Nuclear Engineering and Design 241 (2011) 433–443 Contents lists available at ScienceDirect Nuclear Engineering and Design journal homepage: www.elsevier.com/locate/nucengdes Technical note Comparative study of fast critical burner reactors and subcritical accelerator driven systems and the impact on transuranics inventory in a regional fuel cycle V. Romanello a,∗ , M. Salvatores a,b , A. Schwenk-Ferrero a,∗ , F. Gabrielli a , W. Maschek a , B. Vezzoni a a KIT (Karlsruhe Institute of Technology), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany b CEA Nuclear Energy Division, Cadarache, St-Paul-Lez-Durance 13108, France article info Article history: Received 13 August 2010 Received in revised form 23 September 2010 Accepted 22 October 2010 abstract In the frame of Partitioning and Transmutation (P&T) strategies, many solutions have been proposed in order to burn transuranics (TRU) discharged from conventional thermal reactors in fast reactor systems. This is due to the favourable feature of neutron fission to capture cross section ratio in a fast neutron spectrum for most TRU. However the majority of studies performed use the Accelerator Driven Systems (ADS), due to their potential flexibility to utilize various fuel types, loaded with significant amounts of TRU having very different Minor Actinides (MA) over Pu ratios. Recently the potential of low conversion ratio critical fast reactors has been rediscovered, with very attractive burning capabilities. In the present paper the burning performances of two systems are directly compared: a sodium cooled critical fast reactor with a low conversion ratio, and the European lead cooled subcritical ADS-EFIT reactor loaded with fertile-free fuel. Comparison is done for characteristics of both the intrinsic core and the regional fuel cycle within a European double-strata scenario. Results of the simulations, obtained by use of French COSI6 code, show comparable performance and confirm that in a double strata fuel cycle the same goals could be achieved by deploying dedicated fast critical or ADS-EFIT type reactors. However the critical fast burner reactor fleet requires ∼30–40% higher installed power then the ADS-EFIT one. Therefore full comparative assessment and ranking can be done only by a parametric sensitivity study of both the fuel cycle and the electricity generating costs. © 2010 Elsevier B.V. All rights reserved. 1. Introduction In the last decades, numerous studies have been performed in order to identify appropriate Partitioning and Transmutation (P&T 1 ) strategies, aiming at the reduction of the burden on the geological disposal (see, among many others (Salvatores, 2005)). P&T technologies can help to reduce drastically the radiotoxicity level of the wastes and to reduce the time needed before this level reaches the reference one (e.g. of natural uranium ore) from ∼10 5 years to a few hundred years, i.e. comparable to the period in which technological and engineering developments allow to control the ∗ Corresponding authors. Tel.: +49 7247 82 3406/2489; fax: +49 7247 823 824. E-mail addresses: vincenzo.romanello@kit.edu (V. Romanello), aleksandra.schwenk-ferrero@kit.edu (A. Schwenk-Ferrero). 1 ADS-EFIT: Accelerator Driven System-European Facility for Transmutation; MOX: mixed oxide fuel; CAPRA: Consommation Accrue du Plutonium dans les reac- teurs Rapides; NEA: Nuclear Energy Agency; CER–CER: Ceramic–Ceramic (matrix); OECD: Organisation for Economic Cooperation and Development; CFBu: Critical Fast Burner (reactor) P&T: Partitioning and Transmutation; CR: conversion ratio; PATEROS: PArtitioning and Transmutation European ROadmap for Sustainable nuclear energy; FC: fuel cycle; PWR: Pressurized Water Reactor; FR: fast reactor; SF: spent fuel; KIT: Karlsruhe Institute of Technology; TRU: transuranics; LWR: Light Water Reactor; UOX: Uranium Oxide Fuel; MA: Minor Actinides. radiotoxicity and radioactivity confinement. Moreover, P&T allows in principle also the reduction of the residual heat in a geological repository, with a potential significant impact on the repository size and characteristics. However, to investigate the effectiveness and feasibility of a specific P&T strategy, one has to define a ‘transmuter’ system, and analyse its entire fuel cycle (FC) taking into account the associated reprocessing and fuel fabrication capacities needed. The deploy- ment scenario studies must be specified according to the chosen high level objectives. In the present paper we have investigated the possible use of critical low Conversion Ratio (CR) fast reactors in a so-called ‘double strata’ strategy developed in order to manage Spent Fuel (SF) inven- tories of European countries. The main objective of this scenario has been the total waste minimisation, in a politically heteroge- neous region with nation-specific nuclear energy policies. Similar studies have been performed in the past based on the use of Accel- erator Driven System (ADS) as a transmuter, see (Salvatores et al., 2008) and NEA/OECD Expert Groups (OECD-NEA, 2002; OECD-NEA, 2006). However, in the present investigation the same transuranics (TRU) content and isotopic fuel compositions have been considered for an ADS and a critical fast reactor in order to make the com- parison as transparent as possible. As fuels, mixed oxide (MOX) fuels were used for the fast critical burner reactor whereas for ADS- 0029-5493/$ – see front matter © 2010 Elsevier B.V. All rights reserved. doi:10.1016/j.nucengdes.2010.10.037