Radiation-induced transients on solid and molten Li and K iodides

Conference · Tue Jun 25 00:00:00 EDT 2024

OSTI ID:3014415

Ramos Ballesteros, Alejandro ^[1]; Holmbeck, Gregory Peter ^[1]; Gakhar, Ruchi ^[1]; Woods, Michael Ellis ^[1]; Conrad, Jacy Kathleen ^[1]

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1. Idaho National Laboratory

The study, quantification, and monitoring of iodine in nuclear power generation systems have been paramount due to its environmental and health implications. Thorough speciation and transport studies strengthened the development and deployment of water reactors, which are now required for the new generation of Molten Salt Reactors (MSR), where the fuel and coolant are a complex liquid system of suitable halides. The speciation, radiation-induced chemistry, and transport of iodine (I-127, I-129 and I-131) under extreme conditions of temperature and ionizing radiation are among the challenges for the future implementation of MSR’s. In aqueous systems, the triiodide-iodine-iodide (I3--I2-I-) equilibrium is strongly dependent on the conditions of the medium. In molten iodides and chlorides, the triiodide detection (and its disproportionation) poses challenges due to the extreme conditions of temperature and radiation, but studies have shown a dependence on temperature, absorbed dose and salt composition. Through absorption spectroscopy techniques (diffuse reflectance and high-temperature UV-Vis), as well as resonance (Electron Paramagnetic Resonance) it is possible to identify primary transients induced by ionizing radiation trapped in the solid phase (Solid-state radiolysis), and steady-state main absorption components with a fast-acquisition real-time spectroscopy. The presence of heterogeneous phase (colloids), viscosity changes, and gas evolution are among the observed processes. A specific case of study is speciation in the presence of Ni. A corrosion product with magnetic properties due to unpaired electrons in its electronic structure. Ferromagnetic materials are monitored in solidified salts to identify aggregation and phase separation. Comparative studies of eutectic mixtures of LiI-KI and LiCl-KCl with known addition of dopants will be presented, with a perspective of radiation chemistry and its possible implications in complex systems.

• Research Organization: Idaho National Laboratory (INL), Idaho Falls, ID (United States)
• Sponsoring Organization: USDOE Office of Nuclear Energy (NE); USDOE Office of Science (SC)
• DOE Contract Number: AC07-05ID14517
• OSTI ID: 3014415
• Report Number(s): INL/CON-24-78040
• Resource Type: Conference proceedings
• Conference Information: 78th Northwest Regional Meeting (NORM), Pullman, Washington, 06/23/2024 - 06/26/2024
• Country of Publication: United States
• Language: English

Related Subjects

36 - MATERIALS SCIENCE
38 - RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEAR CHEMISTRY
Molten iodides
Molten salts
Radiation
Radiation chemistry