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Science and Technology of Nuclear Installations
Volume 2009, Article ID 749736, 13 pages
Research Article

The Use of Th in HTR: State of the Art and Implementation in Th/Pu Fuel Cycles

1Department of Mechanical, Nuclear and Production Engineering (DIMNP), University of Pisa, CIRTEN, Largo L. Lazzarino No. 2, 56126 Pisa, Italy
2Energy and Environmental Conditioning Department (DIPTEM), University of Genova, Via all'Opera Pia No. 15/a, 16145 Genova, Italy
3Accident Analysis Division (FWSS), Forschungszentrum Dresden-Rossendorf (FZD), P.O. Box 51 01 19, 01314 Dresden, Germany
4Department of Nuclear Engineering , Ben Gurion University of the Negev, P.O. Box 653, 84105 Beer Sheva, Israel

Received 28 March 2009; Accepted 1 September 2009

Academic Editor: Jim Kuijper

Copyright © 2009 Guido Mazzini et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Nowadays nuclear is the only greenhouse-free source that can appreciably respond to the increasing worldwide energy demand. The use of Thorium in the nuclear energy production may offer some advantages to accomplish this task. Extensive R&D on the thorium fuel cycle has been conducted in many countries around the world. Starting from the current nuclear waste policy, the EU-PUMA project focuses on the potential benefits of using the HTR core as a Pu/MA transmuter. In this paper the following aspects have been analysed: (1) the state-of-the-art of the studies on the use of Th in different reactors, (2) the use of Th in HTRs, with a particular emphasis on Th-Pu fuel cycles, (3) an original assessment of Th-Pu fuel cycles in HTR. Some aspects related to Thorium exploitation were outlined, particularly its suitability for working in pebble-bed HTR in a Th-Pu fuel cycle. The influence of the Th/Pu weight fraction at BOC in a typical HTR pebble was analysed as far as the reactivity trend versus burn-up, the energy produced per Pu mass, and the Pu isotopic composition at EOC are concerned. Although deeper investigations need to be performed in order to draw final conclusions, it is possible to state that some optimized Th percentage in the initial Pu/Th fuel could be suggested on the basis of the aim we are trying to reach.