• 상하수도학회지
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• 제36권5호
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• pp.249-260
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• 2022

The effect of permanganate oxidation was investigated as water treatment strategy with a focus on comparing the reaction characteristics of NaOCl and sodium permanganate (NaMnO₄) in algae (Monoraphidium sp., Micractinium inermum, Microcystis aeruginosa)-contained water. Flow cytometry explained that chlorine exposure easily damaged algae cells. Damaged algae cells release intracellular organic matter, which increases the concentration of organic matter in the water, which is higher than by NaMnO₄. The oxidation reaction resulted in the release of toxin (microcystin-LR, MC-LR) in water, and the reaction of algal organic matter with NaOCl resulted in trihalomethanes (THMs) concentration increase. The oxidation results by NaMnO₄ significantly improved the concentration reduction of THMs and MC-LR. Therefore, this study suggests that NaMnO₄ is effective as a pre-oxidant for reducing algae damage and byproducts in water treatment process.

• 한국수소및신에너지학회논문집
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• 제26권3호
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• pp.271-277
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• 2015

The present paper discusses about noble idea on various reactions including hydrides, hydrogen peroxide and nano-sized metal powders, which do not emit toxic materials as well as carbon dioxide. Here in this paper, the very first-ever concept that heat energy can be generated from the direct reaction between sodium borohydride and hydrogen peroxide is presented. Sodium hydride as fuel can supply hydrogen reacting with oxygen provided by the decomposition of hydrogen peroxide solution. Solid sodium borohydride can be resolved in water and treated as liquid solution for the easy handling and the practical usage although its solid powder can be directly mixed with hydrogen peroxide for the higher reactivity. The thermodynamic analysis was conducted to estimate adiabatic reaction temperatures from these materials. The preliminary experiment on the reactions conducted using sodium borohydride powder and hydrogen peroxide water solution revealed that the self-propagating reaction can occur and that its reactivity increases with an increase of hydrogen peroxide concentration.

• Nuclear Engineering and Technology
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• 제31권6호
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• pp.66-82
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• 1999

The national long-term R&D program, updated in 1997, requires Korea Atomic Energy Research Institute(KAERI) to complete by the year 2006 the basic design of Korea Advanced Liquid Metal Reactor(KALIMER), along with supporting R&D work, with the capability of resolving the issue of spent fuel storage as well as with significantly enhanced safety. KALIMER is a 150 MWe pool-type sodium cooled prototype reactor that uses metallic fuel. The conceptual design is currently under way to establish a self-consistent design meeting a set of major safety design requirements for accident prevention. Some of the current emphasis includes those for inherent and passive means of negative reactivity insertion and decay heat removal, high shutdown reliability, prevention of and protection from sodium chemical reaction, and high seismic margin, among others. All of these requirements affect the reactor design significantly and involve extensive supporting R&D programs. This paper summarizes some of the results of conceptual engineering and design analyses performed for the safety of HAMMER in the area of inherent safety, passive decay heat removal, sodium water reaction, and seismic isolation.

• 공업화학
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• 제9권7호
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• pp.1023-1029
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• 1998

5Cr-1Mo steel을 이용하여 나트륨 분위기에서 미량 물 누출 실험을 수행하였다. 시편에서 미량 물 누출로 인한 누출경로의 완전 re-open time은 129분으로 나타났고, 그 크기는 직경 2mm를 나타냈다. 누출경로는 re-open되기 전에 누출부위를 중심으로 halos현상을 형성하였으며, halos의 크기와 실제 re-open크기와는 다르게 나타났다. 나트륨-물 반응으로 인한 재질의 부식은 나트륨부위로부터 시작되었으며, steam 부위에서는 부식이 발생하지 않았다. 시편 누출부위를 AES로 분석한 결과 Cr의 segregation이 가장 많이 나타났으며, SEM과 EPMA 관찰로부터 나트륨화합물들이 누출부위 주변에 대량 침적되어 있는 것이 관찰되어 나트륨 철 크롬혼합물 형태로 부식생성물들이 혼재되어 있는 것으로 예측되었다.

• 대한화학회지
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• 제17권6호
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• pp.411-415
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• 1973

Cyanide ion과 triphenylmethane dye와의 반응은 cetyltrimethyl ammonium bromide(CTABr)의 cationic micelle에 의하여 현저히 반응속도가 빨라지며 sodium lauryl sulfate(NaLS)의 anionic micelle에 의하여 반응속도가 늦어진다. 또한 CTABr존재하의 반응은 inorganic anion에 의하여 inhibition, 되며 NaLS존재하의 반응은 inorganic cation중의 몇가지, 특히 $Zn^{++},\;Cd^{++}$등에 의하여 현저하게 반응이 빨라지는 salt effect를 나타낸다. 물과 잘 혼합되는 몇가지 유기용매의 micelle catalysis에 대한 영향은 대체로 수용액 일때보다 작게 나타나서 반응속도가 늦어지거나 malachite green과의 반응에서 methanol은 수용액일때보다 반응속도가 빨라지는 특이한 solvent effect를 나타내었다.

• Nuclear Engineering and Technology
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• 제56권1호
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• pp.257-264
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• 2024

The sodium cooled fast reactor (SFR) is one of the Gen-IV reactors with the most operating experience accumulated. Although the technology level is the most mature among the Gen-IV reactors, there is still a safety problem that has not been solved, which is the sodium-water reaction. Since sodium and water are separated only by a heat transfer tube with a thickness of only a few mm, there is inherently a risk of a sodium-water reaction (SWR) accident in the SFR. In this study, it is attempted to quantitatively evaluate the resistance of SWR accidents by replacing the shell and tube steam generator with printed circuit steam generator (PCSG) as a method to mitigate the SWR accident. To do this, a CATS-S (Compact Accident Tolerance Steam Generator-SWR) facility was designed and built. And for the quantitative evaluation of accident resistance, a methodology for measuring the impingement wastage rate was established. As a result of this research, the impingement wastage rate caused by SWR generated in a PCSG was measured first time. It was confirmed that the impingement wastage phenomenon was suppressed in the PCSG, and the accident resistance was higher than that of the SWR through comparison with the experimental results performed in the existing shell and tube steam generator. In conclusion, a PCSG is more resistant to impingement wastage as a result of the SWR accident than existing shell and tube steam generators, and it is estimated that a PCSG can mitigate SWR accidents, an inherent problem of SFR.

• Nuclear Engineering and Technology
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• 제47권6호
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• pp.662-668
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• 2015

A suspension of titanium nanoparticles (Ti NPs) in liquid sodium (Na) has been proposed as a method to mitigate the violent sodium-water reaction (SWR). The interparticle potential between Ti NPs in liquid Na may play a significant role in the agglomeration of NPs on the reaction surface and in the bulk liquid Na, since the potential contributes to a reduction in the long-term dispersion stability. For the effective control of the SWR with NPs, a physical understanding of the molecular dynamics of NPs in liquid Na is key. Therefore in this study, the nonretarded Van der Waals model and the solvation potential model are employed to analyze the interparticle potential. The ab initio calculation reveals that a strong repulsive force driven by the solvation potential exceeds the interparticle attraction and predicts the agglomeration energy required for two 10-nm Ti NPs to be $4{\times}10^{-17}J$. The collision theory suggests that Ti NPs can be effective suppressors of the SWR due to the high energy barrier that prevents significant agglomeration of Ti NPs in quiescent liquid Na.

• Korean Chemical Engineering Research
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• 제55권2호
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• pp.170-179
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• 2017

본 논문은 소듐냉각고속로 원형로 소듐-물 반응 압력완화계통의 급수배출부와 수소방출부의 설계요건 도출을 목적으로 한다. 증기발생기 전열관 누설에 의한 소듐-물 반응 발생 시, 증기발생기 내의 급수 증기를 신속하게 배출하는 조건을 도출하기 위해 급수덤프탱크 가스방출배관의 단면적과 증기발생기 급수배출배관의 수직길이를 변화시켜 연구를 수행하였다. 정상운전과 재장전운전에 대해 각각 계산을 수행하여 급수덤프탱크 가스방출배관의 단면적과 증기발생기 급수배출배관의 수직길이를 결정하였다. 정상운전 조건에서 소듐-물 반응 발생 시, 생성물인 수소에 의해 형성되는 과압이 소듐덤프탱크의 설계압력을 만족시킬 수 있도록 하는 가스방출배관의 직경을 도출하였고, 이 때 대기로 방출되는 수소의 유량과 농도를 계산하였다. 본 논문의 계산결과는 향후 소듐냉각고속로 원형로의 소듐-물 반응 압력완화계통의 설계요건으로 활용될 예정이다.

• 공업화학
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• 제9권5호
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• pp.674-679
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• 1998

액체금속로 증기발생기 전열관 재질로 사용이 예상되는 ferrite steel 시편을 사용해서 소듐분위기에서 미량의 물 누출 실험을 수행하였다. 누출경로는 소듐-물 반응생성물 및 부식생성물에 의한 self-plugging 현상과 열적인 transient 및 전열관의 vibration에 의한 re-opening 메카니즘으로 설명이 가능하였다. 실험결과, 600 Psig의 injection 압력으로 5 g $H_2O$를 소듐분위기 속의 시편으로 누출시킨 경우, 누출초기와 약 70분 경과 후에 약간의 누출 흔적이 보였으나, self-plugging되었던 누출경로는 129분이 경과되자 완전 re-opening된 것으로 확인되었다. 누출시편의 re-opening shape은 2중으로 되어 있었으며, 소듐부위에서 시편 표면에 나타난 re-opening size 약 2 mm의 직경을 나타내었다.

• 한국세라믹학회지
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• 제45권1호
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• pp.54-59
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• 2008

Hydrated sodium silicate with 25 wt% water contents was synthesized by hydrothermal reaction using anhydrous sodium silicate. The hydrated sodium silicate was expanded at $370^{\circ}C$ for 30 min. and then pulverized, classified (- 200 mesh) and press-formed. The samples were heat treated at $400{\sim}900^{\circ}C$ for 30 min. in order to study the expansion characteristics depending on heat treatment temperature. A porous body with closed pore was formed above $600^{\circ}C$. The volume expansion ratio and the pore size were increased and the specific gravity was decreased with increasing heat treatment temperature. However, the volume expansion ratio was decreased and the specific gravity was increased above $850^{\circ}C$ due to the softening of the sodium silicate.