• Journal of the Korean Geotechnical Society
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• v.33 no.7
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• pp.5-16
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• 2017

Soil nailing is the most general method to reinforce the slope by taking pullout and shear resistance force of the nail for stabilizing the slope. Domestic soil nailing design method considers only pullout resistance and does not consider the shear resistance sufficiently. In case of nail, the effect of tensile stress is dominant, but it is desirable to design by considering shear stress as well as tensile stress in case of slope where circle failures occur. Recently, studies on the shear resistance effect of nails have been carried out in the geotechnical field. However, many researches on the shear reinforcement effect of soil nailing have not been conducted until now. Most of the studies are about increasing pullout resistance by improving material, shape and construction method of nail. Therefore, it is necessary to the study on shear resistance of soil nailing and development of new methods to increase the shear force. In this study, large shear test and limit equilibrium analysis have been performed for a new soil nailing method to increase the shear resistance by forming protrusions through pressurized grouting after installing a packer on the outside of deformed bar. The study results showed that shear resistance of protrusion type soil nailing increased compared to soil nailing and it is more effective when applied to the ground with large strength parameters.

• Nuclear Engineering and Technology
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• v.24 no.2
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• pp.178-182
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• 1992

Spent PWR fuel rods have been scanned axially and sectionally to measure the relative gamma-ray intensity of Cs-137 and then bumups of the scanned rods determined by measuring Nd-148 which has been chemically separated. From these experimental results, a linear relation(LR) between the gamma-ray intensity of Cs-137 and the bumup in the range of 10∼35 GWD/MTU was obtained. In order to validate the LR, the Cs-137 gamma-ray intensity of unknown sample was nondestructively measured and the bumup obtained by the LR was compared with that of the Nd-148 method. It is revealed that the results from both methods are in good agreement, and thus it seems to be possible to estimate the bumup of spent PWR fuel rod by measuring nondestructively gamma-ray of fission product Cs-137.

• Journal of the Korean Institute of Gas
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• v.18 no.6
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• pp.40-44
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• 2014

In this study, it is analyzed that a change in the shape of small propane containers made of STS304 when increasing of internal pressure. When internal pressure of a small propane container increased, bottom of end plate is convexly changed. This test is applied to a water bath pressure test to analyze the characteristics of the container. Water bath is able to analyze relationship between internal pressure and volume. In result, shape change section is confirmed because bottom of end plate is convexly changed. In addition, this section tend to decrease internal pressure because a volume increment increase out of proportion to pressure. The results of this study are expected to contribute to improving the safety of the pressure vessel, as well as various small propane container.

• Journal of the Korean Geotechnical Society
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• v.24 no.4
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• pp.101-114
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• 2008

Pressurized grouting is a common technique in geotechnical engineering applications to increase the stiffness and strength of the ground mass and to fill boreholes or void space in a tunnel lining and so on. Recently, the pressurized grouting has been applied to a soil-nailing system which is widely used to improve slope stability. Because interaction between pressurized grouting paste and adjacent ground mass is complicated and difficult to analyze, the soil-nailing design has been empirically performed in most geotechnical applications. The purpose of this study is to analyze the ground behavior induced by pressurized grouting paste with the aid of laboratory model tests. The laboratory tests are carried out for four kinds of granitic residual soils. When injecting pressure is applied to grout, the pressure measured in the adjacent ground initially increases for a while, which behaves in the way of the membrane model. With the lapse of time, the pressure in the adjacent ground decreases down to a value of residual stress because a portion of water in the grouting paste seeps into the adjacent ground. The seepage can be indicated by the fact that the ratio of water/cement in the grouting paste has decreased from a initial value of 50% to around 30% during the test. The reduction of the W/C ratio should cause to harden the grouting paste and increase the stiffness of it, which restricts the rebound of out-moved ground into the original position, and thus increase the in-situ stress by approximately 20% of the injecting pressures. The measured radial deformation of the ground under pressure is in good agreement with the expansion of a cylindrical cavity estimated by the cavity expansion theory. In-situ test revealed that the pullout resistance of a soil nailing with pressurized grouting is about 36% larger than that with regular grouting, caused by grout radius increase, residual stress effect, and/or roughness increase.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.1199-1213
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• 2011

Slurry type shield would be very effective for the tunnelling in a sandy ground, but low slurry pressure could cause a tunnel face failure or a ground settlement in front of the tunnel face. Thus, the stability of tunnel face could be maintained by applying an excess slurry pressure that is larger than the active earth pressure. However, the slurry pressure should increase properly because an excessively high slurry pressure could cause the slurry flow out or the passive failure of the frontal ground. It is possible to apply the high slurry pressure without passive failure if a horizontal impermeable layer is located in the ground in front of the tunnel face, but its location, size, and effects are not clearly known yet. In this research, two-dimensional model tests were carried out in order to find out the effect of a horizontal impermeable layer for the slurry shield tunnelling in a saturated sandy ground. As results, larger slurry pressure could be applied to increase the stability of the tunnel face when the impermeable layer was located in the ground above the crown in front of the tunnel face. The most effective length of the impermeable grouting layer was 1.0~1.5D, and the location was 1.0D above the crown level. The safety factor could be suggested as the ratio of the maximum slurry pressure to the active earth pressure at the tunnel face. It could also be suggested that the slurry pressure in the magnitude of 3.5~4.0 times larger than the active earth pressure at the initial tunnel face could be applied if the impermeable layer was constructed at the optimal location.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2006.11a
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• pp.43-46
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• 2006

Storage air heater(SAH) is a general purpose facility that is used to simulate the high altitude condition of supersonic ground test facility, thurst compensation test of rocket engine nozzle and gas turbine engine combustor test. SAH in KARI is built to simulate the total temperature of the supersonic ground test facility which has a wide flight envelope from altitude 0km, Mach 2 to altitude 25km, Mach 5 and operates up to 1300K, 3.5MPa. In this paper, we introduces the SAH in JAXA which is model of SAH in KARI and summarizes the design process and manufacture of ours.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2004.06a
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• pp.247-247
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• 2004

가압 중수로형 원자력발전소에서는 원자로의 감속재 및 냉각재로 사용하는 중수(heavy water)로 인한 삼중수소(tritium)의 생성이 전체 방사선 준위 상승의 가장 중요한 원인이 되고 있다. 따라서 4기의 중수로가 운전 중인 우리나라에서도 월성원자력 발전소에 삼중수소 제거 설비(Tritium Removal Facility)가 건설 중에 있다. 이 시설로부터 99% 이상의 순도인 삼중수소가 회수되며, 회수된 삼중수소는 장기적인 저장을 위하여 안전하게 포장되어야 한다.(중략)

• Proceedings of the Korean Nuclear Society Conference
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• 1996.05b
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• pp.317-322
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• 1996

고온으로 유지되는 원자로에는 열손실을 줄이기 위하여 단열재가 설치되어 있다. 일반직으로 열손실 시험에서 나타난 실제 열손실은 설계상의 열손실보다 크며, 이의 원인은 단열설계의 부적절, 단열재 설치상의 미흡 등에 기인한다. 본 연구에서는 단열재 두께와 간격에 대한 열전달 특성을 분석하여 단열설계변수를 최적화하며, chimney effect에 의한 열손실 증가를 정량적으로 분석하였다. 본 연구의 결과는 원자로용기 뿐아니라 가압기, 증기발생기 등의 큰 규모의 단열재 설계에 적용될 수 있다.

• Journal of the KSME
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• v.22 no.3
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• pp.169-174
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• 1982

우리나라는 1978 년 고리 1호기의 가동을 효시로 고리, 월성, 영광, 울진에 8기의 원자력발전소를 건설중에 있고 앞으로도 후속기의 착공이 계속될 전망이다. 노형별로 보면 월성1호기가 카나다 에서 개발된 가압식중수로(pressurized water reactor, PWR형)이다. 이 두 노형의 가장 큰 차이 점은 천연우라늄과 농축우라늄을 각각 사용한다는 핵주기상의 차이에 있고 따라서 핵연료집합 체의 구조와 노심관리상에는 큰 차이가 있다. 본 해설을 현재 우리나라에서는 건설되고 있는 PWR형과 CANDU형 원자로 핵연료를 중심으로 이들 각각의 구조, 설계, 재질상의 특성과 지금 까지 밝혀진 핵연료 파혼현상을 고찰하고 이를 대비한 시험평가분야를 검토함으로써 앞으로 다 가올 핵연료 국산화 시대에 도움이 되리라 믿는다.

• Proceedings of the Korean Nuclear Society Conference
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• 1996.05d
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• pp.543-548
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• 1996

국내 가압 경수형 원자력 발전소 주제이실의 바닥에 가장 적합한 화재 감지기 선정을 위하여 원전 심사, 검사시 적용한 국내·외 화재감지기 설계 및 설치에 관한 법규와 규제요건의 종합적인 검토를 수행하고 원전의 주제이실 바닥 환경을 최대로 모의한 시험장치를 이용하여 선형열감지기와 공기 표본 추출형 연기감지기의 동작 성능을 비교 시험하였다. 시험 결과 케이블 화재시 공기 표본 추출형 연기감지기가 감도 및 응답특성이 정온식 선형 감지기 보다 우수한 것으로 확인되었다.