• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2008.11a
• /
• pp.264-269
• /
• 2008

This paper presents the summary of control of abnormal vibration found in the COP motors of a nuclear power plant. All six identical units of COP pump-motor assemblies showed unstable vibration pattern of which one or two showed higher vibration enough to exceed the allowable level from the installation stage. Many trials of test, measurement, overhaul and replacement had been repeated to investigate and solve the problem but only to reach unsatisfactory settlement. Recently several times of site tests are made and followed by significant diagnostic actions in which the authors group participated. It was found that the coupled shafting system of motor and pump is in close resonance with the $1^{st}$ shaft rotating speed. Redesign of topside motor bearing clearance is made to increase bearing stiffness and hence to avoid the resonance which consequently led to reduce the troubled vibration to allowable and stable status.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.12 no.4
• /
• pp.261-271
• /
• 2002

The fluid-elastic instability analysis of the U-tube bundle inside the steam generator is very important not only for detailed design stage of the SG but also for the change of operating condition of the nuclear powerplant. However the calculation procedure for the fluid-elastic instability was so complicated that the consolidated computer program has not been developed until now. In this study, the numerical calculation procedure and the computer program to obtain the stability ratio were developed. The thermal-hydraulic data in the region of secondary side of steam generator was obtained from executing the ATHOS3 code. The distribution of the fluid density can be calculated by using the void fraction, enthalpy, and operating pressure. The effective mass distribution along the U-tube was required to calculate natural frequency and dynamic mode shape using the ANSYS ver. 5.6 code. Finally, stability ratios for selected tubes of the CE type steam generator were computed. We considered the YGN 3.4 nuclear powerplant as the model plant, and stability ratios were investigated at the flow exit region of the U-tube. From our results, stability ratios at the central and the outside region of the tube bundle are much higher than those of other region.

• Computers and Concrete
• /
• v.12 no.5
• /
• pp.627-650
• /
• 2013

This paper deals with application of a non-linear continuum model for reinforced concrete affected by alkali-aggregate reaction (AAR) to analysis of some nuclear structures. The macroscopic behaviour of the material affected by AAR is described by incorporating a homogenization/averaging procedure. The formulation addresses the main stages of the deformation process, i.e., a homogeneous deformation mode as well as that involving localized deformation, associated with formation of macrocracks. The formulation is applied to examine the mechanical behaviour of some reinforced concrete structures in nuclear power facilities located in Quebec (Canada). First, a containment structure is analyzed subjected to 45 years of continuing AAR. Later, an inelastic analysis is carried out for the spent fuel pool taking into account the interaction with the adjacent jointed rock mass foundation. In the latter case, the structure is said to be subjected to continuing AAR that is followed by a seismic event.

• Proceedings of the KSME Conference
• /
• 2001.11b
• /
• pp.735-740
• /
• 2001

In the nuclear power plant, emergency core coolant system(ECCS) is furnished at reactor coolant system(RCS) in order to cool down high temperature water in case of emergency. However, in this coolant system, it occurs thermal stratification phenomena in case that there is the mixing of cooling water and high temperature water due to valve leakage in ECCS. This thermal stratification phenomena raises excessive thermal stresses at pipe wall. Therefore, this phenomena causes the accident that reactor coolant flows in reactor containment in the nuclear power plant due to the deformation of pipe and thermal fatigue crack(TFC) at the pipe wall around the place that it exists. Hence, in order to fundamental identification of this phenomena, it requires the experimental research of modeling test in the pipe flow that occurs thermal stratification phenomena. So, this paper models RCS and ECCS pipe arrangement and analyzes the mechanism of thermal stratification phenomena by measuring of temperature in variance with leakage flow rate in ECCS modeled pipe and Reynold number in RCS modeled pipe. Besides, results of this experiment is compared with computational analysis which is done in advance.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.12 no.1
• /
• pp.36-41
• /
• 2002

The cause and the elimination method for the chattering phenomena were investigated in a check valve attached to the exit of an auxiliary cooling water pump in a Korean nuclear powerplant. From the site experiment and the numerical calculation, the incident angle of the disk was so small that it was not able to produce the sufficient lifting force to overcome the gravitational component of the disk weight. Moreover, it turned out that the installation position was not symmetric for the secondary vortical flow generated inside the elbow so that the flow structure had strongly unstable flow characteristics. From this study, the tapping noise and the chattering phenomena were eliminated exactly by changing the incidence angle of the valve disk and the installation position of the calve body.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2000.06a
• /
• pp.1848-1853
• /
• 2000

Cause and the elimination method for the chattering phenomena were investigated the check valve attached exit of the auxiliary cooling water pump at a korean nuclear powerplant. From the site experiment and numerical calculation the incident angle of the disk was so small that it was not able to produce the lifting force to overcome the component of disk weight. Moreover, it turned out that the installed position was not symmetric for the secondary vortical flow generated inside the elbow, so that the flow structure had strongly unstable flow characteristics. From this technical support, the tapping noise and the chattering phenomena were eliminated exactly by changing the incidence angle of the valve disk and installed position of the check valve.

• Journal of the korean Society of Automotive Engineers
• /
• v.4 no.2
• /
• pp.1-8
• /
• 1982

선진제국의 자동차회사들은 미래의 자동차 또는 특수차량에 이용될 수 있는 가능한 동력 원(powerplant)을 개발하기 위하여 막대한 투자와 인력을 들여 끊임없이 조사와 연구를 계속하고 있다. 이는 보다 성능이 우수한 동려원의 개발에서 비롯되며 근대에 와서는 보편적으로 자동 차에 사용되고 있는 gasoline 및 diesel연료에 의한 내연기관의 문제점(특히 공해와 석유자원의 한계 및 경제성)을 해결코저 그 연구가 다양해지고 있으며 절박한 필요성을 느끼고 있다. 이 분야에 관해 미국 GM사가 연구개발하고 있는 개략을 보면, - Unconnvertional system으로 Turbine, steam, electric, free poston 및 hybrid - Direct coeversion & muclear power system 으로 Thermoelectric power, thermionic power, electrogasdynamics, radioisotope heat source 및 nuclear rector system 등 기초과학분야로부터 응용에 이르기까지 광법위한 연구를 하고 있다. 다음에 본호에서는 unconventional system중 몇가지 project background 그 개요을 소개코저 한다.

• Journal of the Korean Regional Science Association
• /
• v.10 no.1
• /
• pp.89-104
• /
• 1994

Recently, environmental issues have remained high on the agendas of public discussion and economic research. In the case of Korea, democratic movement in the late 80's centered people's concerns on the environmental dispute according to landfill, correctional institution, crematory, and nuclear powerplant, etc., Moreover, the failure to provide these kinds of facilities in time have caused serious social problems associated with environmental protection and economic development. The purposes of this paper are threefolds. First, they organize foreign and domestic NIMBYS case studies which have been settled in a desirable way. The second concern is to analyze the consciousness of NIMBYS resident by making up a questionnaire. Third, they estimate the market values of urban unwanted facilities by employing CVM(Contingent Valuation Method) procedure. The results of the study have a double implication : that NIMBYS resident are reluctant to accept government mechanical compensation based on simple published land values, and that unique concensus to preserve the viability and healthfulness of our environment among three main bodies: residents, people, government is necessary in solving NIMBYS subjects in Korea. In addition, this first implication develops to emphasize the intrduction of releveant measures taken to reconcile NIMBYS disagreement, which are complete openness of government policies, full support of local economic development, and perfect management of pollution protection systems for NIMBYS facilities.

• Journal of Wetlands Research
• /
• v.10 no.2
• /
• pp.179-189
• /
• 2008

Fauna of Shinpo nuclear powerplant site were surveyed during Feb 27-Mar 4, 2003 as a part of ecological environmental survey. This area is well dominated by coniferous trees (Pinus densiflora) aging 15-50 years. In the shoreline black pine (P. thungergii) is the dominant species and was planted for wind protection. Around Shinpo areas inside 50 km in radius was found 170 bird species (18 orders, 40 families) were recorded. Natural monument in the areas were included white-stork(Cygonia boyciana) estimated 8 species of birds. Although the habitat of Shinpo area is deteriorated due to deforestation, illegal hunting, etc. the fauna seems to be rich in species. Despite the sudden halt of KEDO(Korea Peninsula Energy Development Organization) project the conservation efforts and continuous monitoring are required considering a continuation of the project.

• Journal of Wetlands Research
• /
• v.9 no.1
• /
• pp.13-20
• /
• 2007

Fauna of Shinpo nuclear powerplant site were surveyed during Feb 27-Mar 4, 2003 as a part of ecological environmental survey. This area is well dominated by coniferous trees (Pinus densiflora) ranging 15-50 years. In the shoreline black pine (Pinus thungergii) is the dominant species and was planted for wind protection. Around Shinpo areas inside 50 km in radius was found 33 mammal species (3 orders, 15 families), and amphibian-reptiles 6 species (2 orders, 3 families) were recorded. Natural monument in the areas were estimated 6 species of mammals and one species of reptiles. Although the habitat of Shinpo area is deteriorated due to deforestation, illegal hunting, etc. the fauna seems to be rich in species. Despite the sudden halt of KEDO project the conservation efforts and continuous monitoring are required considering a continuation of the project.