• Proceedings of the Korean Radioactive Waste Society Conference
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• 2003.11a
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• pp.196-201
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• 2003

Decontamination means every method that can drop the level of the radioactivities from the materials contaminated with them to the allowable one. In this paper, one of the decontamination methods, the electro-decontamination was described with lots of experiments. Two test specimens contaminated with alpha ray and beta ray respectively were used to compare the decontamination factors between two rays and many experiments were performed in every electrolyte with SUS and Carbon steel test specimens. Sulphuric acid, phosphoric acid, nitric acid, citric acid and oxalic acid were used as the electrolyte. Decontamination Factors (DF) could be compared and analyzed with different electrolyte, current intensities and time.

• Proceedings of the Korean Nuclear Society Conference
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• 1996.05d
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• pp.207-212
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• 1996

실증규모의 수지충전식 전기투석 재생조를 사용하여 농축음극액내 바나듐의 전기화학적 환원 방법에 의한 재생거동을 조사하였다. 전기투석 분리재생 종료후 남아있는 개미산용액을 전해액으로 사용한 농축음극액내 전기투석된 철 및 코발트는 음극액의 pH를 약 4.3내외로 조절하면 전해환원에 의해 전착.제거된다. 또한 농축음극액내 바나듐은 +2가로 전해환원 되어 착화물을 이루고 있는 Vanadous picolinate 형태로 존재하기 때문에 음극액은 농축된 LOMI 제염제로 재생된다. 이 전해환원에 의한 농축음극액의 재생방법은 제염폐액의 전기투석 분리재생 후 피콜리네이트 착화제만을 재사용하는 기존의 재생개념보다 더욱 효과적으로 제염폐액을 재생시켜 재활용할 순 있는 방사성폐기물의 감용효율이 큰 향상된 제염폐액 재생공정이다.

• Journal of Radiation Protection and Research
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• v.27 no.2
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• pp.95-100
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• 2002

Conventional and modified electrolytic decontamination experiment were performed in the 1.7 M solution of sodium sulfate and sodium nitrate tot decontamination of carbon steel as the simulated metal wastes which have been produced in large amounts from nuclear power plants. Anode ant cathode were used as inconel and titanium respective. The reaction time and temperature were 1 hr and $25^{\circ}C$ The analyses were performed of the characteristics such as weight loss arid thickness change of metal waste. suspended solid in electrolyte and SEM observation. In modified electrolyte decontamination system with increased current density ranged from 0.1 to $0.6A/cm^2$, the metal waste showed thickness changes of $0.48{\pm}0.005$ to $67.7{\pm}0.02{\mu}m$ in 1.7 M sodium sulfate and those of $0.06{\pm}0.005$ to $17.7{\pm}0.05{\mu}m$ in sodium nitrate. Metal waste in modified electrolyte decontamination system showed the thickness change of $9.8{\pm}0.01{\mu}m$ while it reacted up to $3.7{\pm}0.03{\mu}m$ in conventional system with $0.3 A/cm^2$ of current density and 1.7 M sodium sulfate. Decontamination efficiencies of modified electrolytic process ate much hither than that of conventional electrolytic process when both are applied to metal waste.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2004.06a
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• pp.72-80
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• 2004

Electrolytic dissolution study was carried out to evaluate the applicability of electrochemical decontamination process using a neutral salt electrolyte as a decontamination technology for the recycle or self disposal with authorization of large amount of metallic wastes contaminated with uranium compounds generated by dismantling a retired uranium conversion plant using SUS-304 and Inconel-600 specimen as the main materials of internal system components of the plant. The effects of type of neutral salt as an electrolyte, current density, and concentration of electrolyte on the dissolution of the materials were evaluated. On the basis of the results obtained through the basic inactive experiments, electrochemical decontamination tests using the specimens contaminated with uranium compounds such as $UO_2$, AUC (ammonium uranyl carbonate) and ADU (ammonium diuranate) taken from an uranium conversion plant were peformed in $Na_2SO_4$ and $NaNO_3$ solution. It was verified that the electrochemical decontamination of the dismantled metallic wastes was quite successful in $Na_2SO_4$ and $NaNO_3$ neutral salt electrolyte by reducing $\beta$ radioactivities below the level of self disposal with authorization within 10 minutes regardless of the type of contaminants and the degree of contamination.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.1 no.1
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• pp.11-23
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• 2003

A study on the electrolytic dissolution of SUS-304 and Inconel-600 specimen was carried out in neutral salt electrolyte to evaluate the applicability of electrochemical decontamination process for recycle or self disposal with authorization of large amount of metallic wastes contaminated with uranium compounds generated by dismantling a retired uranium conversion plant in Korea. Although the best electrolytic dissolution performance for the specimens was observed in a Na2s04 electrolyte, a NaNO$_3$ neutral salt electrolyte, in which about 30% for SUS-304 and the same for Inconel-600 in the weight loss was shown in comparison with that in a Na$_2$SO$_4$ solution, was selected as an electrolyte for the electrochemical decontamination of metallic wastes with the consideration on the surface of system components contacted with nitric acid and the compatibility with lagoon wastes generated during the facility operation. The effects of current density, electrolytic dissolution time, and concentration of NaNO$_3$ on the electrolytic dissolution of the specimens were investigated. On the basis of the results obtained through the basic inactive experiments, electrochemical decontamination tests using the specimens contaminated with uranium compounds such as UO$_2$, AUC (ammonium uranyl carbonate) and ADU (ammonium diuranate) taken from an uranium conversion facility were performed in 1M NaNO$_3$ solution with the current density or In mA/$\textrm{cm}^2$. it was verified that the electrochemical decontamination of the metallic wastes contaminated uranium compounds was quite successful in a NaNO$_3$ neutral salt electrolyte by reducing $\alpha$ and $\beta$ radioactivities below the level of self disposal within 10 minutes regardless of the type of contaminants and the degree of contamination.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2005.06a
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• pp.76-77
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• 2005

• Proceedings of the Korean Nuclear Society Conference
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• 2003.10a
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• pp.462.2-462.2
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• 2003

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2008.11a
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• pp.63-64
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• 2008

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2003.10a
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• pp.82-82
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• 2003

• Proceedings of the Korean Nuclear Society Conference
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• 1995.05b
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• pp.921-927
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• 1995

수지충전식 전해재생조내에서 바나듐-철-Picolinate 착화물이 함유된 모의 LOMI 제염폐액의 재생거동에 대한 공정변수의 영향을 조사하였다. 전기투석에 의해 양이온종이 제염 폐액으로부터 제거되는 재생 분리효율에 대한 전류밀도, 제염폐액 공급유량 및 재생조내 수지층두께 등 공정변수의 영향은 바나듐이온이 가장 크게 받는다. 공정변수의 영향을 총괄 파라미터인 공정변수비 $\alpha$로 정의하여 나타낼 때 재생 분리효율 95%이상을 얻기 위해서는 $\alpha$가 0.2 이하로 유지되어야 한다. LOMI 제염폐액의 재생시 전기투석 flux는 공정변수비, $\alpha$값이 증가함에 따라 철이온이 바나듐이온에 비해 더욱 커지는 경향을 보였다. 재생종료 후 발생되는 음극폐액내 철 및 코발트 등 방사성이온종은 음극액의 초기 수소이온 농도를 조절하면 침전제의 첨가 얼이 음극반응에 의해 음극액의 pH를 산성에서 알카리성으로 바꿀 수 있어, 수산화물 형태의 침전물 입자로 만들어 쉽게 제거할 수 있다. 재생시 바나듐이온은 대부분 $V^{III}$(Pic)$_2$$^{+}$ 착화물형태로 전기투석된다. 음극액으로 formate용액을 사용하면 철 및 코발트 등 방사성이온종을 제거한 음극액은 농축된 LOMI제염제로 회수하여 필요시 산화가를 조정한 후 재생된 착화제와 혼합하여 제염제로 재사용할 수 있어, 더욱 효과적으로 제염폐액을 재생하는 향상된 재생방법이다.다.