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.

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The topic of Nuclear Safety Culture touches several different aspects with contributions from the main organizations involved in nuclear projects and belonging to vendors, utility and regulators. Two nuclear safety directives issued by the European Commission emphasize the fundamental principle of national responsibility for nuclear safety and are implemented in each member country’s legislation. An example of fission implementation is highlighted, referring to the Czech Republic legislation; an example of application in fusion technology is the implementation of the Nuclear Safety Culture in the ITER project, located in Cadarache, in the south of France. The aim of the paper is to highlight the importance of this field, pointing out the cross reference between fission and fusion technology as applied in two countries, with concrete experiences and future prospects for nuclear technologies.