For risk assessment of spent nuclear fuel (SNF) transportation, it is necessary to calculate the damage ratio of SNF rods loaded in the cask. Due to the complexity in the geometry and material properties of SNF, it is impractical to analyze the detailed behavior of every fuel rod and assembly in a single cask model. This study presents a framework for performing cask-level analysis by sequentially simplifying the fuel rods and spent fuel assemblies for fuel damage ratio (FDR) calculation. Using the simplified fuel rod model developed in previous studies, we constructed a CE 16×16 fuel assembly model and presented a methodology to simplify the CE 16×16 assembly model into cuboids. Cask drop analyses were performed to validate the similarity of the detailed CE 16×16 model and the simplified model. Using the proposed simplified models, a procedure for quantifying the bending load and pinch load applied to the fuel rods during the drop impact is presented. The FDR can then be calculated by comparing the quantified loads with their respective failure criteria. Through a case study, the feasibility of the developed framework for systematic and accurate FDR calculation was effectively demonstrated.

The recent release of contaminated water from the Fukushima Daiichi Nuclear Power Plant highlights the need for accurate tritium measurement, particularly near the minimum detectable activity (MDA) of 5 Bq·L−1 set by South Korea’s Nuclear Safety and Security Commission. This study aims to improve low-level tritium measurement accuracy by optimizing the region of interest (ROI) for quench curve determination. These adjustments are crucial for separating tritium signals from background noise. Quench standards were prepared and measured using a liquid scintillation counter (LSC). Three ROIs were analyzed to assess the impact of channel selection on measurement precision: A 20-148 channel range optimized via figure of merit (FOM) analysis, a 20-250 channel range covering tritium’s full beta spectrum, and a broad 1-1024 channel range. Quench curves were obtained by fitting the counting efficiency of each ROI to the quench standards. Tritium samples with six different activity levels were prepared, and their radioactivity was calculated using the quench curves. Selecting appropriate ROIs for quench curve determination is critical for measuring low-concentration tritium accurately. This approach reduces uncertainty and emphasizes reliable methods to improve the precision and consistency of tritium measurements.

육성한 화단국화 품종인 황색 국화(Chrysanthemum morifolium Ramat.)인 ‘한아름볼(Hanarum Ball)’은 충남농업기술원 화훼 연구소에서 모본 ‘Gigi Gold’와 부본 ‘Jinny Ball’을 이용하여 육성되었다. ‘한아름볼’ 품종은 2014년에 인공 교배를 통해 개 발되었으며, 2015년부터 2017년까지 품종 특성을 조사한 후 2017년에 최종 선발되었다. ‘한아름볼’의 초형은 반구형으로, 노랑색 꽃잎(Yellow 5B)을 가진 반겹꽃을 지니고 있으며, 개화 기는 9월 21일이다. 초장은 36.0cm로, 초폭은 66.0cm, 화폭 은 4.1cm, 본당 착화수는 1,147개, 꽃잎수는 81.0개이며, 엽색 은 녹색(Green 137B)이어서, 대조품종인 ‘금방울’과 유사한 형 태와 색을 가지고 있으나, 꽃크기와 착화수, 개화시기에서 차이 를 보였다. ‘한아름볼’은 도로변이나 화단 등 조경용으로 활용 가능하며, 화훼 농가에 새로운 소득원을 제공할 수 있는 품종으 로 기대된다.