Spent nuclear fuel continues to be generated domestically and abroad, and various studies are actively being conducted for interim dry storage and disposal of spent nuclear fuel. The characteristics vary depending on the type of spent nuclear fuel and the initial specifications, and based on these characteristics, it is essential to estimate the burnup and enrichment of spent nuclear fuel as a nondestructive assay. In particular, it is important to estimate the characteristics of spent nuclear fuel with non-destructive tests because destructive tests cannot be performed on all encapsulated spent nuclear fuel in case of intrusion traces in safeguards. Data is made by measuring spent nuclear fuel directly to evaluate burnup of spent nuclear fuel, but computer simulation research is also important to understand its characteristics because past burnup history is not accurately written, and destructive testing is difficult. In Sweden, the dependency of the burnup history in source strength and mass of light-water reactor-type spent nuclear fuel was evaluated, and this part was also applied to MAGNOX in consideration of the possibility of being used to verify DPRK’s denuclearization. SCALE 6.2 TRITON modeling was performed based on public information on DPRK’s 5 MWe Yongbyon reactor, and the source strength of Nb-95, Zr-95, Ru-106, Cs-134, Cs-137, Ce-141, Ce- 144, Eu-154 nuclides were evaluated. Since the burnup of MAGNOX is lower than that of lightwater reactors, major nuclides in decay heat were not considered. The cooling period was evaluated based on 0, 5, 10, and 20 years. In case the discharge timing was different, the total period of discharge and reloading was the same, and the end-cycle burnup was the same, calculations showed that the source strength emitted from major nuclides was evaluated within 2-3% except for Ru-106 and Ce-144 nuclides. Even the burnup step of nuclear fuel is the same, and the reloaded length after discharge is different, i.e., the cooling period between is different at 5, 10, and 20, the source strength of Nb-95, Zr-95, Ce-144, and Cs-137 was evaluated as an error of 1%. Except for Ru-106 and Ce-144, nuclides are highly dependent on burnup. Compared to the case of light-water reactors, the possibility of a decrease in error needs to be considered later because the specific power is low. As a result, radionuclides in released fuel depend on the effects of burnup, discharged and reloaded period, and a cooling period after release, and research is needed to correct the cooling period within the future burnup history. In addition, in this study, it is necessary to select a scenario -based burnup because the standard burnup due to the statistical treatment of discharged fuels was not considered as conducted in previous studies.

귀리, 콩, 감자, 밀에서 유래한 다양한 식이섬유를 밀가루 대신 10-40%까지 대체함에 따른 수화능, 동적점탄성, 용매흡착능 및 in vitro starch digestion을 비교하였다. 귀리, 콩, 감자, 밀에서 유래한 다양한 식이섬유를 식이섬유의 대체비율이 증가할수록 수분흡착능과 팽윤력은 증가한 반면, 수분용해도는 감소하였다. 밀가루 대신 콩과 감자 식이섬유를 대체함에 따라 동적점탄성은 증가하였으나, 귀리와 밀 식이섬유 대체에서는 오히려 감소하는 경향을 보였다. 식이섬유 대체에 따른 밀가루의 용매흡착능 변화를 분석한 결과, 낮은 대체량의 귀리 식이섬유와 높은 대체량의 콩과 감자 식이섬유가 활용 가능성을 보였다. 원료별 식이섬유 대체 시 밀가루 겔의 전분소화 패턴은 식이섬유 대체비율이 증가함에 따라 glucose 방출은 감소하였으나, 원료별 특성에 따른 유의적인 차이는 없었다. 특히, 밀식이섬유를 제외한 귀리, 콩, 감자 식이섬유는 모두 RDS감소와 RS증가에 따른 pGI 저하를 보여 실제 식품소재로 활용 시 가공적성을 유지할 수 있다면 전분소화지연효과를 기대할 수 있음을 확인할 수 있었다. 한편, 식이섬유의 원료에 따른 식이섬유 조성과 전분소화 관련 특성 간 상관관계를 분석한 결과, 전분소화를 지연시키는 효과는 수용성 식이섬유보다는 불용성과 총식이섬유 함량이 중요한 인자임을 알 수 있었다.

지반의 동적 변형 특성인 전단파 속도(V_s), 압축파 속도(V_p), 그리고 그에 따른 포아송 비(v)는 내진 설계나 내진 성능 평가 외에도 구조물의 거동 평가에 필요한 매우 중요한 지반 정수이다. 지난 수십 년 동안 이러한 지반 정수를 효율적이고 정밀하게 측정하기 위하여, 여러 가지 공내 탄성파 시험 기법들이 개발 및 적용되어 왔다. 본 연구에서는 가장 신뢰성이 높은 현장 탄성파 기법인 크로스홀 탄성파 시험을 지반 동적 물성 획득 기법으로 선정하였다. 지하수위 존재 여부에 관계 없이 토사뿐만 아니라 암반을 대상으로 크로스홀 시험을 성공적으로 수행할 수 있도록, 연직 시추공 안에서 지반을 대상으로 횡방향 가진이 가능한 스프링식 발진 장치를 개발하고, 두 곳의 기존 항만 부두 부지와 신규 LNG 저장 시설 두 부지로 구성된 국내 세 지역을 대상으로 크로스홀 탄성파 시험을 실시하였다. 대상 부지에서의 개발 발진 장치 적용을 통한 크로스홀 시험으로부터 지표 부근 토사부터 하부 공학적 기반암 및 지진학적 기반암으로 구성된 암반까지의 깊이별 V_s,\;V_p 및 v와 같은 지반 동적 특성을 매우 효율적으로 결정하였으며, 적용 대상 시설물인 기존 항만 부두 시설물의 내진 성능 평가 그리고 신규 LNG 저장 시설물의 내진 설계를 위한 근본 자료로 제시하였다.

This study evaluated the effect of water level of water resources on water quality in Ulsan. Two reservoirs, Sayeon Dam and Hoeya Dam, were selected and water quality of chemical oxygen demand (COD), total nitrogen (TN) and total phosphorus (TP) were analyzed from 2012 to 2014. And the characteristics of precipitation were also analyzed for 70 years (1945~2014) because runoff of non-point pollutant was strongly affected by precipitation. As a result, water deterioration of Sayeon Dam and Hoeya Dam were affected in accordance with lowering water level. For example, the concentrations of COD and TN was negatively correlated with the water level when the water level of Sayeon Dam was gradually decreased in 2013. The TN concentration was increased to 1.432 mg/L from 0.875 mg/L while the lowest water level of Sayeon Dam was recorded 45 m in 2014. Additionally the concentration of COD and TN was sensitively increased with 0.213 mg/L/m and 0.058 mg/L/m on account of non-point pollutant runoff. It is indicated that hereafter a control of non-point pollutant runoff is the critical factors to maintain water resources because the contribution of non-point pollutant is expected to increase due to the frequent heavy rain events. Therefore, it is necessary to map out a specific plan for non-point pollutant control based on analyses of runoff characteristics, water pollution sources and reduction plans in water pollutants and to establish a water modelling and database system as a preventive action plan.

At the close of the year 1990, tombs in south Korea will cover the area of 940 ㎢, which is 0.9% of the entire landspace. Annual increase of 200,000 tombs is encroaching on landspace by 10 ㎢. It is estimated that the decrease in the forest area caused by tombs results a decrease both in the production of O_2 by 912,000 tons and in the absorption of CO_2 by 1,254,800tons per year. As a result, there will be an increase in the amount of CO_2, which is one of the factors that cause the greenhouse effect.