Currently, the Korean nuclear industry uses ZIRLO as material for nuclear fuel cladding(zirconium alloy). KEPCO Nuclear Fuel is in the process of developing a HANA alloy to enable domestic production of cladding. Cladding manufacture involves multistage heat treatments and pickling processes, the latter of which is vital for the removal of defects and impurities on the cladding surface. SMUT that forms on the cladding surface during such pickling process is a source of surface defects during heat treatment and post-treatment processes if not removed. This study analyzes ZIRLO, HANA-4, and HANA-6 alloy claddings to extensively study the SEM/EDS, XRD, and particle size characteristics of SMUT, which are second phase particles that are formed on the cladding surface during pickling processes. Using the analysis results, this study observes SMUT formation characteristics according to Nb concentration in Zr alloys during the washing process following the pickling process. In addition, this study observes SMUT removal characteristics on cladding surfaces according to concentrations of nitric acid and hydrofluoric acid in the acid solution.

Differences in sugar and salt penetrarion rates of radish depending on size and concentration of solution were examined. 2x2x2 and 4x4x4 cm cube-shaped radish examined in different pickling condition (salt 2, 4, 6, 8% and sugar 5, 10, 15, 20% brix). After 12hr storage, Salt penetration rate of radish cut into 2x2x2 cm was faster than that of 4x4x4 cm in all salt solution. Size dependent sugar penetration showed same tendency with size dependent salt penetration. Also, increase in salt and sugar concentration led to increase in salt and sugar permeation rate.

Zirconium(Zr) nuclear fuel cladding tubes are made using a three-time pilgering and annealing process. In order to remove the oxidized layer and impurities on the surface of the tube, a pickling process is required. Zr is dissolved in HF and HNO3 mixed acid during the process and pickling waste acid, including dissolved Zr, is totally discarded after being neutralized. In this study, the waste acid was recycled by adding BaF2, which reacted with the Zr ion involved in the waste acid; Ba2ZrF8 was subsequently precipitated due to its low solubility in water. It is very difficult to extract zirconium from the as-recovered Ba2ZrF8 because its melting temperature is 1031 oC. Hence, we tried to recover Zr using an electrowinning process with a low temperature molten salt compound that was fabricated by adding ZrF4 to Ba2ZrF8 to decrease the melting point. Change of the Zr redox potential was observed using cyclic voltammetry; the voltage change of the cell was observed by polarization and chronopotentiometry. The structure of the electrodeposited Zr was analyzed and the electrodeposition characteristics were also evaluated.

Differences in sugar and salt diffusion rates of cabbage depending on size and part were examined. Whole, 3x3 and 5×5 cube sliced cabbage examined indifferent pickling condition (salt 2, 4, 6, 8% and sugar 5, 10, 15, 20% brix). After 12hr storage, salt absorption depending on part was determined to be higher in leaf, followed by stem in all salt solution. Sugar distribution was also determined to be higher in leaf, followed by stem, showing same trend with salt diffusion. Salt diffusion was found to be highest in 3×3 sliced cabbage. Where as 5×5 sliced cabbage and then whole cabbage showed lower diffusion rate in all brix sugar solution. Size dependent sugar diffusion showed same tendency with size dependent salt diffusion. Also, increase in salt and sugar concentration led to increase in salt and sugar permeation rate.

Salted Cabbage products purchased from different companies at 4 different districts in South Korea were detected in this study. Cabbage and salt are the main materials for kimchi manufacture. The results of general bacteria contaminated in the samples were 1.4 × 10^5, 6.4 × 10^5, 1.7 × 10^7, 3.6 × 10^7 CFU/g in cabbage and 2.7 × 10³ CFU/g in salt,respectively. The results of coliforms were detected as 2.4 × 10⁴ CFU/g, and there was no Escherichia coli in any sample. Staphylococcus aureus was detected in cabbage as 9.9 × 10², 8.0 × 10¹, and 3.0 × 10³ CFU/g, Bacillus cereus was also found in cabbage as 4.1 × 10³ and 1.0 × 10¹ CFU/g. The results of Campylobacter jejuni and Vibrio paraheamolyticus were 2.4 × 10^6 and 1.0 × 10⁴ CFU/g in cabbage, respectively. 1.0 × 10³ CFU/g for Yersinia enterocolitica was determined in salt. In case of Listeria monocytogenes, the results were 1.5 × 10¹, 1.1 × 10², and 4.5 × 10¹ CFU/g in cabbage. Total batcteria ranged from 1.4 × 10¹ to 4.4 × 10^5 CFU/g were detected in salting solution, from 1.5 × 10⁴ to 1.2 × 10^8 CFU/g in dehydrated salted-cabbage, from 9.4 × 10⁴ ~1.3 × 10^8 CFU/g in minced salted-cabbage. The results of E. coli in samples from different companies were different from one to anther. The results of the contamination of S. aureus and B. cereus showed positive in salting solution and dehydrated salted-cabbage at a portion of companies. V. paraheamolyticus was detected in salting solution. The contamination of Y. enterocolitica ranged from 9.5 × 10² to 1.8 × 10³ CFU/g in salting solution, from 1.7 × 10¹ to 2.7 × 10² CFU/g in dehydrated salted-cabbage, from 1.2 × 10² to 1.3 × 10^8 CFU/g in minced salted-cabbage. The contamination of L. monocytogenes ranged from 8.0 × 10² to 1.7 × 104 CFU/g in salting solution, from 2.8 × 10² to 1.2 × 10⁴CFU/g in dehydrated salted-cabbage. During the manufacture processing of Kimchi, microorganisms were detected in cabbages salted in different concentrations of salt solution at 8%, 10%, 12% and 15% for 5-20 hours. As the results, 3.5 × 10^5 -1.7 × 10^6 , 3.4 × 10^5 - 2.5 × 10^6 , 5.4 × 10^5 - 2.3 × 10^6 , 4.0 × 10^5 - 2.3 × 10^6 CFU/g were detected for E. coli in samples at different treatment conditions. 1.9 × 10⁴- 4.1 × 10⁴, 4.1 × 10³ - 2.8 × 10⁴, 1.5 × 10³ - 7.8 × 10³ , 2.2 × 10⁴- 6.6 × 10⁴CFU/g were detected for S. aureus in samples at different treatment conditions. Salmonella typhimurium was detected in salted cabbage with various salt concentration after salting for 5 hrs, the result ranged from 2.5 × 10^5 to 3.8 × 10^6 CFU/g, and change of microorganism was the smallest in salted cabbage under the concentration of salting solution at 10% for 15 hours. The cabbage salted in 10% salting solution for 15 hours were washed with water for 2 and 3 times, with chlorine for 3 times, and with acetic acid for 3 times. E. coli was detected in the samples washed with water for 2 and 3 times, washed with chlorine for 3 times. The contamination of S. aureus was 3.0 × 10^5 CFU/g in the samples washed with water for 2 times,5.6 × 10³ CFU/g in the samples washed with acetic acid for 3 times, 3.6 × 10^5 CFU/g in the samples washed with water for 3 times and same amount in the samples washed with chlorine for 3 times. According to the results, the contamination of S. aureus was 5.6 × 10³ CFU/g lower in samples washed with chlorine and acetic acid than that in samples washed with water. In case of S. typhimurium, it has been detected in samples washed with water and chlorine, 3.0 × 10¹ CFU/g as the lowest concentration among all the samples was measured in the samples washed with acetic acid for 3 times.

This study was aimed at determining the changes in heavy metal removal efficiency at different acid concentrations in a micro-nanobubble soil washing system and pickling process that is used to dispose of heavy metals. For this purpose, the initial and final heavy metal concentrations were measured to calculate the heavy metal removal efficiency 5, 10, 20, 30, 60, and 120 min into the experiment. Soil contaminated by heavy metals and extracted from 0~15 cm below the surface of a vehicle junkyard in the city of U was used in the experiment. The extracted soil was air-dried for 24 h, after which a No. 10 (2 mm) was used as a filter to remove large particles and other substances from the soil as well as to even out the samples. As for the operating conditions, the air inflow rate in the micro-nano bubble soil washing system was fixed at 2 L/min,; with the concentration of hydrogen peroxide being adjusted to 5%, 10%, or 15%. The treatment lasted 120 min. The results showed that when the concentration of hydrogen peroxide was 5%, the efficiency of Zn removal was 27.4%, whereas those of Ni and Pb were 28.7% and 22.8%, respectively. When the concentration of hydrogen peroxide was 10%, the efficiency of Zn removal was 38.7%, whereas those of Ni and Pb were 42.6% and 28.6%, respectively. When the concentration of hydrogen peroxide was 15%, the efficiency of Zn removal was 49.7%, whereas those of Ni and Pb were 57.1% and 42.6%, respectively. Therefore, the efficiency of removal of all three heavy metals was the highest when the hydrogen peroxide concentration was 15%.

Lab-scale Electrodialysis(ED) system with different membranes combined with before or after pyroma process were carried out to remove nitrate from two pickling acid wastewater containing high concentrations of NO3-(≈150,000 mg/L) and F-(≈160,000 mg/L) and some heavy metals(Fe, Ti, and Cr). The ED system before Pyroma process(Sample A) was not successful in NO3- removal due to cation membrane fouling by the heavy metals, whereas, in the ED system after Pyroma process(Sample B), about 98% of nitrate was removed because of relatively low NO3- concentration (about 30,000 mg/L) and no heavy metals. Mono-selective membranes(CIMS/ACS) in ED system have no selectivity for nitrate compared to divalent-selective membranes(CMX/AMX). The operation time for nitrate removal time decreased with increasing the applied voltage from 10V to 15V with no difference in the nitrate removal rate between both voltages. Nitrate adsorption of a strong-base anion exchange resin of Cl- type was also conducted. The Freundlich model(R2 > 0.996) was fitted better than Langmuir model(R2 > 0.984) to the adsorption data. The maximum adsorption capacity (Q0) was 492 mg/g for Sample A and 111 mg/g for Sample B due to the difference in initial nitrate concentrations between the two wastewater samples. In the regeneration of ion exchange resins, the nitrate removal rate in the pickling acid wastewater decreased as the adsorption step was repeated because certain amount of adsorbed NO3- remained in the resins in spite of several desorption steps for regeneration. In conclusion, the optimum system configuration to treat pickling acid wastewater from stainless-steel industry is the multi-processes of the Pyroma-Electrodialysis-Ion exchange.

시판 pickling spice와 본 실험실에서 개발한 pickling spice를 사용하여 순무피클올 제조한 후 200(에서 저장하면서 이화학 석, 관능적 특성플 분석하였다. 염도, 환원당 함량, L, a 및 b 값, 기계적 경도 측정치는 두 시료간에 차이가 없었으나, 산 E는 본 실험섣에서 개발한 피클링 스파이스로 제조한 순무 페클(이하 순무피클M)이 시판되는 피클링 스파이스로 만든 피클(이하 순무피클P)에 비해 유의적으로 높았다(p