• Journal of radiological science and technology
• /
• v.43 no.5
• /
• pp.389-395
• /
• 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.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2009.03a
• /
• pp.17-22
• /
• 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.

• Special Issue of the Society of Naval Architects of Korea
• /
• 2015.09a
• /
• pp.34-40
• /
• 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
• /
• v.1 no.1
• /
• pp.29-44
• /
• 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.

• Food Science and Industry
• /
• v.50 no.3
• /
• pp.39-50
• /
• 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.

• Journal of the Korean Institute of Gas
• /
• v.28 no.2
• /
• pp.93-104
• /
• 2024

Facility diagnosis is essential for the smooth operation and life extension of rotating equipment used in industrial sites. Compared to other diagnostic methods, vibration diagnosis can find most of the initial defects, such as unbalance, alignment failure, bearing defects and resonance, compared to other diagnostic methods. Therefore, vibration analysis is the most commonly used facility diagnosis method in industrial sites, and is usefully used as a predictive preservation (PdM) technology to manage the condition of the facility. However, since the vibration diagnosis method is performed based on experience based on the standard, it is carried out by experts. Therefore, it is intended to contribute to the reliability of the facility by establishing a system that anyone can easily judge defects by establishing a vibration diagnosis method performed based on experience as a knowledgeable code system. An algorithm was developed based on the ISO-20816 standard for vibration measurement, and the reliability was verified by comparing the results of vibration measurement at various demonstration sites such as petrochemical plant compressors, hydrogen charging stations, and industrial machinery with the results of analysis using a development system. The developed algorithm can contribute to predictive maintenance (PdM) technology that anyone can diagnose the condition of the rotating machine at industrial sites and identify defects early to replace parts at the exact time of replacement. Furthermore, it is expected that it will contribute to reducing maintenance costs and downtime due to the failure of rotating machines when applied to various industrial sites such as oil refining facilities, transportation, production facilities, and aviation facilities.

• Journal of Food Hygiene and Safety
• /
• v.27 no.2
• /
• pp.194-201
• /
• 2012

Facing a number of global food-related accidents, the concept and system for food traceability have been designed and introduced in many countries to manage the food-safety risks. To connect and harmonize the various food traceability-information in food traceability system according to the food supply chain, the coding system of identification-number for food-traceability has to be standardized. The GTIN (Global Trade Item Number) barcode system which has been globally standardized and implemented, is reviewed with the mandatory food-labeling regulation in expiration date of processed foods. The integration of GTIN-13 bar-code system for food-traceability is a crucial factor to expand its function in the food-related industrial areas. In this literature, the standard coding system of identification-number for food-traceability is proposed with 20 digit coding number which is combined with GTIN-13 bar-code (13 digit), expiration date (6 digit), and additional classification code (1 digit). This proposed standard coding system for identification-number has a several advantages in application for prohibiting the sale of hazard goods, food-recall, and inquiring food traceability-information. And also, this proposed coding system could enhance the food traceability system by communicating and harmonizing the information with the national network such as UNI-PASS and electronic Tax-invoice system. For the global application, the identification-number for food-traceability needs to be cooperated with the upcoming global standards such as GTIN-128 bar-code and GS1 DataBar.

• Journal of Food Hygiene and Safety
• /
• v.12 no.1
• /
• pp.26-38
• /
• 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.

• Journal of the Earthquake Engineering Society of Korea
• /
• v.20 no.7_spc
• /
• pp.485-494
• /
• 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
• /
• v.52 no.1
• /
• pp.19-26
• /
• 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.