• 방사성폐기물학회지
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• 제21권3호
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• pp.397-410
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• 2023

This study examined the efficacy of various chlorinating agents in partitioning light water reactor spent fuel, with the aim of optimizing the chlorination process. Through thermodynamic equilibrium calculations, we assessed the outcomes of employing MgCl₂, NH₄Cl, and Cl₂ as chlorinating agents. A comparison was drawn between using a single agent and a sequential approach involving all three agents (MgCl₂, NH₄Cl, and Cl₂). Following heat treatment, the utilization of MgCl₂ as the sole chlorinating agent resulted in a moderate separation. Specifically, this method yielded a solid separation with 96.9% mass retention, 31.7% radioactivity, and 44.2% decay heat, relative to the initial spent fuel. In contrast, the sequential application of the chlorinating agents following heat treatment led to a final solid separation characterized by 93.1% mass retention, 5.1% radioactivity, and 15.4% decay heat, relative to the original spent fuel. The findings underscore the potential effectiveness of a sequential chlorination strategy for partitioning spent fuel. This approach holds promise as a standalone technique or as a complementary process alongside other partitioning processes such as pyroprocessing. Overall, our findings contribute to the advancement of spent fuel management strategies.

• 방사성폐기물학회지
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• 제20권2호
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• pp.193-207
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• 2022

Thermodynamically, TRUO_x, REO_x, and SrO_x can be chlorinated using ammonium chloride (NH₄Cl) as a chlorinating agent, whereas uranium oxides (U₃O₈ and UO₂) remain in the oxide form. In the preliminary experiments of this study, U₃O₈ and CeO₂ are reacted separately with NH₄Cl at 623 K in a sealed reactor. CeO₂ is highly reactive with NH₄Cl and becomes chlorinated into CeCl₃. The chlorination yield ranges from 96% to 100%. By contrast, U₃O₈ remains as UO₂ even after chlorination. We produced U/REO_x- and U/SrO_x-simulated fuels to understand the chlorination characteristics of the oxide compounds. Each simulated fuel is chlorinated with NH₄Cl, and the products are dissolved in LiCl-KCl salt to separate the oxide compounds from the chloride salt. The oxide compounds precipitate at the bottom. The precipitate and salt phases are sampled and analyzed via X-ray diffraction, scanning electron microscope-energy dispersive spectroscopy, and inductively coupled plasma-optical emission spectroscopy. The analysis results indicate that REO_x and SrO_x can be easily chlorinated from the simulated fuels; however, only a few of U oxide phases is chlorinated, particularly from the U/SrO_x-simulated fuels.

• Bulletin of the Korean Chemical Society
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• 제30권9호
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• pp.2066-2070
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• 2009

$Cl_3CCONH_2$ coupled with $PPh_3$ was determined to be an effective reagent for the conversion of carboxylic acids to their corresponding acid chlorides. Subsequently, these acid chlorides were successfully trapped with amines in the presence of 4-picoline, yielding amides. This practical and efficient protocol can be utilized for the synthesis of biological amides in excellent yields.

• 공업화학
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• 제7권3호
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• pp.453-463
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• 1996

$NH_4Cl$을 염소화제로 사용하여 시약 PbS와 Pb함유 자연광물인 방연광의 염소화 반응에 대해 조사하였다. 방연광의 적정 염소화 반응조건은 반응온도 $425^{\circ}C$, 방연광에 대한 $NH_4Cl$의 무게비 4.0, 반응시간 2시간이었다. 이 조건하에서 방연광중의 PbS는 $NH_4Cl$에 의해 효과적으로 $PbCl_2$로 염소화되었으며 그 전화율은 90%였다. 방연광의 염소화 반응에서 염소화제로 사용한 $NH_4Cl$은 $NH_3$와 HCl로 효과적으로 분리되었으며 양론적으로 90%의 $NH_3$를 회수할 수 있었다.

• Nuclear Engineering and Technology
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• 제54권2호
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• pp.653-660
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• 2022

The interaction between UN and CdCl₂ in the LiCl-KCl molten eutectic was studied at 1023 K. The chlorination was monitored by sampling and recording the redox potential of the medium. At 1023 K the chlorination of UN with cadmium chloride in the molten LiCl-KCl eutectic proceeds completely and results in the formation of uranium chlorides. The melts of the LiCl-KCl-UCl₃ or LiCl-KCl-UCl₄ compositions can be obtained by the end of experiment depending on the presence of metallic cadmium in the reaction zone. The higher the concentration of the chlorinating agent, the faster the reaction rate. At [CdCl₂]/[UN] = 1.65 (10% excess) the reaction proceeds to completion in about 7.5 h. At [CdCl₂]/[UN] = 7 the complete chlorination takes 2.5-3 h.

• 자원리싸이클링
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• 제25권3호
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• pp.74-81
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• 2016

고정층 반응기에서 PVC를 염화제로 사용하여 일메나이트 광석 중 철을 선택적으로 제거하기 위한 염화반응에 대하여 조사하였다. 철의 제거율에 미치는 PVC첨가량과 반응온도의 영향에 대하여 조사하였다. 철의 제거율은 PVC 첨가량과 온도가 증가할수록 상승하였다. PVC에서 생성된 HCl가스와 반응한 후의 시편 표면에는 많은 기공이 관찰되었다. 이러한 기공에 의해서 일메나이트 입자의 중앙부분에 있는 철과 반응할 수 있었던 것으로 생각된다. 선택적 염화반응을 속도론적 모델에 의해 조사한 결과 입자 계면에서의 화학반응에 의해서 율속되는 것으로 생각된다. PVC를 사용한 일메나이트의 선택적 염화반응에서 활성화 에너지는 20.47 kJ/mol로 계산되었다.