New irradiation experiments on the behaviour of nuclear fuel have recently started in the High Flux Reactor at Petten, in the Netherlands. The Nuclear Research and Consultancy Group (NRG) says that, by using a new measurement technique, data collected during the experiments could be used to develop new fuels and to optimise the efficiency of existing ones.

The High Flux Reactor at Petten (Image: NRG)

Two types of fuel are being investigated - in the Fuel Creep II project, the fuel samples are made from uranium oxide, while in the INSPYRE project, mixed oxide (MOX) fuel is being examined. Each of the experiments contain six fuel samples, with three different compositions.

Reactor fuel must be safe under any circumstances, including extreme events, in a nuclear reactor, NRG said. "The fissile material in the reactor is exposed to a combination of a high neutron dose and high temperature. It is therefore important to understand the effect of this on the quality and behaviour of the fuel. When refined measurement techniques, such as the one developed by NRG, become available it is possible to study separate processes that occur in the fuel in detail."

NRG expects the first results of the research project to be available within the next few months, with the whole programme due to be completed in 2022.

The generated data will be made available to the partners in the INSPYRE-consortium, which is part of the European Horizon 2020 project. Modellers will use the data to update and improve current fuel performance codes, which are used to predict the behaviour of fuel during irradiation.

The INSPYRE (Investigations Supporting MOX Fuel Licensing in ESNII Prototype Reactors) project focuses on the investigation of fast reactor MOX fuel to support the licensing of the start-up cores of the European Sustainable Nuclear Industrial Initiative (ESNII) reactor prototypes. The EUR9.4 million (USD10.9 million) project - which began in September 2017 and will run through to August 2021 - will receive a maximum contribution from the European Commission of almost EUR4 million. The INSPYRE consortium comprises 14 European partners, including NRG.

INSPYRE will use carefully designed separate effect (modelling and experimental) investigations to accurately describe basic phenomena occurring in the fuel with sound physical models, expanding empirical fuel behaviour knowledge gained in the past in irradiation tests and post-irradiation examinations. It will characterise selected key irradiated fuel samples to fill clearly identified knowledge gaps. The project will also combine and leverage basic and technological research to enhance and extend the reliability range of traditionally deduced empirical laws governing performance of nuclear fuels under irradiation. In addition, it will implement the new models and data obtained in the fuel performance codes used for the design of ESNII systems and apply the improved codes to ESNII relevant conditions.

Researched and written by World Nuclear News