Transmutation of super(126)Sn in Spallation Targets of Accelerator-Driven Systems

• Published in: Journal of nuclear science and technology 2009-01, Vol.46 (1), p.60-75
• Main Authors: Han, Chi Young, Saito, Masaki, Sagara, Hiroshi
• Format: Article
• Language: English
• Subjects: Energy (nuclear); Feasibility; Lead (metal); Liquids; Proton beams; Spallation; Toxicity; Transmutation
• ISSN: 0022-3131
• DOI: 10.3327/jnst.46.60

The practical feasibility of super(126)Sn transmutation in spallation targets of accelerator-driven systems was evaluated from the viewpoints of accumulation of radioactive spallation products and neutron production as well as transmutation amount of super(126)Sn. A cylindrical liquid super(126)Sn target whose length depends on proton beam energy was described, based on a Pb-Bi target design of accelerator-driven system being developed in JAEA. A proton beam of 1.5 GeV-20 mA was estimated to give the transmutation rate of super(126)Sn 6.4 kg/yr, which corresponds to the amount of super(126)Sn annually discharged in 27 LWRs of 1 GWt and 33 GWd/THM. The equilibrium radioactivity of spallation products would reach 9% of that of super(126)Sn transmuted in the spallation target, and the equilibrium toxicity would be just 3%. Some parametric analyses showed that the effective half-life of super(126)Sn could be reduced through a proper reduction of the target size. The super(126)Sn target was calculated to produce 40 neutrons per proton of 1.5 GeV and give a neutron spectrum very similar to that of the reference Pb-Bi target. As a result, the transmutation of super(126)Sn in the spallation target has a high feasibility in terms of better transmutation performance and comparable target performance.