• Nuclear Engineering and Technology
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• 제34권4호
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• pp.286-300
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• 2002

An algorithm for the sodium boiling model has been developed for calculation of the void reactivity feedback as well as the fuel and cladding temperatures in the KALIMER core after onset of sodium boiling. Modeling of sodium boiling in liquid metal reactors using sodium as a coolant is necessary because of phenomenon difference comparing with that observed generally in light water reactor systems. The applied model to the algorithm is the multiple-bubble slug ejection model. It allows a finite number of bubbles in a channel at any time. Voiding is assumed to result from formation of bubbies that (ill the whole cross section of the coolant channel except for the liquid film left on the cladding surface. The vapor pressure, currently, is assumed to be uniform within a bubble The present study is focused on not only demonstration of the vapor bubble behavior predicted by the developed model, but also confirmation of a qualitative acceptance for the model. As a result, the model can represent important phenomena in the sodium boiling, but it is found that further effort is also needed for its completition.

• Nuclear Engineering and Technology
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• 제43권1호
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• pp.63-74
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• 2011

The 600 MWe, pool-type, sodium-cooled, metallic fuel loaded KALIMER-600 (Korea Advanced LiquId MEtal Reactor, 600 MWe) has been conceptually designed with an emphasis on safety by self-regulating (inherent/intrinsic) negative reactivity feedback in the core. Its inherent safety under the ATWS (Anticipated Transient Without Scram) events was demonstrated in an earlier study. Initiating events of an HCDA (Hypothetical Core Disruptive Accident), however, also need to be analyzed for assessment of the margins in the current design. In this study, a hypothetical triple-fault accident, ULOF (Unprotected Loss Of Flow) with a reduced pump halving time, is investigated as an initiator of a core disruptive accident. A ULOF with insufficient primary pump inertia may cause core sodium boiling due to a power-to-flow mismatch. If the positive sodium reactivity resulting from this boiling is not compensated for by other intrinsic negative reactivity feedbacks, the resulting core power burst would challenge the fuel integrity. The present study focuses on determination of the limit of the pump inertia for assuring inherent reactivity feedback and behavior of the core after sodium boiling as well. Transient analyses are performed with the safety analysis code SSC-K, which now incorporates a new sodium boiling model. The results show that a halving time of more than 6.0 s does not allow sodium boiling even with very conservative assumptions. Boiling takes place for a halving time of 1.8 s, and its behavior can be predicted reasonably by the SSC-K.

• 한국식품조리과학회지
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• 제15권4호
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• pp.382-387
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• 1999

This study was conducted to investigate the changes of mineral contents in radish leaves, soybean sprout and chwi namul by cooking method(boiling, steaming, sauting) and cooking time(1, 3, 5 min.). The residual rate of minerals(such as Calcium, Sodium, Potassium, Iron and Magnesium) in radish leaves, soybean sprout and chwi namul by 1 minute sauting was the range of 83.2 to 99.1%. It was shown that sauting was desirable method for all three vegetables. The residual rate by the cooking method was sauting, steaming, boiling, in that order, but boiling in radish leaves and chwi namul were more desirable method than steaming for Calcium use. At the cooking method and cooking time, Potassium content in soybean sprout was reduced remarkably in 5 minutes boiling. Boiling of radish leaves and soybean sprout showed that Sodium was reduced remarkably after 5 minutes of boiling, 54.4% for radish leaves and 19.9% for soybean sprout, respectively.

• 한국의류학회지
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• 제11권1호
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• pp.63-69
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• 1987

Silk fibroin is likely to be hydrolyzed by acids or alkalies at high temperature, and the degree of the hydrolysis has been inferred from the changes in tensile strength and elongation. But, in this experiment, it was intended to infer that from the quantitative changes in terminal aminp group content as well as in tensile strength and elongation. Silk yarn was treated with boiling water, hydrochloric acid, and sodium hydroxide under various conditions. The boiling water somewhat degraded silk fibroin. Silk yarn treated with sodium hydroxide contained more terminal amino group than that treated with hydrochloric acid. This result agreed fairly well with the loss in weight, tensile strength, and elongation: the terminal amino group content increased with the decrease of tensile strength, elongation, and weight. The damage by sodium hydroxide to the silk fibroin was greater than that by hydrochloric acid.

• 대한가정학회지
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• 제23권1호
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• pp.25-31
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• 1985

This study designed not only to elucidate free amino acid, fatty acid composition and mineral content in dried alaska pollack but also to examine calcium, magnesium, poassium and sodium contents in its cooking broth according to each boiling time such as 2.5, 5, 10, 20, and 30 minutes. RESULTS : 1. Glutamic acid in dried alaska pollack was the most abundant free amino acid and was followed in order of aspartic acid, lysin, leucine and histidine. They composed of 50.95% of the total amino acid contents. 2. In dried alaska pollack the most abundant fatty acid was palmitic acid. Essential fatty acid content was 26.57% of the total fatty acid. 3. The calcium, magnesium, potassium and sodium contents in dried alaska pollack showed 10.721 mg%, 9.235mg%, 4072.5mg% and 2299.8% respectively. The amount of magnesium and potassium in cooking broth arrived at the highest level when 20 minute boiling was undertaken and the quantities of magnesium and sodium were the highest when 30 minute boiling was made.

• 한국식품영양과학회지
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• 제15권3호
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• pp.243-248
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• 1986

사골을 8시간, 12시간, 16시간, 20시간 가열하였을 때 용출액 중의 무기질 성분(칼슘, 나트륨, 칼륨, 마그네슘, 인)의 용출량 변화와 총질소 유리아미노산 조성의 변화를 검토한 결과는 다음과 같다. 1) 가열시간이 길수록 칼슘, 나트륨, 칼륨의 용출량은 증가되었다. 칼슘은 8시간에 비해 20시간 가열하면 용출량은 2배 이상 되었지만 칼륨, 나트륨은 8시간에 비해 20시간 가열한 후에도 크게 증가되지는 못했다. 마그네슘은 가열시간이 길어져도 용출량에는 거의 변화가 없었고 20시간 가열한 후에도 용출량은 약 2mg이었다. 반면 인은 8시간에서 최대 용출량을 나타냈고 12시간 이상 가열하면 감소하였다. Ca/P비는 8시간 가열시 1.4이었으나 12시간 이상 가열하면 매우 높아졌다. 2) 총질소량은 가열시간이 길수록 그 용출량도 증가하였고 20시간에서 최대 용출량을 나타냈고 8시간에 비해 거의 2배 가까이 용출되었다. 유리아미노산 조성의 변화를 보면 가열시간이 길수록 glycine, glutamic acid, serine의 용출량은 증가되었다. 그러나 가열시간이 길어져도 아미노산조성의 비율은 거의 일정한 수준을 나타냈다. 아미노산중 가장 함량이 많은 아미노산은 glycine, glutamic acid, alanine, serine 이었다. 이상의 결과를 종합하며 보면 사골을 12시간이상 가열하였을 때 Cp/P비, 다른 무기질 성분의 용출률, 아미노산의 용출량등을 고려하여 볼 때 사골은 12시간 이상 가열하여도 영양성분의 양적인 변화는 크게 기대하기 어려운 것으로 생각되며 사골은 $8{\sim}12$시간 정도 끊이면서 영양성분의 용출량을 증가시키는 다른 조리 방법을 모색하는 것이 바람직 한것으로 생각된다.

• Nuclear Engineering and Technology
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• 제43권3호
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• pp.195-204
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• 2011

The effects on pool boiling heat transfer of aqueous solutions of boric acid ($H_3BO_3$) and sodium chloride (NaCl) as working fluids have been studied. Borated and NaCl water were prepared by dissolving 0.5~5% volume concentration of boric acid and NaCl in distilled-deionized water. The pool boiling tests were conducted using $1{\times}1\;cm^2$ flat heaters at 1 atm. The critical heat flux (CHF) dramatically increased compared to boiling pure water. At the end of boiling tests it was observed that particles of boric acid and NaCl had deposited and formed a coating on the heater surface. The CHF enhancement and surface modification during boiling tests were very similar to those obtained from boiling with nanofluids. Additional experiments were carried out to investigate the reliability of the additives deposition in pure water. The boric acid and NaCl coatings disappeared after repeated boiling tests on the same surface due to the soluble nature of the coatings, thus CHF enhancement no longer existed. These results demonstrate that not only insoluble nanoparticles but also soluble salts can be deposited during boiling process and the deposited layer is solely responsible for significant CHF enhancement.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 2001년도 추계학술발표회요약집
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• pp.170-170
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• 2001

• 한국식품조리과학회지
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• 제9권1호
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• pp.52-56
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• 1993

삼계탕을 남비 및 압력솥에서 각각 30분, 60분, 90분, 120분, 150분, 180분씩 가열했을 때 용출액 중의 무기질 성분(Ca, K, Mg, Zn, Fe, Na, p)의 함량변화를 검토한 결과는 다음과 같다. 1) 삼계탕 용출액 중의 무기질 성분 즉 Ca, K, Mg, Zn, Fe, Na, p의 용출량 변화를 보면, 남비에서는 가열 시간이 경과함에 따라 모두 증가되었지만, 압력솥에서는 Ca, K, Mg, Zn이 가열시간의 경과에 따라 증가된 반면 Fe, Na, p은 120분에서 최대 수치를 보인 후 그 이후에서는 감소되는 추세였다. 2) 가열전 생시료의 Ca/P은 1:0.91이었으나, 가열 후의 Ca과 P의 용출비율은 가열시간에 따라 불규칙적이었는데 남비가 1:3.58∼l:4.68이었고, 압력솥은 1:2.02∼l:3.96의 범위를 나타내고 있다. 이 비율은 칼슘의 체내이용에 이상적인 식사 중의 칼슘과 인의 비율인 1:1∼1:1.5와 비교해서 너무 많은 차이를 보였다. 3) 가열시간에 따른 무기질 용출 증가율은 Ca 경우에서만 남비와 압력솥에서 시간이 지남에 따라 비슷한 증가율을 보인 반면 K, Mg, Na, p 등은 30분에서 60분 동안 남비와 압력솥 모두에서 가장 높은 증가율을 보였다. Zn은 남비의 경우 120분에서 150분 동안, 압력솥에서는 30분에서 60분 동안 가장 높은 증가율을 보였고, Fe은 남비의 경우 90분에서 120분 동안, 압력솥의 경우는 60분에서 90분 동안 가장 높은 증가율을 나타냈다.

• Nuclear Engineering and Technology
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• 제54권12호
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• pp.4759-4775
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• 2022

The RVACS is a versatile and robust safety system driven by two natural circulations: in-vessel coolant and ex-vessel air. To observe interaction between the two natural circulations, SINCRO-IT facility was designed with two different similarity laws simultaneously. Bo' based similarity law was employed for the in-vessel, while Ishii's similarity law for the ex-vessel excluding the radiation. Compared to the prototype, the sodium and air system, SINCRO-IT was designed with Wood's metal and air, having 1:4 of the length reduction, and 1.68:1 of the time scale ratio. For the steady state, RV temperature limit was violated at 0.8% of the decay heat, while the sodium boiling was predicted at 1.3%. It showed good accordance with the system code, TRACE. For an arbitrary re-criticality scenario with RVACS solitary operation, sodium boiling was predicted at 25,100 s after power increase from 1.0 to 2.0%, while the system code showed 30,300. Maximum temperature discrepancy between the experiments and system code was 4.2%. The design and methodology were validated by the system code TRACE in terms of the convection, and simultaneously, the system code was validated against the simulating experiments SINCRO-IT. The validated RVACS model could be imported to further accident analysis.