LWR spent fuel transmutation with fusion-fission hybrid reactors J.L. François a, * , J.J. Dorantes a , C. Martín-del-Campo a , J.J.E. Herrera b a Departamento de Sistemas Energéticos, Facultad de Ingeniería, Universidad Nacional Autónoma de México, Paseo Cuauhnáhuac No. 8532, Col. Progreso, C.P. 62550, Jiutepec, Morelos, Mexico b Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México, A.P. 70-543, 04511 México, D.F., Mexico article info Article history: Received 18 June 2012 Received in revised form 8 February 2013 Accepted 12 February 2013 Keywords: Fusion-fission transmutation system Nuclear waste transmutation Spent fuel management Fusion-fission hybrid reactors abstract In this paper the transmutation of light water reactors (LWR) spent fuel is analyzed. The system used for this study is the fusion-fission transmutation system (FFTS). It uses a high energy neutron source pro- duced with deuterium-tritium fusion reactions, located in the center of the system, which is surrounded by a fission region composed of nuclear fuel where the fissions take place. In this study, the fuel of the fission region is obtained from the recycling of LWR spent fuel. The MCNPX Monte Carlo code was used to setup a model of the FFTS. Two fuel types were analyzed for the fissile region: the mixed oxide fuel (MOX), and the inert matrix fuel (IMF). Results show that in the case of the MOX fuel, an important Pu- 239 breeding is achieved, which can be interesting from the point of view of maximal uranium utili- zation. On the contrary, in the case of the IMF fuel, high consumption of Pu-239 and Pu-241 is observed, which can be interesting from the point of view of non-proliferation issues. A combination of MOX and IMF fuels was also studied, which shows that the equilibrium of actinides production and consumption can be achieved. These results demonstrate the versatility of the fusion-fission hybrid systems for the transmutation of LWR spent fuel. Ó 2013 Elsevier Ltd. All rights reserved. 1. Introduction One of the open issues of the nuclear technology is the strategy followed at the back-end of the fuel cycle. It is clear that the closed cycle is preferable than the open cycle in terms of sustainability. Very closely related with this issue is the strategy followed for the spent fuel management of light water reactors (LWR). The radio- toxicity of the spent fuel of LWR is first dominated by the short half- life fission products, and later by the long lived isotopes: the acti- nides (transuranics). Several investigations are under way around the world aimed at transmuting the actinides in order to reduce their radiotoxicity and volume. Transmutation in LWR has been studied by: Franceschini and Petrovi c, 2008; Fukaya et al., 2009; Núñez-Carrera et al., 2008; Seino and Sekimoto, 1998; Youinuo and Vasile, 2005; Zabuno glu, 2008, in fast reactors: Broeders et al., 2000; Massara et al., 2009; Nicolaou and Tsagas, 2006; Salvatores et al., 2009; Slessarev, 2006, 2008, in accelerator driven systems: Cometto et al., 2004, 2008; Marsodi et al., 2002; Park et al., 2003; Salvatores, 2005; Sasa et al., 2004; Westlen and Seltborg, 2006. Concerning the fusion-fission transmutation systems (FFTS), studies are in progress by different research groups around the globe. Different concepts are under study: the tokamak-based high- power-density compact fusion neutron source (Kotschenreuther et al., 2009), the reversed-field pinch toroidal magnetic configu- ration as a neutron source (Fiksel et al., 2009), the axisymmetric mirror as a neutron source (Ryutov, 2005), the laser based fusion test facility (Obenschain et al., 2009), the fusion-fission hybrids driven by heavy-ion inertial fusion (Meier et al., 2003), the driven subcritical fission research reactor using a cylindrical inertial electrostatic confinement neutron source (Miley et al., 2002), among others. The FFTS has been theoretically designed based on experimental fusion reactors. The reactor studied in this work relies on its simple design, small size and relative low expected cost. It uses a high energy neutron source, which produces neutrons from the deuterium-tritium fusion reaction. This source is located in the center of the system, and is surrounded by a fission region composed of fuel where the fission reactions take place. In this paper the well-known MCNPX (Monte Carlo N-Particle eXtended, versión 2.6.0) (Pelowitz, 2008) code was used to setup a model of the FFTS, and for studying the transmutation capabilities of this type of device, in particular for LWR spent fuel management. Two fuel types were analyzed: the mixed oxide fuel (MOX: Mixed OXide), and the inert matrix fuel (IMF). * Corresponding author. Tel.: þ52 5556223016. E-mail addresses: juan.louis.francois@gmail.com (J.L. François), JDC_4201@ yahoo.com.mx (J.J. Dorantes), cecilia.martin.del.campo@gmail.com (C. Martín-del- Campo), herrera@nucleares.unam.mx (J.J.E. Herrera). Contents lists available at SciVerse ScienceDirect Progress in Nuclear Energy journal homepage: www.elsevier.com/locate/pnucene 0149-1970/$ e see front matter Ó 2013 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.pnucene.2013.02.005 Progress in Nuclear Energy 65 (2013) 50e55