For the fabrication of the Si negative electrode in Li-ion batteries (LIBs) containing the cross-linking polymer binder, in this work, the urethane acrylate (UA) oligomer was synthesized via a simple synthetic process. The cross-linked poly(urethane acrylate) (CPUA)/carbone black (CB)/Si composite (CPUA/CB/Si composite) was fabricated through reactions between their reactive vinyl segments in the UA oligomer. Interestingly, the CPUA/CB/Si composite showed better cycle performance than the poly(vinylidene fluoride) (PVdF)/CB/Si composite (PVdF/CB/Si composite) and the polyurethane (PU)/CB/Si composite (PU/CB/Si composite). The CPUA/CB/Si composite had the best lithiation of about 2586 mAh g-1. The UA oligomer showed a good compatibility with the electrode materials and current collector after and before a curing process.

As part of strengthening pyro safety measures, the Korea Atomic Energy Research Institute is developing LIBS (Laser-Induced Breakdown Spectroscopy) application technology to analyze molten salt components in electrolytic recovery device in real time. LIBS performs qualitative and quantitative analysis by analyzing the spectrum of energy emitted by atomizing and ionizing elements on the surface of a salt sample with a high-focused laser. Since salt easily corrodes metal, it must be managed in an environment with a dew point of -40°C or lower. In this study, we designed and manufactured a device that places a rod-type sampling stick on a mounting base, automatically moves it to the optimal measurement position for LIBS, and retrieves the sample. Its characteristics are as follows. First, LIBS is stationary and does not move. Second, the sample stick is placed on a mounting base and can rotate 360 degrees. Third, according to the command, the sample stick automatically moves to the optimal measurement position of LIBS with three degrees of freedom (X, Y, Z). Fourth, the salt attached to the sampling stick is recovered for chemical analysis by driving the gripper mounted at the bottom of the Z axis, Z axis, and rotation axis (R). The X, Y, and Z movement distances of this device are each 100 mm, rotation is 360 degrees, grip stroke is 50 mm, and position accuracy is ±20 m. Once the performance test of the automated salt sample analysis device is completed, it will be installed in a dry room with a dew point of - 40°C or lower. Samples will be collected remotely in connection with the electrolytic recovery device and gantry robot built in the dry room. We plan to conduct experiments to seat the sample stick. Ultimately, we plan to conduct comprehensive experiments in conjunction with LIBS.

The homogeneity of radioactive spent ion exchange resins (IERs) distribution inside waste form is one of the important characteristics for acceptance of waste forms in long-term storage because heterogenous immobilization can lead to the poor structural stability of waste form. In this study, the homogeneity of metakaolin-based geopolymer waste form containing simulant IERs was evaluated using a laser-induced breakdown spectroscopy (LIBS) and statistical approach. The cation-anion mixed IERs (IRN150) were used to prepare the simulant spent IERs contaminated by non-radioactive Cs, Fe, Cr, Mn, Ni, Co, and Sr (0.44, 8.03, 6.22, 4.21, 4.66, 0.48, and 0.90 mg/g-dried IER, respectively). The K2SiO3 solution to metakaolin ratio was kept constant at 1.2 and spent IERs loading was 5wt%. For the synthesis of homogeneous geopolymer waste form, spent IERs were mixed with K2SiO3 solution and metakaolin first, and then the fresh mixture slurry was poured into plastic molds (diameter: 2.9 cm and height: 6.0 cm). The heterogeneous geopolymer waste form was also fabricated by stacking two kinds of mixtures (8wt% IERs loading in bottom and 2wt% in top) in one mold. Geopolymers were cured for 7d (1d at room temperature and 6d at 60°C). The hardened geopolymers were cut into top, middle, and bottom parts. The LIBS spectra and intensities for Cs were obtained from the top and bottom of each part. Cs was selected for target nuclide because of its good sensitivity for measurement. Shapiro-Wilk test was performed to determine the normality of LIBS data, and it revealed that data from the homogeneous sample is normal distribution (p-value = 0.9246, if p-value is higher than 0.05, it is considered as normal distribution). However, data from the heterogeneous sample showed abnormal distribution (p-value = 7.765×10-8). The coefficient of variation (CoV) was also calculated to examine the dispersion of data. It was 31.3% and 51.8% from homogeneous and heterogeneous samples, respectively. These results suggest that LIBS analysis and statistical approaches can be used to evaluate the homogeneity of waste forms for the acceptance criterion in repositories.

During electrorefining, fission products, such as Sr and Cs, accumulate in a eutectic LiCl-KCl molten salt and degrade the efficiency of the separation process by generating high heat and decreasing uranium capture. Thus, the removal of the fission products from the molten salt bath is essential for reusing the bath, thereby reducing the additional nuclear waste. While many studies focus on techniques for selective separation of fission products, there are few studies on processing monitoring of those techniques. In-situ monitoring can be used to evaluate separation techniques and determine the integrity of the bath. In this study, laser-induced breakdown spectroscopy (LIBS) was selected as the monitoring technique to measure concentrations of Sr and Cs in 550°C LiCl-KCl molten salt. A laser spectroscopic setup for analyzing high-temperature molten salts in an inert atmosphere was established by coupling an optical path with a glove box. An air blower was installed between the sample and lenses to avoid liquid splashes on surrounding optical products caused by laser-liquid interaction. Before LIBS measurements, experimental parameters such as laser pulse energy, delay time, and gate width were optimized for each element to get the highest signal-to-noise ratio of characteristic elemental peaks. LIBS spectra were recorded with the optimized conditions from LiCl-KCl samples, including individual elements in a wide concentration range. Then, the limit of detections (LODs) for Sr and Cs were calculated using calibration curves, which have high linearity with low errors. In addition to the univariate analysis, partial least-squares regression (PLSR) was employed on the data plots to obtain calibration models for better quantitative analysis. The developed models show high performances with the regression coefficient R2 close to one and root-mean-square error close to zero. After the individual element analysis, the same process was performed on samples where Sr and Cs were dissolved in molten salt simultaneously. The results also show low-ppm LODs and an excellent fitted regression model. This study illustrates the feasibility of applying LIBS to process monitoring in pyroprocessing to minimize nuclear waste. Furthermore, this high-sensitive spectroscopic system is expected to be used for coolant monitoring in advanced reactors such as molten salt reactors.

A great variety of plastics are used in IT products, which differ not only by plastic type but also by color and presence of additives such as brominated flame retardants (BFRs). In this study, to identify the plastics containing BFRs and heavy metals (i.e., Pb, Hg, Cd, Cr6+), laser-induced breakdown spectroscopy (LIBS) was used. Polypropylene (PP)-type black plastic samples that were obtained from three different types of used electric cookers were analyzed. The spectrum peaks observed in the LIBS system confirmed the presence of BFRs and heavy metals. The number of Br peaks were identified and the data were compared with the previous atomic spectra database. In the near future, the recycling of plastics from e-waste may become more important not only to reduce the amount of waste requiring treatment but also to eliminate the plastics containing hazardous components and compounds.

표준 시료의 분광 분석으로부터 획득한 각 원소별 파장 특성 값과 검사대상 미지 시료로부터의 파장 분석 결과를 비교함으로써 미 지 시료에 함유된 원소의 정성 및 정량 분석을 가능하게 하는 것이 LIBS이다. 본 연구에서는 콘크리트 내구성에 영향을 미치는 주요 열화 요인 을 규명하는 것에 대하여 LIBS의 적용 가능성을 실험적으로 분석하였다. 즉, LIBS를 통해 염화물, 황산염, 탄산화 모르타르 시험체에 대한 유 해 열화인자 정량 검출 실험을 실시함으로써 콘크리트 열화 진단의 LIBS 적용 가능성을 연구하였다. 염화물과 황산염 시험체 각각에 대하여 LIBS 실험을 실시한 결과 농도가 증가할수록 염소 및 황 이온의 LIBS 스펙트럼 파장 강도가 선형적으로 증가하는 것을 알 수 있었다. 탄산화 시 험체의 경우 탄산화 노출 기간에 따른 탄소 이온 LIBS 스펙트럼 파장 강도는 다소 비선형적으로 증가하는 것으로 나타났다. 이상의 실험결과 로부터 콘크리트 열화 진단에 LIBS의 적용가능성을 부분적으로 확인할 수 있었으며, 콘크리트 탄산화의 경우 시멘트 자체에 탄소 성분이 함유 되어 염화물 및 황산염 시험체의 정량 검출과는 다소 상이한 결과를 보인 것으로 추정된다. 따라서 콘크리트 탄산화에 대하여 LIBS를 적용하 기 위해서는 보다 다양한 매개변수 연구가 수행되어야 할 것으로 사료된다.

매년 많은 양의 플라스틱 폐기물이 발생되면서 폐플라스틱을 순환 자원화하기 위해 여러 공공기관, 연구소에서는 폐플라스틱 자동선별 시스템을 구축하기 위한 노력을 하고 있다. 이미 국내 지자체 재활용 선별장 등에서는 근적외선 분광법(NIR)을 활용한 자동선별 시스템을 구축 및 활용하고 있지만 검정색 플라스틱 제품군의 물리적 성상인 근적외선 파장의 과도한 흡수로 인한 스펙트럼 분석이 어려워 자동분류가 힘든 실정이다. 이러한 문제들을 해결하기 위해 NIR 분광장비가 아닌 LIBS 분광기를 사용하여 데이터를 구축 및 분석하고 지능형 알고리즘을 이용하여 자동 선별이 가능한 흑색 플라스틱의 재질별 선별 분류기 구축하고자 한다. LIBS분광장비는 시료가 기체, 액체 및 고체 상태와 관계없이 주기율표 상의 거의 모든 원소에 대하여 정성 정량 분석이 가능한 장비로 시료의 전처리 과정이 필요 없으며, 분석 시간이 매우 짧기 때문에 실시간 분석이 가능하다는 장점을 가진다. 이러한 LIBS 분광장비를 이용하여 데이터를 추출하고 이를 분석하여 인공지능 알고리즘을 이용한 분류기를 설계하고자 한다. 검은색 플라스틱을 인공지능 알고리즘을 통하여 재질별 자동 선별하도록 설계하여 산업적･경제적인 효율의 향상을 기대할 수 있다.