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.
To determine the acceptability of Grain Utilization Value Added (GUVA) Japonica rice variety developed by the International Rice Research Institute (IRRI) and South Korea’s Rural Development Authority (RDA), home use tests were conducted in n=69 businesses that were using Japonica rice. In general, they were satisfied with the Japonica brands, because they provided them with the particulars needed in their Japanese and Korean dishes. According to them, the value and quality of the Japonica rice justify the price. However, the GUVA Japonica Rice variety’s positive ratings were significantly lower compared to the brands they were used to. This applied to both their overall and attributespecific evaluations. Among the attributes, size, shape, aroma, and stickiness received significantly lower ratings compared to the other Japonica varieties. For them, it was too small, too round, less aromatic, and less sticky which may lead to challenges in preparation consequently affecting the commercial acceptability of the dishes they offer. Even with this experience and perception, they were still willing to consider the GUVA Japonica Rice when it was available in the market. Using the Van Westendorp pricing model, GUVA Japonica yielded a price of PHP 51.00 (1.01 USD) which was competitive. These findings provide recommendations for measures that should be put in place so that value chain players can preserve and maintain quality until the rice reach the business market.
저방사성폐수지, 제올라이트, 가연성잡고체 혼합폐기물을 유리화하기 위해서 AG8W1 후보 유리와 가연성잡고체 단독으로 유리화하기 위하여 DG-2 후보유리가 개발되었다. 두 후보유리의 화학적 내구성을 평가하기 위하여 PCT와 VHT 침출시험이 수행되었다. 7일 PCT 침출시험 수행결과 AG8W1과 DG-2의 주요 원소별 침출률은 기준유리(benchmark glass SRL-EA) 보다 낮게 나타남을 알 수 있었고 미국 Hanford 유리고화체 규제치 보다 낮은 결과를 나타냄을 알 수 있었다. 또한, 120일 동안의 시험에서도 주요 원소인 B, Na, Si, Li가 SRL-EA 보다 낮게 나타남을 볼 수 있었다. VHT 침출시험 수행결과 AG8W1, DG-2의 침출률(leach rate)은 각각 , 로써 미국 Hanford 규제치 보다 낮은 결과를 나타냈다. 결과적으로 유리화 시설 상용운전 시 사용예정인 이들 후보유리들의 침출은 안정화되어 있었으며 화학적 내구성이 우수함을 알 수 있었다.
Prediction method for the long-term chemical leaching amount from by-product/recycled materials such as waste concrete and steel slag and so on is necessary to widely promote their effective utilization and evaluate their environmental safety. Although there are the batch leaching tests and the column leaching test as the testing methods for evaluating the long-term leaching behavior, the leaching mechanism and the testing result compatibility in both tests has insufficiently been clarified yet. Thus, the prediction of the leaching behavior from the by-product/recycled materials used in actual civil works and their environmental safety evaluation are by no means certain. This paper shows the difference between the batch leaching tests and the column leaching tests in the chemical leaching behavior of Cu-slag. The batch leaching tests were conducted under liquid/solid ratio = 10, liquid = distilled water, stirring strength = 0, 30, or 120 rpm. After a certain elapsed time, the leaching solution was exchanged with the pure distilled water and then the stirring was restarted. The elapsed time was set at 1, 2, 4, 8, 16, 32 days. The column leaching tests were also conducted under the same conditions as those of the batch leaching tests in order to evaluate the effects of the pore distribution and the pore flow velocity in the Cu-slag column on the leaching behavior. In the column leaching tests, the effluent passing through the column was circulated as the influent (Fig. 1). The leaching duration in the column tests can be equivalent as that in the batch tests, so that the difference in the leaching behavior between the batch leaching tests and the column leaching tests may be dependent on the pore-scale heterogeneous flow and path generated in porous materials. Figure 2 shows the leaching rate evaluated from the batch leaching tests and the column leaching tests. In the same fluid velocity levels, the leaching rate in the column tests was larger than that in the batch tests. The leaching rate has been considered large with the fluid velocity. Although the fluid velocity generated by the stirring was the same as the flushing velocity on the surface of the Cu-slag in the batch tests, the fluid velocity in the column tests was enhanced because the permeant liquid was concentrated into the limited pore space in the Cu-slag column. Thus, the pore-scale heterogeneous flow and path generated in porous materials should be evaluated in order to clarify the compatibility between the batch leaching tests and the column leaching tests.
자외선 차단제는 해변 및 실외수영장에서 물놀이 시 사용되는 경우가 많으나, 기존의 자외선 차단효과 측정방법 및 기준은 내수성 시험방법을 포함하고 있지 않아, 그 확립이 요구되고 있다. 따라서 본 연구를 통하여 내수성 자외선 차단제의 자외선 차단지수 평가방법에 관하여 한국인의 특성에 맞는 시험방법을 확립하고자 하였다. 내수성 자외선 차단제의 자외선 차단지수 평가방법을 표준화하기 위하여, 외국과 우리나라의 자외선 차단지수 측정방법을 비교하였고, 우리나라의 자외선 차단지수 측정방법을 내수성 자외선 차단지수 측정방법에 적용할 수 있음을 알 수 있었다. 내수성 자외선 차단제 선별 시험을 통해 제품의 적합성을 검증하였고 내수성 자외선 차단지수 측정방법의 변수를 설정, 확인 시험을 하였다. 물 온도 23 ∼ 32 ℃에서 내수성 자외선 차단지수 비교 시험을 한 결과, 이 범위 안에서 온도는 내수성 자외선 차단지수에 통계학적으로 의의 있는 영향을 미치지 않음을 알 수 있었으며, 물의 흐름 변화에 따른 내수성 자외선 차단지수는 43.61 ± 1.96, 43.92 ± 1.62 그리고 42.65 ± 2.41로 결과의 유의적 차이는 없었다. 그러므로 피험자의 적절한 활동을 대신하기 위한 대안으로 지속적인 20 min 물 순환이 적절하다고 사료된다.