Work

Evaluating reducibility of strontium and barium-containing oxides by lithium metal in molten LiCl during oxide reduction of pyroprocessing

Year: 2025

Type: article

Abstract: Oxide reduction (OR), the first electrochemical step in pyroprocessing of used nuclear fuel, converts oxide fuel constituents into metals in molten LiCl. During this process, many fission products, including Sr and Ba, transfer from the fuel matrix into the salt phase through chemical reactions and dissolution, with over 70% reported to dissolve. However, the specific chemical pathways remain unclear because the original chemical forms of these species (e.g., binary oxides, complex oxides, ABO x phases) and their interactions with Li or LiCl are not well identified. Some oxides may first be reduced by Li before reacting with LiCl, but this has not been systematically examined. This study investigates the reducibility of representative Sr- and Ba-containing oxides (SrO, SrZrO 3 , SrMoO 4 , BaO, BaZrO 3 , BaMoO 4 ) by Li metal at 650 °C to clarify their behavior during the initial stage of OR. Metal–salt reactions were also examined using pure Sr and Ba. Simple oxides and some complex oxides underwent partial reduction, whereas BaZrO 3 and BaMoO 4 were hardly reduced. Metallic Sr and Ba reacted with LiCl to form soluble chlorides, indicating that oxides with higher reducibility are more likely to convert to chlorides and partition into the salt during OR.

Source: Nuclear Engineering and Technology

DOI: 10.1016/j.net.2025.104033

Authors: Eun-Young Choi, Namchoel Kim, Seol Kim, Dokyu Kang, Jaesu Rru

Institutions: Korea Atomic Energy Research Institute, Korea University of Science and Technology

Language: English

Topic: Molten salt chemistry and electrochemical processes

Subfield: Fluid Flow and Transfer Processes

Field: Chemical Engineering

Domain: Physical Sciences

Open Access status: gold

Estimated APC paid: $200

Funders: National Research Foundation of Korea, Ministry of Science and ICT, South Korea