• Proceedings of the Korean Radioactive Waste Society Conference
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• 2004.06a
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• pp.278-284
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• 2004

The processes for the smelting of a metal product and the solidification of a molten salt were developed respectively to treat the products from the electrochemical reduction process. The method for the separation of a metal product in a magnesia container from the residual. salt and consequent smelting of it to a metal ingot by the multi step heating in vacuum was proposed. The new concept using a dual vessel and a salt valve was also suggested for the solidification of a molten salt into a regular size and shape which is suitable for the transport and measurement. The results obtained in the study will be applied to the design of the hot cell demonstration system of the Advanced Spent Fuel Conditioning Process of KAERI.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.8 no.1
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• pp.77-84
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• 2010

Reduction of oxides has been investigated for the volume reduction and recycling of the spent oxide fuel from commercial nuclear power plants. Various oxide reduction methods were proposed and KAERI (Korea Atomic Energy Research Institute) is currently developing an electrochemical reduction process using a LiCl-$Li_2O$ molten salt as a reaction medium. The electrochemical reduction process, the front end of the pyroprocessing, can connect the PWR (Pressurized Water Reactor) oxide fuel cycle to a metal fuel cycle of the sodium cooled fast reactor. This paper summarizes KAERI efforts on the development, improvement, and scale-up of the oxide reduction process.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2005.11a
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• pp.233-233
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• 2005

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.2 no.4
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• pp.239-244
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• 2004

In order to enhance an oxidation resistance of the pure uranium metal under air condition, a small quantity of niobium(Nb) which is known to mitigate metal oxidation is added into uranium metal as an alloying element. A simulated metallic uranium alloy, U-Nb has been fabricated and then oxidized in the range of 200 to $300^{\circ}C$ under the environment of the pure oxygen gas. The oxidized quantity in terms of the weight gain(wt%) has been measured with the help of a thermogravimetric analyzer. The results show that the oxidation resistance of the U-Nb alloy is considerably enhanced in comparison with that of the pure uranium metal. It is revealed that the oxidation resistance of the former with the niobium content of 1, 2, 3, and 4 wt% is : 1) 1.61, 7.78, 11.76 and 20.14 times at the temperature of $200^{\circ}C$ ; 2) 1.45, 5.98, 10.08 and 11.15 times at $250^{\circ}C$ ; and 3) 1.33, 4.82, 8.87 and 6.84 times at $300^{\circ}C$ higher than that of the latter, respectively. Besides, it is shown that the activation energy attributable to the oxidation is 17.13~21.92 kcal/mol.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2003.11a
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• pp.395-400
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• 2003

For the long term storage safety study of the metallic spent fuel, U-Nb, U-Ti, U-Ni, U-Zr, and U-Hf simulated metallic uranium alloys, known as corrosion resistant alloys, were fabricated and oxidized in oxygen gas at $200^{\circ}C~300^{\circ}C$. Simulated metallic uranium alloys were more corrosion resistant than pure uranium metal, and corrosion resistance increases Nb, Ni, Ti in that order. The oxidation rates of uranium alloys determined and activation energy was calculated for each alloy. The matrix microstructure of the test specimens were analyzed using OM, SEM, and EPMA. It was concluded that Nb was the best acceptable alloying elements for reducing corrosion of uranium meta] considered to suitable as candidate.

• Proceedings of the Korean Nuclear Society Conference
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• 1998.05b
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• pp.497-502
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• 1998

후행핵연료주기 정책 미결정국형 사용후핵연료 관리기술 개발을 위하여 자원으로서 가치가 있는 PWR 사용후핵연료를 대상으로 새로운 관리개념을 설정하였으며 본 개념을 뒷받침하는 요소기술들에 대한 비방사성 검증시험을 수행하였다. 본 논문에서는 이와 관련한 사용후핵연료 차세대관리 공정개념을 소개하고 모의 PWR 사용후핵연료의 금속전환 시험결과와 금속전환체의 관리상에 필수적으로 검토되어야할 핵임계안전성과 열안전성에 대한 예비해석 결과를 소개코자 한다.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2009.11a
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• pp.345-345
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• 2009

전기화학적 환원 기술을 이용한 고온 용융염 전해환원의 결과 생산되는 금속전환체는 다공성 특성에 의해 전해환원의 매질인 용융염을 함유하게 된다. 전해환원과 후속 전기화학 공정인 전해정련의 전해질은 각각 LiCl과 LiCl-KCl 공융염으로 상이하기 때문에 이렇게 금속전환체에 포함된 LiCl 염이 동반되어 전해정련 공정에 도입될 경우 전해정련 공정의 공융염 조성을 어긋나게 한다. 이에 따라 금속전환체의 잔류염은 효과적으로 제거되어야 하며 공정으로 감압 증류에 의한 잔류염 제거 공정이 고려되고 있다. LiCl은 증기압이 비교적 낮기 때문에 감압의 고온 조건이 공정에 필요하다. 그러나 상평형도 분석 결과 전해환원 공정에서 산화물을 담아 음극으로 사용되어 환원된 금속전환체와 함께 도입되는 SUS 재질의 바스켓과 사용후핵연료 금속전환체의 주된 원소인 우라늄과는 공융할 수 있기 때문에 LiCl 증발 온도는 $720^{\circ}C$ 이하로 유지되어야 한다. 이와 같은 조건에서 LiCl 증발 속도를 높이기 위해서는 감압 조건이 필수적이다. 본 연구에서는 감압조건에서 LiCl 휘발 실험을 위해 폐쇄형 및 개방형 반응기를 제작하여 압력 조건 및 Ar 유량 등에 따른 LiCl 휘발율을 측정하였다. 증발된 LiCl은 일정 감압 조건에서 분말형으로 냉각부위에 회수 될 수 있었으나 완전 진공 조건에서는 결정형으로 냉각 부위에 응축되는 것으로 확인 되었으며 일정 진공 조건에서는 Ar 유량에 따라 증발량이 의존하지 않는 것으로 나타났다. 연구 결과 증발염의 취급 빛 이송을 위해 분말형 회수를 목표로 설정할 수 있었으며 공정조건으로 일정 수준의 감압 조건을 제시하였다. 이 후 후속 연구로 장치의 대형화 및 증발 속도 향상을 위한 추가적인 연구가 계획되어 있으며 연구 결과에 기초하여 공학규모 파이로 공정 시설인 PRIDE에 도입될 장치의 기초 설계 자료를 생산할 예정이다.

• Proceedings of the Korean Nuclear Society Conference
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• 2002.10a
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• pp.338.2-338
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• 2002

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2012.05a
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• pp.296-297
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• 2012

전기 방사(Electrospinning)를 이용하여 하이브리드 태양전지용 금속 메쉬 제조에 관한 연구를 진행하였다. 금속 메쉬 제조를 위해 각종 고분자 물질을 이용한 용액에 이용하여 금속 섬유를 제조하였으며, 전기 방사된 고분자 금속 섬유는 열처리를 이용해 금속 섬유를 전환시켰다. 각각 제작된 금속 섬유의 형상 및 조성 그리고 전기적 특성을 관찰하여 금속 메쉬 제작에 영향을 미치는 각종 요인들을 분석해 보았다.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.4 no.4
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• pp.335-344
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• 2006

In this paper a computer program was developed, which simulates the Li reduction process of PWR spent fuel, and the amount of a produced metal or chloride compound was calculated at the various amount of Li with the program. It establishes a database, which is composed of some characteristics related to a chemical reaction equation and thermodynamic data, and it calculates the transformed rate of PWR spent fuel oxide at the certain amount of Li by using the database as input data. As the results of the performance test of the program, it was validated that the transformed values of oxides, except for $Eu_2O_3$ and $Sm_2O_3$, were almost the same to within about a 6 % error with those calculated by the previous code and that the calculated amount of Li was also exactly consistent with the theoretical one, which is used for a complete reaction of each oxide in a single chemical reaction. A relationship between Li and the transformed metal of each oxide was analyzed on the basis of the quantities calculated with the verified development program. Of the results, when the amount of Li was given to be 250 mole, the 83.73 percentage of $UO_2$ was transformed into U while the remainder was still to be $UO_2$. In addition, it was appeared that the 297 mole of Li was needed to completely convert $UO_2$ into U.