For Dry Storage of Spent Nuclear Fuel (SNF), all moisture must be removed from the dry storage canister through subjected to a drying process to ensure the long-term integrity. In NUREG-1536, the evacuation of most water contained within the canister is recommended a pressure of 0.4 kPa (3 torr) to be held in the canister for at least 30 minutes while isolated from active vacuum pumping as a measure of sufficient dryness in the canister. In the existing drying process, the determination of drying end point was determined using a dew point sensor indirectly. Various methods are being studied to quantify the moisture content remaining inside the canister. We presented a moisture quantification method using the drying process variables, like as temperature, pressure, and relative humidity operation data. During the drying process, it exists in the form of a mixed gas of water vapor and air inside the canister. At this time, if the density of water vapor in the mixed gas discharged out of the canister by the vacuum pump is known, the mass of water removed by vacuum drying can be calculated. The canister is equipped with a pressure gauge, thermometer and dew point sensor. The density of water vapor is calculated using the pressure, temperature and relative humidity of the gas obtained from these sensors. First, calculate the saturated water vapor pressure, and then calculate the humidity ratio. The humidity ratio refers to the ratio of water vapor mass to the dry air mass. After calculating the density of dry gas, multiply the density by the humidity ratio to calculate the density of water vapor (kg/m3). Multiply the water vapor density by the volume flow (m3/s) to obtain the mass value of water (kg). The calculated mass value is the mass value obtained per second since it is calculated through the flow data obtained every second, and the amount of water removed can be obtained by summing all the mass values. By comparing this value with the initial moisture content, the amount of moisture remaining inside the canister can be estimated. The validity of the calculations will be verified through an experimental test in the near future. We plan to conduct various research and development to quantify residual water, which is important to ensure the safety of the drying process for dry storage.

원자력발전소내 습식저장중인 사용후핵연료의 건식저장을 위해서는 캐니스터 내부에 사용후핵연료를 옮겨 담은 이후, 건 식저장 캐니스터 내장품이나 사용후핵연료 다발의 부식방지 및 피복관의 열화방지를 위해 모든 수분은 제거해야 한다. 캐 니스터 내부의 수분을 제거하는데 사용할 수 있는 기체강제순환 건조시스템 개발을 위한 연구개발이 진행중이다. 본 연구 에서는 기체강제순환 건조시스템 설계, 제작을 위한 예비설계를 수행하였다. 예비설계에는 캐니스터 내부 잔존수분 제거를 위한 건조사례조사, 건조관련 규격이나 표준, 건조합격기준, 건조장치구성, 현장요구분석, 습식저장중인 사용후핵연료 특성 을 포함하였다. 예비설계를 통하여 기체강제순환 건조시스템의 설계 개념도와 P&ID를 도출하였고, 이를 활용하여 건조시 스템 제작을 위한 상세설계를 수행할 것이다.

In this paper, numerical simulations are performed for the drying process of potato chip in a microwave oven with multiple waveguides, with the purpose of enhancing the uniformity in temperature distribution. A simulation model is built and simulated using COMSOL Multiphysics software. The simulation model uses 5 different positions of waveguides to see whether it affects the heat distribution in the material. In order to know the final temperature result of the material after it comes out of the cavity on a moving conveyor belt, the average temperature values along the direction of the conveyor belt motion are calculated and plotted. From the results, the best waveguide position is determined to get the best temperature distribution in the potato chips.

Freeze drying for porous Mo was accomplished by using MoO3 powder as the source and camphor-naph- thalene eutectic system as the sublimable material. Eutectic composition of camphor-naphthalene slurries with the initial MoO3 content of 5 vol%, prepared by milling at 55o C with a small amount of oligomeric dispersant, was frozen at -25o C. The addition of dispersant showed improvement of dispersion stability in slurries. Pores were generated subse- quently by sublimation of the camphor-naphthalene during drying in air for 48 h. To convert the MoO3 to metallic Mo, the green body was hydrogen-reduced at 750o C, and sintered at 1100o C for 2 h. The sintered samples, frozen by heated Teflon cylinder, showed large pores with the size of about 40 µm which were aligned parallel to the sublimable vehicles growth direction. The formation of unidirectionally aligned pores is explained by the rejection and accumulation of solid particles in the serrated solid-liquid interface.

The researcher inquired drying characteristics by reflecter shape. Near infrared ray (NIR) is very useful in various drying field. The researcher compared and investigated, temperature about reflecter's shape with numerical analysis method and experimental method. The researcher also investigated about distance between a lamp and a drying target plate using experimental method. As far as a experimental method is concerned, the researcher used the thermal image processing system for changing distance between a lamp and a drying target plate into H=500mm, 600mm and 700mm. Also presented experimental results are compared about thermal image for temperature distribution at each cases. As a result, the researcher has come to the H=700mm about best result in this study.

마늘의 저장성(貯藏性) 향상(向上)을 위한 기초자료(基礎資料)를 얻기위해 난지계(暖地系)인 남해재래(南海在來)와 한지계(寒地系)인 달성재래(達成在來)를 각각(各各) 시기별(時期別)로 수확직후(收穫直後) 구(球)의 기부(基部)로부터 줄기길이를 7cm 및 25cm로 남긴 후 열풍건조기(熱風乾燥機)에서 로 1일(日) 12시간(時間)씩 4일간(日間) 건조(乾燥)한 후 중량감소율(重量減少率)을 관행건조(慣行乾燥)와 비교(比較)하고 저장중(貯藏中) 발근(發根), 맹아(萌芽) 및 부패정도(腐敗程度)를 조사(調査)한 결과(結果)는 다음과 같다. 열풍건조(熱風乾燥) 4일후(日後)의 중량감소율(重量減少率)은 남해재래(南海在來)의 7cm 구(球)에서는 관행건조(慣行乾燥) 13일(日)의 효과(效果)가 있었으며 25cm 구(球)에서는 14일(日)의 효과(效果)가 있었다. 달성재래(達成在來)는 7cm 처리(處理)의 4일간(日間) 열풍건조(熱風乾燥) 효과(效果)는 조기수확(早期收穫), 적기수확(適期收穫), 만기수확별(晩期收穫別)로 관행건조일수(慣行乾燥日數)에 각각(各各) 22일(日), 18일(日), 16(日)의 효과(效果)가 있었으며 25cm처리(處理)의 4일간(日間) 열풍건조(熱風乾燥) 효과(效果)는 조기수확(早期收穫), 적기수확(適期收穫), 만기수확별(晩期收穫別)로 각각(各各) 관행건조(慣行乾燥)의 18일(日), 16일(日), 14일(日)의 효과(效果)가 있었다. 저장초기(貯藏初期)의 사경(砂耕)에 의한 발근(發根), 맹아(萌芽)는 열풍건조구(熱風乾燥區)가 관행건조구(慣行乾燥區)에 비하여 지연(遲延)되는 경향(傾向)을 보였다. 저장후기(貯藏後期)의 인편상태(鱗片狀態)는 열풍건조(熱風乾燥)가 관행건조(慣行乾燥)에 비해 식용가능(食用可能)한 인편수(鱗片數)가 많았으며 부패인편수(腐敗鱗片數)는 적었다.

The effect of mixed oil on the drying characteristics of sewage sludge in oil vacuum evaporation systems was studied. The experimental results showed that the drying rate with cooking oil was faster than that with refined oil due to the difference of thermal conductivity and composition of mixed oil. However, the heating value of all dried sludge was enhanced and the moisture content was below 1% due to penetration of oil into the microbial cells in sludge during the drying procedure. TGA analysis of sludge mixed with the refined oil, which had a higher volatility, showed the slope of the primary falling period was sharply declined. The result of DTA analysis also showed that the first peak was higher than the second peak and corresponded with the phenomena observed in the TGA analysis. In the DTA analysis, the temperature of the primary peak and the secondary peak of dried sludge were comparatively lower than those of raw sludge. Therefore, mixed oil could decrease the self-ignition temperature in an oil-sludge mixing system. In case of waste cooking oil, the TGA and DTA results showed similar results to those of raw sludge, but the DTA results showed that the secondary peaks of dried sludge were narrower and sharper than those of raw sludge. Overall, mixing oil could be a principal factor in controlling the drying efficiency and thermal properties of sludge-derived fuel in oil vacuum evaporation systems.

폐기물의 높은 수분함량은 폐기물 에너지화에 있어 효율을 저해시키는 주된 요인이다. 기계적･생물학적 처리(Mechanical Biological Treatment, MBT)는 생분해성 폐기물의 매립량을 줄이고, 고형연료 생산을 통한 에너지회수를 위해 적용된 기술이다. 최근에는 고품질의 고형연료를 생산하고자 MBT 시설에서 생물학적 처리공정으로 Bio-drying 공정을 적용하고 있다. 본 연구에서는 현재 가동중인 기계적 선별공정 중심의 생활폐기물 고형연료화 시설에서 배출되는 선별 잔재물을 대상으로 Bio-drying이 진행되는 과정에서의 수분제거 특성을 파악하였다. 또한, 특정 범위(45~50℃)로 배출가스의 온도가 유지될 수 있도록 송풍량 자동제어 방식을 적용하였으며, 단일방향의 공기공급에서 기인되는 수분함량의 불균질 분포를 해소하기 위해 송풍방향의 전환을 실시하였다. 2주 동안의 Bio-drying을 통해 폐기물의 40.3%이 감량되었으며, 초기 수분중량 대비 79.4%의 수분이 제거(건조)되었음을 확인하였고, Bio-drying 전/후 폐기물의 수분함량은 각각 43.0 및 14.8%로 분석되었다. Bio-drying 공정에서의 water balance 수립을 통해 송풍방향 전환시점에서의 평균 수분함량이 19.8%로 추정된 반면, 폐기물 상층의 수분함량은 39.0%로 분석되었다. 송풍방향의 전환 이후 실험종료 시점에서의 폐기물 상/중/하층의 수분함량은 각각 23.1, 13.3 및 16.0%로 분석되어, 송풍방향의 전환을 통해 폐기물 상층 수분함량의 효과적인 감소와 수분함량의 균질 분포가 유도될 수 있음을 확인하였다. 또한, 송풍량 자동제어 방식의 적용을 통해 배출가스 온도의 상승 및 하강 시점에서의 송풍량 증가 및 감소에 의해 배출가스의 온도가 특정 범위 내에 존재할 수 있었음을 확인하였으며, 송풍량의 변화가 수분 제거속도를 상승시키는 요인으로 작용한 것으로 분석되었다.

The drying and fuel technologies for sewage sludge have been developed due to the prohibition of ocean dumping and new renewable portfolio standard. This study was performed to enhance the quality of sludge derived fuel and compare drying characteristics for thickened and digested sewage sludge at different temperature, pressure and mixing oil conditions in oil vacuum evaporation system. In addition to investigate calorific value and characteristic analysis of dried sludge. The thickened and digested sludge used in this study were taken from municipal sewage treatment plant and coagulated using polymer (C-310P) in laboratory. The drying rate was increased with temperature and degree of vacuum and it was 25 mL/kg-sludge·min at 110oC and –450 mmHg. The moisture content of dried sludge products showed very low within 1% in the range of 0.4 ~ 0.8%. The evaporation rate of thickened sludge was lower than digested sludge and the constant evaporation period was also shorter. Compared the effect of waste cooking oil and refined waste petroleum oil on drying efficiency, the waste cooking oil showed more effective than refined oil in evaporation rate and drying time. The carbon and hydrogen contents of dried sludge with refined oil were higher than waste cooking oil. The low heating value of thickened dried sludge was higher than digested dried sludge about 400 kcal/kg and both of dried sludge showed high calorific value more than 4,000 kcal/kg.

곡물냉각기를 이용한 벼 건조 및 저장시스템의 최적 운영조건을 구명하기 위하여 Box의 complex algorithm을 기초로 한 최적화 프로그램을 개발하였다. 개발한 최적화 프로그램을 이용하여 반입물량에 따른 시스템의 소요비용이 최소화되는 최적 1차 건조 후 함수율과 건조 및 냉각기의 최적소요 대수를 결정하였다. 그 결과를 요약하면 다음과 같았다. 벼의 건조비용은 최종함수율이 낮을수록 증가하였으며, 톤당 건조비용은 6 톤 건조기에 비해 20 톤