Re-evaluation of Radiation-Energy Transfer to an Extraction Solvent in a Minor-Actinide-Separation Process Based on Consideration of Radiation Permeability

ABSTRACT

Absorbed-dose estimation is essential for evaluation of the radiation tolerance of minor-actinide-separation processes. We propose a dose-evaluation method based on radiation permeability, with comparisons of heterogeneous structures seen in the solvent-extraction process, such as emulsions forming in the mixture of the organic and aqueous phases. A demonstration of radiation-energy-transfer simulation is performed with a focus on the minor-actinide-recovery process from high-level liquid waste with the aid of the Monte Carlo radiation-transport code PHITS. The simulation results indicate that the dose absorbed by the extraction solvent from alpha radiation depends upon the emulsion structure, and that from beta and gamma radiation depends upon the mixer-settler-apparatus size. Non-negligible contributions of well-permeable gamma rays were indicated in terms of the plant operation of the minor-actinide-separation process.

KEYWORDS:

• Absorbed-dose estimation
• phits
• minor actinides separation
• radiolytic stability
• TODGA

Acknowledgments

The authors would like to thank Dr Yasuji Morita, Dr Yasutoshi Ban, Dr Keisuke Morita, Dr. Nao Tsutsui, and Mr. Shinobu Hotoku for the fruitful discussions on the radiation feasibility evaluation of the minor actinides separation, and we also thank the PHITS developing team members in JAEA for their valuable assistance for the radiation transport simulations.

Supplementary material

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