• 대한방사선기술학회지:방사선기술과학
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• 제43권5호
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• pp.389-395
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• 2020

The evaluation of radioactivated components of heavy-ion accelerator facilities affects the safety of radiation management and the exposure dose for workers. and this is an important issue when predicting the disposal cost of waste during maintenance and dismantling of accelerator facilities. In this study, the FLUKA code was used to simulate the proton treatment device nozzle and classify the radio-nuclides and total radioactivity generated by each component over a short period of time. The source term was evaluated using NIST reference beam data, and the neutron flux generated for each component was calculated using the evaluated beam data. Radioactive isotopes caused by generated neutrons were compared and evaluated using nuclide information from the International Radiation Protection Association and the Korea Radioisotope association. Most of the nuclides produced form of beta rays and electron capture, and short-lived nuclides dominated. However, In the case of ⁵⁴Mn, which is a radioactive product of iron, the effect of gamma rays should be considered. In the case of tritium generated from a material with a low atomic number, it is considered that handling care should be taken due to its long half-life.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2009년도 춘계 학술발표회
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• pp.17-22
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• 2009

Reliability analyses were performed to quantify the risk in axially loaded large-scale pile foundations in consideration of pile-soil interaction and uncertainties on various design variables. The finite difference method based on an equivalent soil spring model and a load transfer method and Monte Carlo simulation method are integrated in the framework of reliabilty analysis. The applicability and efficiency of the proposed method in the safety assessment of axially loaded pile-soil system was verified using a realistic example. Since the proposed method can explicitly consider uncertainties in various design variables, and quantify failure probability of a pile foundation, it can be used to estimate risk, to obtain basic informations for life cycle cost analysis, and to develop code requirements for a reliability-based design of pile foundations.

• 대한조선학회 특별논문집
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• 대한조선학회 2015년도 특별논문집
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• pp.34-40
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• 2015

The design, procurement and fabrication of FPSO project ordered by Inpex Browse, Ltd. have been currently carried out by DSME(Daewoo Shipbuilding Marine and Engineering Co.). The unit will be installed and operated in the Ichthys field offshore of North-Western Australia and there are the particular design requirements to do with performance on the environment loads corresponding to max. 10,000 years return period wave. Also, the operational life of FPSO has to be over 40 years. With this background, this paper introduces the structural design procedure of crane pedestal foundation operated in north-western Australia offshore. The design of crane pedestal foundation structure is basically based on international design code (i.e. API Spec. 2C), Classification society's rule and project specifications. The design load cases are mainly divided into the crane normal operating conditions and crane stowed conditions according to environment conditions of the offshore with 1-year, 5-year, 10-year, 200-year and 10,000-year return period wave. This design experience for crane pedestal foundation operated in north-western Australia offshore will be useful to do engineering of other offshore crane structures.

• Advances in concrete construction
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• 제1권1호
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• pp.29-44
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• 2013

Post earthquake fire (PEF) can lead to the collapse of buildings that are partially damaged in a prior ground-motion that occurred immediately before the fire. The majority of standards and codes for the design of structures against earthquake ignore the possibility of PEF and thus buildings designed with those codes could be too weak when subjected to a fire after an earthquake. An investigation based on sequential analysis inspired by FEMA356 is performed here on the Life-Safety performance level of structures designed to the ACI 318-08 code after they are subjected to two different earthquake levels with PGA of 0.35 g and 0.25 g. This is followed by a four-hour fire analysis of the weakened structure, from which the time it takes for the weakened structure to collapse is calculated. As a benchmark, the fire analysis is also performed for undamaged structure and before occurrence of earthquake. The results show that the vulnerability of structures increases dramatically when a previously damaged structure is exposed to PEF. The results also show the damaging effects of post earthquake fire are exacerbated when initiated from second and third floor. Whilst the investigation is for a certain class of structures (regular building, intermediate reinforced structure, 3 stories), the results confirm the need for the incorporation of post earthquake fire in the process of analysis and design and provides some quantitative measures on the level of associated effects.

• 식품과학과 산업
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• 제50권3호
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• pp.39-50
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• 2017

In order to secure competitiveness of the home meal replacement (HMR) industry from a long-term perspective, development of packaging and processing technologies must be achieved. The development of technology that can secure freshness, nutrition, and taste but secures the shelf life is the key to the future growth of HMR. The future of HMR can be considered in terms of nutrition, environment and safety. From the nutritional point of view, it is expected that development of healthy HMR such as low-salt, low-sugar, low-fat, and high fiber and premium HMR with functional ingredient enhanced, and personalized HMR for silver, infant and patients will be done. And it is expected that development of HMR utilizing environmentally friendly food or local food, development of energy reduction and environmentally friendly disinfection technology, development of environmentally friendly packaging material, and providing information on HMR preparation using QR code and RFID from the environmental and safe point of view.

• 한국식품위생안전성학회지
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• 제27권2호
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• pp.194-201
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• 2012

식품이력추적관리번호는 식품이력추적관리를 위한 식별의 기준으로서 식품이력정보와 직접적으로 연결되어 있으며, 식품공급체인에 따라 각 단계별로 기록, 관리, 보관하는 이력정보를 연결시키는 연결고리의 역할을 하는 중요한 인자이다. 그럼에도 불구하고 우리나라에서 가공식품에 대한 식품이력추적관리번호를 자율적으로 부여하는 방식을 적용하고 있어 혼란이 야기되고 있는 실정이다. 실제 식품이력추적관리번호는 식품관련 산업분야에서 운영되고 있는 기존의 식별방법과 조화롭게 연계되지 않으면 그 효용성과 적합성이 낮아 산업현장과 소비자로부터 외면 받을 수밖에 없는 처지에 놓이게 될 것이다. 본 연구에서는 가공식품에 대하여 국제적으로 사용되는 바코드체계와 국내의 식품관련 법규를 접목하여 식품이력추적관리번호를 부여하는 표준화 방안을 제안하였다. 또한 이러한 식품이력추적관리번호를 실제 산업현장의 운영체계에 활용할 수 있는 방안도 함께 제시하였다. 제안하는 식품이력추적관리번호는 총 20자리로서 해당 상품(식품)의 기본정보에 해당하는 13자리의 GTIN 바코드, 표시기준으로 의무화된 6자리의 유통기한(제조년월일 또는 품질유지기한), 1자리의 추가정보(공장식별코드 또는 생산관리단위)로 구성되도록 하였다. 이러한 부여체계는 식품 산업과 유통(판매) 현장에서 운용되고 있는 기존 시스템과의 연계성을 높이고 식품이력추적관리체계의 도입에 따른 투입비용을 최소화하여 식품이력추적관리체계의 도입을 활성화하기 위한 목적도 포함하고 있다. 이는 국제적인 추세와 기존의 식품관련 정책 및 규정과도 무리 없이 조화가 이루어진다. 또한 식품이력추적관리 로고를 별도로 부착하여 식품이력추적관리번호를 인식하는 방법을 안내하여 소비자의 인식을 제고하고 식품이력추적관리번호를 최소 판매 포장단위에 추가로 표기하기 위한 별도의 투입비용을 제거하는 효과도 고려하였다. 식품이력추적관리시스템은 이력정보를 종합적으로 기록 관리 연계 활용하여 식품사고 발생 시 명확한 원인규명과 이력추적을 통한 위해식품의 신속한 차단 및 회수, 식품과 관련된 이력정보 제공 등의 기능을 수행하여야 한다. 본 연구에서 제안하는 식품이력추적관리번호의 표준화 방안은 현재 운영되고 있는 "위해상품 판매차단시스템"에서 위해식품을 신속하고 정확하게 차단하는 기능을 향상시킬 수 있을 뿐만 아니라 "위해식품 회수지침"에 따른 체계적인 회수과정과 검증체계 역시 효율적으로 도입할 수 있도록 하는 효과가 있다. 또한 전자통관시스템인 "UNI-PASS"와의 연계는 모든 수입식품을 대상으로 식품안전관리 범위를 확대할 수 있으며 "전자세금계산서 제도"에서 기록되는 거래정보와의 연계로 유통과정에 대한 투명한 관리체계의 도입을 앞당길 수도 있는 기폭제가 될 수 있다. 또한 소비자의 알권리 충족을 위한 식품이력정보의 조회과정에서 식품이력추적관리번호의 표준화로 입력오류를 최소화할 수 있을 뿐만 아니라 기존의 바코드 인식기능에 유통기한과 추가정보를 조회하는 기능을 부가적으로 도입하면 스마트 기기나 키오스크를 활용하여 실시간으로 식품이력정보를 조회할 수 있게 하는 장점도 있다.

• 한국식품위생안전성학회지
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• 제12권1호
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• pp.26-38
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• 1997

The quality changes of hams and sausages in refrigerated storage were investigated. Seven types of hams and six types of sausages produced in Korea were collected from markets and stored at 1$0^{\circ}C$ according to the Food Code of Korea, and then chemical, microbiological, textural and sensory characteristics were evaluated at 30, 40 and 50 days. The proximal analysis showed considerable variation in fat with less variation in moisture and protein. The pH values of hams and sausages slightly changed with no consistent difference. Water activity values of all samples except one type of sausage were consistent over time in refrigerated storage. No purge losses of hams were observed except two types of samples in the intial stage. Several types of sausages showed purge losses with no consistency and one type of sausage showed consistent purge losses (0.44~11.29%) during the storage. The volatile basic nitrogen (VBN) content of hams and sausages was still within 20 mg% (Standard and Specification of Korea) on the 50th day, although the VBN of all samples significantly increased over time (p<0.05). The thiobarbituric acid (TBA) values of hams and sausages were well below 1.0 during the storage, although the TBA values of all samples significantly increased (p<0.05). However it was noticed that one type of ham and two types of sausages showed TBA values of 0.945, 0.928 and 0.978, respectively. All the standard plate counts (SPCs) of hams during the storage period showed a level below 30 CFU/g except one type of sample with 103 CFU/g at 50 days. All the SPCs of sausages showed a level below 50 CFU/g except one type of sample with 102 CFU/g and two types of samples with 104 CFU/g on the 50th day. Coliform groups were not counted in all samples during the storage. Instrumental texture analysis showed that springiness, cohesiveness, chewiness, gumminess and adhesiveness slightly changed with no consistent difference. The hardness of the hams showed a decreasing tendency, and the hardness of the sausages an increasing tendency with no significant difference. Sensory evaluation for color, flavor, taste, texture and overall acceptability showed decreasing tendencies over time (p<0.05). The scores of the five sensory characteristics maintained the medium level of quality at the termination of the experiment. Although the results indicated that the ham and sausage samples were acceptable after the 50 days' storage at 1$0^{\circ}C$, the shelf-life of the samples should be determined considering the rapid growth of bacteria and the high TBA values at 50 days.

• 한국지진공학회논문집
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• 제20권7_spc호
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• pp.485-494
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• 2016

The risk-based assessment, also called time-based assessment of structure is usually performed to provide seismic risk evaluation of a target structure for its entire life-cycle, e.g. 50 years. The prediction of collapse probability is the estimator in the risk-based assessment. While the risk-based assessment is the key in the performance-based earthquake engineering, its application is very limited because this evaluation method is very expensive in terms of simulation and computational efforts. So the evaluation database for many archetype structures usually serve as representative of the specific system. However, there is no such an assessment performed for building stocks in Korea. Consequently, the performance objective of current building code, KBC is not clear at least in a quantitative way. This shortcoming gives an unresolved issue to insurance industry, socio-economic impact, seismic safety policy in national and local governments. In this study, we evaluate the comprehensive seismic performance of an low-rise residential buildings with discontinuous structural walls, so called piloti-type structure which is commonly found in low-rise domestic building stocks. The collapse probability is obtained using the risk integral of a conditioned collapse capacity function and regression of current hazard curve. Based on this approach it is expected to provide a robust tool to seismic safety policy as well as seismic risk analysis such as Probable Maximum Loss (PML) commonly used in the insurance industry.

• Nuclear Engineering and Technology
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• 제52권1호
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• pp.19-26
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• 2020

Small nuclear reactor features higher power capacity, longer operation life than conventional power sources. It could be an ideal alternative of existing power source applied for special equipment for terrestrial or underwater missions. In this paper, a 25kWe heat pipe cooled reactor power source applied for multiple use is preliminary designed. Based on the design, a thermal-hydraulic analysis code for heat pipe cooled reactor is developed to analyze steady and transient performance of the designed nuclear reactor. For reactor design, UN fuel with 65% enrichment and potassium heat pipes are adopted in the reactor core. Tungsten and LiH are adopted as radiation shield on both sides of the reactor core. The reactor is controlled by 6 control drums with B₄C neutron absorbers. Thermoelectric generator (TEG) converts fission heat into electricity. Cooling water removes waste heat out of the reactor. The thermal-hydraulic characteristics of heat pipes are simulated using thermal resistance network method. Thermal parameters of steady and transient conditions, such as the temperature distribution of every key components are obtained. Then the postulated reactor accidents for heat pipe cooled reactor, including power variation, single heat pipe failure and cooling channel blockage, are analyzed and evaluated. Results show that all the designed parameters satisfy the safety requirements. This work could provide reference to the design and application of the heat pipe cooled nuclear power source.

• 한국산학기술학회논문지
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• 제22권4호
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• pp.1-9
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• 2021

A60급 갑판 관통 관은 선박과 해양플랜트의 화재 발생 시 인명의 보호와 화염전파를 방지하기 위해 갑판 구획에 설치되는 방화 장치이다. A60급 갑판 관통 관이 새로 개발되거나 기존의 설계가 변경될 경우 국제해사기구의 화재시험절차 규정에 따라 A60급 갑판 관통 관의 방화성능을 검증하도록 요구하고 있다. 따라서, 본 논문에서는 신규 개발된 선박과 해양플랜트용 A60급 갑판 관통 관의 방화 설계의 적합성을 평가하기 위해 과도 열전달 해석을 수행하였고, 화재시험을 통해 해석결과의 타당성을 검증하였다. 또한 A60급 갑판 관통 관의 열전달 특성은 관의 직경, 내부형상 그리고 재질과 같은 설계 사양에 따라 비교하여 검토하였다. 과도 열전달 해석은 범용 유한요소법 소프트웨어인 ABAQUS/Implicit를 사용하여 수행하였으며, 해석결과의 검증을 위한 화재시험은 해사안전위원회에서 규정한 화재시험절차 코드에 따라 수행하였다. 본 연구에서 검토한 A60급 갑판 관통 관의 방화성능은 국제 해상안전규정을 만족하였고, 재질 사양의 설계가 중요한 것으로 나타났다. 최대 시험온도를 기준으로 SUS316L 재질의 측정온도는 S45C 재질보다 평균적으로 25% 낮게 나타났고, 이때 각 재질의 열전도계수와 비열의 차이는 각각 17%와 58%였다.