• Journal of Korean Tunnelling and Underground Space Association
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• v.16 no.2
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• pp.193-201
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• 2014

This paper presents the development of simulation system on EPB shield TBM Hood operation. In recent, EPB shield TBM is widely used in the tunnel construction. Since the hood system of the EPB shield TBM is most important to excavate the tunnel, it is necessary to perform the simulation of hood system to investigate the design and operation parameters prior to tunnel construction. In order to carry out this study, the scaled simulation system was designed and developed. The model tests were performed to verify the developed system. During the simulation, the earth pressures developed in the chamber during tunnelling were measured to evaluate the operation technique. The test results obtained by the developed simulation system show clearly the similar behaviour of TBM hood compared with the field data. It was also found that the ground loss during tunnelling is dependent on the change of earth pressure in chamber. Therefore, the simulation system developed in this study will be very useful to evaluate the operation technique of the TBM hood prior to tunnel construction. In addition, this system will be applied in a various condition of ground to get the operating information.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.6D
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• pp.623-629
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• 2010

Recently, the Shield TBM (Tunnel Boring Machine) construction method is used gradually to increase at the Tunnel Constructin site. However the design and application of the Shield TBM were carried out without sufficient investigation of the ground conditions in the construction site. Due to insufficient understanding to the corresponding equipment is frequently occurring unexpected construction cost and extension of a construction period. The most suitable alternative construction method was determined by analyzing tunneling rate, duration, construction cost of shield machine and tunneling data of alternative method. The result of the case study is suggested as follows. First, the accurate soil exploration on the construction site should be preceded to prevent from tunneling stoppage and schedule delay. Second, the most suitable selection of the shield machine to the ground conditions of the construction site should be executed based on the investigation. Third, the best alternative method for boring of hard rock section is 'hard rock blasting after open cut and cover method'.

• Nuclear Engineering and Technology
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• v.2 no.3
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• pp.149-161
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• 1970

This paper describes a detailed investigational performance on the gamma radiation shield effect of heavy concretes that were manufactured by the use of mineral ores produced domestically and which may be possibly applied for the biological shield design. Ten different kinds of mineral ores were collected for use as the aggregates, physical test and chemical analysis for them were carried out to select the aggregate with a better property. Through the experimental investigation on the shielding effect of various concretes with different combination of concrete components such as water-cement and fine-coarse aggregate ratios, it was possible to derive some criteria for the best condition being capable of obtaining the concretes with high density and good uniformity. Data on the shielding-effectiveness of the different concretes were obtained by performing collimated beam experiment using 60Co gamma-ray. Analyzing the shielding-efficiency, shielding-concrete specific gravity and biological shield cost, the optimum condition of yielding the best economic shielding design, with low cost and good spatial distribution to some extent was determined.

• Nuclear Engineering and Technology
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• v.52 no.8
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• pp.1784-1791
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• 2020

The 14 MeV neutron generator facility is being developed by the Institute for Plasma Research India to conduct the lab scale experiments related to Indian breeding blanket system for ITER and DEMO. It will also be utilized for material testing, shielding experiments and development of fusion diagnostics. Occupational radiation exposure control is necessary for the all kind of nuclear facilities to get the operational licensing from governing authorities and nuclear regulatory bodies. In the same way, the radiation exposure for the 14 MeV neutron generator facility at the occupational worker area and accessible zones for general workers should be under the permissible limit of AERB India. The generator is designed for the yield of 10¹² n/s. The shielding assessment has been made to estimate the radiation dose during the operational time of the neutron generator. The facility has many utilities and constraints like ventilation ducts, accessible doors, accessibility of neutron generator components and to conduct the experiments which make the shielding assessment challenging to provide proper safety for occupational workers and the general public. The neutron and gamma dose rates have been estimated using the MCNP radiation transport code and ENDF -VII nuclear data libraries. The ICRP-74 fluence to dose conversion coefficients has been used for the assessment. The annual radiation exposure has been assessed by considering 500 h per year operational time. The provision of local shield near to neutron generator has been also evaluated to reduce the annual radiation doses. The comprehensive results of radiation shielding capability of neutron generator building and local shield design have been presented in the paper along with detailed maps of radiation field.

• Journal of Korea Society of Industrial Information Systems
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• v.7 no.4
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• pp.37-45
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• 2002

In this study, to measure the density and moisture of compaction, it is designed to use the 2 neutron and 5 gamma-ray detectors. Also, it can be know that Co-60 gamma-ray and Cf-252 neutron source are more useful for this system, because discharge of radiation are better than other sources. They are more profitable to improve their accuracy. Especially, to remove the interference of their reciprocal action between neutron and gamma-ray detectors it is designed shield materials with lead between 2 neutron and 5 gamma-ray detectors each other. It is performed the optimal design to shield under the suggested values completely. Because this system will use portable, so decrease of their weight are so important. For this reason, it can be decrease their weight of 5.2[kg] with shield material between each detectors and it can be think mote easy to carry and use on the industrial Spot.

• Journal of Korean Tunnelling and Underground Space Association
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• v.22 no.3
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• pp.311-321
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• 2020

In this study, coefficient of variation for the seismic load effect on the segment lining was calculated. The statistical characteristics of the soil property were analyzed for the probability characteristics of domestic soil. In order to calculate the coefficient of variation for the seismic load effect, the MCS technique was applied, and the closed-form equation was applied to calculate the seismic load effect. As a result of calculating the coefficient of variation, the coefficient of variation of the seismic load effect on the weathered soil was analyzed in the range of 0.06~0.15, and the coefficient of variation was judged to be used as basic data for designing the limit state of the shield tunnel on seismic condition.

• Proceedings of the Materials Research Society of Korea Conference
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• 2003.03a
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• pp.236-236
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• 2003

• Magazine of korean Tunnelling and Underground Space Association
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• v.23 no.4
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• pp.49-57
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• 2021

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.551-552
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• 2011

In this study new evaluation method of eddy currents in conductive shielding sheets are introduced. This method is based on the magnetic flux linkage in rectangular cells. According to this method the allocated amount of memory and the calculation time can be reduced. In this method calculation of magnetic field in any space can be performed by summing contributions of source currents and eddy currents in conductive shielding sheets. This method is applicable to the design of magnetic field-shield.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.10
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• pp.1713-1719
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• 2008

A high temperature superconducting power cable (HTS power cable) was applied large current capacity by no resistance in normal state. Fault state was risen out of over-current but, it was limited to resistance. This study was modeling equivalence, and unbalanced state analyzed operating characteristic of HTS power cable. The equivalence model was composed superconductor, shield, and former part. This model simulation was appeared conductor and shield current in normal state, but unbalanced state was appeared former current as rise current by resistance. So it need to sufficiently influenced the quench characteristic when the former design.