Anticipation of the needs linked with new generation reactors: COGEMA Logistics casks developments

The fast growth of the world's economy coupled with the need for natural resources use optimization and, the risk of climate change, make energy supplies one of the 21. century most daring challenges. The high reliability and efficiency of nuclear energy, its competitiveness in an electricity market impacted by a new oil shock are as many factors in favour of the 'renaissance' of this greenhouse gas free energy. More than 20 reactors are currently under construction worldwide and ambitious plans for new buildings have been initiated notably in China and India. In Western Europe, the foundation stone of the first evolutionary European Pressurized Reactor (EPR) was laid on September 2005, 12, in Olkiluoto, Finland. In France, EDF made the decision to launch the construction of an EPR on the Flamanville site. Constellation Energy and Areva formed recently a joint enterprise providing the business framework through which a first fleet of evolutionary reactors could be deployed in the USA. Other countries have expressed their wish to consider nuclear energy in their energy mix. Stirring of nuclear 'renaissance' are now discernible either through the development of new reactors or extensive programs of reactor life extension. Such programs cannot be disconnected from the optimization of the fuel cycle strategy. Competitiveness relies indeed upon the optimal fuel utilization. The fuel cycle cost may be lowered by higher average burnups. For example, target values for the EPR are over 60 000 MWd/tHM corresponding to initial U235 enrichment up to 5% for UO2 fuels. The possibility of 'moxifying' the EPR up to 50% is another key for flexibility. Investigations towards a greater flexibility do not concern only the core management but also the spent fuel management. Increased flexibility is indeed sought to keep open all back-end options. Quick evacuation of fuel assemblies unloaded from the core is in particular considered, thus assigning the level of performance of the cask to be used. To accompany the 'nuclear renaissance' and the related fuel design and fuel management evolution, it is crucial to anticipate the associated needs in terms of cask development notably for the spent fuel management. It is the reason why an ambitious R and D program has been set up at COGEMA Logistics. It aims at proposing innovative solutions oriented by the trends guiding this 'renaissance': the proposed systems have indeed to accommodate Spent Fuel Assemblies (SFAs) characterized by ever increasing burn-ups, fissile isotopes contents, and total inventory. Flexibility may potentially mean quick evacuation of UO2 or MOX spent fuel with high thermal power to be dealt with. As described in the present paper, these evolutions directly guide the R and D actions on thermal and structural analysis, criticality and containment. The approach shall also include predictable licensing processes in an ever-demanding regulatory environment. The paper has the following structure: I. Evolutionary casks for evolving needs; II COGEMA Logistics R and D on evolutionary packagings; 1- The objectives of COGEMA Logistics R and D on evolutionary packagings; 2- Which R and D actions are currently implemented to anticipate evolving needs?; 2-1 Building an R and D program; 2-2 High performance design solutions for subcriticality; 2-3 Solutions for thermal and structural management; 2-4 Solution for enhanced shielding design; 2-5 Solutions for double containment systems; 2-6 Solutions for shock absorbers; 3- Examples of packaging developments; III Conclusion. To summarize, COGEMA Logistics is actively involved in Research and Development to accompany the improvement brought by Areva in fuel design and management linked either to extensive programs of nuclear plant life extension or to new constructions, such as Areva's European Pressurized Reactor. These evolutions coupled with needs for ever higher flexibility in terms of spent fuel management clearly guide the packaging evolutions; they have to accommodate UO2 or MOX fuels with ever increasing burn-ups thus higher fissile isotopes contents. These fuels may have to be handled without lengthy cooling periods after their unloading from the cores. All these trends clearly impact R and D actions on thermal and structural analysis, criticality and containment. Evolutionary casks compliant with the IAEA 96 have already stemmed from anticipation (for instance the TNTM 106 or TNTM 9/4 casks) or are under design notably with the TNTM 112 cask. These concepts are first born of an expanding family of new generation casks; it integrates needs for the decades to come while contributing to improved competitiveness of nuclear energy and to sustainable development with dose reduction, increased lifetime components and low environmental impact solutions