• 한국기계연구소 소보
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• s.14
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• pp.157-168
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• 1985

In cargo vessels, hatch covers are used to prevent sea water from penetrating into the cargo hold and to keep the vessels buoyant. And also they can be used as cargo loading devices as in container ships. In this paper, hatch covers are classified according to their operation method and their characteristics are briefly demonstrated. Systematic description on the scantling of the hatch cover panel and how to determine the capacity of the hydraulic power system fir folding hatch cover panels are also presented. The hydraulic power system is selected from the result of dynamic analysis of the movements of the hatch cover panels when stored on the upper deck. The hatch coaming height is determined as shortly as the hydraulic cylinders can be installed. This study deals with the hatch cover system of the medium sized multi-purpose cargo vessel, but the results of this study can be applied to large-sized cargo vessels with a slight change of the input data in the calculations. Further research on the high pressure pump, hydraulic cleating system and hydraulic piping will realize domestic production of the whole hatch cover system which have been supplied from foreign makers until now

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.3
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• pp.445-451
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• 2002

The refractory-lined pipe is used to protect the system from high-temperature of the internal flow. The property of the refractory has an effect upon the stress analysis for fluid catalytic cracking(FCC) unit piping design. The equivalent elastic modulus and density considering steel and refractory must be applied in the stress analysis of the system. In the research, the theoretical method to obtain the value of the equivalent property is introduced and then the parametric analysis is carried out to understand the characteristic of the material properties, and the stress analysis is performed with reactor, the part of FCC unit.

• Proceedings of the KSME Conference
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• 2001.06a
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• pp.964-968
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• 2001

The refractory-lined pipe is used to protect the system from high-temperature of the internal flow. The property of the refractory has an effect upon the stress analysis for fluid catalyst cracking(FCC) unit piping design. The equivalent elastic modulus and density considering steel and refractory must be applied in the stress analysis of the system. In the research, the theoretical method to obtain the value of the equivalent property is introduced and then the parametric analysis is carried out to understand the characteristic of the material properties.

• Proceedings of the KWS Conference
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• 1996.10a
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• pp.19-34
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• 1996

A review was made of fatigue failures of nuclear power plant components in Japan, which were experienced in service and during periodical inspection. No case has been recently reported of a service fatigue failure of a reactor pressure vessel itself, excluding nozzle corner cracks, that occurred many years ago. But, service fatigue failures have been occasionally experienced in piping systems, pumps, and valves, on which fatigue design seems to have been inadequately applied. The causes of fatigue failures can be divided into two categories: mechanical-vibration-induced fatigue and thermal-fluctuation-induced fatigue. Vibration-induced fatigue failure occurs more frequently than is generally thought. The lesson gleaned from the present survey is a recognition that a service fatigue failure may occur due to any one or a combination of the following factors: (1) lack of communication between designers and fabrication engineers, (2) lack of knowledge about a possibility of fatigue failure and poor consideration about the effects of residual stresses, (3) lack of consideration on possible vibration in the design and fabrication stages, and (4) lack of fusion or poor penetration in a welded joint.

• Journal of the Korean Society of Safety
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• v.16 no.4
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• pp.14-21
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• 2001

SG-365 steel is an important material End used for manufacturing a pressure vessel and gas piping. In this investigation, the elastic plastic fracture toughness of this material is evaluated by the unloading compliance method according to the ASTM E8l3-97 and E1152-97 method on the smooth and side groove In specimens. The effect of smooth and side groove is studied on the elastic plastic fracture toughness. The side grooved specimen is very useful in estimation of the $J_{IC}$. Because it is much easier than the smooth specimen to the onset of the ductile tearing by the R curve method. Besides. it improves the accuracy of toughness values, decreases the scattering of them and crack tunneling effect and shear lip by the side groove.

• Proceedings of the KSME Conference
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• 2007.05b
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• pp.2961-2966
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• 2007

When the pressure at the weak spot established at a certain part of a high pressure vessel or piping system exceeds a design pressure, this weak spot is burst, and the pressurized gas emitted through the weak spot will cause a compression wave system. In this connection, in the present study, an experimental study by using a conventional shock tube facility is performed to estimate the effects of the material of diaphragm, curvature radius and thickness of materials on the valve opening time in diaphragm. Pressure sensor having 500kHz in natural frequency is installed at 35mm downstream of the rupture diaphragm to measure the static pressure history of propagating and being accumulated compression wave. 4 kinds of materials are used as diaphragm that is aluminium, copper, stainless steel and zinc. The diaphragm radii of curvature R are ${\infty}$, 120mm and 60, respectively. And the depth for $90^{\circ}$ groove is 0.04mm. It is found that the smaller the tensile strength and elongation of the rupture diaphragm is, the smaller the radius of curvature of the rupture diaphragm is, and for the same conditions the thinner the thickness of the rupture diaphragm is, the shorter the valve opening time becomes. Also, the tensile strength, elongation and the radius of curvature of the rupture diaphragm for the same conditions are smaller, the maximum pressure rise caused by the coalescences of the compression wave is smaller. Finally the pressure ratio is higher, the valve opening time is shortened and gradient of pressure increment is more steepen.

• Proceedings of the SAREK Conference
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• 2007.11a
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• pp.310-315
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• 2007

The FTL has been developed to be able to irradiate test fuels at the irradiation hole(IR1 hole) by considering its utility and user's irradiation requirements. FTL consists of In-Pile Test Section (IPS) and Out-of-Pile System (OPS). Test condition in IPS such as pressure, temperature and the water quality, can be controlled by OPS. For safety assurance IPS is designed to have dual stainless steel pressure vessel and OPS is composed of main cooling water system, emergency cooling water system, LMP(letdown, make-up, purification) system, etc. FTL Conceptual design was set up in 2001, basic design had completed including a design requirement, basic piping & instrument diagram (P&ID), and the detail design in 2004. In 2005, the development team carried out purchase and manufacture hardware and make a contract for construction work. FTL construction work began on August, 2006 and ended on March, 2007. After FTL development which is expected to be finished by 2008, FTL will be used for the irradiation test of the new PWR-type fuel and can maximize the usage of HANARO.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.39 no.4
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• pp.405-413
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• 2015

In the US, the number of cases of subterranean water contamination from tritium leaking through a damaged buried nuclear power plant pipe continues to increase, and the degradation of the buried metal piping is emerging as a major issue. A pipe blocked from corrosion and/or degradation can lead to loss of cooling capacity in safety-related piping resulting in critical issues related to the safety and integrity of nuclear power plant operation. The ASME Boiler and Pressure Vessel Codes Committee (BPVC) has recently approved Code Case N-755 that describes the requirements for the use of polyethylene (PE) pipe for the construction of Section III, Division 1 Class 3 buried piping systems for service water applications in nuclear power plants. This paper contains tensile and slow crack growth (SCG) test results for high-density polyethylene (HDPE) pipe welds under the environmental conditions of a nuclear power plant. Based on these tests, the fracture surface of the PENT specimen was analyzed, and the fracture mechanisms of each fracture area were determined. Finally, by using 3D finite element analysis, limit loads of HDPE related to premature failure were verified.

• Journal of the Korean Institute of Gas
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• v.16 no.4
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• pp.59-64
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• 2012

The dispersion of gas discharged from the vent pipes of pressure relief valves attached LPG (Liquefied Petroleum Gas) storage tank was studied. In general, vent pipes should be positioned so that they discharge vertically upwards in a safe place, and installed so that, in the event of ignition of discharged gas, flame impingement on any vessel, equipment or piping is avoided[1][2]. In Korea, on the other hand, there are various type of the end of vent pipes because there is no rule for discharge directions from the vent pipes. In this paper, we took 4 types of vent directions from the pipes in to account, such as vertically upward, vertically downward, vertically 4-way and horizontally 2-way direction. A software package, FLACS, was adopted to simulate gas dispersion from the vent pipes. We found that vertically downward, vertically 4-way and horizontally 2-way discharge from vent pipes were undesirable to avoid ignition on near ground. Therefore, it was obvious that vertically upward opening of a vent pipe is the best option to discharge in a safe place.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2006.04a
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• pp.1025-1032
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• 2006

The PVRC(Pressure Vessel Research Council) damping is for the response spectrum analysis of the piping system. In this study, the possibility to apply it to the time history analysis is evaluated to reduce the higher conservatism for the structural integrity. The evaluation was performed for the surge line connecting the pressurizer to the hot-leg, and the whole mode includes the RCS and the building structures with the surge line. The analyses were performed using ANSYS code. The first modal analysis shows the modes of the surge line are isolated from those of the other structures. The composite modal damping was calculated with PVRC damping for the surge line and RG 1.60 damping for the other structures by using ANSYS routines. Of the calculated composite modal damping values, the composite modal damping values related to the modes of the surge line were replaced with the PVRC damping values with respect to its frequencies. With this replacement, the composite modal damping values of the other structures were not changed. Based on this decouple characteristics, the time history analyses for the seismic events with PVRC damping for the surge line were performed. And the results show the resultant loads can be reduced by up to 50%.