Currently, the Korea Atomic Energy Research Institute is conducting research on the development of technology to reduce the disposal area for SF (Spent nuclear Fuel). If the main radionuclides contained in SF can be separated and recovered according to their characteristics (long half-life, high mobility and high heat load) and uranium oxide which is expected to be the final residue, can be made into solids, the burden of the permanent disposal area of the SF will be greatly reduced. The waste form that end up in the repository must be verified for ease of manufacture and stability of the block. And, in order to increase the loading efficiency, a large block manufacturing technology is needed. This study describes the background of introducing PSA (Particle Size Analyzer) which is one of the necessary equipment for manufacturing UO2 blocks using slip casting, the method of using the equipment and performance verification of the equipment using standard samples. The particle size affects the sintering quality by the way the particles rearrange themselves during sintering. Powders of small particles are generally less free flowing and more difficult to compress, they form thin pores between the particles and sinter to higher density. In contrast, larger particle has a lower sintered density. Therefore, accurate particle size measurement and the selection of a suitable particle size are important. For this purpose, a PSA was installed in nuclear cycle experiment research center. To verify the performance of the equipment, a standard sample of 1.025 μm was analyzed. We got an average particle size of 1.0293 μm and standard deviation of 0.0668 μm. This value was within the uncertainty(±0.018 μm) of the sample’s certificate. In the future, this equipment will measure the size of UO2 (depleted uranium) powder and to produce large scale uranium oxide blocks.

2022년 10월부터 2023년 5월까지 친환경 딸기재배 농가에서 점박이응애는 칠레이리애응애와 사막이리응애, 진딧물은 콜레마니진디벌을 대상으로 하는 천적처리구와 유기농자재를 사용하는 관행방제구에서 천적의 해 충 밀도억제 효과를 조사하였다. 천적처리구에서 점박이응애 성충 밀도는 잎당 1.5마리 이하, 알은 4개 이하로 관리되었고, 사막이리응애는 잎당 최대 0.4마리까지 증가하여 점박이응애 밀도억제에 많은 영향을 미친것으로 보인다. 반면, 관행방제구에서 점박이응애 밀도는 천적 방사구에 비하여 오히려 많은 발생량을 보였지만, 3월 9일부터는 사막이리응애의 증가와 유기농자재의 효과로 점박이응애 밀도는 급격하게 감소하였다. 진딧물 천적 처리구에서 진딧물 밀도는 1월부터 발생하였으며 3월 상순에 잎당 0.3마리까지 증가하였으나 이후 감소하였고, 콜레마니진디벌은 진딧물 발생이 많지 않아 3.9마리/㎡(2회) 방사하는 데 그쳤다. 한편, 관행방제구 포장의 진딧 물은 유기농자재의 영향으로 거의 발생하지 않았다.

Reticulitermes speratus (Kolbe) is economically important pest in East Asia including Korea, Japan and China where they infest wooden structures in urban areas. In this study, we report the first record of R. speratus speratus from Korea, which was verified using soldier morphology and molecular characteristics obtained from a mitochondrial gene. R. speratus speratus Kolbe, 1885 (Blattodea: Rhinotermitidae) are found in several provinces, mainly southern regions in Korea, whereas R. speratus kyushuensis are distributed throughout the country. Our morphological comparison showed that R. speratus speratus can be distinguishable from R. speratus kyushuensis by the ratio of the posterior postmentum width to length. In the molecular comparison, R. speratus speratus revealed genetic differences of 3.06% (range 2.60–4.10%) from R. speratus kyushuensis using cytochrome oxidase subunit II gene sequences.

Spodoptera litura Fabricius, 1775 (Lepidoptera: Noctuidae) is a serious crop pest with a long-distance migratory flight. To date, the DNA barcode region has been widely used in genetic diversity analysis studies of Spodoptera litura. However, the DNA barcode region showed maximum variation rate of S. litura, which from 18 regions in South Korea, was 0.608% (nine haplotypes) in previous study. In this study, four mitochondrial genes (ND4, ND4L, ND1, 16s rRNA) have higher intra-specific variation rates than the DNA barcode region. Among the four genes, The variation rate of the 16s rRNA region was confirmed to be a minimum of 0.203% (2bp) and a maximum of 1.824% (18bp). Finally, the 16s rRNA region with the highest PCR amplification efficiency and highest variation rate was selected as a high-efficiency molecular marker.