The OECD Nuclear Energy Agency (NEA), Idaho National Laboratory, and International Atomic Energy Agency (IAEA) co-organised the Sixth International Workshop on Structural Materials for Innovative Nuclear Systems (SMINS-6). The workshop was held in Idaho Falls (ID, US) from 12 to 15 September 2022, hosted by Idaho National Laboratory, in co-operation with the International Atomic Energy Agency (IAEA).

Materials research is a field of growing relevance for advanced nuclear systems, such as Generation IV reactors, small modular reactors and micro reactors, transmutation systems and fusion devices. For these different systems, structural materials must be selected or developed to address the specific challenges of their foreseen operational environments. This requires both cross-cutting research programmes and advanced experimental/simulation facilities to characterise and evaluate the performance of materials.

The purpose of this workshop was to stimulate an exchange of information on current materials research programmes for different innovative nuclear systems with a view to identifying and developing potential synergies.

The workshop covered fundamental studies, modelling and experiments on innovative structural materials including cladding materials for advanced nuclear systems such as thermal/fast systems, sub-critical systems, as well as fusion systems.

Five main topics were suggested and a panel discussion was organised:

1. Fundamental studies
2. Metal alloys
3. Ceramic and ceramic composites
4. Advanced/novel materials
5. Evolution of material properties
6. Panel discussion on complex concentrated alloys for nuclear applications

Fundamental studies: identification of mechanisms driving the response of materials under the conditions expected in innovative nuclear systems. These mechanisms may be described at the atomic or at higher scale. Multiscale approaches, together with related problems of scale bridging are of special interest along with advanced simulation techniques and data driven modelling/learning. Ion and neutron irradiation experiments, and subsequent characterisation of materials microstructure are included. 

Metal alloys and ceramic and ceramic composites: in- and out-of-core applications with the scope of data availability and gaps; experimental and modelling needs for specific components; link between R&D, standardisation and experimental protocols; mechanical properties. Discussions on code development and implementation plans are also of interest.

Advanced/novel materials: complex concentrated alloys, functionally gradient materials, nano-grained materials, grain boundary engineered materials, nano-precipitation-strengthened materials and micro-laminates. Design, processing and joining will focus on novel and advanced methods (including numerical approaches) for the production and optimisation of materials and components: for instance, high-performance coating, additive manufacturing, laser sintering, and innovative joining techniques for similar and dissimilar materials.

Evolution of material properties: experimental and modelling studies of degradation modes; time-dependent properties, mechanical properties, thermal properties, radiation tolerance, environmental resistance.

Please note that fuel-cladding interactions and zirconium alloys for fuel cladding were not be covered in this edition of the workshop. Other novel materials for accident tolerant fuel cladding in LWR systems are within the scope of the meeting.

Plenary lectures and technical sessions were organised according to the topics listed above.

A panel discussion session on complex concentrated alloys for nuclear applications (opportunities and limitations) and a poster session covering all technical subjects were also held.

Scientific and Organising Committee

Fanny Balbaud (CEA, Chair of the Expert Group on Innovative Structural Materials)

Céline Cabet (CEA, Co-chair of the Expert Group on Innovative Structural Materials)

Marta Serrano (CIEMAT)

Lorenzo Malerba (CIEMAT)

Brian Connolly (University of Manchester)

Yong Dai (PSI)

Jian Gan (INL)

Stuart Maloy (LANL)

James Marrow (University of Oxford)

Nariaki Okubo (JAEA)

Satoshi Ohtsuka (JAEA)

Manuel Pouchon (PSI)

Dmitry Terentyev (SCK•CEN)

Mychailo Toloczko (PNNL)

Yugang Wang (Peking University)

Alfons Weisenburger (KIT)

Davide Costa (NEA)

Local Organising Committee

Colin Judge, Director of Advanced PIE and Characterization Division, INL

Jian Gan, Manager of Advanced Characterization Department, INL

Candice Lord, Administrative Assistant, Characterization and Advanced PIE Divison, INL

Steven Hayes, Director of Nuclear Fuels and Materials Division, INL

Allen Roach, Manager of Irradiated Fuels and Materials Department, INL

Rebekah Thompson, Administrative Assistant, Nuclear Fuels and Materials Divison, INL