Corrosion Behavior of Hastelloy C-276 for Carbon-anode-based Oxide Reduction Applications

Jeon, Min Ku,Kim, Sung-Wook,Choi, Eun-Young Korean Radioactive Waste Society 2020 방사성폐기물학회지 Vol.18 No.3

The corrosion behavior of Hastelloy C-276 was investigated to identify its applicability for carbon-anode-based oxide reduction (OR), in which Cl₂ and O₂ are simultaneously evolved at the anode. Under a 30 mL·min^-1 Cl₂ + 170 mL·min^-1 Ar flow, the corrosion rate was less than 1 g·m^-2·h^-1 up to 500℃, whereas the rate increased exponentially from 500 to 700℃. The effects of the Cl₂-O₂ composition on the corrosion rate at flow rates of 30 mL·min^-1 Cl₂, 20 mL·min^-1 Cl₂ + 10 mL·min^-1 O₂, and 10 mL·min^-1 Cl₂ + 20 mL·min^-1 O₂ with a constant 170 mL·min^-1 Ar flow rate at 600℃ was analyzed. Based on the data from an 8 h reaction, the fastest corrosion rate was observed for the 20 mL·min^-1 Cl₂ + 10 mL·min^-1 O₂ case, followed by 30 mL·min^-1 Cl₂ and 10 mL·min^-1 Cl₂ + 20 mL·min^-1 O₂. The effects of the chlorine flow rate on the corrosion rate were negligible within the 5-30 mL·min^-1 range. A surface morphology analysis revealed the formation of vertical scratches in specimens that reacted under the Cl₂-O₂ mixed gas condition.

Corrosion Behavior of Inconel X-750 for Carbon Anode Oxide Reduction Application

Jeon, Min Ku,Kim, Sung-Wook,Lee, Sang-Kwon,Choi, Eun-Young Korean Radioactive Waste Society 2020 방사성폐기물학회지 Vol.18 No.3

The corrosion behavior of the Inconel X-750 alloy was investigated for its potential application under a Cl₂-O₂ mixed gas flow in an Ar atmosphere. The corrosion rate was found to be negligible at temperatures up to 400℃ under a flow rate of 30 mL·min^-1 Cl₂ + 170 mL·min^-1 Ar, whereas an exponential increase was observed in the corrosion rate at temperatures greater than 500℃. The suppression of the corrosion reaction due to the presence of O₂ was verified experimentally at flow rates of 30 mL·min^-1 Cl₂ (4.96 g·m^-2·h^-1), 20 mL·min^-1 Cl₂ + 10 mL·min^-1 O₂ (2.02 g·m^-2 ·h^-1), and 10 mL·min^-1 Cl₂ + 20 mL·min^-1 O₂ (1.34 g·m^-2·h^-1) under a constant Ar flow rate of 170 mL·min^-1 at 600℃ for 8 h. The surface morphology analysis results revealed that porous surfaces with tunnel-type holes were produced under the Cl₂-O₂ mixed-gas condition. Furthermore, the effects of the Cl₂ flow rate on the corrosion rate were investigated, indicating that its impact was negligible within the range of 5-30 mL·min^-1 Cl₂ at 600℃.

Preliminary Study on Chlorination Reaction of Lithium Carbonate for Carbon-Anode-Based Oxide Reduction Applications

Jeon, Min Ku,Kim, Sung-Wook,Choi, Eun-Young Korean Radioactive Waste Society 2021 방사성폐기물학회지 Vol.19 No.2

The reaction between Li₂CO₃ and Cl₂ was investigated to verify its occurrence during a carbon-anode-based oxide reduction (OR) process. The reaction temperature was identified as a key factor that determines the reaction rate and maximum conversion ratio. It was found that the reaction should be conducted at or above 500℃ to convert more than 90% of the Li₂CO₃ to LiCl. Experiments conducted at various total flow rate (Q) / initial sample weight (W_i) ratios revealed that the reaction rate was controlled by the Cl₂ mass transfer under the experimental conditions adopted in this work. A linear increase in the progress of reaction with an increase in Cl₂ partial pressure (pCl₂) was observed in the pCl₂ region of 2.03-10.1 kPa for a constant Q of 100 mL·min^-1 and W_i of 1.00 g. The results of this study indicate that the reaction between Li₂CO₃ and Cl₂ is fast at 650℃ and the reaction is feasible during the OR process.

무증상의 현미경적 혈뇨의 비뇨기과적 고찰

구자현,서병욱,김영호,송윤섭,전윤수,김민의,이남규,박영호 순천향의학연구소 1998 Journal of Soonchunhyang Medical Science Vol.4 No.2

We intended to know whether all of the patients with asymptomatic microscopic hematuria should be urologically investigated routinely. We reviewed the medical records with asmptomatic microscopic hematuria from January 1995 to December 1997. Urological studies included intravenous urography or ultrasonography, urine cytology, cystoscopy and biopsy, urine AFB smear and culture and urine PCR for AFB. The age with patients ranged from 9 to 74 years(mean age: 39.7 years). Benign diseases were found in elderly patients and patients with high degree of hematuria, but there was no patients who had urological malignant disease. According to the results, we suggest that follow-up with urine cytology is sufficient to younger patients or low degree of hematuria with asymptomatic microscopic hematuria.

부신 결핵에 의한 Addison씨병 1예

송치운,구본정,안봉수,전준식,안미애,이진홍,송민호,김영건,노흥규 충남대학교 의과대학 지역사회의학연구소 1995 충남의대잡지 Vol.22 No.2

Addison's disease is a rare primary adrenal insufficient disorder resulting from chronic deficiency of adrenal cortical hormones. Clinical manefestations are generalized weakenss, weight loss, hyperpigmentation (especially sun exposed area and mucous membrane), hypotension, hyponatremia, hyperkalemia, gastrointestinal symptoms (involving anorexia, nausea, vomiting, abdominal pain). A 34-year-old woman has experienced slowly progressive generalized weakenss and skin pigmentation, anorexia, nausea, vomiting with ascites and diffuse abdominal pain. On the time of admission, her main clinical manifestations were anorexia, nausea, vomiting, fatigue, generalized weakness, amenorrhea, hair loss, diffuse abdominal pain revealed as Addison's disease due to bilateral adrenal tuberculosis. Her adrenal insufficient symptoms were recovered with the replacement of adrenocortical hormones and antituberculous medications. After treatment, Her skin pigmentation was decreased and menstruation was reappeared. Here we experienced one cases of Addison's disease with tuberculous peritonitis.

성인 음낭수종의 치료로서 Window Operation의 효용성

서병욱,박영호,이남규,전윤수,김민의,김영호,송윤섭,구자현 순천향의학연구소 1999 Journal of Soonchunhyang Medical Science Vol.5 No.1

We intended to determine the usefulness of window operation for adult hydrocele repair. We reviewed medical records of 132 patients from January 1995 to June 1998 with primary hydrocele and evaluated complications and recurrence rates of eversion and/or excision, plication, and internal drainage technique. Recurrence rate was highest in internal drainage technique as 85.2%, and those of eversion and/or excision and plication technique were 1.3% and 4%, respectively. Complication rate was highest in eversion and/or excision technique, and lowest in internal drainage technique. Although complication rate was lowest in window operation, this operation could not be successful due to high recurrence, and we suggest that this operation should be abandoned for hydrocele repair.

서울의 PPNG 발생 빈도(1991-1992)

김재홍,윤기범,박평원,김영진,전경민,김영태,김중환,곽호,구상완,송민석,유옥,지혜구,김동원,문상은,박영립,정승호,성범진,성순제,엄주용,황정열,이기홍,이주협,전태진 대한화학요법학회 1994 대한화학요법학회지 Vol.12 No.1

The prevalence of PPNG among pretreated gonorrhea cases isolated at the STD clinic of Choong-Ku Public Health Center in Seoul has been studied and reported annually since 1981. In 1991, 123 strains of N.gonorrhoeae were isolated, among which 58(47.1%) were PPNG. In 1992, 98 starains of N.gonorrhoeae were isolated, among which 51(52.0%) were PPNG. In all, 109(49.3%) strains were found to be PPNG among 221 strains isolated between 1991-1992. The prevalence of PPNG in Seoul showed increased tendency till 1989, thereafter, it has been stationary or slightly decreasing.

여성 하부요관석환자에서 무마취하 요관경하 배석술

박영호,송윤섭,임용순,김영호,이남규,구자현,서병욱,김민의,전윤수 순천향의학연구소 1999 Journal of Soonchunhyang Medical Science Vol.5 No.2

Although ureteroscopy(URS) has been used widely to remove ureteral calculi, there is an argument against the belief that anesthesia or admission is needed for URS. We evaluated the experience of URS without anesthesia in female patients. From September 1997 to July 1998, URS was performed in 31 female patients without anesthesia. EHL(Electrohydraulic Lithotripsy) was used in 21 patients with impacted or large stone over 5mm. All patients were given oral antibiotics for 3 days and follow-up KUB was taken to confirm successful removal of the stone one week after the procedure. Successful treatment was defined as complete removal of the stone or residual fragments less than 2mm. Overall success rate was 96.7%(30 cases among 31 cases). All but one patient tolerated with analgesia through the entire procedures. There were only minimal complications such as mild flank pain and hematuria. So, we recommend that non-anesthetic ureteroscopic removal of stone as the first choice for treatment of lower ureteral stones in female based on the minimal morbidity, high success rate and low cost.

Corrosion Behavior of Stainless Steel 316 for Carbon Anode Oxide Reduction Application

Jeon, Min Ku,Kim, Sung-Wook,Choi, Eun-Young Korean Radioactive Waste Society 2020 방사성폐기물학회지 Vol.18 No.2

Here, the stability of stainless steel 316 (SS-316) was investigated to identify its applicability in the oxide reduction process, as a component in related equipment, to produce a complicated gas mixture composed of O₂ and Cl₂ under an argon (Ar) atmosphere. The effects of the mixed gas composition were investigated at flow rates of 30 mL/min O₂, 20 mL/min O₂ + 10 mL/min Cl₂, 10 mL/min O₂ + 20 mL/min Cl₂, and 30 mL/min Cl₂, each at 600℃, during a constant argon flow rate of 170 mL/min. It was found that the corrosion of SS-316 by the chlorine gas was suppressed by the presence of oxygen, while the reaction proceeded linearly with the reaction time regardless of gas composition. Surface observation results revealed an uneven surface with circular pits in the samples that were fed mixed gases. Thermodynamic calculations proposed the combination of Fe and Ni chlorination reactions as an explanation for this pit formation phenomenon. An exponential increase in the corrosion rate was observed with an increase in the reaction temperature in a range of 300 ~ 600℃ under a flow of 30 mL/min Cl₂ + 170 mL/min Ar.

Preliminary Mass Flow Diagram of a Thermochemical Process for Decontamination of Radioactive-combustible Waste

Min Ku Jeon,Sung-Wook Kim,Maengkyo Oh,Hee-Chul Yang,Keunyoung Lee 한국방사성폐기물학회 2022 한국방사성폐기물학회 학술논문요약집 Vol.20 No.2

The Korea government decided to shut down Kori-1 and Wolsung-1 nuclear power plants (NPPs) in 2017 and 2019, respectively, and their decommissioning plans are underway. Decommissioning of a NPP generates various types of radioactive wastes such as concrete, metal, liquid, plastic, paper, and clothe. Among the various radioactive wastes, we focused on radioactive-combustible waste due to its large amount (10,000–40,000 drums/NPP) and environmental issues. Incineration has been the traditional way to minimize volume of combustible waste, however, it is no longer available for this amount of waste. Accordingly, an alternative technique is required which can accomplish both high volume reduction and low emission of carbon dioxide. Recently, KAERI proposed a new decontamination process for volume reduction of radioactivecombustible waste generated during operation and decommissioning of NPPs. This thermochemical process operates via serial steps of carbonization-chlorination-solidification. The key function of the thermochemical decontamination process is to selectively recover and solidify radioactive metals so that radioactivity of the decontaminated carbon meets the release criteria. In this work, a preliminary version of mass flow diagram of the thermochemical decontamination process was established for representative wastes. Mass balance of each step was calculated based on physical and chemical properties of each constituent atoms. The mass flow diagram provides a platform to organize experimental results leading to key information of the process such as the final decontamination factor and radioactivity of each product.