Transmutation of long-lived fission products in an advanced nuclear energy system

• Published in: Scientific reports Vol. 12; no. 1; p. 2240
• Main Authors: Sun, X. Y., Luo, W., Lan, H. Y., Song, Y. M., Gao, Q. Y., Zhu, Z. C., Chen, J. G., Cai, X. Z.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 09.02.2022; Nature Publishing Group; Nature Portfolio
• Subjects: 639/4077; 639/766; Beryllium; Cesium; Cesium radioisotopes; Clean energy; Fission products; Humanities and Social Sciences; Iodine; Lasers; Lead; Monte Carlo simulation; multidisciplinary; Nuclear energy; Reactors; Science; Science (multidisciplinary); Thermal power
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-022-06344-y

Disposal of long-lived fission products (LLFPs) produced in reactors has been paid a lot attention for sustainable and clean nuclear energy. Although a few transmutation means have been proposed to address this issue, there are still scientific and/or engineering challenges to achieve efficient transmutation of LLFPs. In this study, we propose a novel concept of advanced nuclear energy system (ANES) for transmuting LLFPs efficiently without isotopic separation. The ANES comprises intense photoneutron source (PNS) and subcritical reactor, which consist of lead–bismuth (Pb-Bi) layer, beryllium (Be) layer, and fuel, LLFPs and shield assemblies. The PNS is produced by bombarding radioactive cesium and iodine target with a laser-Compton scattering (LCS) γ-ray beam. We investigate the effect of the ANES system layout on transmutation efficiency by Monte Carlo simulations. It is found that a proper combination of the Pb-Bi layer and the Be layer can increase the utilization efficiency of the PNS by a factor of ~ 10, which helps to decrease by almost the same factor the LCS γ-beam intensity required for driving the ANES. Supposing that the ANES operates over 20 years at a normal thermal power of 500 MWt, five LLFPs including 99 Tc, 129 I, 107 Pd, 137 Cs and 79 Se could be transmuted by more than 30%. Their effective half-lives thus decrease drastically from ~ 10 6 to less than 10 2  years. It is suggested that this successful implementation of the ANES paves the avenue towards practical transmutation of LLFPs without isotopic separation.