The UK National Nuclear Laboratory (NNL) has been developing its capability in high‑temperature water corrosion over the past years in collaboration with the University of Bristol, UK. As part of this work, studies have been undertaken on nuclear fusion‑specific material Eurofer‑97, a reduced activation ferritic‑martensitic steel. Eurofer‑97 is a structural coolant‑facing candidate material for the European DEMO water‑cooled‑lithium‑lead breeder blanket design.

A microflow electrochemical cell assembly and Halbach array have been developed for use with the high‑temperature water testing suite. The microflow cell assembly, when combined with a potentiostat, can provide information on corrosion at increased flow velocities. The Halbach array allows experiments to be conducted  to assess the impact of magnetic fields which are used for plasma confinement in DEMO. For an insight into the effect of stress corrosion cracking, small‑scale tensile specimens have been exposed to high‑temperature water. Eurofer‑97 has also been characterised using scanning and transmission electron microscopy following irradiation by Fe ions and exposure to high‑temperature water.

NNL is due to start a three‑year programme in collaboration with the UK Atomic Energy Authority (UKAEA) and Lucideon Ltd to study the high‑temperature water oxidation and environmentally-assisted cracking behaviour of Eurofer‑97 as part of the EUROfusion programme. This paper will demonstrate the capabilities and versatility of the autoclave facility as well as preliminary information on the upcoming programme with UKAEA.