[en] This paper delivers key results from the European project NC2I-R (Nuclear Cogeneration Industrial Initiative Research) supporting the development of an industrial initiative to demonstrate nuclear cogeneration of heat and power with High Temperature Reactors as an effective low-carbon technology for industrial market applications. The NC2I-R project was run from 2013 to 2015 by a consortium of 20 companies. It was co-financed by the European Commission and was an 'executive' project of the European nuclear stakeholder platform SNETP, specifically one of its pillars, the Nuclear Cogeneration Industrial Initiative (NC2I). (authors)

[en] HTR-TN (high temperature reactor - technology network) has been created in 2000 for building a coherent partnership for the development of HTR technology in Europe. For that purpose, HTR-TN elaborated a road-map for the emergence of a new generation of industrial HTRs. Through the fifth EURATOM Framework Programme (FP5), HTR-TN recovered the basis of past European HTR experience, addressed key feasibility issues for Generation IV high temperature systems and made significant advances in the fields of reactor physics (improved calculation methods), fuel (high quality fabrication and very high burn-up behaviour), waste management, qualification of materials for higher performance, component development and definition of safety approach for modular HTRs. In the sixth Framework Programme (FP6), a new integrated project, RAPHAEL, continues the technology developments addressed in FP5 and explores solutions for improving HTR performances towards higher temperatures (above 900 C degrees) and burn-up (up to 200 GWd/tHM): the VHTR objective. Moreover HTR-TN initiated other complementary actions in FP6. The RAPHAEL project has launched key experiments for HTR development: continuation of the graphite irradiation programme started in FP5 in HFR to higher fluences and temperature, test of a heat exchanger element in a helium loop (HE-FUS3, ENEA), irradiation of representative fuel coating material samples for modelling the evolution of their properties, fuel accident heat-up tests in the KUFA facility, integral air ingress tests (NACOK, FZJ), isotopic analysis of fuel irradiated to very high burn-up (170 GWd/tHM). The main motivation for developing a new generation of HTRs is their potential for providing high temperature heat for industrial processes. But coupling a nuclear reactor with an industrial process is very challenging. Therefore after developing base technologies for modular HTRs in FP5 and FP6, the future objective should be the demonstration of such a coupling by a large scale prototype experiment matching a HTR heat source and an industrial application. (author)

[en] Arising from the EU 5^th and 6^th Framework Programs (FP’s), the purpose of this paper is to present the achievements gained in the area of HTR & VHTR component development within the 5th FP HTR-E project and the future work activities to be realized in the frame of the new RAPHAEL project (6^th FP). The HTR-E R&D project started on 1st January , 2002 with 14 partners, from industry and research centres involved in HTR development: Framatome ANP, CEA, Zittau university, NRG, FZ Juelich, Empresarios Agrupados, NNC, Jeumont, S2M, Ansaldo, von Karman institute, Heatric, EV Oberhausen, Aubert et Duval. The work programme concerned the technical developments of innovative components of a modern HTR with a direct cycle, with references to industrial projects existing at the time (GTMHR, PBMR) for direct cycle HTR. The main tasks performed within the HTR-E Work Packages were as follows: • The helium turbine (WP1), the recuperator heat exchanger (WP2), the electro-magnetic and catcher bearings of the turbo-machine (WP3) and the helium rotating seal: dry gas system, fluid film barrier, canned magnetic bearings (WP4). Based on past experiences and specific calculations, design recommendations of such components were proposed. Experimental tests were also performed to validate the recommended concepts for electro-magnetic bearings and recuperator heat exchanger. • The tribology (WP5). Sliding innovative components in helium environment were particularly concerned (stator seals, control rod mechanisms…). The experience feedback was analysed and complementary tests have been carried out by CEA and Framatome ANP. • The helium purification system (WP6). This work package provided recommendations on impurity content in the helium atmosphere for a modern HTR in accordance with the materials proposed for the innovative components. (author)

[en] The (European) High Temperature Reactor Technology Network (HTR-TN) was created in 2000 by the main industrial and Research actors of nuclear energy in Europe for elaborating a strategy for developing advanced HTR technology towards industrial application and for taking initiatives for implementing this strategy, most particularly through the Euratom funded R and D programmes. HTR-TN members are convinced that the main market push for industrial deployment of a new generation of HTR will not come from utility needs for electricity generation, but from industrial process heat needs: even if HTR can be considered for satisfying particular niches of the electricity market, there will not be any incentive for utilities already experienced in the exploitation of large LWR to take the risk of a significant technology change, when no evident competitive edge would result from it. On the contrary, HTR is the sole nuclear system that can address heat needs of a large number of industrial processes that require a higher temperature than the temperature provided by all other types of industrial reactors. The possibility for HTR to address the industrial process heat market is a strong asset, as it opens to HTR a large market which is presently looking for solutions to reduce drastically CO₂ emissions, but at the same time it is a huge challenge: industrial exploitation of nuclear energy has been for the time being focused on electricity generation for which user requirements are relatively uniform. The versatility of process heat needs in terms of power, temperature, reliability, etc. will require a much larger flexibility of the nuclear heat source, which is not usual for nuclear industry, looking for competitiveness through standardisation. Therefore HTR-TN considers that the top priority innovation for HTR present development should not be missed: it is to demonstrate at an industrial scale the technical, industrial and economical feasibility of the coupling of a HTR with a process heat application, even at a reasonable temperature level ∼500-700 deg. C), and not necessarily to search for higher temperatures ∼ 800-1000 deg. C), which will be reached in the longer term, if there are significant market needs for such temperatures. After a period of 7 years dedicated to the development of base HTR technologies within several projects of the 5. and 6. Euratom Framework Programmes, HTR-TN proposes to launch in the 7. Framework Programme the development of a demonstrator coupling a HTR with an industrial process heat application. Such a development cannot be performed by the nuclear industry and research alone: it requires a close partnership with end-user industries. As a first step for building such a partnership, HTR-TN proposes, together with partners of different industries (steel, chemistry...) and Technical Support Organisations of Safety Authorities a preliminary project preparing the launching of the demonstrator design, by assessing the technical, economical and safety feasibility of the coupling, proposing coupling architectures, identifying the technical and licensing issues for coupling and defining a programme of development for the reactor, the heat transport system and the industrial heat application. (authors)

[en] The PUMA project -the acronym stands for 'Plutonium and Minor Actinide Management in Thermal High-Temperature Gas-Cooled Reactors'- was a Specific Targeted Research Project (STREP) within the EURATOM 6th Framework Program (EU FP6). The PUMA project ran from September 1, 2006, until August 31, 2009, and was executed by a consortium of 14 European partner organisations and one from the USA. This report serves 2 purposes. It is both the 'Publishable Final Activity Report' and the 'Final (Summary) Report', describing, per Work Package, the specific objectives, research activities, main conclusions, recommendations and supporting documents. PUMA's main objective was to investigate the possibilities for the utilisation and transmutation of plutonium and especially minor actinides in contemporary and future (high temperature) gas-cooled reactor designs, which are promising tools for improving the sustainability of the nuclear fuel cycle. This contributes to the reduction of Pu and MA stockpiles, and also to the development of safe and sustainable reactors for CO₂-free energy generation. The PUMA project has assessed the impact of the introduction of Pu/MA-burning HTRs at three levels: fuel and fuel performance (modelling), reactor (transmutation performance and safety) and reactor/fuel cycle facility park. Earlier projects already indicated favourable characteristics of HTRs with respect to Pu burning. So, core physics of Pu/MA fuel cycles for HTRs has been investigated to study the CP fuel and reactor characteristics and to assure nuclear stability of a Pu/MA HTR core, under both normal and abnormal operating conditions. The starting point of this investigation comprised the two main contemporary HTR designs, viz. the pebble-bed type HTR, represented by the South-African PBMR, and hexagonal block type HTR, represented by the GT-MHR. The results (once again) demonstrate the flexibility of the contemporary (and near future) HTR designs and their ability to accept a variety of Pu- and Pu/MA-based fuels (possibly in combination with thorium), and to obtain a significant reduction of the Pu- respectively Pu/MA content, while maintaining, to a large extent, the well-known standard (U-fuelled) HTR safety characteristics. However, this will require some changes in the reactor design. Studies have furthermore shown that fuel with a 'diluted' kernel ('inert-matrix') improves the transmutation performance of the reactor. A study on proliferation resistance, taking into account several possible proliferation pathways, highlights that a prismatic (V)HTR core would be amenable to conventional safeguards accounting and verification procedures, with fuel blocks accounted for individually in the same way as LWR fuel assemblies. However, a modified approach would be needed in pebble bed cores because of the impracticability of accounting for individual fuel spheres. When dealing with minor actinide bearing fuel helium generation is an important issue. Experiments have shown that He will be released from the kernel, but not from fresh kernels. Indeed, fresh fuel has shown a remarkable stability up to 2500 degrees C. For modelling purposes, 100% release of helium from the kernel is justified. The diluted kernel concept was first invoked by Belgonucleaire brings many benefits. The fuel modelling studies have clearly indicated the advantages that can be gained by dilution. Essentially, for a given buffer layer thickness, more volume is available to accommodate the CO and He released. Chemical thermodynamic models have been deployed to design a kernel that will show limited CO production. The most important point here is that substoichiometric Pu or Am oxides are essential. Further improvement can be achieved by chemical buffering of the fuel by the addition of Ce sesquioxide, which takes up oxygen to form the dioxide. Ultimately any coated particle design must be validated in an irradiation test. Though not possible to perform an irradiation programme in the PUMA project, the feasibility of such a programme has been demonstrated, and the initial data needed to launch such a test has been generated. Pu/MA transmuters are envisaged to operate in a global system of various reactor systems and fuel cycle facilities. Fuel cycle studies have been performed to study the symbiosis to other reactor types/systems, and to quantify waste streams and radio toxic inventories. This includes studies of symbiosis of HTR, Light Water Reactor (LWR) and Fast Reactor (FR) systems, as well as the assessment of the technical, economic, environmental and socio-political impact. It is e.g. shown that a Pu/MA-loaded HTR may have a considerable, positive impact on the reduction of the amount of TRU in disposed spent fuel and high level waste.

[en] Since the late 1990, the European Union (EU) was conducting work on High Temperature Reactors (HTR) confirming their high potential in terms of safety (inherent safety features), environmental impact (robust fuel with no significant radioactive release), sustainability (high efficiency, potential suitability for various fuel cycles), and economics (simplifications arising from safety features). In April 2005, the EU Commission has started a new 4-year Integrated Project on Very High Temperature Reactors (RAPHAEL: Reactor for Process Heat And Electricity) as part of its 6^th Framework Programme. The European Commission and the 33 partners from industry, R and D organizations and academia finance the project together. After the successful performance of earlier HTR-related EU projects which included the recovery of some earlier German experience and the re-establishment of strategically important R and D capabilities in Europe, RAPHAEL focuses now on key technologies required for an industrial VHTR deployment, both specific to very high temperature and generic to all types of modular HTR with emphasis on combined process heat and electricity generation. Advanced technologies are explored in order to meet the performance challenges required for a VHTR (900-1000 deg C, up to 200 GWd/tHM). To facilitate the planned sharing of significant parts of RAPHAEL results with the signatories of the Generation IV International Forum (GIF) VHTR projects, RAPHAEL is structured in a similar way as the corresponding GIF VHTR projects. (authors)

[en] It is already 10 years since the (European) High Temperature Reactor Technology Network (HTR-TN) launched a program for development of HTR technology, which expanded through three successive Euratom framework programs, with many projects in line with the network strategy. Widely relying in the beginning on the legacy of the former European HTR developments (DRAGON, AVR, THTR, etc.) that it contributed to safeguard, this program led to advances in HTR/VHTR technologies and produced significant results, which can contribute to the international cooperation through Euratom involvement in the Generation IV International Forum (GIF). the main achievements of the European program, performed in complement to efforts made in several European countries and other GIF partners, are presented: they concern the validation of computer codes (reactor physics, as well as system transient analysis from normal operation to air ingress accident and fuel performance in normal and accident conditions), materials (metallic materials for vessel, direct cycle turbines and intermediate heat exchanger, graphite, etc.), component development, fuel manufacturing and irradiation behavior, and specific HTR waste management (fuel and graphite). Key experiments have been performed or are still ongoing, like irradiation of graphite and of fuel material (PYCASSO experiment), high burn-up fuel PIE, safety test and isotopic analysis, IHX mock-up thermohydraulic test in helium atmosphere, air ingress experiment for a block type core, etc. Now HTR-TN partners consider that it is time for Europe to go a step forward toward industrial demonstration. In line with the orientations of the 'Strategic Energy Technology Plan (SET-Plan)' recently issued by the European Commission that promotes a strategy for development of low-carbon energy technologies and mentions Generation IV nuclear systems as part of key technologies, HTR-TN proposes to launch a program for extending the contribution of nuclear energy to industrial process heat applications addressing (1) the development of a flexible HTR that can be coupled to many different process heat and cogeneration applications with very versatile requirements, (2) the development of coupling technologies for such coupling, (3) the possible adaptations of process heat applications required for nuclear coupling, and (4) the integration and optimization of the whole coupled system. As a preliminary step for this ambitious program, HTR-TN endeavors to create a strategic partnership between nuclear industry and R and D and process heat user industries. (authors)

[en] This paper describes the history, rationale, objectives and current status of the transatlantic GEMINI Initiative (www.gemini-initiative.com) signed in June 2014 between the US NGNP Industry Alliance (NIA) and the European Nuclear Cogeneration Industrial Initiative (NC2I) as a common effort towards demonstration and deployment of nuclear cogeneration with intrinsically safe High Temperature Gas-cooled Reactors (HTGR). The NIA and the NC2I are comprised of major actors in the fields of nuclear and process heat user industries, energy supply and nuclear technology development companies, and collectively embody long-standing European and American experience in HTGR technology. (authors)

[en] It is already 10 years since the (European) HTR Technology Network (HTR-TN) launched a programme for the development of HTR Technology, which expanded through 3 successive Euratom Framework Programmes, with many coordinated projects in line with the strategy of the Network. Widely relying in the beginning on the legacy of the former European HTR developments (DRAGON, AVR, THTR...) that it contributed to safeguard, this programme led advances in HTR/VHTR technologies and produced significant results, which can benefit to the international HTR community through the Euratom involvement in the Generation IV International Forum (GIF). The main achievements of the European programme performed in complement to national efforts in Europe and already taking into consideration the complementarity with contributions of other GIF partners are presented: they concern the validation of computer codes (reactor physics, system transient analysis from normal operation to air ingress accident and fuel performance in normal and accident conditions), materials (metallic materials for the vessel, the direct cycle turbines and the intermediate heat exchanger, graphite...), component development, fuel manufacturing and irradiation behaviour and specific HTR waste management (irradiated fuel and graphite). Key experiments have been performed or are still ongoing, like irradiation of graphite to high fluence, fuel material irradiation (PYCASSO experiment), high burn-up irradiated fuel PIE, safety test and isotopic analysis, IHX mock-up thermo-hydraulic test in helium atmosphere, air ingress experiment for a block type core, etc. Now HTR-TN partners consider that it is time for Europe to go a step forward towards industrial demonstration. In line with the orientations of the 'Strategic Energy Technology Plan (SET-Plan)' recently issued by the European Commission, which promotes a strategy for the deployment of low carbon energy technologies and mentions Generation IV nuclear systems as one of the key contributors to this strategy, HTR-TN proposes to launch a programme for extending the contribution of nuclear energy to industrial process heat applications addressing jointly 1) The development of a flexible HTR able to be coupled to many different process heat and cogeneration applications with very versatile requirements 2) The development of coupling technologies with industrial processes 3) The possible adaptations of process heat applications which might be needed for coupling with a HTR and 4) The integration and optimisation of the whole coupled system. As a preliminary step for this ambitious programme, HTR-TN endeavours presently to create a strategic partnership between nuclear industry and R and D and process heat user industries. (authors)

[en] The PUMA project, a Specific Targeted Research Project (STREP) of the European Union EURATOM 6. Framework Program, is mainly aimed at providing additional key elements for the utilisation and transmutation of plutonium and minor actinides (neptunium and americium) in contemporary and future (high temperature) gas-cooled reactor design, which are promising tools for improving the sustainability of the nuclear fuel cycle. PUMA would also contribute to the reduction of Pu and MA stockpiles and to the development of safe and sustainable reactors for CO₂-free energy generation. The project runs from September 1, 2006 until August 31, 2009. PUMA also contributes to technological goals of the Generation IV International Forum. It contributes to developing and maintaining the competence in reactor technology in the EU and addresses European stakeholders on key issues for the future of nuclear energy in the EU. An overview is presented of the status of the project at mid-term. (authors)