Small modular reactors (SMRs) are getting attention as an alternative to fossil fuel power stations due to versatile application and carbon dioxide reduction. Although various types of advanced reactors are being developed, water-cooled SMR will be first deployed on a commercial scale. The International Atomic Energy Agency (IAEA) and regulatory bodies are trying to identify safeguards issues of water-cooled SMRs as the first priority. IAEA begins to develop a safeguards plan by asking for the facility’s specification in a given format, a design information questionnaire (DIQ). Then, IAEA periodically performs safeguards activities such as design information verification (DIV) and physical inventory verification (PIV). In this sense, we utilize research and power reactor DIQ for water-cooled SMRs (NuScale, SMART, i-SMR and KLT-40S). Most of the questions are answered with open information. For undisclosed answers, pressurized water reactor (PWR) features are described. Safeguards issues in water-cooled SMR originate from core modularization. As the nuclear material flows are diversified, the number of safeguards measure will be increased while staff are reduced in SMRs. Instrumentation for safeguards should be developed to reduce worker’s fatigue level. Intensive arrangement of fuel assemblies may also need unique devices to secure their visibility or detectability. A transparent floor with a surveillance system or advanced Cherenkov viewing device may be adopted to enhance containment and surveillance. Meanwhile, some questions could be more elaborate regarding safeguards. First, question #38 cannot confirm the time of occurrence of weapon-grade plutonium for reactor operation. Second, the answers in questions #46 and #49 are primitive to identify a place to generate an undeclared fissile material. Therefore, the current DIQ should be revised to get a detailed burnup report and spatial distribution of neutron flux.

For this study, we established a system for the CPU cooling performance evaluation and conducted performance tests on air-cooling and water-cooling to understand the effect of the CPU cooling method on performance. For the performance evaluation, the test chamber and water-cooling system were set up, the workload S/W was selected, and a case file was created. In the case of the air-cooling, the CPU temperature is sensitively affected by the outside air temperature, the direction of the board installation, and the influence of the airflow formed around it, and may cause a lot of fluctuations in the CPU temperature. When the water-cooling system was applied, the CPU temperature decreased from 75℃℃ to 37℃ compared to the air-cooled type under the test conditions of 28.5℃ and 3LPM cooling water supply temperature and flow rate. As the CPU clock speed increased due to the decrease in temperature, it was found that the job execution time was reduced by 15~23%. In the future, it is expected that using this performance evaluation environment established through this study will enable us to easily conduct test evaluations for various processors, cooling methods, and changes in operating conditions.

PURPOSES : In this experimental study, the resistance of blended cement concrete containing air-cooled slag (AS) and water-cooled slag (WS) to freeze–thaw action was investigated. For comparison, the durable performance of ordinary Portland cement (OPC) concrete exposed to a similar damage environment was also evaluated. METHODS : Based on the ASTM C 666 standard, the relative dynamic modulus of elasticity, mass ratio, surface electric resistivity, and compressive strength of blended cement concrete specimens were periodically measured and compared with those of OPC concrete to evaluate the durability of concrete exposed to the freezing-thawing environment. In addition, microstructural characteristics of deteriorated concrete parts were evaluated using scanning electron microscopy (SEM) and energy dispersive spectroscopy techniques to detect products formed by freeze–thaw action. RESULTS : It was found that the resistance of blended cement concrete containing AS and WS to freeze–thaw action was significantly better than that of OPC concrete. Furthermore, the SEM results revealed the frost damage of OPC concrete, owing to the formation of thaumasite. CONCLUSIONS : The application of AS in concrete can effectively improve the durability of concrete, particularly in freeze–thaw environments.

PURPOSES : This paper presents the experimental results of tests conducted on concrete produced with air-cooled (AS) and water-cooled (WS) ground blast-furnace slag exposed to multi-deterioration environments of carbonation and scaling. METHODS : Carbonated and uncarbonated concrete specimens were regularly monitored according to the ASTM C 672 standard to evaluate the durability of concrete exposed to both scaling and combined carbonation and scaling conditions. Additionally, mechanical properties, such as compressive strength, flexural strength, and surface electric resistivity, were analyzed. RESULTS : It was found that concrete specimens produced with AS and WS had a beneficial effect on the mechanical properties because of the latent hydraulic properties of the AS and WS mineral admixtures. Moreover, carbonated concrete showed good scaling resistance in comparison to uncarbonated concrete, particularly for concrete produced with AS and WS. CONCLUSIONS : The improved scaling resistance of carbonated concrete showed that AS is a suitable option for binders used in cement concrete pavements subjected to combined carbonation and scaling.

PURPOSES : Durability of concrete is traditionally based on evaluating the effect of a single deterioration mechanism such as freezing & thawing action, chloride attack, carbonation and chemical attack. In reality, however, concrete structures are subjected to varying environmental exposure conditions which often results in multi-deterioration mechanism occurring. This study presents the experimental results on the durability of concrete incorporating air-cooled slag(AS) and/or water-cooled slag(WS) exposed to multi-deterioration environments of chloride attack and freezing & thawing action. METHODS: In order to evaluate durable performance of concretes exposed to single- and multi-deterioration, relative dynamic modulus of elasticity, mass ratio and compressive strength measurements were performed. RESULTS: It was observed that multi-deterioration severely affected durability of concrete compared with single deterioration irrespective of concrete types. Additionally, the replacement of cement by AS and WS showed a beneficial effect on enhancement of concrete durability. CONCLUSIONS : It is concluded that resistance to single- and/or multi-deterioration of concrete is highly dependent on the types of binder used in the concrete. Showing the a good resistance to multi-deterioration with concrete incorporating AS, it is also concluded that the AS possibly is an option for concrete materials, especially under severe environments.

The world-wide need to reduce the energy used and the greenhouse gases emitted during cement manufacture has led to the pursuit of more eco-efficient materials, such as ground granulated blastfurnace slag(GGBS) and fly ash. Especially, GGBS is a by-product generated during the manufacture of pig ions. GGBS can be divided into water-cooled slag(WS) and air-cooled slag(AS). With comparison of WS, the AS is formed by allowing the molten slag to cool relatively slowly under ambient conditions. This study presents experimental findings on the mechanical and durability performance of cement concrete pavement with replacement of cement by WS and/or AS. In order to produce concrete specimens, total replacement of cement by GGBS(WS+AS) was fixed at 40% by mass. Concrete specimens were regularly monitored for the variation of mechanical properties such as flexural strength, compressive strength and initial surface absorption. In addition, in order to assess durability of concrete pavement with WS and/or AS, the chloride ion penetration resistance and scaling resistance tests were adopted, and the corresponding results were compared to those of plain concrete pavement. The test results indicated that the performance of concrete pavement was significantly dependent on the replacement level of WS by AS. Concrete specimens incorporating 20% replacement level of AS showed a poor mechanical performance, while 5% replacement of AS showed a beneficial effect both mechanical and durability performance. Especially, the 5% AS replacement led to the higher resistance of concrete pavement against frost-salt action. Based on the experimental results, the present study would be helpful to design high-performance cement concrete pavement.

전해산화수의 식품가공에의 적용 확대를 위해 51로 냉각한 전해산화수에 아가리쿠스 버섯을 1분간 침지 세정하여 5에 저장하면서 저장중 품질변화를 살펴보았다. 전해산화수 세정처리에 의해 총균수는 초기균수의 1/88로 대장균군은 cfu/g 이하로 감소하였다. 그리고 5 저장 중 pH, 산도, 관능적 특성을 살펴본 결과, 저장 7일까지 전해산화수로 처리한 아가리쿠스가 무처리구에 비해 저장성이 우수한 것으로 판단되었으나 경도의 경우 저장 4일 후부터 전해

쑥갓과 케일을 시료 중량 50배의 5로 냉각한 전해산화수에 2분 3회 다단침지 처리한 후 저장중의 품질변화를 조사한 결과, 쑥갓의 경우 총균수는 무처리 쑥갓에 비해 평균 1/130, 대장균군수는 평균 1/1,170, 케일의 경우 총균수는 무처리 케일에 비해 평균 1/870, 대장균구수는 평균 1/470 수준으로 감소하였으나 1 저장 6일후 부터는 무처리, 수도수 침지 처리구와 유사한 수준으로 증가하였다. 저장중 중량감소율은 쑥갓과 케일 모두 저장