Fusion-Driven Transmutation of Fission Product Cesium in its Elemental Form

Abstract

Assuming fission reaction as a dominant energy source for a long-term perspective, the goal of transmutation of fission products is to cut their increasing accumulation and to keep their inventories at easily manageable level. Opposite to relatively short-lived 137 Cs (T1; 2 =30 yr) whose natural decay converge equilibrium mass to the level of order of 1 t per GW of fission energy, an approach to similar equilibrium inventory for longlived 135 Cs (T1; 2 =2.3x 10 6 yr) requires artificial transmutation that preassumes its isotopic separation in the most studies. The present paper addresses cesium transmutation without preliminary isotope separation that means an approach to equilibrium for all the isotopes including stable 133 Cs. A high-flux blanket driven by Fusion Neutron Source with ITER-like parameters is proposed to transmute cesium in the elemental form. Transmutation efficiency is estimated in terms of equilibrium inventory and characteristic time to reach equilibrium both governed by the mean lifetime of nuclides in transmuter. The analytical results show that the mean lifetime of the target isotope 135 Cs is as short as 21 yr which is in more than order of magnitude shorter than achieved in advanced fission reactors. It reveals that one Fusion Neutron Source with ITER-like parameters could transmute elemental cesium from 23 PWRs, the fraction of power associated with transmutation being as small as 3%.

Transmutation of 126Sn in Spallation Targets of Accelerator-Driven Systems

“…8. The neutroninduced transmutation is almost driven by emitting only nu-cleons or a light nucleus such as deuteron, triton, 3 He, and alpha. Particularly, the greatest contribution of (n,xn) reactions prevents it from converting 126 121 Sn, and 113 Sn) with a half-life of less than 1 year.…”

“…Almost all the SLSPs decay out during the cooling time. 3 H and 125 Sb are responsible for the magnitude of total equilibrium radioactivity of spallation products. Figure 17(a) shows the time evolution of radioactivity calculated by using Eq.…”

Transmutation of126Sn in Spallation Targets of Accelerator-Driven Systems

“…8. The neutroninduced transmutation is almost driven by emitting only nucleons or a light nucleus such as deuteron, triton, 3 He, and alpha. Particularly, the greatest contribution of (n,xn) 113 Sn) with a half-life of less than 1 year.…”

“…1) A fusion neutron source of specific quality was proposed there as a candidate for the transmutation of LLFPs. Succeeding research studies [2][3][4][5][6] have been performed on the LLFP transmutation by using highly moderated fusion neutron source in a high-flux fusion-driven blanket. The results showed that LLFPs could be effectively transmuted in the thermal flux blanket of fusion neutron source with the intensity typical for the ITER project.…”

Evaluation of reactivity monitoring techniques at the Yalina – Booster subcritical facility

“…Second, at fusion neutron energies ( 14MeV for the D-T reaction), transmutation of ssion products is possible through several reactions, such as (n, γ), (n, 2n), (n, 3n), (n, p), (n, d) or (n, α), while for lower energy neutrons, such as ssion neutrons, the only relevant process is (n, γ). Recent reviews of the potential of transmutation of certain ssion products (Cs-137, I-129, Sn-126, Zr-93) in fusion devices are [296,297,298,337,343,344].…”