• Nuclear Engineering and Technology
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• 제53권6호
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• pp.1747-1755
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• 2021

This paper presents floating absorber for safety at transient (FAST) which is a passive safety device for sodium-cooled fast reactors with a positive coolant temperature coefficient. Working principle of the FAST makes it possible to insert negative reactivity passively in case of temperature rise or voiding of coolant. Behaviors of the FAST in conventional oxide fuel-loaded and metallic fuel-loaded SFRs are investigated assuming anticipated transients without scram (ATWS) scenarios. Unprotected loss of flow (ULOF), unprotected loss of heat sink (ULOHS), unprotected transient overpower (UTOP) and unprotected chilled inlet temperature (UCIT) scenarios are simulated at end of life (EOL) conditions of the oxide and the metallic SFR cores, and performance of the FAST to improve the reactor safety is analyzed in terms of reactivity feedback components, reactor power and maximum temperatures of fuel and coolant. It is shown that FAST is able to improve the safety margin of conventional burner-type SFRs during ULOF, ULOHS, UTOP and UCIT.

• Nuclear Engineering and Technology
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• 제47권3호
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• pp.227-239
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• 2015

The thermal, mechanical, and neutronic performance of the metal alloy fast reactor fuel design complements the safety advantages of the liquid metal cooling and the pool-type primary system. Together, these features provide large safety margins in both normal operating modes and for a wide range of postulated accidents. In particular, they maximize the measures of safety associated with inherent reactor response to unprotected, doublefault accidents, and to minimize risk to the public and plant investment. High thermal conductivity and high gap conductance play the most significant role in safety advantages of the metallic fuel, resulting in a flatter radial temperature profile within the pin and much lower normal operation and transient temperatures in comparison to oxide fuel. Despite the big difference in melting point, both oxide and metal fuels have a relatively similar margin to melting during postulated accidents. When the metal fuel cladding fails, it typically occurs below the coolant boiling point and the damaged fuel pins remain coolable. Metal fuel is compatible with sodium coolant, eliminating the potential of energetic fuel-coolant reactions and flow blockages. All these, and the low retained heat leading to a longer grace period for operator action, are significant contributing factors to the inherently benign response of metallic fuel to postulated accidents. This paper summarizes the past analytical and experimental results obtained in past sodium-cooled fast reactor safety programs in the United States, and presents an overview of fuel safety performance as observed in laboratory and in-pile tests.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 1997년도 춘계학술발표회논문집(2)
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• pp.207-213
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• 1997

The computational scheme on a irradiation temperature of U-10Zr fuel was established considering porosity formation, bond sodium infiltration and constituent redistribution. Thermotransport theory was adapted to model the redistribution phenomenon. As a results, the bond sodium seems to be logged in the outer region of fuel slug. The main driving force for constituent redistribution appears to be the Zr solubility change along to radial position of the fuel. It is evident that the heat of transport also has some contribution to the redistribution.

• Corrosion Science and Technology
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• 제9권6호
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• pp.233-238
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• 2010

Hot-dipped Al-Mg-Si coatings to alternate Zn and Zn alloy coatings for steel were examined on metallographic structure, corrosion resistance, sacrificial ability, formation and growth of inter-metallic compounds, and mechanical properties. Near the eutectic composition of quasi-binary system of Al-$Mg_2Si$, very fine eutectic structure of ${\alpha}$-Al and $Mg_2Si$ was obtained and it showed excellent corrosion resistivity and sacrificial ability for a steel in sodium chloride solutions. Formation and growth of Al-Fe inter-metallic compounds at the interface of substrate steel and coated layer was suppressed by addition of Si. The inter-metallic compounds layer was usually brittle, however, the coating layer did not peel off as long as the thickness of the inter-metallic compounds layer was small enough. During sacrificial protection of a steel, amount of hydrogen into the steel was more than ten times smaller than that of Zn coated steel, suggesting to prevent hydrogen embrittlement. Al-Mg-Si coating is expected to apply for several kinds of high strength steels.

• 한국안전학회지
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• 제12권3호
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• pp.106-113
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• 1997

The thermal characteristics of two binary mixtures by sodium azide/manganese dioxide and ferric oxide, two ternary mixtures by sodium azide/silicon dioxide/manganese dioxide and ferric oxide were studied to obtain the basic data of gas-generating agents for air bags. The thermal reaction for all mixtures started at about $420^{\circ}C$, but the temperature at which the reaction rate reached a maximum was different with the states of samples. According to reaction results, nitrogen, nitrogen oxide and nitrogen dioxide were detected by GC-MS and so many kinds of new chemicals from sodium azide and metal oxide mixtures by XRD. NMS is considered as most stable and reasonable mixture for this types of gas-generating agents.

• 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.

• Nuclear Engineering and Technology
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• 제53권3호
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• pp.932-941
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• 2021

This paper suggests a fracture simulation method for SFR metallic fuel pin under accident condition. Two major failure mechanisms - creep damage and eutectic penetration - are implemented in the suggested method. To simulate damaged element, stress-reduction concept to reduce stiffness of the damaged element is applied. Using the proposed method, the failure size of cladding can be predicted in addition to the failure time and failure site. To verify the suggested method, Whole-pin furnace (WPF) test and TREAT-M test conducted at Argonne National Laboratory (ANL) are simulated. In all cases, predicted results and experimental results are overall in good agreement. Based on the simulation result, the effect of eutectic-penetration depth representing failure behavior on failure size is studied.

• 대한화학회지
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• 제21권1호
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• pp.60-66
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• 1977

m-Phenylenediamine(以下 MPD로 略함)과 resorcinol(以下 RES로 略함)을 몰比를 달리하면서 포름알데히드와 酸化觸媒 존재하에서 反應시켜 生成되는 附加共縮合型 樹脂를 流動파라핀을 사용하여 서스펜젼重合시켜 60∼80 mesh의 粒狀重合體를 合成하고 이를 精製한후 5, 10, 15, 20, $25{\%}$의 水酸化 나트륨 水溶液으로 처리한후, 原樹脂와 이들 알칼리 處理樹脂의 金屬이온들에 대한 吸着性을 檢討하였다. $Cd^{2+}$이온에 대한 흡착성은 原樹脂보다 水酸化나트륨水溶液을 처리한 경우 현저히 吸着性은 向上되지만 MPD : RES의 몰比 가 增加함에 따라 原樹脂의 경우와는 달리 減少하는 경향을 나타내며 $Pb^{2+}와\;Al^{3+}$이온들은 알칼리처리로 吸着能增加와 더불어 MPD : RES의 몰比가 2 : 1에서 最大値를 나타내며 $Ca^{2+}$이온의 경우는 MPD : RES의 몰比가 1 : 1에서 최대치를 나타내고 있다. $Mg^{2+}과\;Co^{2+}$이온들은 거의 類似한 傾向을 나타내어 MPD : RES의 몰比增加와 더불어 吸着能은 減少하는 傾向을 나타낸다. $Hg^{2+}$이온의 경우는 特異하며 MPD : RES의 몰比가 減少함에 따라 吸着能은 현저히 增加하는 경향을 나타내어 窒素含宥킬레이트와의 結合性이 强한 一般性과 잘 一致하고 있다. 이 系의 樹脂들은 輕金屬 이온(例 $Ca^{2+},\;Mg^{2+}$) 들보다 重金屬이온(例 $Cd^{2+},\;Hg^{2+}$)들에 對한 吸着力이 현저히 優秀하다.

• 한국잠사곤충학회지
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• 제36권1호
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• pp.37-43
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• 1994

네 종의 서로 다른 인산염을 견정련 보조제로 사용한 경우에 있어서, 정련용수 중 금속이온의 봉쇄, 정련용액의 pH 변화, 그리고 연감효과에 대하여 검토하고 아래와 같은 결과를 얻었다. 1. 칼슘경도성분에 대한 봉쇄효과는 TSPP와 SPD가 높은 봉쇄효과를 나타내었으며, SPM과 SHP는 비교적 낮은 봉쇄효과를 보였다. 2. 철성분에 대한 봉쇄효과는 SHP와 TSPP가 우수한 봉쇄능력이 있었다. 3. 4종의 인산염 중 TSPP와 pH값이 가장 높지만 비누에 비해서는 낮다. 4. 정련속의 pH값은 인산염의 종류에 따라 많은 차이가 있었으나 pH값이 클수록 정련효과가 크게 나타났다.

• 한국수산과학회지
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• 제17권6호
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• pp.492-498
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• 1984

We have reported the seasonal and portional variation in the composition of uronic acid of alginic acid from Ecklonia cava in the previous study. In the present paper, uronic acid block structure of alginic acid from Ecklonia cave was investigated, and some related properties such as viscosity, the dependence on temperature and substitution of metallic ion were also discussed. The proportion M block was highest amnog three blocks in both of frond and stipe. The average values of M and G block ratios were $51.6|%\;and\;32.3\%$ in the frond, whereas $45.7\%\;and\;38.6\%$ in the stipe, respectively. The proportions of alternating blocks in the frond and stipe were similar, and the values were $16.1\%$ in the frond and $15.6\%$ in the stipe. The viscosity of $1\%$ sodium alginate solution was almost inversely proportional to the M/G and/or M block ratio. Viscosities were marked maximum from summer to autumn and minimum winter to spring. In the value of lower M/G and M block ratio, the viscosity seemed to have a considerable dependence on temperature. The temperature dependence was more appearant in the alginic acid from the frond (M/G ratio, 0.95; M block, $54.2\%$) collected in July and the stipe (M/G ratio, 1.61; M block $47.6\%$) in April. The affinity with metallic ion appeared higher in order of $Pb^{2+}>Cu^{2+}>Co^{2+}>Zn^{2+}$. The amounts of metallic ion exchange of the $Pb^{2+},\;Cu^{2+},\;Co^{2+}\;and\;Zn^{2+}$ were ranged from 3.4. to 4.7, 2.5 to 3.2, 1.8 to 2.2 and 1.6 to 1.7 meq/(g. sodium alginate), respectively.