As of 2023, there are a total of 24 nuclear power plants (NPPs) in operation in Korea, with 21 pressurized water reactors (PWRs) and three pressurized heavy water reactors (PHWRs). Korean NPPs discharge radioactive effluents into the environment every year. Radioactive effluents from NPPs contain various radionuclides and materials, including 3H, 14C, Noble gas, particulates, and iodine Among the radioactive effluents discharged from Korean NPPs, 14C is a pure beta emitter with a half-life of 5,730 years. The human body can inhale and ingest 14C to cause internal exposure. In addition, the amount of 14C present in the environment is decreasing, but the amount of 14C discharged from NPPs is increasing. 14C discharged to the environment can be inhaled and ingested by the public around NPPs through various pathways. For this reason, it is very important to monitor and manage 14C because it affects the dose of the public around NPPs. Therefore, this study compared and analyzed the average emissions of 14C discharged from PWRs and PHWRs during the recent 10 years (2012-2021). An average of the public dose due to 14C released from NPPs depending on the reactor types from 2012 to 2021 was also compared. It is inevitable to discharge radioactive effluents while operating NPPs. Korea Hydro & Nuclear Power (KHNP) manages and monitors radioactive effluents released into the environment. According to a survey and analysis of 14C discharged from PWRs and PHWRs and the average dose of the public over the recent 10-year (2012-2021) around Korean NPPs, 14C released from PWR accounted for 3.1% of the total discharge but accounted for more than 93.67% of the total public dose. In addition, 14C discharged from PHWRs accounted for 1.12% of the total discharge, but its resulting dose to the public accounted for more than 83.87% of the total public dose. As a result of analyzing the public dose due to 14C from 2012 to 2021, it was gradually increasing every year. Based on these results, monitoring and managing 14C discharge and its resulting doses to the public are important in the future.

Radioactive materials from nuclear power facilities can be released into the atmosphere through various channels. Recently, the dispersion of radioactive materials has become critical issue in Korea after Kori Unit 1 and Wolsong Unit 1 were permanently shut down. In this study, annual atmospheric dispersion factors were compared based on the continuous release and purge release using the XOQDOQ computer program, a method for calculating atmospheric dispersion factors at commercial nuclear power stations. The meteorological data analyzed in this study was based on the Shin Kori nuclear power meteorological tower which has the largest operating nuclear power plants in Korea, for three years (from 2008 to 2010). The analysis results of the dispersion factor of the radioactive material release obtained using the XOQDOQ program showed that the difference between the continuous release and purge release was within two times. This study will be valuable helpful for revealing the uncertainty of the predictive atmospheric dispersion factor to achieve regulation.

본 연구는 점오염원인 하수종말처리장으로부터 배출되는 물의 수질을 분석하고 배출수의 영향을 받는 어류 중 지점들에서 공통적으로 출현하는 어종인 피라미 (Z. platypus) 를 선택하여 조직학적 변화를 참조하천 지점의 수질과 어류 조직을 비교·분석하였다. 2019년 6월 27~28일 하수종 말처리장 4곳 (대전, 전주, 청주, 익산)의 채집 결과, 참조하 천에서 22종 450개체로 가장 많은 종수 및 개체수가 확인 되었다. 지점별로 5개체씩 2~3년생 피라미의 조직표본을 제작하여 아가미와 근육조직 (피부조직)을 관찰한 결과, 참조하천을 제외한 나머지 지점의 조직은 병리적인 양상을 나타내었다. 수질분석 결과, 각 WTP에서는 배출수질 기준을 준수 혹은 더 좋은 수질로 방류하고 있었다. 그러나 하수종말처리수 배출수 및 방류수계 수질에서 오염도지표를 나타내는 항목인 BOD, COD, TP, TN, SS 값이 참조하천에 비해 높은 것으로 나타났다. 빈약한 어류상과 바이오마커로 이용된 종의 조직병리학적 상태는 참조하천에 비해 낮은 수질에서 기인한 것으로 추측되며, 따라서 원인이 되는 하수종말처리장 배출수 수질개선이 이루어져야 할 것으로 사료된다.

본 연구에서는, 혐기성 처리수에 용해된 바이오가스의 회수를 위해 불화 실리카/고분자 중공사 복합막을 제조하 고 막접촉기에서의 성능을 평가하였다. 복합막은 상용 폴리에테르이미드인(PEI) Ultem®을 이용하여 만든 중공사막 표면에 불 화 실리카를 강력한 공유 결합을 통해 코팅하는 방법으로 제조되었다. 막접촉기는 바이오가스로 포화된 수용액을 중공사의 외부에 공급하고, 중공사 내부로 기체를 투과시키는 방법으로 운전하였다. 높은 공극률을 가진 중공사막(PEI-fSiO2-A)은 액상 속도가 0.03 m/s일 때 메탄 회수 유량이 8.25 × 10-5 cm3 (STP)/cm2⋅s에 달했고 불화 실리카에 의해 표면 소수성이 매우 높 아져 물과의 접촉각이 75.6°에서 120~122°로 향상되었다. 본 연구에서 제조된 복합막은 바이오가스의 투과 속도와 소수성 모 두에서 탈기용으로 제조된 상용 폴리프로필렌 막보다 우수한 성능을 나타냈다.

최근 한국에서 원전해체는 중요한 이슈이다. 원전의 운영 시와 비교해볼 때, 원전 해체 시에는 방사성물질의 방출이 크지 않을 것으로 예상되지만, 주민은 항상 방사선피폭으로부터 보호되어야 한다. 이에 대한 효과적인 관리를 위해, 연간 방출관리치와 방출한도치를 원자력안전위원회 고시 및 일반인 선량한도 기준으로부터 유도하였다. 기체상 유출물에 의한 대기 확산 및 침적 인자는 신고리 발전소 기상탑에서 2008년부터 2010년까지 3년간 수집 된 기상자료를 토대로 XOQDOQ 컴퓨터 코드를 이용해서 평가하였다. 선량평가는 ENDOS-G 컴퓨터 코드를 사용하였다. 이 컴퓨터 코드를 이용하여 기체상 유출물의 연간 방출관리치 및 방출한도치를 평가한 결과, 핵종별로 차이가 있었는데, 이는 연령에 따른 방사선민감도의 차이에 기인한다고 할 수 있다. 본 평가 방법 및 결과는 향후 원전 해체 시 방사성유출물 관리에 중요한 정보를 제공할 수 있을 것으로 판단된다.

This study was intended to evaluate the removal efficiency of nutrients in effluents of wastewater using microalgae. Microalgae used in the culture experiment collected in stream and reservoir located in Gyeongsangbuk-do. Dominant species in prior-culture tank were Monoraphidium contortum, Scenedesmus acutus, Coelastrum microporum and Chlorella sp. Dominant species in synthetic wastewater culture under the 4000 Lux and 8000 Lux were Chlorella sp. and Scenedesmus obliquus. The removal efficiency of NO3-N under the 4000 Lux and 8000 Lux were 27.2%~88.1% and 63.0%~83.6% respectively. The removal efficiency of PO4-P under the 4000 Lux and 8000 Lux showed above 93%. Removal efficiency of nutrients of 1.0×106 cells mL-1 inoculation concentration was more higher than that of nutrients of 1.0×105 cells mL-1 and 1.0×107 cells mL-1 inoculation concentration. Microalgae cultured in synthetic wastewater removed 94.9% of TN and 90.0% of TP. The removal rate of TN and TP in synthetic wastewater were 1.961 mg L-1 day-1 and 0.200 mg L-1 day-1 respectively. Nutrient removal efficiency of microalgae according to kinds of wastewater showed the highest in the private sewage.

Euiam and Paldang Reservoirs have often been facing water quality problems, such as eutrophication, algal blooms and off-flavors by treated wastewater effluent (TWE) in the North-Han and the Han River basins, but little is examined on the direct biological effect of TWE. This study tested algal growth potential (AGP) of four TWEs discharged into Euiam and Paldang Reservoirs to evaluate water fertility in September 2014 and March and September 2015. Test alga was used Anabaena circinalis isolated from Paldang Reservoir. Mean concentration of T-N and T-P in TWEs was 3,956.7 μg N L-1 and 50.8 μg P L-1, and the proportion of NO3-N and PO4-P to the total fraction was 72.1% and 40.8%, respectively. Both N and P were high in TWEs, but much higher N than P concentration indicates strong P-limitation. As a consequence, the maximum AGP was determined by PO4-P concentration (r=0.998, p<0.01). Mean AGP value was 15.4 mg dw L-1 among four effluents indicating its eutrophic condition. Due to the establishment of tertiary (advanced T-P) treatment method in the studied plants recently, P concentration was significantly decreased in TWEs compared to the years prior to 2012. However, P concentration seems to be still high enough to cause eutrophication and algal blooms. Therefore, wastewater treatment to P-free level needs to be considered if effluents are directly discharged into the drinking water resources.

Daecheong Reservoir was made by the construction of a large dam (>15 m in height) on the middle to downstream of the Geum River and the discharge systems have the watergate-spillway (WS), a hydropower penstock (HPP), and two intake towers. The purpose of this study was to investigate the limnological anomalies of turbid water reduction, green algae phenomenon, and oligotrophic state in the lower part of reservoir dam site, and compared with hydro-meteorological factors. Field surveys were conducted in two stations of near dam and the outlet of HPP with one week intervals from January to December 2000. Rainfall was closely related to the fluctuations of inflow, outflow and water level. The rainfall pattern was depended on the storm of monsoon and typhoon, and the increase of discharge and turbidity responded more strongly to the intensity than the frequency. Water temperature and DO fluctuations within the reservoir water layer were influenced by meteorological and hydrological events, and these were mainly caused by water level fluctuation based on temperature stratification, density current and discharge types. The discharges of WS and HPP induced to the flow of water bodies and the outflows of turbid water and nutrients such as nitrogen and phosphorus, respectively. Especially, when hypoxic or low-oxygen condition was present in the bottom water, the discharge through HPP has contributed significantly to the outflow of phosphorus released from the sediment into the downstream of dam. In addition, HPP effluent which be continuously operated throughout the year, was the main factor that could change to a low trophic level in the downreservoir (lacustrine zone). And water-bloom (green-tide) occurring in the lower part of reservoir was the result that the water body of upreservoir being transported and diffused toward the downreseroir, when discharging through the WS. Finally, the hydropower effluent was included the importance and dynamics that could have a temporal and spatial impacts on the physical, chemical and biological factors of the reservoir ecosystem.

The development of alternative water resources has emerged as an effective method for solving drought of water resources due to extreme weather and increase in water consumption. Recently, in Korea, there has been active research on reverse osmosis desalination technology, wastewater reuse using forward osmosis membranes, and the forward osmosis(FO)-reverse osmosis(RO) hybrid process combining these two technologies. In this study, the basic performance of FO membranes manufactured by three domestic and international manufactures such as Microfilter Co., Ltd., Toray Chemical Korea Inc., and Hydration Technologies Inc., were investigated for wastewater reuse. In addition, as an experiment to select feed solution, the selected membranes were operated 48 consecutive hours using three secondary effluents pretreated by the UF membrane with a pore size of 0.1 μm and auto strainer with pore sizes of 1 μm and 100 μm as feed solution. Although there was not much difference in the operating performance. Thus, the treated water using the 100 μm auto strainer was selected as feed solution applied to the assessment.

Excess phosphorus in water has become a crucial aspect concerning the eutrophication. Experiments were carried out to fabricate particles of iron oxide to polymer and the beads were then calcinated. It was found that adsorption process most satisfactory fitted to Langmuir equation (R2>0.92) with maximum adsorption capacity 2.663 mg P/g adsorbent. Equilibrium of adsorption was reached after 3 h, while the initial adsorption rate increased from 0.46 mg/g-h to 3.83 mg/g-h when the bead iron content increased from 40.4 mg Fe/g to 160 mg Fe/g. This research was supported by a project (No. 2013001390002) from the Korea Environmental Industry & Technology Institute funded by the Ministry of Environment and the Brain Korea 21 Plus program of the Korean government.