commissioning process of the subsea pipeline and the prediction method of the pressure variation in the pipeline using it were proposed. The predicted results were compared with field test results and its effectiveness was verified. The proposed analysis procedure is expected to contribute to the productivity improvement of the subsea pipeline installation project by enabling the prediction of pressure variation through pipeline heat transfer simulation from the initial design stage of the subsea pipeline installation project.

• Journal of the Korean Institute of Gas
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• v.26 no.6
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• pp.59-64
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• 2022

Currently, 787 hydrogen tube trailer are in operation as of the end of October 2022, and a maximum of 340 kg is transported in a Type 1 seamless container at a pressure of up to 200 bar. The current safety management system and facility management are in good condition, but the system and facility structure improvement are needed to strengthen safety. Accordingly, this paper simulated and analyzed an accident case that occurred on the Daejeon-Dangjin highway on December 28, 2021 during the process of expanding the supply and operation of hydrogen tube trailer according to the hydrogen energy activation policy. Based on the results, suggestions were made on how to improve the safety of hydrogen tube trailer.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.9 no.1
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• pp.20-24
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• 2013

Reactor Vessel Internals(RVIs), which are installed within the reactor pressure vessel and support the fuel assembly, take responsibility for safety of reactor core. In operating Nuclear Power Plants(NPPs), the RVIs have been exposed to severe conditions such as neutron irradiation, high temperature, high pressure, and high velocity of coolant flow and have degraded by materials aging with long-term operation. Therefore, the effective aging management plan and the appropriate regulatory requirements are necessary to maintain the integrity of RVIs. The purpose of this paper is to provide a review guide for Periodic Safety Review(PSR) of RVIs in presurized water reactor. The review guide is developed based on the revised review guides and reports established from IAEA and USNRC, and the analysis results of design characteristics, aging mechanisms, and operating experiences of RVIs in domestic and international NPPs. Consequently, the developed review guide for PSR of RVIs is expected to contribute an overall strategy and standard for the PSR of RVIs.