Phase Behavior of the Ternary NaCl-PuCl3-Pu Molten Salt

• 발행기관: 한국방사성폐기물학회
• 저자명: Toni Karlsson Cynthia Adkins Ruchi Gakhar James Newman Steven Monk Stephen Warmann
• 간행물 정보: 『Journal of Nuclear Fuel Cycle and Waste Technology (JNFCWT)』Vol.21 No.1, 55~64쪽, 전체 10쪽
• 주제분류: 공학 > 공학일반
• 파일형태: PDF
• 발행일자: 2023.03.30

국문 초록

There is a gap in our understanding of the behavior of fused and molten fuel salts containing unavoidable contamination, such as those due to fabrication, handling, or storage. Therefore, this work used calorimetry to investigate the change in liquidus temperature of PuCl3, having an unknown purity and that had been in storage for several decades. Further research was performed by additions of NaCl, making several compositions within the binary system, and summarizing the resulting changes, if any, to the phase diagram. The melting temperature of the PuCl3 was determined to be 746.5°C, approximately 20°C lower than literature reported values, most likely due to an excess of Pu metal in the PuCl3 either due to the presence of metallic plutonium remaining from incomplete chlorination or due to the solubility of Pu in PuCl3. From the melting temperature, it was determined that the PuCl3 contained between 5.9 to 6.2mol% Pu metal. Analysis of the NaCl-PuCl3 samples showed that using the Pu rich PuCl3 resulted in significant changes to the NaCl-PuCl3 phase diagram. Most notably an unreported phase transition occurring at approximately 406°C and a new eutectic composition of 52.7mol% NaCl–38.7mol% PuCl3–2.5mol% Pu which melted at 449.3°C. Additionally, an increase in the liquidus temperatures was seen for NaCl rich compositions while lower liquidus temperatures were seen for PuCl3 rich compositions. It can therefore be concluded that changes will occur in the NaCl-PuCl3 binary system when using PuCl3 with excess Pu metal. However, melting temperature analysis can provide valuable insight into the composition of the PuCl3 and therefore the NaCl-PuCl3 system.

키워드

Molten salt Plutonium trichloride Phase diagram Melting temperature Calorimetry