• Nuclear Engineering and Technology
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• v.55 no.10
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• pp.3543-3548
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• 2023

Shutdown chemistry evolution is performed in nuclear power plants at each refueling outage (RFO) to establish safe conditions to open system and minimize inventory of corrosion products in the reactor coolant system (RCS). After hydrogen peroxide is added to RCS during shutdown chemistry evolution, corrosion products are released and are removed by filters and ion exchange resins in the chemical volume control system (CVCS). Shutdown chemistry evolution including RCS clean-up time to remove released corrosion products impacts the critical path schedule during RFOs. The estimation of clean-up time prior to RFO can provide more reliable actions for RCS clean-up operations and transients to operators during shutdown chemistry. Electric Power Research Institute (EPRI) shutdown calculator (SDC) enables to provide clean-up time by Co-58 peak activity through operational data from nuclear power plants (NPPs). In this study, we have investigated the results of EPRI SDC by shutdown chemistry data of Co-58 activity using NPP data from previous cycles and modeled the estimated clean-up time by EPRI SDC using average Co-58 activity of the NPP. We selected two RFO data from the NPP to evaluate EPRI SDC results using the purification time to reach to 1.3 mCi/cc of Co-58 after hydrogen peroxide addition. Comparing two RFO data, the similar purification time between actual and computed data by EPRI SDC, 0.92 and 1.74 h respectively, was observed with the deviation of 3.7-7.2%. As the modeling the estimated clean-up time, we calculated average Co-58 peak concentration for normal cycles after cycle 10 and applied two-sigma (2σ, 95.4%) for predicted Co-58 peak concentration as upper and lower values compared to the average data. For the verification of modeling, shutdown chemistry data for RFO 17 was used. Predicted RCS clean-up time with lower and upper values was between 21.05 and 27.58 h, and clean-up time for RFO 17 was 24.75 h, within the predicted time band. Therefore, our calculated modeling band was validated. This approach can be identified that the advantage of the modeling for clean-up time with SDC is that the primary prediction of shutdown chemistry plans can be performed more reliably during shutdown chemistry. This research can contribute to improving the efficiency and safety of shutdown chemistry evolution in nuclear power plants.

• Journal of Bio-Environment Control
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• v.23 no.4
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• pp.293-302
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• 2014

This study was carried out to develop rain shelter which can make an appropriate size and environment for Chinese cabbage rainproof cultivation. Fifty three farms with chinese cabbage rainproof cultivation system have been investigated to set up width and height of rain shelter. Mostly the width of 6m was desired for rain shelter and the height of 1.6m for their eaves, so these values were chosen as the dimensions for rain shelter. After an analysis of their structural safety and installation costs by the specifications of the rafter pipe, Ø$25.4{\times}1.5t$ and 90cm have been set as the size of rafter that such size costs the least. This size is stable with $27m{\cdot}s^{-1}$ of wind velocity and 17cm of snow depth. Therefore it is difficult to apply this dimension to area with higher climate load. In order to sort out such problem, the rain shelter has been designed to avoid damage on frame by opening plastic film to the ridge. Once greenhouse band is loosen by turning the manual switch at the both sides of rain shelter and open button of controller is pushed then switch motor rises up along the guide pipe and plastic film is opened to the ridge. Chinese cabbage can be damaged by insects if rain shelter is opened completely as revealed a field. To prevent this, farmers can install an insect-proof net. Further, the greenhouse can be damaged by typhoon while growing Chinese cabbage therefore the effect of an insect-proof net on structural safety has been analyzed. And then structural safety has been analyzed through using flow-structure interaction method at the wind condition of $40m{\cdot}s^{-1}$. And it assumed that wind applied perpendicular to side of the rain shelter which was covered by insect-proof net. The results indicated that plastic film was directly affected by wind therefore high pressure occurred on the surface. But wind load on insect-proof net was smaller than on plastic film and pressure distribution was also uniform. The results of structural analysis by applying pressure data extracted from flow analysis indicated that the maximum stress occurred at the end of pipe which is the ground part and the value has been 54.6MPa. The allowable stress of pipe in the standard of structural safety must be 215 MPa or more therefore structural safety of this rain shelter is satisfied.

• Journal of the Society of Disaster Information
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• v.10 no.4
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• pp.518-527
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• 2014

Our society is changed and diversified rapidly and such tendency is accelerated day after day and has made a lot of problems in the many fields. The important thing we have to recognize is such tendency has a bad effect recently on the safety system in Korea. So it is time to enhance the national safety system and moreover recently Sewol-ho(passenger ship) went down in the sea, it made people remind the importance of national safety system. With this incident, Korean government decided to establish the national safety communication network against the disaster. At this time, I will propose several ideas about the national safety communication network. 1. It must to be established an unified network to contact people who is on a disaster site anytime and anywhere. This is most important element on all disaster sites. 2. PS-LTE technology must to be adopted to the network because it has many advantages including various multimedia services compared to the TETRA in the past. 3. 700MHz is the most efficient band for the network because it has wide cell sites coverage compared to 1.8GHz. 4. Satellite communication system is needed to the network for back-up. 5. It will be effective to adopt Social Media to the communication network system like a Twitter or Facebook for sharing many kinds of information and notifying people of warning message. 6. It can make the network more useful to introduce the latest technology like a sensor network. And Korean government has to improve the system related to the disaster including law and operating organization.

• Journal of the Korean Institute of Gas
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• v.5 no.1
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• pp.1-6
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• 2001

The main objective of this study is to determine if the sources of AE in corroded specimens of aluminum could be identified iron the characteristics of the waveform signals recorded during fatigue loading. Coupons of notched 2024-T3 aluminum with or without corrosion (at the notch) were subjected to fatigue loading and the AE signals were recorded using non-resonant, flat, wide-band transducers. The time history and power spectrum of each individual wave signal recorded during fatigue crack growth were examined and classified according to their special characteristics. Five distinct types of signals were observed regardless of specimen condition. The waveform and power spectra were shown to be dependent on specimen condition. During the initial phase of crack growth, the signals obtained in the as-received specimens are most probably due to transgranular cleavage caused by extrusion and intrusion under fatigue loading. In the corroded specimen the signal are probably generated by intergranular cleavage due to embrittlement of grain boundary neat the pitting tip. The need for additional research to further validate these findings is indicated.

• Microbiology and Biotechnology Letters
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• v.26 no.5
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• pp.379-386
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• 1998

Deterioration of food is in general caused by the presence of microorganisms and chemical compounds of food itself. There exists antimicrobial compound in the food, however, addition of food antiseptics, additives, or physico-chemical processing is a common practice. The safety of artificial chemical antiseptics became a serious public concern, therefore, new natural antiseptic compounds are in need to be developed. We have isolated a new natural antifungal protein (KBS-B2) from Astragal seed through ammonium sulfate precipitation and column chromatography using FPLC Mono-S and Superose 12HR. The purified protein inhibited growth of Candida albicans, and spore germination of food spoiling fungi such as Aspergillus ochraceus, Penicillium expensum, P. digitatum and Botrytis cineria. Antifungal effect of the KBS-B2 protein could be directly assayed by bioautography overlaying the fungal spores on the electrophoresed acrylamide gel. The comparison of N-terminal amino acid sequences of the KBS-B2 with known antifungal protein revealed that had 50% homology to thaumatin and zeamatin like proteins.

• Proceedings of KOSOMES biannual meeting
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• 2006.05a
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• pp.207-212
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• 2006

The noise levels on board ship recognized at Europe in the early 1970s and the noise regulations on board ship began to put in a statutory form. After that, in 1982 "International Code on Noise Levels on Board Ships" adopted by IMO and it became standard to the newly built ship and remain so to this day. Especially, the ship engine room, which have huge main engine and various kinds of subsidiary machines, is under an extremely loud condition and so the worker who works in it is easy to lose his hearing. Recently, each nation regulates the allowable noise exposure time by law to protect the industrial employee from the occupational hardness of hearing. In our country, the allowable noise exposure time is regulated by the labor standard law but the international provisions regulated by IMO have been applied in case of the ship engine room. In this paper, the cabin's noise levels of cargo-passenger ships plies south-west coast line were investigated.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.31 no.6
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• pp.96-101
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• 2003

Korea Sounding Rocket(KSR)-III onboard telemetry system has acquired various data from subsystems and sensors in the rocket, and radiated PCM/FM data using two S-band antennas during the flight. Simultaneously， it is necessary that the ground receiving systems track the rocket, and receive and decode telemetry data. Also post processed telemetry data are needed to be broadcasted on ethernet network in real time. Range safety display system displays flight trajectory using telemetry data in mission control center, and so flight manager makes a decision for flight termination from the trajectory This paper describes operating technique about telemetry reception, the development for the realtime data processing system, and the results for telemetering reception on fight test. We telemetered, processed, and broadcasted numerous telemetry data during the flight test successfully.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.53 no.2
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• pp.165-173
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• 2020

Fish roe is among the most valuable food resources produced by fisheries. Raw fish roe requires processing for conversion into hygienic, marketable, and consumer-acceptable forms. In this study, to investigate the food compositional characteristics of various types of fish roe, we applied vacuum freeze-drying to prepare fish roe concentrates (FRCs) from roe of Alaska pollack Theragra chlcogramma, bastard halibut Paralichythys olivaceus, and skipjack tuna Katsuwonus pelamis. The FRC yield ranged from 22.7 to 26.7 g/100 g roe. The major constituents of FRCs were protein (65.4-79.6%), moisture (2.8-6.2%), lipids (8.5-18.3%), and ash (4.8-7.2%). Potassium, sulfur, sodium, and phosphorus were the major mineral elements of FRCs, and the major amino acids were aspartic acid (9.0-10.4 g/100 g protein), glutamic acid (13.2-14.5 g/100 g protein), lysine (8.4-8.6 g/100 g protein), and leucine (8.3-9.7 g/100 g protein). Vacuum freeze-dried FRCs differed among fish species in terms of amino acid composition and electrophoresis protein band distribution. Therefore, FRCs are an excellent source of protein nutrition and an appropriate protein fortification material in human foods or animal feed.

• Journal of Advanced Navigation Technology
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• v.15 no.1
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• pp.11-17
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• 2011

In this paper, we consider the frequency sharing feasibility of Fixed Satellite Service (FSS) with Microwave Landing System (MLS) allocated in the C-band. On the basis of characteristics of MLS and FSS suggested by ITU and safety standards of MLS by ICAO, three interference scenarios are built and numerical simulations are carried out for investigating the frequency sharing between the two systems. From the simulation results, we calculate the separation distance between MLS and FSS ground antennas, required for frequency sharing by employing standard protection limits regulating the interference to noise ratio (I/N) of the receiver.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.3
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• pp.519-526
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• 2016

As marine accidents happen frequently, it is required to establish a marine traffic monitoring system, which is designed to improve the safety and efficiency of navigation in VTS (Vessel Traffic Service). For this aim, recently, X-band marine radar is used for extracting the sea surface information and, it is necessary to retrieve wave information correctly and provide for the safe and efficient movement of vessel traffic within the VTS area. In this paper, three different current estimation algorithms including the classical least-squares (LS) fitting, a modified iterative least-square fitting routine and a normalized scalar product of variable current velocities are compared with buoy data and then, the iterative least-square method is modified to estimate wave information by improving the initial current velocity. Through several simulations with radar signals, it is shown that the proposed method is effective in retrieving the wave information compared to the conventional methods.