The solid-state chemistry of uranium is essential to the nuclear fuel cycle. Uranyl nitrate is a key compound that is produced at various stages of the nuclear fuel cycle, both in front-end and backend cycles. It is typically formed by dissolving spent nuclear fuel in nitric acid or through a wet conversion process for the preparation of UF6. Additionally, uranium oxides are a primary consideration in the nuclear fuel cycle because they are the most commonly used nuclear fuel in commercial nuclear reactors. Therefore, it is crucial to understand the oxidation and thermal behavior of uranium oxides and uranyl nitrates. Under the ‘2023 Nuclear Global Researcher Training Program for the Back-end Nuclear Fuel Cycle,’ supported by KONICOF, several experiments were conducted at IMRAM (Institute of Multidisciplinary Research for Advanced Materials) at Tohoku University. First, the recovery ratio of uranium was analyzed during the synthesis of uranyl nitrate by dissolving the actual radioisotope, U3O8, in a nitric acid solution. Second, thermogravimetric-differential thermal analysis (TG-DTA) of uranyl nitrate (UO2(NO3)2) and hyper-stoichiometric uranium dioxide (UO2+X) was performed. The enthalpy change was discussed to confirm the mechanism of thermal decomposition of uranyl nitrate under heating conditions and to determine the chemical hydrate form of uranyl nitrate. In the case of UO2+X, the value of ‘x’ was determined through the calculation of weight change data, and the initial form was verified using the phase diagram for the U-O system. Finally, the formation of a few UO2+X compounds was observed with heat treatment of uranyl nitrate and uranium dioxide at different temperature intervals (450°C-600°C). As a result of these studies, a deeper understanding of the thermal and chemical behavior of uranium compounds was achieved. This knowledge is vital for improving the efficiency and safety of nuclear fuel cycle processes and contributes to advancements in nuclear science and technology.

Cymbidium ‘Aroma Pink’는 국립원예특작과학원에서 2017년 도에 육성한 신품종으로, 2000년에 C. Lucky Rainbow ‘Lapin Hot’과 C. eburneum을 인공교배하여 개발된 품종이다. 교배 후 기내파종과 하우스 순화를 통해 120개의 실생묘를 얻었고, 그 중 화색, 엽형, 꽃대 및 생육특성 등을 고려하여 3계통을 1차 선발하였고, 2011년부터 2016년까지 특성 검정을 통하여 품종의 안정성과 균일성을 확인하였다. 그 결과, 최종적으로 ‘00-1174-100’한 계통을 선발하였고 ‘원교 F1-62’로 계통명을 부 여한 후, ‘Aroma Pink’로 명명하였다. ‘Aroma Pink’ 품종은 백 색 바탕에 꽃받침 일부가 연한 분홍색, 순판 가운데가 노란색 을 띄며 화형은 꽃잎과 꽃받침이 약간 안쪽으로 오므라드는 안 아피기 형태이며 꽃의 길이와 폭은 6.1cm, 5.2cm로 작은 편이다. 전체적으로 동그란 화형과 중형종 크기는 모본인 C. Lucky Rainbow ‘Lapin Hot’과 유사하나 진한 적색 순판 대신 부본의 노란색 순판과 화색을 닮아 강렬한 느낌보다는 전체적으로 화 사한 느낌을 준다. 꽃대는 평균 2.9개 발생하고 화서당 꽃 수 가 6.5개로 적은 편에 속하지만, 부본인 C. eburneum 원종의 향기를 가지고 있다. 또한 직립한 꽃대에 늘어짐이 적은 잎을 가져 전체적으로 안정적인 형태를 이루며 개화시기는 3월경으 로 만생종에 속한다. 한편 고온에 의해 화색이 탁해질 수 있 으나, 전반적으로 재배 관리가 용이한 편이다.

This study was conducted to evaluate the efficacy of mulberry cake mixed diet on larval growth of Protaetia brevitarsis. As a result of adding mulberry cake to oak fermented sawdust and mulberry fermented sawdust, the survival rate of P. brevitarsis larvae were higher than those of the control when mass rearing larvae. When fed oak fermented sawdust with 3, 5% and 10% of mulberry cake, the cumulative proportion of larvae over 2.5g was 92.9% at 65 days, 90.8% at 55 days, and 96.3% at 45 days after rearing at 25±1℃, respectively. When fed mulberry fermented sawdust with 3%, 5% and 10% of mulberry cake, the cumulative proportion of larvae over 2.5g was 86.2% at 85 days, 90.7% at 75 days, and 91.5% at 75 days after rearing at 25±1℃, respectively.

This study was conducted to evaluate the efficacy of mulberry leaf mixed diet on larval growth of Protaetia brevitarsis. As a result of adding mulberry leaves to oak fermented sawdust, the survival rate of P. brevitarsis larvae were higher than those of the control when mass rearing larvae. When fed oak fermented sawdust with 5%, 10% and 20% of mulberry leaves, the cumulative proportion of larvae over 2.5g was 93.1% at 65 days, 95.6% at 55 days, and 93.9% at 55 days after rearing at 25±1℃, respectively. Also, heavy metals were not detected in larvae of P. brevitarsis fed on mulberry leaves.

This study was conducted to evaluate the time required to sell Protaetia brevitarsis larvae when larvae fed on three kinds of fermented berries sawdust, such as mulberry, raspberry, and blueberry. The first instar larvae were reared in a plastic container(543x363x188mm) with designated feeds, and investigated the cumulative proportion of larvae more than 2.5g at rearing room regulated at 25±1℃ with 50~60% under 16:8(L:D). When we reared larvae for about 45 days with fermented blueberry sawdust, the cumulative proportion of larvae with more than 2.5g was over 70%. It was about 40 days shorter than fermented oak sawdust. For each group, the average survival rates of larvae at the possible time for sale were 72~93%.

In order to develop the D. adamsi breeding technique that is highly likely to be used as an emotional pet insect, the results of the D. adamsi was collected in the large exhibition Jang Tae-san in Daejeon to the indoor breeding began to spawn after 10 days after the training, the egg laying period was 33.6 days, the average number of spawn per female was 27.7, and the period was 11.8 days. D. adamsi larvae bred with food of oak-boiled molted two times, the duration of 1st larvae development was 11.8 days, 2nd larvae 14.5 days, and the third larvae was 29.4, and the larvae were used to build houses using Masato(soil) and in the pupae, and then in April of the following year. D. adamsi has a characteristic to build a house with fallen leaves and spawn one or two eggs in the fallen leaves, and the results of the spawn mat test using fallen leaves, leaf mold and a sawdust, etc., and the number of spawn was high in the Masato was spread about 3 ~ 5cm, and a fallen leaves on a 10 cm or so, and the growth and survival rate of the larvae were also high. Larvae breeding density was 2 ~ 3 ℓ in the container size to raise the object was normal growth, the higher the density mortality was high and the growth was sluggish. Larvae feeding conditions were normally developed in dry fallen leaves and fermented fallen leaves, compared to the sterile fallen leaves, oak sawdust, sterile fallen leaves and oak sawdust was abnormal, the mortality rate was higher than 50%.