Nuclear power plants in Korea stores approximately 3,800 drums of paraffin solidification products. Due to the lack of homogeneity, these solidification products are not allowed to be disposed of. There is therefore a need for the separation of paraffin from the solidification products. This work developed an equipment for a selective separation of paraffin from the solidification product using the vacuum evaporation and condensational recovery method in a closed system. The equipment mainly consists of a vacuum evaporator and a condensational deposition recovery chamber. Nonisothermal vacuum TGAs, kinetic analyses and kinetic predictions were conducted to set appropriate operation conditions. Its basic operability under the established conditions was first confirmed using pure paraffin solid. Simulated paraffin solidification product fixing dried boric acid waste including nonradioactive Co and Cs were then fabricated and tested for the capability of selective separation of paraffin from the simulated waste. Paraffin was selectively separated without entertainment of Co and Cs. It was confirmed that the developed equipment could separate and recover paraffin in the form of nonradioactive waste.

Various types of tanks are used in nuclear power plants, and sludge composed of various organic substances and inorganic oxides contaminated with radioactive materials may be present at the bottom of a tank of a radioactive waste treatment device. In addition, glassy and fixative oxide contamination layers are accumulated on the inner wall of the tank depending on the tank material, usage and degree of oxidation. Such contaminated sludge is the main cause of radiation exposure to workers when dismantling nuclear power plant tanks. In addition, the waste filters generated by filtration of contaminated sludge is treated as secondary radioactive waste, and this radioactive waste not only occupies a lot of disposal space, but also the disposal cost is continuously increasing. Therefore, it is necessary to develop a technology that does not generate waste filters as much as possible. To solve this problem, NILEPLANT Co., Ltd. registered a patent named “Filtering apparatus” based on previous research and manufactured a rotary filtration membrane device through detailed design. The rotary filtration membrane device is composed of three or more multiple rotary filtration membranes, and can remove fine particles in wastewater as well as sludge accumulated inside a radioactive contamination tank. In addition, considering the site characteristics of special conditions such as nuclear power plants, it was designed to show excellent performance in removing fine particles while minimizing the area where the device is installed. The rotary filtration membrane device is designed and manufactured as a double cylinder structure that combines a hydro cyclone filter type body and an inner partition wall, and is equipped with a filter cloth-based rotary cylinder filter to process sludge through the filter cloth in addition to inertial. In addition, the patented principle enables self-backwashing without stopping the filtration process, extending the life of the filter and minimizing waste filters. The filtration performance, self-backwashing function, and sludge behavior of the rotary filtration membrane device manufactured based on the detailed design were evaluated through experiments, and improvements to obtain more effective filtration performance were derived. Accordingly, it is expected that the more improved rotary filtration membrane device can be effectively used to remove sludge generated during the dismantling of nuclear power plants in the future.

우리나라는 대규모 유류오염사고가 발생한 경우 방제자원이 충분하지 않아 방제에 어려움을 겪었으며, 또한 방제에 동원된 어선이 효과적인 방제를 수행하지 못해 작업비용이 거부되는 사례도 이전 사고에서 경험하였다. 이에 대규모 유류오염사고 등을 대비하여 방제자원을 사전에 확보하고 또한 유류오염으로 인하여 많은 피해를 입게 되는 오염지역의 어선을 효율적으로 활용할 수 있는 방안의 일환으로 소형 선박에 장착하여 기름을 회수할 수 있는 효율적 장비를 개발하고 이를 정책화하는 것이 중요한 대안이 될 수 있다. 이를 위해, 본 연구에서 국내 실정에 맞는 소형선박 장착용 기름회수장비 개발을 위한 예비 단계로서 이러한 장비의 장착에 적합한 대상 선박의 선정을 위한 연구를 수행하였다.

광케이블은 유리를 가는 실처럼 만든 광섬유에 빛을 통하여 신호를 보내어 정보를 보내는 원리로써, 송신측에서 반도체 레이저에 의하여 정보를 빛으로 변환한 후 전송하면 수신측에서 전기 신호로 변환하여 정보를 수신하는 체계이며, 주요 성분은 PE등의 플라스틱 수지와 철, 알루미늄, 광섬유(SiO2 또는 GeO2)등으로 구성되어 있다. 현재 광케이블의 수요가 급증함과 동시에 폐광케이블 발생량 또한 급속도로 증가되고 있으며, 연간 약 3만톤 가량이 발생되나 재활용업체에서는 소형규모의 단순탈피장치로 외피인 HDPE(합성고밀도폴리에틸렌)만을 회수하고 다량의 플라스틱 수지와 알루미늄, 광섬유에 포함되어있는 광물자원(Ge 150만원/kg) 등은 단순 적재해 놓거나 매립, 소각하는 등 관련 재활용 기술이 매우 낮은 실정이다. 따라서 본 연구는 폐광케이블 재활용을 위하여 자동화 공급 기술, 선택적 국부가열, 절개 및 선별등의 기술을 통하여 각각의 유용자원을 분리/회수할 수 있는 1Ton/day 이상의 폐광케이블 자원회수장치를 연구하였다.

This study aims to analyze region-specific trends in changing greenhouse gas emissions in incineration plants of local government where waste heat generated during incineration are reused for the recent five years (2009 to 2013). The greenhouse gas generated from the incineration plants is largely CO2 with a small amount of CH4 and N2O. Most of the incineration plants operated by local government produce steam with waste heat generated from incineration to produce electricity or reuse it for hot water/heating and resident convenience. And steam in some industrial complexes is supplied to companies who require it for obtaining resources for local government or incineration plants. All incineration plants, research targets of this study, are using LNG or diesel fuel as auxiliary fuel for incinerating wastes and some of the facilities are using LFG(Landfill Gas). The calculation of greenhouse gas generated during waste incineration was according to the Local Government's Greenhouse Emissions Calculation Guideline. As a result of calculation, the total amount of greenhouse gas released from all incineration plants for five years was about 3,174,000 tCO2eq. To look at it by year, the biggest amount was about 877,000 tCO2eq in 2013. To look at it by region, Gyeonggido showed the biggest amount (about 163,000 tCO2eq annually) and the greenhouse gas emissions per capita was the highest in Ulsan Metropolitan City(about 154 kCO2eq annually). As a result of greenhouse gas emissions calculation, some incineration plants showed more emissions by heat recovery than by incineration, which rather reduced the total amount of greenhouse gas emissions. For more accurate calculation of greenhouse gas emissions in the future, input data management system needs to be improved.